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Double mid side, part 2: comparing the different rigging options

July 22, 2025

DMS with Schoeps CCM4V side-address cardioids and CCM8 fig 8: the ideal configuration, and in the most transparent mount and windshield I can muster, but does it actually out-perform other setups?

Introduction

In Part 1 of this three-part blog-post on double mid-side I covered the rigging options for DMS using SDC mics. In this second part, I explore the differences between the rigging options, focusing on the option with side-by-side end-address cardiods and the, theoretically, rather better option with side-address cardioids: are there any audible differences? And I also include some clips of recordings to give a sense of the differences between different DMS set ups: that doesn’t just mean how the mics are configured, but, also, different mics.

Shadowing

One of the criticisms thrown at any configuration of coincident mics, but especially at those with multiple mics, is of the impact of shadowing, where elements of the mic shock-mounts or, more substantially, adjacent mics colour the sound. Of the three DMS configurations that with the most obvious shadowing is, of course, the option with side-by-side cardiods: you wouldn’t normally choose to stick something the size of mic immediately adjacent to and projecting forward from a cardioid mic capsule and there is no doubt that, visually, it looks clunky. But does it sound noticeably different?

For those interested, I did some tests on the shadowing effect in such a clustered DMS rig (using MKH 8000 mics), recording pink noise played bay through one of my Vivid S12 monitors to the forward-facing cardioid in the DMS array, and then moved the fig 8 and rear-facing cardioid away (the mics were carefully set up with a separate stand for the forward-facing mic so that it remained exactly in position when the other mics were removed). This was done with the mic on axis and then 45 degrees off axis, so that, in the latter, the body of the rear-facing mic was shadowing the forward mic.

Pink noise recording by forward-facing MKH 8040 cardioid mic on axis to sound source with mic clear (green) and within DMS rig (red).

Pink noise recording by forward-facing MKH 8040 cardioid mic at 45 degrees to sound source with mic clear (green) and within DMS rig (red).

You can see from the spectrograms below that there was more of an impact on the high frequencies as expected at 45 degrees. Of itself this doesn’t show whether the differences of the single, unimpeded, cardioid mic vs the identically positioned mic within its DMS cluster are significant, so, by way of comparison we can look at some similar tests exploring the impact of two windshields (which I have shown previously). First we have the MKH 8030 with the Min-ALTO 115 basket turned side-on to the speaker source so that the fig 8 mic is on axis to the sound source:

Pink noise test with Mini-ALTO 115 with MKH8030 fig 8 mic aimed at speaker: green is the bare mic on the shock-mount and the red overlay is the recording with the basket added.

And for another comparison, here is the same fig 8 test repeated with a Rycote Cyclone.

Pink noise test with Cyclone (small) with MKH8030 fig 8 mic aimed at speaker: green is the bare mic on the shock-mount and the red overlay is the recording with the basket added.

In short, the impact of shadowing in the DMS mic array is measurable, but is far less significant than the impact of these two windshields, where the fig 8 (obviously a key element of DMS) is affected by the structure of the windshield baskets, with the particularly noticeable difference in the Cyclone basket doubtless largely due to the substantial plastic ring for its end cap.

And to return to our shadowing tests for the DMS rig, we can listen to how the effect of shadowing actually sounds. I used the same means of removing the fig 8 and rear-facing cardioid without disturbing the forward-facing cardioid’s position as before, and again placed the mics in front of a single speaker (Vivid S12) in my studio and played back a short section of a recent recording of mine of a singer-guitarist (Luke Chapman), angling the mics on axis to the speaker and then at 45 degrees. Here are the resulting mono sound files:

First, here is the pair of recordings of the forward-facing cardioid mic on axis, with no surrounding mics, and then shadowed within the cluster of DMS mics:

Second, here is the pair of recordings of the forward-facing cardioid mic at 45 degrees, with no surrounding mics, and then shadowed within the cluster of DMS mics (the body of the rear-facing cardioid mic shadowing the forward-facing mic in particular):

Obviously, comparisons should not be made between the on-axis and the 45-degree recordings as, by definition, the mic has moved!

I suspect many listening to these examples may be surprised by how little difference there is between the two recordings (clear mic and shadowed mic) in each set up (on axis and at 45 degrees). Certainly, I was reassured that shadowing effects are less than might be feared with this more clustered version of the two options that use end-address cardioids. Obviously use of longer and larger mics (think two MKH 40s and an MKH 30) would have a greater effect, but, conversely, two still shorter cardioids (think of those 23.5mm-long Nevaton MC59uS/C2 mics) would reduce the effect more (subject to the impact of any mounts).

Of course, shadowing is only one potential downside with the clustered DMS rig with two side-by-side cardioids: both cardioids are necessarily offset from the centre of the fig 8 capsule, typically by around 12mm or more. With MS normally the recordist aims to align the mics so that one capsule is precisely directly above the other and as close as possible. Losing that vertical alignment, of course, risks introducing comb filtering to sounds directed at the mics from the horizontal plane (or whatever plane the mics are tilted toward): likewise, increasing the vertical spacing between the mics will introduce more comb filtering and narrow the horizontal band where the effects are minimal or non-existent. The last isn’t an issue with DMS with two side-by-side cardioids (indeed, it can allow the vertical distance between the fig 8 and cardioid capsules to reduce), but the former is: the question, again, is does this matter? I have heard the results of MS recordings of classical music with the mics side-by-side, which sound fine (for example search out the recordings of ex-BBC engineer, Roger Long, who, as ‘Rolo46’, has posted many marvellous MS classical music recordings on Gearspace using side-by-side MS mics, mostly with an MKH 30 pair), but do the theorists, who frown at such setups, have a point? My aim was to test this, simplifying matters by doing so with an MS pair, comparing vertically aligned mics with one with the mid mic offset as if for this DMS configuration, but, try as hard as I could, I simply could not get any method to work convincingly: I tried indoors with a single speaker, but comb filtering for the shifted mid mic was obscured by comb filtering from the room (few studios are entirely free of comb filtering: and evidently mine isn’t!), and I tried outdoors (the poor man’s anechoic chamber!), but just couldn’t get reliable, repeatable or convincing results. Perhaps I will have a moment or revelation and work out what I need to do, but in the meantime I’m sorry to have come up short: you’ll just have to hang your hat on whichever side of the debate convinces you most . And, of course, one can learn something from the comparative field recordings below (or, better, your own), which compare the different rigs in action.

Minimizing the impact of the shadowing of end-address cardioid mics when rigged side-by-side with the ultra-short Nevaton MC59uS/C2 mics.

Field testing the different DMS rigs

On which note, I left behind such tests and took the mics into the field, to compare some real DMS rigs. This looked at a combination of different rigging approaches and, closely related, different microphones. I could have added a third variable of different windshields, but, to make things more fairly comparable, I have stuck with the same windshields in each set of field of tests. Being unadventurous (or just lazy?!), the tests comprise a series of my regular ‘quiet’ village street recordings: birdsong (plenty of swifts screaming overhead this summer), passing cars, and a bit of Foley-esque sound (as I open doors and gates, and stomp around aimlessly) cover quite a few bases. The cocker spaniels even joined in at one point with a bit of snuffling (honest, it wasn’t me!).

