ORTF – Dr Badphil

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:

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.

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.

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.

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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Audio Gear DIY Projects

ORTF in a Mini-ALTO? Part 1: design

April 28, 2025

Introduction

The long-awaited Mini-ALTO windshields are rolling off the production line as fast as Radius Windshield’s small team can manage and are evidently going down a storm. As readers of this blog know, I’ve been playing with the Radius hoops since introduced and, more latterly, the pre-production Mini-ALTO 115 windshield (which I tested here). With the latter, my first thought was to stick a mid-side (MS) pair inside it and then, for a bit of fun, a double mid-side array. Well, the slightly mad schemes – at the opposite end of the spectrum size-wise from my DIY Mega-Blimp project – continue. In this case, the project began when John and Simon at Radius asked if I could squeeze an ORTF rig into a Mini-ALTO: not as a commercial commission, I must hasten to add, but just knowing I like a challenge and am always up for esoteric mic-mounting solutions. My first reaction was no, but thinking on it more – and having been rather immersed in ORTF lately (or, rather, an eight-mic ORTF-3D rig using Nevaton mics) – I decided to have a go.

The design problems

Straight off the bat there seemed two main issues. First, there was the common problem for anybody trying to fit ORTF pairs in a windshield: mic length means the capsules end up too near the basket edge for effective wind protection. Not for nothing did Rycote make a larger diameter windshield specifically for ORTF, and a much larger diameter for ORTF was one of the reasons behind my Mega-Blimp. With the diminutive 80mm diameter of the Mini-ALTO the problem is even greater than with a more standard 100mm diameter windshield. Second, the Mini-ALTOs have small rear pods and various – all longer – front pods, none of which are swappable from front to rear due to the polarity of the magnets that hold them in place: what would be needed is a longer rear pod and, ideally, matching pods front and rear. A third, more minor issue, is that the Mini-ALTOs are designed to be aimed at the subject on the longitudinal axis, so the base pivots the wrong way.

The design solutions

The solution to the small diameter of the Mini-ALTO – insofar as there could be one – was to use short mics and to offset the mic mounts from the centre-line of the windshield as far as possible. Most of the familiar small SDC mics are still too long, not least as connectors and, even when hard wired, projecting cables come into play: even the small Schoeps CCM4s seem too long once cables (and, for the popular Lemo version, connectors) are factored in, although the diminutive Schoeps CMC 1 KV preamp (with its side-exit cable) and an MK 4 capsule should fit. The Sennheiser MKH 8040, of which I own a pair, also seemed feasible, if only the short MZL connector (which can be used instead of the XLR module) didn’t have such a long rubber boot (itself over a long brass nipple) and then a cable projecting from this. Realizing I didn’t know what was inside an MZL, I worked out how to open one (OK, I just crudely levered the innards out with a penknife: but, no, it wasn’t one my precious Sennheiser MZL 8003 remote cables that I butchered!), and saw that there was scope to have a side-exit. A quick slice with a Dremel blade removed the brass nipple, and it was equally easy to drill a hole in the brass casing: 10 minutes and I had my proof of concept. I wasn’t convinced about my skills to take apart an MZL properly or to wire them up, so, in exchange for doing the slicing and drilling of a batch of forty (that was a fun lunchtime activity!), Ed Kelland at ETK Cables made up some cables for me: I suspect his right-angled custom MZLs might sell like proverbial hot cakes, if I don’t grab them all myself (the super-short MKH 8000 mics that result are really useful for all sorts of other arrays, not just ORTF)!

My working through to the shorter MZL solution, with the mics in an early iteration of the ORTF mount.

And here’s the cable I am actually using, kindly put together for me by experienced wireman Ed Kelland at ETK Cables.

With mic length sorted – or minimized as far as I could achieve using a mic commonly used for field recording and production sound – it was time to move on to the second problem. The key to mounting the mics was, of course, to keep the hoops where they normally sit in a Mini-ALTO, but have them hold a bar to which the mics are clipped. I had been doing the same for the ORTF-3D rig, so it was an obvious choice. Then it was just a matter of making various iterations of the design (thanks to the 3d-printer) until I got the right balance between keeping the capsules away from the basket edge on one side, and the keeping the back of the mics (or the customized MZLs) away from the other side. It was really satisfying that by the time I got to the sixth version (there were other changes along the way) I got the centre of the diaphragms on the centre-line of the windshield: there’s nothing magical about that (getting it back from the centre-line would have been better in such a small windshield), but at least it doesn’t feel as if the design leaves the mic capsules right up close to the basket. And clearance at the rear is enough that the mics don’t knock against the basket in normal use: I assumed that an ORTF-equipped windshield would not be handheld by a circus acrobat recording themselves in action…

The model of the bar and clips shown with the mics, giving main dimensions.

The finished design, 3d printed and tilted sideways so I could photograph it.

Rear view: you can see the ball joint I am using instead of the standard base.

End view with pod attached: the rear of mic clearance is actually better than this photo suggests, partly due to perspective, and partly because the basket narrows very slightly at the central plastic ring (which isn’t near the mics).

