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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

Sennheiser MKH 8090 for mid-side: the Goldilocks mid mic for field recording?!

May 7, 2025
The MKH 8090 (centre) with its siblings, left to right: MKH 8020 (omni), MKH 8030 (fig 8), MKH 8040 (cardioid) and MKH 8050 (supercardioid).

Introduction

It’s funny how reluctant some are to try an omni as the mid mic in a mid-side pair (seemingly afraid that this will make for a mono recording) despite it often being the best tool for the job. But I have had many queries now about whether a wide cardioid will strike a sweet spot between an omni and a cardioid when paired up with an MKH 8030 for mid-side recording. Normally, I swap between omni, cardioid and supercardioid mid mics, but recently, thanks to the good folks at Sennheiser, I have extended my available mid-mic options to include the wide cardioid MKH 8090. And so has begun my exploration as to whether – and this is said only partly tongue-in-cheek – it is something of a Goldilocks mic, hitting the perfect balance between omni (MKH 8020) and cardioid (MKH 8040) options, or, alternatively, whether – in practical use – for many it represents too fine a mid-point between these polar patterns, if, indeed, it can be described as a ‘mid-point’.

These things are personal, of course, reflecting both taste and subject matter, but in this blog post I will focus on a series of recordings made with the different mid-side pairs at the same time, so hopefully it will be of some use to a few readers – especially those who cannot try the different polar patterns before buying. And, although I have demonstrated the supercardioid (MKH 8050) mid-mic options previously, in comparison to the MKH 8020 and MKH 8040, I have included it again here for completeness. I have omitted the Sennheiser shotgun mid-mic options (MKH 8060 and MKH 8070) for three good reasons: first, mid-side recording with an interference tube mid mic is a very different beast and usually, though not always, for very different purposes than field recording or music recording; second, it is very hard to think of a set-up that could adequately cope with simultaneous recordings or such differently sized mid mics (well, not one that doesn’t involve at least four fig 8s); and, third and most conclusively, I don’t have either! Likewise, it would be rather tricky to include a fig 8 as the mid mic in a typical windshield, given the required orientation of the mic.

The specs

I don’t want to repeat what can be read in detail on Sennheiser’s website, but, nonetheless, a quick comparison of the polar and frequency response charts is a useful starting point, not least as they are rarely seen grouped together for these four mics.

Polar patterns of the omni MKH 8020, wide cardioid MKH 8090, cardioid MKH 8040 and supercardioid MKH 8050.

The most obvious feature of the polar pattern of a wide cardioid such as the MKH 8090 is the absence of a null, with the pattern looking rather that of an omni, albeit consistently reduced at the rear by around 7dB.

Frequency response graphs of the omni MKH 8020, wide cardioid MKH 8090, cardioid MKH 8040 and supercardioid MKH 8050.

In contrast to the situation with polar plots, the frequency response graphs see the MKH 8090 wide cardioid look much more like its cardioid sibling than the omni. The two most noticeable differences from the cardioid are the earlier high-frequency peak and the slightly flatter curve below 100Hz: this is still a long way from the MKH 8020 omni with its almost flat response down to 10Hz.

Test rig for the MKH 8090 comparisons as a mid mic for mid-side: two clusters of three mics, each comprising an MKH 8030 with two SDC siblings (MKH 8020, MKH 8040, MKH 8050 and MKH 8090), on a custom 3d-printed bar (with Radius Windshield hoops for the shock-mounts) in a Mega-Blimp.

Test rig

Even rigging four alternative mid mics is no doddle, especially for outdoor field recording, so I have done some thinking and, inevitably, a bit of 3d printing to make a suitable mount. Although, as readers of this blog will know, I am not overly concerned about the often rather theoretical (or at least often imperceptible) issues of shadowing, even I think a cluster of four mics around a single fig 8 seems a bit too congested, so I split the mics into two pairs each with its own MKH 8030 side mic, spacing the two groups of mics 170mm apart on a 3d-printed bar I made up, and mounted within my roomy Mega-Blimp. It is not perfect, of course, but each MS pair can’t occupy exactly the same space at the same time and be free of other mics nearby, so its is a reasonable compromise, and one, I feel, that doesn’t obscure or misrepresent the differences between the various pairs.

