You may be aware of my efforts in the world of three-dimensional audio recording; I’ve been a proponent of Ambisonics in particular, since my first experience of a fully three dimensional playback in the late 1970s at Calrec’s Soundfield Microphone demonstration studio in Hebden Bridge, Yorkshire. I’m still involved in that field and have a collection of microphones and recordings that continue to be of use, but three years ago, just as the Covid pandemic that shut down our world began to take effect, I’d taken delivery of a rather different 3D system, a low-cost 3D printer, produced, ironically, in China.
Way back last century, when the only real choice of CAD programs for Apple Computers was one called MiniCAD, I’d discovered that it had the possibility of modelling in three dimensions, and in a bored moment in between previews at The Donmar Warehouse, I’d created a more or less accurate 3D model of a lighting hook-clamp. Later on, I’d drawn a K&M Microphone boom stand and a few other basic bits and pieces and had started to try and put together some symbols that would help with laying out an orchestra pit. Then other parts of my life rather took over, MiniCAD became Vectorworks and I concentrated on other aspects of work, until, frustrated with the need to take both a boom pole and a microphone stand on location recording sessions, I looked at the possibility of making a set of tripod legs that could be attached to a boom-pole to convert it into a stand. Out came Vectorworks and a shamelessly plagiarised version of the sliding leg attachment system that Manfrotto used on their 5001 Nano Stand was devised. Next came the problem of getting it produced and back then, 3D printers were large, expensive and not a great way of producing one-off designs unless you were planning to go into mass-production, so I shelved the plan once again, until a visit to my friends at Autograph Sound & Recording revealed that they’d invested in a 3D printer and were willing to print something out for me, which they duly did. And that’s when I discovered the Manfrotto NanoPole, which does more or less what my idea did, so that was pretty much a non-starter, but the seed of designing and printing bits and pieces was sown and when Creality came out with their range of self-assembly 3D printers at an affordable price, I put my money down and soon I was on my hands and knees trying to follow a set of ideograms that made Ikea instructions look positively intuitive.
I bolted it all together, loaded a couple of the models that came on the MicroSD card and printed out a small cartoon dog, storage units for the tools, extra bits for the printer, and a trinket box, all pretty successfully. And then the pandemic struck: in the UK as in other parts of the world, there was a shortage of suitable personal protective equipment (PPE) and what was available was going straight to hospitals, leaving many care home workers dangerously exposed. The Czech inventor and maker of 3D printers, Josef Prusa and his team came up with an open source design for parts of a face mask that anyone with a 3D printer could produce and so for the next month, that’s what my little printer turned out: one headband and lower mask reinforcement every three hours or so, day in day out. Batches of twenty were delivered to a central collection point where full masks were assembled and passed on free of charge to whoever needed them.
Companies and individuals all over the world responded and tens of thousands of masks were made and distributed to try and alleviate the problem and I was happy to be a very small part of that effort. It did tie up the printer, however, and the constant wear on the moving components took its toll, and eventually, I relegated mine to producing the odd prototype, passing on my designs to a one-man 3D printing operation in a coastal town, not too far from London, where his rather more sturdy printers and his much greater expertise make a better job of printing my models that I do.
But that’s jumping the gun: what did I do after the great mask-making session had finished? Well, the first thing I did was unearth the MiniCAD drawing of the hook clamp that I’d made and export what’s known as an .stl (stereolithography) file, and load it into a little program called a slicer, which chops the drawing into layers and then produces a set of instructions that the printer uses to determine what temperature the special printing filament melts at, where to move the printing head to, and then how to squeeze the appropriate amount of melted plastic filament out of a very fine nozzle, building up the solid device, layer by layer. That file is transferred to the printer on an SD Card, selected from a menu, and the command to print is given. And what should then happen is that the printer starts to heat up all the bits that need heating, in the sort of printer I use, the print nozzle and the plate on which the model will be built, and once that’s done, the three servos that control the movement of the print head, the build plate and the printing filament start to do their magic and eventually, all things being equal, which in my experience is about a one in five chance, you get a solid representation of your 3D drawing, which is rather exciting.
There’s stuff to learn, which can, at times, seem to be some arcane form of alchemy: slicing, filament temperatures, retraction, stringing, elephant’s foot, and other strange phrases, and I have a lot still to learn, so whenever I need anything special printed, I send the files off to the aforementioned chap on the south coast with his 3D printer-farm and a wealth of knowledge that I’m too old, and probably too lazy to acquire.
But I persevered with the design work: first, a small kitchen accessory for my wife, then a rack for holding screwdrivers above my tiny and cluttered workbench, and then the first audio accessory; a rack-mountable headphone hanger. This went through a whole series of variations to cope with different sizes and included one that fitted into an XLR mounting-hole that could be changed to suit various sizes and retract into the mount when not needed. I’m still rather pleased with that one as a design exercise, although it’s really not a lot of use if you don’t have a spare hole in your XLR patch-bay.
Then a show I was working on needed a prop period microphone: it didn’t have to work, it just had to look more or less accurate. The simplest one I could find that worked for the designer was an old STC 4017, a pretty simple thing to make, and it did the job: the addition of some ex-army Belling terminals making it look more the part.
The picture shows a later variation with a handle for another show, and fitted with a cheap dynamic mic insert, not needed in the end.