First off, I set up two rigs comprising the Schoeps CCM4V side-address cardioids and CCM8 fig 8 trio, and the Sennheiser MKH 8040 cardioids and MKH 8030 fig 8 mics for DMS with the mics side-by-side, recording with a Sound Devices 788T at 24bit/96kHz. In both cases I used Mega-Blimps for the windshields. With such large surround sound rigs two seems a sensible limit: three or more would mean that they are spaced rather too far apart to be comparable. Here is a short clip (1:34) of the resultant recordings, with one mono file for each mic (levels balanced according to mic sensitivity, but with no other processing) so that you can play around with them in, say, the Schoeps DMS or Harpex-X plugins: I use both for DMS processing.

a) Sennheiser:

b) Schoeps:

c) and here are two stereo files, generated in Reaper using Harpex-X (with the Blumlein stereo preset):

Second, here are the mono files for a similar test comparing DMS with the Sennheiser MKH 8040 cardioids and MKH 8030 fig 8 mics vs the Nevaton MC59uS/C2 and MC59/8 mics, again using Mega-Blimps for both rigs:

d) Sennheiser:

e) Nevaton

f) and here are two stereo outputs, generated using Harpex-X (with the Blumlein stereo preset):

And, finally, here are the mono files for another garden test, this time with a bit of wind (but no low-pass filtering applied), comparing DMS with the Schoeps CCM4V side-address cardioids and CCM8 fig 8 vs the Nevaton MC59uS/C2 and MC59/8 mics, again using Mega-Blimps for both rigs:

g) Schoeps:

h) Nevaton:

i) and here are two stereo outputs, generated using Harpex-X (with the Blumlein stereo preset):

Now anyone who downloads all those files and listens to them deserves a medal!

Conclusions

It is extraordinarily difficult to draw conclusions that are relevant to others’ use of DMS (not least since the use of side-address and end-address cardioids inherently means using different mics), but, nonetheless, I will have a stab at this. First off, although generally relaxed about multi-mic coincident pairs and the impacts of shadowing and small offsets, I came into these tests with an expectation that the acoustic problems of side-by-side cardioids in what is doubtless the most popular configuration of DMS would be more noticeable than they have proved to be. In reality, and that is with the caveat that I have not been testing DMS with bulkier SDCs such as the MKH 30 and MKH 40, they are much less significant than the impact of many windshields, especially those that were not designed to offer as much transparency to the sides and rear as to a forward-facing directional mic. So, if the aim is to place a DMS rig in a Radius Windshields Mini-ALTO or a Rycote Cyclone, then the consequences of the mic configuration are nothing compared to the impact of the windshield. However, if using a windshield with much better all round transparency such as the Cinela Pianissimo or, if boom pole use is not needed, one of my Mega-Bimps, then the impact of the different configurations will come into play. But this then gets very complex for several reasons: yes, the Schoeps CCM4V side-address cardioids and CCM8 fig 8 offer good alignment and little no shadowing (both from the other mics and the mounts), so using them in a Cinela Zephyx (for lightness) or Mega-Blimp (for more transparency) would offer the best performance from that perspective. But, at the same time, they have higher self-noise than the MKH 8030 + 2x MKH 8040 setup and lack the more humidity-proof RF technology of the Sennheiser mics. And, of course, the Nevaton MC59/8 + 2x MC59uS/C2 rig offers the most minimal shadowing for DMS with side-by-side cardioids (due to the very short length of the cardioids) as well as the lowest self-noise. As for the sound, well that’s one for individuals. I think the Nevaton DMS rig is the best sounding irrespective of mic configuration, but I may be missing something that more refined ears can pick up. Or perhaps it is just taste: it’s not as if top end classical music recordists all prefer the same mics or the same mics for a specific task.

And, just to add complexity where you don’t need it, I was surprised by the difference between the two plugins I have been using – Schoeps’s own DMS plugin and Harpex-X. In part, at least, this seems a product of the Schoeps plugin having built-in gain and frequency response compensation for its mics (which, evidently, isn’t appropriate for other mics), but the upshot is that it is very easy to get more significant differences by processing the recordings differently than it is from the actual mics or configurations used.

If you have all these mics (or, indeed, other good options) the selection criteria will need to balance all these factors: if you have some of the mics only, then that will simplify the choices; and if you have none of the options, but are thinking of one, then the usefulness of the mics for different purposes are likely to come into play (e.g. would you have use for Schoeps CCM4V side-address cardioids, or would end-address cardioids be more use?).

As for my choices? Well, I don’t own the Schoeps mics, so that does simplify things as the advantages of side-address cardioids wasn’t clear enough for me to buy the mics (especially with no other Schoeps mics in my locker), so DMS for me will be MKH 8000 mics (for tougher conditions) in a Mega-Blimp; otherwise, I will be using the Nevaton MC59/8 + 2x MC59uS/C2 rig in the same windshield for, as I said, to my ears, the best sound and, less subjectively, for even lower self-noise. And for ultra-compact DMS, should I ever need it, I would use either rig in a Nanoshield (the Nevaton DMS won’t fit in a Mini-ALTO, and the Sennheiser rig isn’t suited to the Mini-ALTO due to the fig 8 position in relation to the chunky plastic rings). But, the question I still need to address for my own use is whether DMS is preferable to horizontal B-format: and that, of course, is for Part 3 of my DMS blog-post series!

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Audio Gear DIY Projects

Double mid-side, part 1: rigging options.

July 17, 2025

Introduction

Like many, I have used double mid-side (DMS) from time to time and, doubtless less typically, I have used horizontal native B-format arrays too: I have written a couple of blog posts on the latter already. Given that DMS can be converted to horizontal B-format and vice versa, I have wondered why DMS is much more widely used and, more specifically, about the practicalities of mounting both arrays: in short, are the two advantages of DMS in use that a) it requires one fig 8 mic only (vs the two for native B-format) and b) that it lends itself better to compact mounting that fits more easily in a windshield? And if DMS is often achieved using this compact mounting – with the three horizontal mics clustered together – would it be better if implemented more spaciously, and with less difficulty in terms of mounting the rearward-facing cardioid, along the lines of a horizontal B-format array?

Now, fear not, this isn’t a blog post about the theoretical side of DMS (or, indeed, native/horizontal B-format) nor, for that matter, about why anyone should use it in preference to affordable ambisonic mic options (and there are compelling reasons): for that, you are much better in the care of Dr Helmut Wittke (CEO of Schoeps) and his colleagues in publications such as this: Wittek, H., Haut, C., and Keinath, D., Double M/S – a Surround recording technique put to test (Schoeps paper, 10.03.2010).

Rather, this post is about some of my dabbling with practical implementations of DMS rigs both generally and in the context – or constraints – of windshields, and with reference to the analogous horizontal B-format rigs. I include some examples of commercially available DMS mounts (past and present) along with some of my own solutions. I hope it isn’t too much of an idiosyncratic ramble, and that it may chime with or, even, be useful for others.

NB having drafted much this blog post I found it rather long and, also, dividing into a few key sections, so I have divided into three separate blog-posts. This one, (part one), is concerned purely with the rigging options: my take on the options for how to mount mics for DMS. It is concerned with SDC mics and, also, doesn’t go into DMS with shotgun mics: it is primarily focused on rigs suitable for taking into the field (i.e. in windshields). Part 2 concerns practical comparison of the different rigs, not least exploring the reality of shadowing effects caused by mics sitting close to other mics. Part 3, to follow very soon, explores the practical differences between DMS and horizontal B-format set ups: there is so much in common – and conversion from one to the other is simple mathematically – but what are the practical pros and cons? Parts 2 and 3 include sound samples that you can download and play with.

Different mic mounting options for DMS

When using small-diaphragm condensers (SDCs) there are three main ways you can configure the three mics needed for DMS:

1) end-address mid mics combined with a side-address fig 8, so that all three horizontally-oriented mics are aligned vertically (typically the central mic is the fig 8, but not always so);

2) end-address mid mics combined with a side-address fig 8, so that all three horizontally-oriented are clustered more closely than in option 1, forming a tightly spaced triangle, but with the two mid mics horizontally offset from the centre of the array (the fig 8 can be above or below the mid mics); and

3) side-address mid mics oriented vertically, flanking, from above and below a horizontally-oriented fig 8.

These three configurations are shown with unmounted mics in the image below:

The three fundamental mic configurations for DMS, for clarity shown here without the complexity of mic support. In all three photos the view is as if from the side of the array and front is to the left.