Village street

Although the garden has changed dramatically here over recent months (much of the reason why blog posts have been a little thin on the ground of late!), the nominally quiet village street – used as a frequent test bed for me – seems as noisy as ever, with a ripe mixture of sounds. In the recordings below, you can hear the curious thumps from inside a Waitrose van delivering to a neighbour, followed by its departure, along with passing vehicles and birdsong.

First up, we have MS with the omni MKH 8020 mid mic:

Second, we have MS with the wide cardioid MKH 8090 mid mic:

Third, we have MS with the cardioid MKH 8040 mid mic:

And finally we have MS with the supercardioid MKH 8050 mid mic:

Test recording down at the North Norfolk Railway: always a good test to have a rumbling and hissing locomotive passing, followed by the rattling carriages, even if anyone about assumes I am something of an uber-trainspotter!

Down at the station

Risking large crowds on a bank holiday Monday, I tootled off to Holt station on the North Norfolk Railway, which is another familiar haunt of mine for mic tests, positioning myself a little way from the platforms, opposite the signal box and right next to a signal (I do like the double clunk the latter makes). Funnily enough, it was unexpectedly quiet in terms of people, although the distant hum of traffic and the more disturbing near continuous thunder of aeroplanes overhead were ever present. Here is a snippet, with the signal changing and then a small 0-6-0ST saddle tank setting off, pulling a short train of three Victorian carriages and leaving another train (pulled by an xxxx) hissing steam at the platform:

Following the same sequence as before, first up we have MS with the omni MKH 8020 mid mic:

Second, we have MS with the wide cardioid MKH 8090 mid mic:

Third, we have MS with the cardioid MKH 8040 mid mic:

And finally we have MS with the supercardioid MKH 8050 mid mic:

Conclusions

In the strict sense there are no universal conclusions to be drawn from these tests, with their purpose being simply to illustrate the differences in the polar patterns of the MKH 8090 and its MKH 8020, MKH 8040 and MKH 8050 siblings when used as the mid mic in a mid-side pair. Inevitably, to some these tests will serve to show how the less directional MKH 8090 and MKH 8020 mid mics work well and are viable alternatives to the more commonly used cardioid and supercardioid mid mics. To others, these tests will show how radically different the four mid mics are. Such is the nature of listening tests even without confirmation bias rearing its ugly head. From a personal view, and drawing on wider use than the few test clips presented here, I have been very impressed by the stereo image presented in mid-side with the MKH 8090 mic. Unless more rear rejection is needed from the null of a cardioid or the deeper bass response of an omni is required (and often the bottom end of the MKH 8020 needs rolling off in field recordings), the MKH 8090 is a compelling option, and one I have been using increasingly in my field recordings. In short I am so glad to have it in my arsenal of mics. Now making such finely gradated choices between polar patterns can be hard when field recording compared, say, to setting up mics for an acoustic music recording in a more controlled indoor space, due to the fact that outdoors sound sources can be unpredictable and constantly swapping mics can become impractical, so, in that sense, having an option between a cardioid and an omni can just make life more complex. But, equally, field recording can involve frequent recordings of the same sound source, or similar sound sources, in familiar or similar locations, and for many an experienced recordist having more finally gradated choices in polar patterns can be useful. And if you are just kicking off with mid-side recording and are uncertain as to which initial mid-mic polar pattern to choose, then, just possibly, this post might provide some food for thought.

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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.
Front view.
End view.
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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Audio Gear

Musings on mic cases…

December 9, 2024
Two very different manufacturers’ mic cases from Rycote (left) and Sennheiser (right): both have their strong points, but neither seem suited to use in the field.

I appreciate it’s a little thing, but good mic cases for use in the field are not as easy to buy as you might think. Obviously, the needs of different recordists vary: if you are a classical music recordist travelling to a concert hall or church with a mass of mics and other more bulky equipment, then, perhaps, a large Peli case might be the answer. A similar solution might also suit the smaller mic collection of a sound mixer on set, where a sound cart means that equipment is bulky anyway. But for most of my use, and I suspect that of many others, I need mic cases that take up very little space in whatever I am carrying, yet keep the mics safe and easily accessible, be this for music recording on location or field recording for ambiences or sound effects. This short blog post is for those in the same boat, especially those who have yet to find a solution that works for them: others, I am sure, will have come up with better solutions than mine, or at least ones more suited to their needs.