Bitten by the prop microphone bug, I decided to try my hand at something more complicated and another STC microphone, the model 4021, or the Apple & Biscuit as it came to be known, was my first foray into printing separate parts: sections that could then be assembled into a whole.
This was also not a bad effort, so I upped my game and went for an RCA Varacoustic: that took a while to get right, because I couldn’t be sure of the exact dimensions, although I finally found a full description on-line that gave me enough information to be reasonably accurate and I’m rather pleased with this one as well: the cable entry gave me a few problems, especially the spring-style strain relief, until I realized that I could buy cheap 1/4” jack plugs with pretty much the right spring for very little and the design was complete, especially when Mark, my printing guru, told me that he could print the RCA logo background in red, as it should be.
Next came the Western Electric 600A, the fabled microphone of the 1920s, spring-mounted in a circular frame and attached to a table stand. That’s another one that needs assembling, but the end result is not too bad. Strangely, the biggest problem with these older designs is finding the right material for the grille cloth and I went through several alternatives before a friend who’s into book-binding suggested a material called Mull and the RCA leaflet mentioned Organdie and the combination of the two seems to work pretty well.
The next challenge was to be the iconic BBC-Marconi Ribbon Microphone, the AXBT. Whenever you see pictures of old-style British radio broadcasters, the AXBT is there, with the BBC logo prominently displayed, a beautiful bronze body and perforated metal grille, sometimes a bit dented and discolored, but very obviously a serious piece of kit. I’d seen a photo of a prop version being used in a show and, although it was a brave effort, it didn’t look quite right, so I began the research. Luckily, there’s rather more information out there for this particular microphone and some very detailed photographs, especially those on the amazing website at coutant.org which is a treasure trove of photographs and information. Design work began, learning some useful extra tricks in Vectorworks also began, and test sections were designed, output as .stl files and printed, either badly by me, or properly by Mark, at Seaside3D. He also found a filament which, although not perfect, was a good starting point for the bronze colour, and also pointed me to something called Black Antiquing Wax, which is the sort of stuff that dodgy antique dealers use for making things look a lot older than they actually are. It’s expensive and messy to apply, but it does the job and the first prototype was finally finished.
This was seen by the sound designer of the show where I’d seen the original prop version, and he promptly commissioned three more for when the show went on tour later in the year.
For completeness, I’ve added a stand adapter that fits perfectly into the special stand that the BBC used, one of which happens to reside in the studio at The Royal Academy of Dramatic Art. The current model, while still not perfect, does have a support inside that will take a standard microphone clip and has three period binding posts, to which it’s possible to wire an XLR internally and have a working microphone. Then, whilst designing a version in gold filament, to celebrate Autograph Sound’s 50th anniversary, the completist in me decided that it did actually need a proper ribbon motor and I was off down another rabbit hole, designing the mounting for the magnets and an adjuster for tensioning the incredibly delicate ribbon. Once finished, and before it went off to its final destination in the Autograph office, I used it to record a few cello cues for a show at was working on, with my wife, the cellist, preferring it to the rather more analytical sound of my Schoeps MK4.
During the course of all this, I upgraded my own printer: the Creality has gone to a colleague, who has rediscovered his own interest in 3D printing, and I’m now the proud owner of a Prusa i3 MkIII., which is a much sturdier piece of kit. With that installed, in reasonably quick succession, came a pretty respectable model of an RCA 44, followed by the latest, the RCA 77DX, both with their appropriate desk stands. A very helpful rental company allowed me to photograph and measure their actual models in exchange for doughnuts, which was a fair exchange, I think.
But the big stuff is not the only way I use the 3D printer: my niece had a doll’s house from when she was younger that she wanted her own children to be able to play with, but the front door and some of the shutters had broken hinges and could I match them up and print them out? I could and I did, which made her and the kids very happy. A large internally-illuminated moon lamp for their bedroom followed, as did a case for my nephew’s DJI drone, both of those from other people’s downloadable designs and, more recently, I unearthed my film scanner to start scanning some old pictures I’d taken of shows I’d worked on, only to discover that the latch which held the film-strips in place had broken. Half an hour in Vectorworks and twenty minutes on the printer and a new latch, just as good as the old one, was screwed into place.
For my own use, I’ve printed terminal covers for the smart batteries that power my portable kit for when I’m travelling by air, simple push-on caps for the Neutrik XX range of XLRs to convert them into low-profile versions and some custom microphone mounts, including a combined protector and mount for DPA4097 microphones, when I use them as float mics.
An interesting challenge given to me by one West End musical balance engineer was to design an asymmetrically profiled, electrically conductive fader cap for a DiGiCo desk which, having discovered that you can get electrically conducting printer filament, albeit for a bit of a premium, I managed to do, and which, in the opinion of both him and his A2, are more responsive than the originals.
I have one invaluable tool without which I’d be lost and that’s a set of digital measuring calipers, which means I can design to an accuracy of .1mm, or 1/64th of an inch, which is vital for creating the smaller parts.
So go ahead and invest in one if you like tinkering, or just find someone who’s got one and know how to use it, do your own designs in any of the 3D design programs, as long as they’ll export an .stl file, and enter the wonderful world of DIY 3D fabrication. Oh, and in case you’re wondering, spares for the film scanner, long since out of production, can be found on the internet, but at eye-watering prices, so I think my printer has paid for itself, several times.
.