The composite image above shows that, with the end-address mics (options 1 and 2), the forward-facing mic and fig 8 are easy to mount in the manner of a simple mid-side pair, with the complexity coming from the addition of a rearward-facing cardioid, the body of which projects awkwardly away from the front of the other two mics. In a studio context this can be supported by a separate mount and stand, but this still requires fiddly alignment and is a real pain when adjusting the location of the array to the best position. Obviously, mounting the three mics together is more practical and, indeed, is essential for use in the field in a windshield.

Option 1 – end-address cardioids, all aligned

This option with the three mics aligned vertically, is perhaps harder to rig, but with shorter mics (such as Sennheiser MKH 8000 mics with MZLs, and Schoeps CCM mics) it is more feasible. Cinela, for one, has effective windshield mounting solutions shown below, where in each example the rearward-facing mic is supported by pairs of thin struts to reduce acoustic impact. In both these designs the central mic has a long plastic holder to extend the mic to the quite widely-spaced OSIX isolators, necessary to counteract the mass of the three mics at the front.

Cinela Pianissimo with DMS rig, with the mics (Sennheiser MKH 8030 + 2 x MKH 8040) aligned vertically: photo courtesy of Cinela.

In this variation from Cinela, for Schoeps mics, the three mics are again aligned vertically, but the fig 8 mic (CCM8) is at the top: photo courtesy of Cinela.

Of course, where DMS rigs involve a shotgun for the forward mic, then the fig 8 and the rearward facing cardioid can be clipped above and below the long body of the shotgun: this is a not entirely satisfactory use of DMS given the polar pattern of a shotgun mic and the irregular response off-axis arising from its interference tube. With a little bit of head scratching and some 3d printing, similar options can DIY’d, although any shock-mount needs to be able to counter the front-heavy loading.

My 3d-printed DMS rig with the MKH 8030 and 8040 mics aligned vertically and in a Rycote InVision shock-mount. The mics are fairly unimpeded (even the cable – from ETK Cables with custom MZLs – for the top cardioid is routed through the clip and along the null of the fig 8), but, obviously, the rig is rather front-heavy and too tall for most windshields.

Option 2 – end-address cardioids, side-by-side

This mounting option, where the two end-address cardioid mics are positioned side-by-side, has become a common approach. As with the vertical configuration (above), mic length can quickly make things unwieldy: even the modest 78mm length of the Rycote CA-08 cardioid, plus a low-profile XLR connector, makes for a rather long projection of the front (rear-facing) mic, as shown here:

DMS with Rycote mics, showing the significant forward projection of the rear-facing cardioid despite its fairly short (78mm length).

The more diminutive Sennheiser MKH 8000 mics with MZL connectors instead of XLR modules are, of course, the intended mics for my Rycote Cyclone DMS Kit 1, and show rather better the more compact end-result of the side-by-side cardioids in this option :

The Rycote Cyclone DMS Kit 1 with half of the basket shell in place, and with the basket and supporting arm fully removed. MKH 8030 and 8040 mics.

The constraints of the hoop size (which precludes vertical alignment) meant I also adopted this approach with my DMS mount for MKH 8000 mics in the diminutive Radius Windshields Mini-ALTO 115. As with the Rycote Cyclone DMS Kit 1, this uses thin stainless-steel bars to keep the clips aligned, but also uses the small front ring of the MKH 8030 fig 8 as a fixing point for a clip: it is workable if you need an extremely compact DMS array in a windshield, but is a bit fiddly to set up. Moreover, unlike MS pairs in the Mini-ALTO, DMS rigs in this windshield – or at least my attempts! – end up with the fig 8 mic between the hoops, so that the sideward-facing lobes of the mic are aimed directly at the rather chunky plastic ring where the two windshield pods join: obviously not ideal.

Another rig with DMS using the compact side-by-side cardioid approach: in this case my initial 3d-printed design for the Radius Mini-ALTO. MKH 8030 and 8040 mics, with a triple MZL cable by ETK Cables.

A more recent – simplified – variant of the above, which is much easier to use (no fiddly rods). Again, MKH 8030 and 8040 mics, with a triple (customized) MZL cable by ETK Cables.

While this configuration for DMS is arguably easier to mount and is certainly more compact, there are two obvious downsides. First, the coincidence of the mics in the horizontal plane is lost, with both cardioid mics horizontally offset from the centre of the array. Given how much care is usually taken with MS rigs to ensure that the capsules of the two mics are aligned vertically, to ensure coincident time of arrival (and phase coherence) of sounds from the (usually predominant) horizontal plane at the two mics, this might seem problematic for higher frequencies (depending on spacing, but typically above c.10kHz). Such concerns are often over emphasized by the theorecticians, however, and in practical use – even recording, say, classical music – the effects of even side-by-side MS pairs are not always evident: one to bear in mind and check for your usage and ears, perhaps. The second downside, is that the mics are more obviously shadowing each other than when positioned exactly vertically above each other. The physics are undeniable, but, again, whether it matters or not will come down to how critical the recording is and the nature of the sound source. I will explore this – with sound samples – in Part 2 of my DMS blog-post series. And, of course, mic size comes into play: for example an MKH 30 + 2 x MKH 40 MS rig is quite a different beast to the MKH 8030 + 2 x MKH 8040 rig, especially if the latter uses MZL connectors as in the photos above. And you can take the miniaturization of the cardioid further: below is a photo of my Nevaton DMS rig using their new diminutive MC59uS/C2 cardioid mic, which is only 23.5mm long, with their MC59/8 fig 8. In this case the mics are too wide (22mm diameter) to fit in a Radius hoops (and are here shown on a Rycote Nanoshield shock-mount, although would work in any Rycote or similar windshield), but the difference in size between the fig 8, with its XLR connection, and the tiny cardioids makes mounting a bit easier and, of course, any shadowing effect is reduced to some extent by the shortness of the cardioids. On the downside, the MC59/8 has no front part to be used for support as in my MKH 8030-based DMS rigs above.

DMS rig with MC59uS/C2 cardioid mics and MC59/8 fig 8, using a Rycote Nanoshield shock-mount. This is a fairly clean (in the sense of minimizing shadowing from mics and mount parts) version of the side-by-side cardioid option, although the ‘lollipop’ design of the fig 8 means supporting that rear-facing cardioid out front is a tad trickier. Now if someone would make a fig 8 mic with fixings on the front/top (say a couple of M3 threaded holes) that would make life so much easier for DMS rigging!

DMS rig with MC59uS/C2 cardioid mics and MC59/8 fig 8: head-on view. The cardioids use magnetic mounts.

Option 3 – using side-address cardioids

This mounting option, using side-address cardioids, used to have two commercially-produced options in the form of the Cinela Z-DMS-CCM (for the Cinela Zephyx, launched in 2005) and the Schoeps/Rycote WSR DMS LU (introduced by 2005), which were both designed for the Schoeps CCM8 + two CCM4V combination. The Schoeps/Rycote mount is certainly discontinued, although I understand that the Cinela mount, although no longer on their website, is still produced occasionally as a special item: make certain you ask nicely! The Schoeps option was used to illustrate Wittek et al’s paper on DMS and appears to have been Schoeps’s preferred implementation of DMS for some time, but currently the DMS options on their website use end-address mid mics either in Rycote Cyclone or Cinela Pianissomo windshields. The Schoeps/Rycote and Cinela methods of rigging the DMS setups with side-address cardioids are quite different as you can see from the photos below:

Schoeps/Rycote WSR DMS LU, with Schoeps CCM8 + two CCM4V: photo courtesy of Schoeps.

Cinela Z-DMS-CCM shock-mount for the Cinela Zephyx, again for the Schoeps CCM8 + two CCM4V combination: photo courtesy of Cinela.

I came across both these mounts for DMS with the side-address Schoeps CCM4V only more recently when wondering if my thoughts on adapting the approach taken for horizontal B-format rig to DMS had any precedents: evidently, there is nothing new under the sun! Of course, both the Cinela and Schoeps/Rycote mounts could be used for horizontal B-format too, but I have no idea if that has ever been done: you would hope so.