First off, needless to say, are the cases that come with mics from the manufacturers. These vary hugely, although few are cases you would want in the field. The Schoeps ‘Desert Island Stereo Set’ is a welcome exception, with a diminutive stereo pair of mics and mic clips (perhaps of less use) in a dinky little Peli case, and is in sharp contrast to their usual wooden cases that are not so practical or space efficient in the field. My Rycote mics have compact cases, but are for individual mics or pairs, and the bulk soon adds up when taking several into the field. Their rather nice finish also doesn’t seem quite right and robust for the field. As for my Sennheiser MKH 8000 series mics, well they come in the same massive plastic cases as the older and larger MKH mics, so again are ones to leave at home.

The Rycote mic protector case (20cm model) and one of the three mic tubes inside: although I haven’t really found the overall case great (hence the label still on it all these years later!), the internal mic mic tubes have been useful!

My first foray into mic cases for the field was the Rycote mic storage case, which looked the part: a fabric-covered tough plastic cylinder containing three plastic tubes for the individual mics. It could have been good if only the three individual plastic tubes were a comfortable fit (they were far too tight, though, puzzling, not everyone found this to be so!), and again was bulky: not bag friendly enough for me. I never really used the outer case, but have used the individual plastic tubes for some years, and I know others like similar tubes (they can be bought much more cheaply outside the audio world). As the number of mics grew, however, I found a bunch of tubes knocking around the bottom of my bag less than ideal. That said, I do find them of use for shotgun mics, which are, of course, hard to combine with other shorter mics in a single case. What I wanted was a protective case that could hold a bunch of these shorter SDC mics together, and whilst looking into what others have found (including cigar travel cases!) I had the idea (doubtless not original) of using semi-rigid cases for 2.5″ external hard drives. They come with a bit of variance in size between makes and are well-suited to a bunch of smaller SDCs. The only problem was keeping the mics separate, so they didn’t bump into each other, and for that I used lens cloths, tucking up the mics for bed before zipping up the cases. The lens cloth business is not the hassle it sounds, but it does mean that when opening the case you can’t instantly see which mic is which.

More compact SDC mic storage and transport in shell cases for 2.5″ external hard drives. Here shown with relatively long AKG Blue Line mics, but shorter SDC mics can fit across the width of such cases. The right-hand image shows how I have actually used such cases, with a lens cloth protecting the mics from each other.

So after a couple of years of this, and with some of my mics not neatly fitting into such cases or not doing so efficiently, I began to wonder if there could be a better solution. I had another good look at the smaller Peli cases, thinking about 3d-printing a tray to fit, but for my SDC mics, the model sizes just didn’t seem spot on. And that is when I stumbled across rigid cases for 3.5″ hard drives, which, being a little larger than their 2.5″ cousins, seemed the perfect size for my use. Now these vary hugely and many don’t look suited for repeated opening and closing (I guess they are for storing internal HDDs in an office or store environment?), I found some (an obscure brand!) that are more robust: really tough plastic cases, a reasonable hinge and locking clip, good seals and shock resistance (dense EVA foam), yet overall size not too large: at 172mm x 125mm x 43mm, they still slip easily into my smallest field-recording bag. With a bit of a search and you will find the same or perhaps a better model. And with a 3d-printed tray (yes, more fun with the new 3d printer!), the mics sit neatly and securely (with the perfect amount of pressure from the lid’s lining in the dense EVA foam) and I can see all the mics at a glance – like a box of chocolates. So that’s my current solution for SDC mics today and easily the best I have found. I have no doubt it will change in the future as my mic collection changes or, perhaps, when I struggle to find similar replacement cases in the future, but the basic premise will remain. As I said, only a little thing, but perhaps my musings will help someone!