As for the short rear pod and unequal length of pods, Radius sorted that by getting a couple of pairs of symmetrical pods made up for these tests. That was easy – at least for me. The reason I wanted a couple of pairs is that I was concerned about the impact of the plastic ring that marks the division between the end-cap and cylindrical body of the basket. The large thick plastic ring (bigger at one end) of the dedicated Rycote ORTF windshield has an impact on the sound, and I have been concerned with the impact of large plastic elements in other designs when using mid-side pairs: for example, the chunky ring on a Cyclone has a measurable impact on the sideways-facing fig 8 mic (which may or may not matter for a recording). The Mini-ALTO end-cap rings are nothing like as chunky and such plastic elements don’t worry many a recordist, but I think it will be instructive to test the difference between a pair of shorter 90mm pods (where the end-cap rings sit inside the 110 degree angle between the mics) and longer 136mm pods (where the end-cap rings sit outside the 110 degree angle between the mics). I will cover these tests and, also, some field recording tests in part 2 of this blog post (by which time, I hope, Radius may have made a fur to fit the new windshield lengths: it will be good to compare how it performs in wind against, say, an MS pair in a Mini-ALTO 115).

Mini-ALTO baskets, top to bottom: 136mm symmetrical pair; 90mm symmetrical pair; and, bottom, my standard 115 model (the smallest) with its unequal front and rear pods.

And, finally, to the problem of the mic base pivot being oriented 90 degrees from what would suit ORTF. Well, for that I just 3d-printed a new base for the Mini-ALTO that has a 3/8″ thread and fitted it to a Gravity MS QT 1 BQuick-Tilt Microphone Adapter. A slightly clunky and chunky solution for now, but I know that Simon and Tim at Radius have been working on a small ball-joint mount anyway that will work with the Mini-ALTOs.

What is less certain is whether they will take my ORTF design and refine it into an actual injection-moulded product. I guess that will depend partly on the testing (do come back for part 2 of this blog post) and partly on practicalities and whether they think there is a market. But, even if not, just as with the other parts I have designed to fit Radius hoops (e.g. the MS clips), I will make the parts shown freely available for 3d printing: of course, this would be rather dependent on the matching pods becoming available!

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DIY Projects

ORTF: working towards a minimalist approach

November 15, 2024

The near-coincident ORTF stereo pair has a huge following that extends way beyond the remit of the body for which it was invented – the Office de Radiodiffusion-Télévision Française – and long after its demise in 1975. The required 110 degrees angling of the mics and diaphragm centres at 170mm spacing can be set up with any stereo bar. Or you can always use the Schoeps MSTC 74 ORTF mic (or its predecessor, the MSTC 64), where the spacing and angles are built in. And if you don’t have nearly £3k to spare, there’s the similarly designed Superlux S502 at around £100. But, evidently, there are many that find setting the angles and spacings on a stereo bar too fiddly by far (it’s certainly harder to eyeball 110 degrees than a right-angle); many who don’t want to splash out on a dedicated (but inflexible) Schoeps solution; and many who want something of higher quality than the Superlux. As a result there are many dedicated ORTF mounts available for SDC mics. These include offerings by major mic companies, such as DPA’s CXO4000 (which can also mount an XY pair) and, more recently, commercially available 3d-printed options. Ostensibly neat solutions, these dedicated mounts hold the mics directly, and can then be fixed directly to a mic stand: attempts to introduce shock-mounts then become clumsy, typically using Rycote lyres for the whole rig (fixed on a stem protruding from the bottom of the ORTF mic holder, and at 90 degrees to the intended use: a real shot in the foot). Come to think of it, an effective shock-mount or suspension for the Schoeps MSTC 64/74 or Superlux S502 isn’t immediately obvious: a Shure donut perhaps?

ORTF using a standard stereo bar (the small K&M 23550) and the smallest lyre/hoop mounts that I know: the Radius Windshields RAD field edition mounts. Rycote InVision INV 6s would be a larger alternative. The red hoops are a test run of softer 55D shore ones, and will go into production soon in a more subtle dark green. This is a fairly minimalistic ORTF rig with properly set up shock-mounts, but there is no denying that setting angles and spacing is a bit fiddly.

With a 3d-printer to hand, I wondered about a neater solution, using mics mounted correctly in suspensions (as if, for example, using a pair of Rycote InVision INV 6s or, smaller, Radius Windshields RAD field edition mounts on a standard stereo bar), which would then be fixed to a dedicated ORTF bar: the best of both worlds. First off, I designed a simple mount with size slots to fit both Rycote lyres and Radius Windshield hoops. The latter can fit Rycote mounts, but not vice versa. The three slots to each channel allow a bit of flexibility in the placement of the lyres/hoops for different mic models. I added a cable grip at the rear to help isolate the mics from cable-borne vibrations and, for my personal usage, designed this to perfectly grip a Sennheiser MZL cable: in my usage the ORTF mount will be used for MKH 8040 mics with MZLs. Taking a more minimalist route with MZLs made me think a bit more about the suspensions and clips, so I ordered a pair of 19/20mm clips from Radius (much more minimal than their chunky universal clips) and a pair of their 8mm clips (designed to hold the rear of a Sennheiser MZL or a Schoeps Lemo connector). This works fine although there is a mildly disconcerting slope to the mics as a result of the centres of the two clips being slightly different (they didn’t originate as such a pair), but the ORTF mount can be angled freely anyway: for this the bar makes use of a Gravity Quick-Tilt Microphone Adapter (MS QT 1 B).