The two different configurations of horizontal B-format figs I have been using (the revised version having the omni mic rigged vertically, so that its polar pattern is more consistent at high frequencies in the horizontal plane): the similarity to DMS with side-address cardioids is evident.

Coming at my own attempts for DMS with the side-address Schoeps CCM4V (and I am grateful to Schoeps for loan of the mics to test this) was, of course, from the perspective of using horizontal B-format either without any windshield (e.g. for location music recording, as with my bagpipe recordings last year) or within one of my Mega-Blimps. The latter, being much larger than windshields used with the commercially produced mounts, mean that a) the windshield basket can be oriented as designed and b) there is scope to reduce the proximity of structural supports around the mics. If the advantage of using side-address cardioids is that one can avoid the cluster of mics and consequence colouration arising from using end-address mics for the most demanding and critical applications, then it seems worth keeping the mics as free as possible of other sources of colouration, be that the windshield basket structure or the supports for the mics. Anyway, that is the rationale behind my DMS mount for the Mega-Blimp, albeit with a balance struck between transparency and isolation from structure-borne noise: i.e. the mics need shock-mounts (in this case mainly Radius Windshield hoops, but also using Rycote lyres where this reduces obstructions in front of the mics). The result does look similar to the horizontal B-format mount, although there are some significant tweaks to the geometry of the design to better fit the three Schoeps mics than the MKH 8000 mics.

Mount for DMS with Schoeps CCM4V side-address cardioids and CCM8 fig 8 for indoor recording. The hoops and clips, plus the vertical arm to hold the top mic are the main residual items affecting the sound pickup, but the effects are limited to the rear-facing cardioid (the top mic).

Of course, such mounts that aim to minimize colouration are quite large, especially the revised version with its deeper rearward projection, but they fit happily in even my standard-sized Mega-Blimp, which, of course, minimizes additional colouration with its sparse and thin (mostly 3mm diameter) basket structure.

DMS mount (first version) in the shorter, standard, Mega-Blimp.

As with the horizontal B-format mic, such a rig presents challenges for the rear-facing upper mic, which here, as with the Schoeps/Rycote WSR DMS LU, has some on axis obstacles, in this case being the hoop and mic clip of the central mic, quite close to the cardioid, and beyond that the 18mm-wide vertical element of the mount. Looking at this more closely, it is, of course, possible to remove the hoop and mic clip by swapping to a Rycote lyre, which supports the fig 8 mic from underneath (and I have made provision in the mount for use of a rear lyre with a 9.5mm mount for the Lemo connector). And the impact of the 18mm-wide rear bar can be addressed by making this much thinner – in this case a slim 8mm (I tried 6mm, but that seemed too flimsy) – and also by moving this further still from the mic. There’s no such thing as a free lunch, however, with the downside of this version being less lateral stiffness for the arm to the upper mic (so not one to use if the mount is being subjected to much vibration). This revised version can be seen below.

Revised mount for DMS with Schoeps CCM4V side-address cardioids and CCM8 fig 8 for indoor recording, with the design modified to reduce the residual impact of structural elements on the rear-facing capsule. I could do with building in some cable clips to this design as with the previous version!

For windshield use only, of course, it is possible to remove the need for an arm extending upwards to the top mic by adopting the approach previously used for one of my horizontal B-format rigs, which removes obstacles in front of the topmost (i.e. rear-facing cardioid) mic without the penalty of introducing more wobbliness to it.

The most transparent solution – well, that I can come up with! – for DMS in the Mega-Blimp, with separate mountings for the bottom and centre mics, and the top mic.

A detail showing the largely unencumbered rear-facing (topmost) cardioid, which is a contrast to the situation in most DMS rigs.

So here we have it: an exploration of the three configurations used for DMS with SDC mics. Commercially available solutions exist for the first two options (with end-address cardioids), but are thin on the ground, to say the least, for the third option (with side-address cardioids). In all three cases there is significant scope for DIY solutions: indeed, for any particular mics this might well be essential. Hopefully some of my ramblings – or at least the photos – might inspire others to their own DMS solutions. Meanwhile, stay tuned for the practical comparisons in Part 2 and Part 3.

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Audio Gear DIY Projects

XY in a Mini-ALTO

July 11, 2025

During my recent experiments to see whether you could fit an ORTF pair into the diminutive Mini-ALTO windshields from Radius Windshields, I began to wonder whether any of the four mics I found that worked for that purpose would allow other stereo configurations in the windshields, including XY. Of the mics I used for the ORTF experiment, the DPA 4011 capsule with the MMP-GS preamp was the only one short enough, having an overall length of 33mm; but the mic pair was on loan only and had a little too much self-noise for my liking (OK, 18dBA isn’t that bad!). You can imagine, then, that I was delighted to receive a pair of an upcoming smaller version of the Nevaton MC59 cardioid. The standard MC59S + 59/C sounds excellent and has low self-noise (8.6dBA), and is already a short mic at 47mm: rather incredibly, and largely due to the miniaturization of the preamp (just 5.5mm long), the MC59uS + 59/C2 combination halves that to give a length of just 23.5mm, and, with a side-exit cable, its effective length is less than half that of its sibling. I will be looking at the mics in more detail in different posts, but suffice it to say here that the idea with the MC59uS + 59/C2 has been to keep the same acoustic and electrical specs as the larger standard version.

Anyway, with such small mics in hand there was scope to have a play with the idea of XY in a Mini-ALTO. First up was the challenge of mounting the mics, and here I took advantage of the MC59uS having magnets in its base (goodness knows how they were squeezed in!), so I used some powerful Neodymium magnets (Simon Davies at Radius kindly sent me some of the ones they use in the windshields) and incorporated these into a mount: the rebated form of the magnets means it is really easy to keep them secure and not popping out.

3d-printed mount sans microphones, showing the magnet pairs (above the M3 brass insert fixings that fix these mounts to the overall XY mount). The mount has two halves, which are bolted together to form a 19mm diameter cylinder that is held by the Radius hoops.

With the mics popped on the mounts: I do like the magnetic mounts – super slick!

And some head-on views with and without one of the Mini-ALTO pods, along with a rear view.

So there you go: another fun test with a bit of 3d-modelling and printing for another type of stereo in a Mini-ALTO. As with my mid-side pairs, this fits comfortably in the smallest model – the Mini-ALTO 115. I’m very much aware that the MC59uS + 59/C2 mic is not yet in production (first batches are planned in October-November) and will be fairly expensive (more than the standard MC59/C models) and, therefore, won’t be a choice for every recordist. But, as I said in the Mini-ALTO ORTF post, if DIYers are wanting a much more affordable ultra-short cardioid, but still with decent specs and sound, then the Primo EM200 (which is what I believe is used in the well-respected Line Audio CM4) could easily be housed in an equally short, if not shorter, body: in fact, I’m rather puzzled that none of the many small businesses making Primo-capsuled mics haven’t done so already. Perhaps there are other mics that might fit. Whatever the case, I hope this small project might inspire others to have a play: the modularity of Radius hoops is a call to inventiveness!

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Audio Gear

ORTF in a Mini-ALTO part 3: which mics fit?

May 27, 2025

Four ORTF solutions for the Radius Windshields Mini-ALTO. Clockwise from top left: Sennheiser, Schoeps. DPA and Nevaton.

Introduction

In part 1 of this three-part blog-post series, I described the challenge of getting an ORTF pair into the new and diminutive (80mm diameter) Mini-ALTO from Radius Windshields and in part 2 I covered testing. In both cases I used the Sennheier MKH 8040 with an adapted (side-entry) MZL connector as this is one of the shortest cardioid mics available and, of course, due to its RF design, is particularly well suited to – and is a popular choice for – recording outdoors. That I had a pair also helped! While the MKH 8040 is an excellent choice, obviously it would make the chances of Radius Windshields turning this proof of concept into an actual product all the more likely if other mics could be used too, and that is subject of this post.

Just a reminder of the Sennheiser MKH 8040 solution,with its customized MZL connectors (courtesy of ETK Cables) covered in parts 1 and 2 of this three-part blog post.