Slightly bigger, rigid and sealed 3.5″ hard drive cases. The EVA foam insert at the top (I removed the bottom one and replaced it with the 3d-printed insert tray to fit specific mic models) is dense and not prone to break down easily like many foams: it applies just enough pressure to hold the mics securely in place.
And the same again, but loaded with Sennheiser MKH 8000 mics (left) and Rycote mics (right). My current solution: for how long though?!
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DIY Projects

3d printing clips for the Radius Windshield hoops

October 27, 2024
At last, mid-side clips integrated into a shock-mount, yet easily swappable with clips for a single mic.

Mid-side clip for 19mm Ø mics

When Radius Windshields launched and produced their RAD shock-mounts one of the unique features was that the mic clips could be unscrewed from the hoops and switched to something different. A radical difference from, say, the Rycote Invision series shock-mounts, where the mic clips and lyres are all one moulding. This has provided scope for Radius to produce dedicated clips for the older MKH 50 etc. mics and, ultimately, to produce dedicated MS clips, doing away with the need to use clips to fix a mic to the shock-mount then a pair of back-to-back clips to attach the second mic to the first. A fiddly faff and also bedeviled by the lack of back-to-back clips with a close spacing, which is preferable for mid-side recording. I have been encouraging Simon Davies at Radius to produce MS clips, and this is now in train using some of the ideas I have proposed. While their nice injection-moulded version is awaited, here is my version for a MS clip to fit their RAD-1 and RAD-2 hoops, and designed for 19mm Ø mics such as the MKH 8000 series and the Rycote SDC series. I should add that Simon Davies at Radius Windshields has supported me in putting this design out into the public domain, which follows similar release of their first prototype for others to 3d print (their initial design was rather different to mine, and their upcoming production version, with a central bolt and a consequently wider spacing as this is tightened). The approach I have taken with this clip is very much a product of many discussions with Simon – via email – on MS clips and other Radius items in development, but also reflective of the company’s refreshingly open engagement with sound recordists.

One of the nice things about the Radius Windshields hoops is that they fit to Rycote shock-mounts such as the InVision INV 7 here, so you can make good use of existing hardware.
CAD drawing, created using Onshape, for the MS clip.

In designing this MS clip I have gone for a spacing of 2.5mm between the mics, which is nice and close but still provides just enough room to allow two MKH 8030 mics to be inserted for a Blumlein pair of two fig 8 mics(the MKH 8030 having a wider front part to the mic). The mics are given enough grip by the springiness of the clips, and this took quite a bit of work to get right: in particular, the internal seemingly circular clips are made up of several different radii so that they hold the 19mm Ø mics properly as the necessarily undersized opening is enlarged by insertion of the mic to give sufficient grip. I have printed them in both PLA and PETG filament (with solid infill) so nothing fancy is required: the PETG filament gives a bit more flexibility and is what I have been using for them mainly. If you are determined you can break them, but, of course, that applies to many a commercial-produced back-to-back clip!

There are two bits of metal hardware that you will need for each clip, which comprise an M3 thin square nut (standard size 5.5mm x 1.8mm), and one of the same M3 socket head button flange screws that Radius use, in this case 12mm long. Of course, you can just use the existing screws that come with your RAD-1 and RAD-2 shock-mounts, so strictly the only extra part you need is the square nut. Stainless steel A2 is best. I got both the nuts and some of the extra screws from Westfield Fasteners (in the UK).

You can go to the file here in Onshape and export in STL, STEP, 3mf etc. file format as required. Note that the clip looks a little skewed or angled when printed: this is deliberate since loading it with two mics opens up the two clips elements a little and consequently, with this built-in angling of the lower circle, the MS clip sits properly square and central (i.e. with the mic centres exactly one above the other) when in use.

MS clip showing vertical alignment when loaded with a pair of mics: a bit of a fiddle to compensate for the skewing effect when the clips are expanded to take the mics, but worth get right.

And, yes, with the MS pair nicely in the Radius Windshield hoops, you can not only retrofit them to InVision shock-mounts or, say, a Rycote Modular windshield, but even, with a bit of ingenuity, get them into a Rycote Nano Shield: with the rather high-set mount for the lyres in the Nano Shield there is not a lot of height to play with (which makes back-to-back clips a very imperfect solution: the top mic ends up right by the basket), so a 3d-printed mounting bar (here’s a link to this too) and mounting the Radius hoops on the underside gives a good workable solution.