With the same hoops mounted on the 3d-printed ORTF bar.

And angled a bit to show the construction of the ORTF bar more clearly.

So far so good, but when talking to Simon Davies at Radius about the different centres of the clips, he suggested that I try the two clips individually: that is, use one hoop only (the curved profile giving the new hoops more stability when used singly than the flat lyres from his Rycote days), and suggested I try the 8mm clip only. That was food for thought, so with the ORTF mount I tested the following:

8mm clip with single RAD-2 (21b) hoop x 2 (the control)

8mm clip with single hoop 21b vs two 21b hoops with 19/20mm + 8mm clips

8mm clip with single hoop 21b vs 19/20mm clip with single hoop 21b

8mm clip with single hoop 21b vs 8mm clip with single RAD-1 (21a) hoop

8mm clip with single hoop 21b vs single Rycote lyre 72 shore

8mm clip with single hoop 21b vs no shock-mount (another sort of control!)

With structure-borne noise transmitted from a suspended floor via the stand, the 8mm clip with a single hoop 21b sounded the best: in my test it offers less transmission of the lower frequencies than the 19/20mm hoop (or the latter with two hoops and an 8mm clip in the rear hoop), which I suspect is due to the fact that the 8mm clip is holding the rubber element at the rear of the MZL rather than the mic body direct. I couldn’t really hear/see any difference between the RAD-2 (21b) and RAD-1 (21a) hoops with the single 8mm clip. The single Rycote lyre worked OK on its own with such a light mic, but, connecting to the mic body, again transmitted much more than the 8mm clip. The absence of any shock-mount was definitely much worse than any of the clip/hoop/lyre combinations, as one would expect! So the conclusion is that the single-hoop and 8mm clip is an excellent idea for an ORTF mount for static mics with MZLs (sans windshield: or, indeed, inside a large windshield).

So with these useful tests in mind, I quickly modeled and printed a shorter version of the ORTF mount, this time with just with two slots – for one hoop for each mic. With the RAD hoops set with the concave side forward (orientation of the hoops is irrelevant as long as opposing if in a pair), the MKH 8040 sits nicely forward of any suspension or mount that could have an acoustic effect, and the whole arrangement has a certain minimalistic elegance (though I say it as shouldn’t, as my great grandmother would say).

Here’s the 3d model of the mini ORTF mount/bar.

A view of the single-hoop ORTF mount, this time with the 62D-shore hoops.

The view from the rear: the cable grips are important to both stop transmission of vibrations along the cables, and also to set the angle of the mics. I was a little sceptical that the cable clips would do both, but testing very much shows they do. Obviously differently sized cables than the Sennheiser MZLs used here would need different cable clips in the 3d-printed mount, but that’s part of the beauty of 3d-printing: you can design something that works for you!

It was only yesterday, after having modeled and printed these different ORTF mounts, that I received the 55D test hoops from Radius Windshields, in their ‘Evil Red’ colour. I had suggested the idea to Simon Davies as with Rycote lyres I felt that many end up using too stiff a suspension for a lightweight static mic with no windshields – be that for indoor effects or for music recording. Both Rycote and Radius are primarily geared to production sound markets, and those using mics statically often forget this and that there is a substantial difference between the needs of a mic that is moving – often quite quickly – on a boom-pole or in a pistol grip (think of the momentum involved) and a mic that is completely static, and where the aim of the suspension is to reduce the impact of structure-borne noise transmitted from, or through, the floor and then through the stand. So today I tested the 55D shore hoops on the mini ORTF bar, and they reduced low-frequency transmitted sound significantly, which can be useful on those occasions where you do not want to roll-off the low end of the mic. The MKH 8040 mics with MZLs mounted in 55D hoops (in the eventual production colour of dark green) and the mini ORTF bar (which I will now 3d print in black) will make a very minimalistic, discreet and well-suspended pair that are quick to set to the ORTF configuration on those occasions when I steer away from my favoured MS pairs. Sorted, as they say!

Just for completeness, here’s my comparison of the effectiveness of the 55D hoops vs the 62D hoops:a useful reduction in low-frequency structure-borne noise for those occasions (particularly when recording music: think of organ recordings, or even a standard piano where the lowest note is 27.5Hz) where you don’t want to use a high-pass filter.

Obviously the ORTF mounts shown here are very much tailored to my use, with MKH 8040 mics with MZL cables, but just in case anybody else wants to 3d-print these ORTF bars (free of course!), here is a link to the larger version for two Radius hoops/Rycote lyres per mic and here is the link for the more minimal one for a single Radius hoop. For others with very different mics and different cables, perhaps this DIY project will give a bit of inspiration!

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