The MKH 8040 with its shortened MZL has a total length of 54mm although the key measurement is the 47mm length of the 19mm diameter part of the mic (the heavily tapered 7mm part of the modified connector beyond that has no implications when angled for ORTF, as you can see from the overhead photo above). This enables the centre of the diaphragms of the ORTF mic pair (angled, of course, at 110 degrees and spaced 170mm apart) to be on the centre-line of the windshield: that is, 40mm from the basket in all directions. There is little point jamming mics into a windshield if they end up right near the basket since this simply hampers the effectiveness of the wind-noise reduction, so that central location remained a requirement as I looked at other candidates. A maximum length of around 47mm – and without any problematic projections of connectors or rear cables beyond that – rules out mics with XLR connectors (and I have excluded cardioid lav mics on the basis of high self-noise), but there are a few viable options that I have identified and have tested: these are all modular mics from makers of microphones aimed at (though by no means exclusive to!) professional recordists (i.e. not cheap) – Schoeps, DPA and Nevaton.

Few of the less expensive small mics have modular designs with small preamps and no XLR connector. For example, the seemingly short Rycote CA-08 is 78mm long and you need to allow for a low-profile XLR too – another 25mm – bringing it to over 100mm and over twice the length that would work effectively for ORTF in a Mini-ALTO. Even mics assembled, like many a DIY mic, with Primo capsules – such as the small Line Audio CM4 (77mm long + 25mm low-profile XLR) or the Sonorous Objects SO.103 (52mm + 25mm low-profile XLR) and SO.3 (83mm) – are too long, although, of course, such mics are reminders that for the practically minded it would be easy enough to use the same capsules (e.g. the Primo EM200, which is what I believe is used in the Line Audio CM4) to make a suitably short mic without an XLR connector. And, equally, there may well be budget-friendly mics from manufacturers that would suit ORTF in a Mini-ALTO that I have missed: I hope so!

Small (and all modular) cardioid mics comprising, left to right: the Nevaton MC59S preamp with M59/C capsule; the Sennheiser MKH 8040 with a modified (side-entry) MZL connector; the Schoeps MK4 capsule with the CMC 1 KV preamp; and, the baby of the foursome, the DPA 4011 capsule with the MMP-GS preamp.

Schoeps – CMC 1 KV and MK4

Compared to the Sennheiser MKH 8000 series, the offerings from Schoeps are varied and complex and it took me a fair bit of time – and a few blind alleys – to identify exactly which model (and there is only one) would fit the criteria for ORTF in a Mini-ALTO. Schoeps aficionados will doubtless snigger mercilessly at this unfamiliarity, but, anyway, eventually I happened across the CMC 1 KV, which was introduced in 2022. It is a short preamp (the shortest version of the CMC 1) with a side-entry cable, which, when combined with a MK 4 cardioid capsule, gives an overall mic length of 45mm. With a steel element in its rear it can be used with magnetic mounts (several were supplied in the case) and is very much designed as a plant mic (for example, useful for recording dialogue in cars, where mic placement is always tricky) or for any other purpose where such a short length is required. Of course, it would have been nice if one of the more popular Schoeps preamps would have fitted the Mini-ALTO for ORTF, but at least the CMC 1 KV takes any of the popular MK capsules. And while only some may have the preamp in their kit already, others may find it a handy addition for a compact ORTF rig and for plant mic use and worth purchasing (it’s similarly priced to the other CMC 1 amplifiers).

Having identified the best Schoeps mic to fit the Mini-ALTO for ORTF, the good folks in Durlach (in Karlsruhe) sent me a pair to test: sadly this is just a loan and not to keep!

Schoeps CMC 1 KV + MK 4: the wooden case includes three magnetic mounts for the mic and, of course, the capsule and preamp.

Right, that’s enough looking at the fancy Schoeps wooden case and contents: onto the ORTF rig itself. Adapting the proof of concept set up for the MKH 8040 to the CMC 1 KV + MK 4 was very straightforward: given the similar mic length, all that needed changing was to make some 20mm mic clips (the MKH 8000 mics being Ø19mm) and, as a consequence, very slightly tweak the joining part of the bar. The side-exit cables are a little beefier and less flexible than the custom dual MZL cables from ETK Cables for the MKH 8040, but that’s understandable because – at 3m long – they aren’t intended to be used purely inside a windshield: so careful clipping of the cable becomes essential to reduce cable-borne noise.

Schoeps CMC 1 KV + MK 4 in the ORTF mount for the Mini-ALTO.

Composite view – from above – of the Schoeps CMC 1 KV + MK 4 in the ORTF mount, with the Mini-ALTO basket.

DPA – 4011 with MMP-GS or MMP-ES preamp

Back in 2013 DPA launched the MMP-ES, which is a small preamp measuring only 12mm long and with a side-exit cable. This was followed in 2016 by the similarly-sized MMP-GS, with the only difference being that the latter has a micro-dot connection rather than an XLR: rather neatly, and admittedly beside the point for this exercise, this allows many DPA SDCs to be powered from 5V and, therefore, used with wireless transmitters. Combined with a DPA 4011 cardioid capsule, the MMP-GS (or the MMP-ES) gives an overall length of 33mm which is remarkable, and significantly shorter than the other options considered here. Initially I did wonder whether such a short length meant I could tease it away from the centre-line of the windshield to increase wind performance, but modelling the capsule position with the cardioid polar pattern showed that this would be disadvantageous: the wide 110-degree angling of ORTF does mean that the centre of the windshield is best. So keeping the capsule position centrally meant making a new ORTF bar, which was easy enough with 3d-printing, but set me thinking: if Radius do take this forward, an adaptable bar for at least several different mic models seems ideal. One for their skilled designer, Tim, I think! Back to the DPA pair: in short, they fit (of course) and more easily than the other mics. Although the 4011 cardioid capsule is quite popular, the MMP-ES and MMP-GS are less common, but, as with the Schoeps, they do have their uses for small plant mics etc.: worst case, existing 4011 cardioid owners seeking super-compact ORTF could buy the short preamps and, at least, they are not crazily expensive (about £350 + VAT). For some users the 18 dB(A) self-noise might be a little high – it is certainly above the 13 dB(A) of the MKH 8040 – but that’s rather besides the point: many use the DPA 4011 for recording, and love how it sounds.

In this case I won’t include a photo of all that comes with a new pair since, although DPA were also kind enough to send me a pair for testing (super-speedily too, but, again, sadly just a loan!), they were a much-loved pair in a small pouch.

DPA 4011 with the MMP-GS. With such small and light mics I have gone for the softest (55-shore) hoops that Radius produce: the production version of these is a more subdued green and this ‘evil red’ was just the colour of the test run.

Now, as a complete aside, the shortness of the DPA 4011 with the MMP-GS or MMP-ES preamp opens up opportunities for other near-coincident stereo pairs, where the mics aren’t so obliquely angled. DIN and NOS both have the mics at 90 degrees to each other, which can be easily achieved with the short DPA mic with the centre of the diaphragm remaining on the centre-line of the Mini-ALTO. The 300mm spacing of a NOS pair would require a little longer Mini-ALTO than the two ORTF test versions made for these tests by Radius, but the DIN pair fits fine with a pair of the 136mm pods (the longer of the two sets provided)…but this is a digression from ORTF!

DPA 4011 with the MMP-GS. The ridged body of the preamp meant it was necessary to modify the 19mm mic clips with internal grooves: these provide really neat positioning and extra protection against the mics moving, and can be used with standard 19mm diameter mics.