While I am at it, here’s another view of the MS clips in Radius hoops being used in a Nano Shield: a pretty dinky MS set up!
Yes you can fit three mics into a RAD-1 and RAD-2 shock-mount!

Triple mic clip for 19mm Ø mics

For something a little more esoteric, I have also created a triple-mic mount to fit the Radius RAD-1 and RAD-2 hoops. Such a triple configuration of mics is something I have used from time to time for MMS (i.e. mid-side but with two different mid mics with different polar patterns – say omni and supercardioid – facing forward so that the polar pattern of the mid mic can be chosen in post) or side-by-side Blumlein with, say, a single supercardioid for recording a singing guitarist, as I demonstrated recently here. Previously I have had to use two pairs of back-to-back clips to connect three mics, which is a fiddle. As I said, a bit esoteric, but that’s the fun with 3d printing: making the commercially unviable possible.

In terms of design, this drew on the mid-side clip, but the loading of the three mics had an impact on the form of the different near circular forms, so even more complex curves were necessary to ensure a snug fit for each mic. I also chose to beef up the thickness of the clip a little, to 3mm, due to fear of the additional forces involved getting three mics into a single clip; and then angled the top interface/mating part by 3 degrees to allow for the change in angle arising from the necessary expansion of the individual clips due to inserting all three mics. In all, nine iterations were required, and doubtless there is room for improvement still: things like best thickness vary a little with filament used. I used a slightly different approach to the fillets, but that is a subtle change. The solid modelling takes a few minutes only, but the printing at finest quality takes an age! The interface, or mating, with the Radius hoops is the same as for the mid-slide clip, so the same size nut and screw are needed. I suspect not many will want to print this model – it is largely presented as showing the potential for very specific mic clips (inc. DIY) offered by the interchangeable design of the Radius hoops – but if you do want to use it, then you can download it (again freely) here from Onshape and choose which file format suits you for export.

And here are the triple clips as 3d printed.

EDIT (6.1.2025) More triple mic clips: double mid side (DMS)

I’ve also spent some time playing around with mic clips for double mid side (DMS), and, spurred on by receiving a Mini-ALTO 115 from Radius Windshields for field testing, I revisited this. DMS always feels a bit clunky (it’s that rearward-facing mid mic out front that seems so odd) and, though I’m never overly concerned about it, shadowing does seem more obvious than in, say, side-by-side Blumlein of MS. But using MKH 8000 mics with MZL connectors at least goes some way to reducing the bulk of the mics. With the size of the Radius hoops there is no scope for three mics in a vertical line so, as with, say, the Rycote Cyclone DMS kits, I have gone for the two mid mics set side-by-side (although facing opposite directions, of course) with the fig 8 centrally above. The wider front part of the MKH 8030 means that this needs to be taken into account by the front clip that holds it too: the fig 8 provides the only common mic spanning between the two mic clips, and there isn’t much to grab onto at the front, so I decided – like many a DMS rig – to include a couple of metal rods (these are chopped down ones, 2mm in diameter, that were redundant from a Rycote MS stereo Cyclone kit 5 – where they are superfluous and, indeed, prevent better rigging). Anyway, here are a few images of the model (you can download the front and rear clips from Onshape) and the resultant rig.

Rear clip for DMS, showing holes for 2mm connecting rods.
Front clip for DMS.
The 3d-printed clips with connecting rods in place.
And the DMS rig set up in Radius hoops (the mount looks a little different since this includes the ‘smiley face’ adapter that allows the RAD-2 shock-mount to be used with the Mini-ALTO windshield).

EDIT (8.5.2025) A 19-20mm variant of the MS clip

I have been asked whether I could make a version of the MS clip that allows a combination of Schoeps (20mm diameter) and MKH 8000 (19mm) mics, so have modeled this and you can download from/view in Onshape here. There is a caveat: at the time of writing I have no Schoeps mics, so the fit of the 20mm hoop is my best estimate for the right amount of grip. And here’s an image of the 3d model.

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