Nevaton MC 59/C

Nevaton is doubtless not as well known to many as DPA, Schoeps and Sennheiser, but the company has a long history going back to its roots in Leningrad in 1947. In 2024 the company relocated from Russia to Austria, to Siegendorf near Vienna, so, hopefully, the mics (as well as servicing) will now become more readily available in Europe and the rest of the world: they are an immensely friendly and approachable company. I first became aware of the mics via Magnús Bergsson’s wonderful Hljóðmynd – Soundimage website: despite a brimming mic locker, which includes some fantastic mics, Magnús is full of praise for the Nevaton MC59 models that he uses. While the designers at Nevaton have a much shorter preamp (the MC 59uS) and a shorter cardioid capsule (MC 59/C2) in development at present, even their existing MC59S preamp with the MC59/C cardioid capsule measures just 47mm in length in total, so it was an obvious choice for testing for ORTF in the Mini-ALTO: also, it was an easy choice as, by happy chance, I had a pair on their way to me courtesy of Egor and Dmitry for testing more generally (and this time, I should hasten to add for full disclosure, to keep). At 22mm diameter the MC59/C is the widest of the four mics used in these tests, but that slight chunkiness allows use of a larger diaphragm (Nevaton say it has ‘a membrane diameter of 20mm, and the active part is 16.5mm’), with consequent scope for lower self-noise: the specs give a remarkable 6dB(A). I lack the anechoic chamber to check this properly, but, with my rudimentary tests (mics buried under duvets recording nothing in a quiet house, a high-pass filter applied to remove low end rumble of any passing tractors, and levels adjusted in post for different – measured – sensitivities), the MC59/C cardioid mic had notably less self-noise (which I measured at around 7dB less) than that of the MKH 8040 (13dB(A)), or indeed the Schoeps and DPA mics.

Now there’s a mic box small and rugged enough that one can actually take into the field: a much-appreciated detail!

With a similar length to the Sennheiser MKH 8040 and Schoeps CMC 1 KV + MK4, the MC59/C pair could have utilized a similar ORTF mount for the Mini-ALTO, but the clips would have added to the already significant 22mm diameter, edging towards the basket or, alternatively, pushing the centre of the mic diaphragms over the centre-line of the windshield. Besides, the MC59S preamps have a neat mounting option with three M2-threaded holes at the rear of the mic, which allow for very precise positioning of the mics. As, of course, the mics weren’t going directly into a suspension hoop, this seemed the best option, and the result is the most minimal of the mounting bars for the different mics in these tests.

Nevaton MC59/C showing the rather different approach I took to the ORTF mount.

Composite view – front on – of the Nevaton MC59/C with the Mini-ALTO basket.

Field recordings

This isn’t the place for a detailed comparison of the pros and cons of the different cardioid mics, along with a range of comparative recordings. But, that said, some field testing does seem relevant, not least to check that the different mics function reasonably in the Mini-ALTO as ORTF pairs. So with a suitable breeze blowing, I headed outside with four windshields and a Sound Devices 788T – yet again to record the village street with wind in the trees and a nearby hedge, birdsong, passing cars and, dominating the first half of the recording, an RAF jet flying over. The last lacks the emotive power of that famous 1942 BBC recording of nightingales when 147 RAF bombers flew overhead, but I left it in as a proxy for recording thunder(!) – you can easily skip past it.

A blustery day for testing, but, then, this is really all about windshields!

Here are some clips of the recordings, with 40dB gain at the recorder and another 10dB in post (and the levels were matched using the Schoeps as the reference, following my previous 1kHz tone sensitivity tests of the mics). No high-pass filtering or any other modifications were made to the recordings.

First up, for reference, with the already tested Sennheiser MKH 8040 pair:

Next up, the Schoeps CMC 1 KV with MK 4:

Third, we have the DPA MMP-GS with 4011:

And, finally, here is the Nevaton MC59/C:

I’ve leave you to listen, download (even tinker with levels) and draw your own conclusions, but it is just worth noting, first, that in such conditions the higher self-noise of the DPA MMP-GS with the 4011 capsule is hardly noticeable, and, second, that the effect of wind is less noticeable with the Schoeps MK 4 due, of course, to its different frequency response: less low end is often an advantage for field recording and, in these breezy conditions with the small size of the Mini-ALTO windshield normally any recordist would apply a high-pass filter. None of the mics showed any increased susceptibility to wind, or other issues, over the MKH 8040, which, as tested in part 2 of this blog-post series, was on a par with its mid-side counterpart in a Mini-ALTO 115.

Conclusions

So there we have it: from my initial doubts about squeezing an ORTF pair into a Mini-ALTO to workable demonstrations of four mics, including examples from three of the most well-known manufacturers, plus the less well-known (at least in much of the world) but quite remarkable Nevaton MC59/C. The Sennheiser MKH 8040 might well be the most commonly considered option of these mics for field recording, due to its RF design, but it does require a bespoke MZL connector for such a compact ORTF set up: that said, this is less costly than the short preamps required for the popular Schoeps MK4 and DPA 4011 capsules respectively. And, uniquely, the Nevaton requires nothing other than its standard form. While the cable can be swapped out easily for the MKH 8040 for either a different MZL cable or (with the XLR module added back to the mic) an XLR cable, the DPA, Nevaton and Schoeps mics all have cables hard-wired to their preamps. Obviously, attractiveness of ORTF in a Mini-ALTO (should an ORTF version be produced) will come down to the balance between any need for extreme compactness, wind performance, acoustic transparency and cost. The last relates very much to the subject of this post: a recordist with the right capsules and preamps already would be well-placed; others may need to pick up a pair of short preamps to fit existing capsules or, in the case of the MKH 8040, a modified MZL cable; and some may need to buy entirely new mics to fit – and none of these mics can be described as cheap. For me, it has been an interesting exercise – even if it might seem slightly ironic given my work on Mega-Blimps at the other end of the size spectrum – and, certainly, I will no longer default to MS simply on practical grounds for the those occasions when I really do need a compact rig: in my case, the diminutive Sound Devices MixPre-3 and a Mini-ALTO 115 with MS or, now, a Mini ALTO 90+90 with ORTF, with a small stand/tripod and short cables, provides a minimalist kit when needed and when conditions allow. I suspect many others – with their evident desire for tiny and portable rigs – would find still more use of a Mini-ALTO ORTF solution. Let’s see what Radius produce!

UPDATE 8.7.2025 – Radius release pod and fur kit for ORTF, so here are the (free) 3d-models to help you use this

While their own versions of my ORTF mounts or, hopefully, a clever adaptable mount that doesn’t need to be quite so mic specific, will take Radius some time (injection-moulded parts take time to develop, and there are more urgent items in the queue), producing paired front and back 90mm pods and a fur to fit to suit ORTF is a much simpler matter, and today Simon Davies has confirmed that these will be going ahead next week. For these you will need a Radius mount and, of course, will need to 3d-print the mounts I created for this project. For the MKH 8000 version you will also need the custom MZL cable from ETK Cables. Anyway, here are links to the (freely available) 3d models for printing on Onshape, and to other parts (nuts, screws and brass inserts: for these I link to the suppliers I use, but doubtless you will find equivalents, especially if not in the UK).

And do remember: these are all parts I developed for my tests, so reflect the filament I used (PETG HF), the 3d printer I used (Bambu Lab A1 Mini) and the fasteners I used. You may need to tweak the models to better suit your materials and printer. And, of course, you may want to improve upon the designs I come up with. Certainly I expect any eventual injection-moulded design from Radius to be stronger and more sophisticated than my attempts!

General parts

Connector, or post, from ORTF bar to Radius hoops – this uses 12mm M3 socket head button flange screws as supplied with Radius products anyway, but will also require thin M3 square nuts.

Mini-ALTO base adapter – not essential, but it allows you to fit a 3/8″ threaded ball head and angle the windshield correctly for ORTF (the Mini-ALTO can be tilted but end-to-end, which isn’t useful for ORTF), and for this you will also need a thin 3/8″ hex lock nut.

To fit the mic clips to the ORTF bars you will also need 8mm M3 socket head button flange screws and M3 brass inserts: these are the ones I use, and anything very different may require the holes to be resized.

Mount for Sennheiser MKH 8040

ORTF bar for MKH 8040

Right-hand mic clip for MKH 8040

Left-hand mic clip for MKH 8040

Mount for Schoeps CMC 1 KV + MK4

ORTF bar for Schoeps CMC 1KV + MK4

Right-hand clip for Schoeps

Left-hand clip for Schoeps

Mount for DPA 4011 with MMP-GS or MMP-ES preamp

ORTF bar for DPA

Right-hand clip for DPA

Left-hand clip for DPA

Mount for Nevaton MC59/C

ORTF bar for Nevaton

Right-hand clip for Nevaton

Left-hand clip for Nevaton

Given the the Nevaton mics usefully screw to the ‘clips’ at their rear, you will need M2 socket cap screws.

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Audio Gear

ORTF in a Mini-ALTO part 2: testing

May 11, 2025

Introduction

Following on from part 1, where the design of fitting an ORTF pair into the diminutive Mini-ALTO was covered (using a pair of Sennheiser MKH 8040 mics with modified MZL connectors), this second part of the blog post concerns testing the compact rig. There are two main aspects that I wanted to test to see if such an ORTF rig is usable: transparency (i.e. how much does the windshield colour the sound) and wind protection.

Composite view of ORTF in a Radius Windshields Mini-ALTO showing the position of the mics with two 90mm pods.

Composite view of ORTF in a Radius Windshields Mini-ALTO showing the position of the mics with two 136mm pods.

Transparency

My main concern with colouration was not just the basket structure in general, but the thicker plastic rings that mark the join of the end caps to the cylindrical part of the windshield basket. The impact of such rings can be quite discernible with set ups in some windshields: others have noted the impact of the large rear plastic ring in the Rycote ORTF windshield, and I have noted and measured the impact of the still chunkier ring in the Rycote Cyclone on the sideward-facing lobes of the fig 8 mic when used for mid-side recording. The rings in the Mini-ALTO are much less substantial than in these examples, but, given the 80mm diameter of the basket, they are closer to the mics, so the key questions are: i) is the impact measurable?; ii) is there a difference between the impact in the two different pod sizes? and, iii) if there is a measurable impact, does this matter – i.e. does it translate to noticeable issues when making field recordings?

Without an anechoic chamber it is difficult to get an exact read on the transparency of any windshield, but, as I did with my original Mini-ALTO 115 test, for a reasonable quick and dirty test I placed a bare mic on the windshield ORTF shock-mount in front of a speaker (in my treated studio) playing pink noise, then carefully added the windshield pods without moving the mic for a second recording. I did this with the ORTF bar oriented square-on to the speaker (0 degrees), at 45 degrees and side-on to the speaker (90 degrees). I repeated the exercise for both the 90mm and 136mm pod sizes. The results for each pair of recording were compared using a spectrum analyzer and overlaid as follows:

Pink noise test with Mini-ALTO with ORTF bar square-on to the speaker (0 degrees), using one of the two mics only: green is the bare mic on the shock-mount and the red overlay is the recording with the 90mm basket pods added.

In these tests with the ORTF bar square-on to the speaker the sound is arriving at the cardioid mic about 63 degrees off-axis. In the case of the 90mm pods the plastic ring for the end caps is directly between source and capsule, whereas with the longer 136mm pods the ring sits beyond the direct line. Given this, it is not surprising to see a greater impact when the 90mm pods are used, in addition to some generally increasing attenuation of high frequencies, although the significant colouration only kicks in at 15.2kHz and above.

Pink noise test with Mini-ALTO with ORTF bar at 45 degrees to the speaker, using one of the two mics only: green is the bare mic on the shock-mount and the red overlay is the recording with the 90mm basket pods added.

In these tests with the ORTF bar at 45 degrees to the speaker the sound is arriving at the cardioid mic about 16 degrees off-axis. In the case of the 90mm pods the direct line between source and capsule is through the end cap of the windshield, whereas with the longer 136mm pods the direct line is through the cylindrical part of the basket and near to the end cap ring. It is interesting to see that, despite the seeming greater significance of the plastic ring to the 136mm pods at this angle, the colouration arising from the basket is a little less than with the 90mm pods.

Pink noise test with Mini-ALTO with ORTF bar at 90 degrees to the speaker, using one of the two mics only: green is the bare mic on the shock-mount and the red overlay is the recording with the 90mm basket pods added.

In these tests with the ORTF bar at 90 degrees to the speaker the sound is arriving at the cardioid mic at 35 degrees off-axis. In the case of both the 90mm and 136mm pods the direct line between source and capsule is along the longitudinal axis of the windshield and, thus, through the centre of the end cap of the windshield: in short, the mic position relative to the sound source, apart from being angled, is very much in accordance with a mono directional mic in the windshield as per the original design intention. As a result, the impact of the basket is minimal (and comparable to my previous tests of the Mini-ALTO 115 with a supercardioid mic), although a couple of troughs at high frequencies – at 15.2kHz and 17kHz – are visible with the 90mm pods.

For the purposes of comparison, here is my previous test of an MKH 8030 with the Min-ALTO basket turned side-on to the speaker source so that the fig 8 mic is on axis to the sound source:

This is useful, since it shows that – within the limitations of this testing methodology – that the ORTF pair in the Mini-ALTO with 90mm and 136mm pods is less affected by the basket than the fig 8 mic in the Mini-ALTO 115. And for another comparison, here is the same fig 8 test repeated with a Rycote Cyclone.

The more significant impact of the Cyclone basket is doubtless largely due to the substantial plastic ring for its end cap.

The pink noise testing evidently shows some impact of the Mini-ALTO basket on the ORTF set up, much of which is a general and modest loss of high frequencies, with a few more obvious anomalies over 15kHz. The colouration, however, looks better than feared, not radically different between the two pod sizes, and, above all, less significant than that with a fig 8 in the Mini-ALTO 115 and far less than with a fig 8 in a Rycote Cyclone.

As I noted when I tested the Mini-ALTO 115, there is one thing demonstrating differences with this pink noise test or, indeed, more exhaustive and expert tests in an anechoic chamber, but how does the colouration actually sound? It is hard to come up with a perfect test, especially with limited resources, but I have settled on an approach that some at least may find informative. Eschewing the variability of successive live recordings, I placed the ORTF rig in front of a pair of speaker (Vivid S12s) in my studio and played back a short section of a recent recording of mine of a singer-guitarist (Luke Chapman), angling the ORTF bar square-on to the speaker, and with the mic aligned to the speaker so that it was 55 degrees off-axis. This positioning ensured that the plastic ring for the end cap was exactly on the line between the speaker and the mic with the 90mm pod, so very much the worse case positioning. Here are the resulting mono sound files:

If really keen, you can download the files and set them up in a DAW and flip between short repeated sections of each pair, which is what I have done. In both the recordings with the windshield you can hear the expected slight change to the high frequencies when the basket is added, as anticipated following the pink noise tests, but I would suggest that it is subtle and, therefore, unlikely to be of great significance to the majority of those making sound recordings in the field. Perhaps more importantly, there seems little practical reason to favour the longer 136mm pods over the more compact 90mm pods in terms of transparency: of course, there may be differences in wind protection, which is what we will explore next.

Wind protection

The laws of physics dictate that the small 80mm diameter of the Mini-ALTO cannot offer the wind protection of larger basket designs, and that was never the intention behind its compact design. That said, the small windshield performs reasonably well outdoors, and I was surprised in my original tests in breezy conditions to note that it outperformed the Rycote Nano Shield, which, although another smaller basket windshield design, has a larger cross-section (measuring internally 86mm high and, with its elliptical form, 107mm wide), although testing confirmed that larger windshields did provide better wind reduction. The questions I have for ORTF in a Mini-ALTO, therefore, are not how it compares to the same in much larger baskets, but the following: i) is there a noticeable difference in the wind reduction performance between the two different (i.e. 90mm and 136mm) pod sizes; and ii) how does the wind protection for an ORTF pair compare to that afforded to other rigs in a Mini-ALTO? With the last, I was particularly interested to see how the ORTF pair compares to a mid-side pair in a Mini-ALTO: if performance was similar to the last, then, given that I have been happy to use MS pairs in the Mini-ALTO where wind conditions allow and where compactness is paramount, this would mean that the ORTF design is similarly viable from a functional point of view.

First off, the matching front and rear pods provided by Radius Windshields for this whole experiment mean that the two Mini-ALTOs are non-standard lengths, so a couple of bespoke furs had to be made by the sewing department in Stroud. These are of the same, longer pile, grey fur that Radius provides as an option for the existing Mini-ALTOs and I have matching ones for my Mini-ALTO 115s. It might seem trivial or obvious, but it is important to have identical furs when testing the wind performance of the different rigs and pod sizes. Wind tests in the real world, where wind is turbulent and not laminar, are never quite as easy as you might think: simultaneous recordings are essential, of course, but the windshields have to be placed a bit apart to avoid one protecting or otherwise affecting the other, so wind gusts can vary a bit in terms of impact and timing. The other difficulty is matching mics: despite my growing mic locker I don’t have a stash of multiple MKH 8040 mics, but just one pair. My solution to this problem has been to record a single channel in each of the two Mini-ALTO ORTF rigs, which is fine: we are after a comparison of the wind performance of the two different sized pods not making beautiful stereo recordings, and this serves the purpose just as effectively. And for the comparison between ORTF and mid-side, where single-channel recording could be a bit misleading (i.e. comparing one channel of ORTF to, say, just the side mic of an MS pair seems like apples to oranges), I used the pair of MKH 8040s in ORTF in one of the test Mini-ALTOs and a MS pair of MKH 8030 and MKH 8090 in the Mini-ALTO 115 I use for MS: I’ve noted very little difference in wind performance with the wide cardioid vs the cardioid mics in MS.

Starting off with the windshields with no fur, here is an excerpt of a windy gust on a pretty breezy day, with the ORTF rig using 90mm pods compared to the Mini-ALTO 115 with an MS pair (MKH 8090 and MKH 8030).

And then compared using a spectrum analyzer and overlaid as follows:

Wind gust test with Mini-ALTO 115 with MS pair (MKH 8090 and MKH 8030) in green, with Mini-ALTO 90+90mm ORTF (MKH 8040) in red.

Both listening to the sound file and viewing the spectrum analyzer show that the ORTF pair in a Mini-ALTO with 90mm pods more than holds its own against the MS pair in the Mini-ALTO 115, each with the bare basket. But it is equally clear from the audio that the the differences are not constant. Moreover, we need to think about the impact of wind direction on performance, given that the two stereo pairs sit at 90 degrees to each other in relation to their windshields: in this example both mic pairs were side on to the wind direction, so that the ORTF windshield presented its small end-on form to the wind while the MS pair’s windshield presented its side to the wind. Changing this around by rotating the mic stand 90 degrees, here is a second set of recordings with the mics facing directly into the wind, so that the windshield housing the MS pair was end-on and the windshield housing the ORTF pair was side on.

The impact of wind on the MS pair is less in this second test compared to that on the ORTF pair. What we can draw from these comparisons, however, is that overall the ORTF pair in the 90mm pods seems to hold its own compared to the the Mini-ALTO 115 with an MS pair, with both baskets being bare.

Moving onto tests with furs added, which, of course, reflects more typical usage of the Mini-ALTOs outdoors, here we have a pair of ORTF and MS recordings with the wind coming from the side:

And then with the mic stand rotated 90 degree so that the two pairs are aimed into the wind, albeit with the ORTF pair’s windshield side-on to the wind and the MS pair’s windshield end-on to the wind:

So, the fur (while, of course, reducing wind noise) does not change the situation: the broadside offered by the windshield when an ORTF pair faces into it and the broadside of the windshield offered when an MS pair faces at 90 degrees to the wind are what creates the most windnoise. With this caveat, which has implications for usage (in any given situation one array may outperform the other: equally it could be argued that wind direction and sound source direction – if not negotiable by moving the mic position – might influence choice of mic array), there is no obvious difference in the overall wind performance and, to some extent, this is predictable given the mic capsule locations and orientations in the two arrays.

So now we should turn to the matter of the two pod sizes for the prototype ORTF rig: does the increased volume of the 136mm pod windshield offer an advantage in wind reduction over its shorter counterpart with the 90mm pods? For this, of course, I was able to orient the two windshields identically, and recorded a single cardioid in the ORTF rig in each simultaneously.

First up we have the 90mm pods (with fur) facing so that the wind direction was end-on to windshield:

And then the simultaneous recording using a Mini-ALTO with 136mm pods (with fur):

And then the mic stand was rotated 90 degrees so that wind direction was side-on to the windshields:

There is again some gust to gust variability between the two windshields, doubtless reflecting the highly localized differences in the turbulent wind you get in the real world, but there is nothing in these short clips (or, indeed, the much longer recordings I made) to suggest that the longer version of the ORTF Mini-ALTO with its 136mm-long pods outperforms the shorter 90mm version. This applies in both orientations into and at 90 degrees to the wind.

Conclusions

So what’s the verdict? Is an ORTF pair viable in the diminutive Mini-ALTO? If so, is a short symmetrical Mini-ALTO with two 90mm pods as effective as a longer version? My short answer is, yes, an ORTF pair is viable in a Mini-ALTO and that the advantages of pods longer than 90mm are so small as to be insignificant: so you might as well use the more compact 90mm pod version. Moreover, I would suggest that an ORTF pair is just as viable in a Mini-ALTO as a mid-side pair, although the number of cardioid mics that are short enough to make use of the 80mm diameter windshield for ORTF are few and far between: so far I have identified the MKH 8040 used here, the Schoeps CMC1 KV + Mk4, the Nevaton MC59S(C) and the upcoming DPA MMP-GS with the existing 4011 capsule as suitable candidates, and, in a third blog post, will be testing at least some of these. And there well be other mics that would fit without resulting in capsules close to the windshield basket. There are other caveats to add to this, but these are very much the same as with the Mini-ALTO for use with a mono directional mic: above all, a small diameter windshield will – all other things being equal – perform less well at reducing wind noise than a larger windshield; and, second, the structure of a basket, especially with significantly chunky plastic components, will provide colouration of sound above and beyond the curtailing of high-frequencies that is inherent to any fabric covering of a mic. So, of course, a Cinela Albert is a better bet for ORTF in terms of acoustic transparency and wind performance (as, indeed, is my own TIG-welded Mega-Blimp), but that’s not really the point: the Mini-ALTO is designed – above all – to be compact, to offer modest wind protection, and to allow rapid changing between bare mics and full basket. Now the latter, which is so relevant to production sound recording with a supercardioid or shotgun mic, may not be quite so relevant to an ORTF pair, but compactness is relevant to many recording in the field. Many people do seem to love dinky little recording rigs with miniscule recorders and lightweight stands (if a stand at all). For them, moving from a pair of furry slip-on covers for an ORTF pair on a stereo bar to a Mini-ALTO containing an ORTF pair would offer better wind performance and a more practical, transportable and robust form for the setup. For those already using ORTF in larger blimps, then a Mini-ALTO ORTF rig offers more compactness for those times when (small) size really matters, just as is the case for using the Mini-ALTO instead of larger windshields for MS or even DMS. Given that many windshields – I am thinking especially of traditional cylinder types such as the Rode, Rycote Modular and Rycote ORTF windshields – don’t have noticeably less colouration than a Mini-ALTO, for many it just comes down to size vs wind reduction: just as it would for a mono supercardioid or shotgun mic. So, yes, ORTF in a Mini-ALTO is usable and will appeal to many. Whether or not that translates to commercial viability is beyond me, not least given the small number of mics that are short enough: that is one for Simon Davies and the team at Radius Windshields to ponder. If the two blog posts on this experiment have piqued your interest, do get in touch with them (they are eminently approachable and responsive) and let them know as feedback will doubtless influence where they go with this!

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