By Bob Crowley
Just a few years ago, Hugh Tripp and I were both at medical giant, Boston Scientific. Hugh managed extremely complex and technical medical device development and testing. I ran the superbly staffed Imaging and Sensing laboratory where we discovered new ways to find, see and even hear diseases within the human body.
Hugh had worked at Acoustic Research in his early days, and went on to become an expert in designing and manufacturing hundreds of different medical and acoustics products. I began modifying microphones and transducers, and doing music recording back in the ’70s, and later invented a new way to make an ultra-miniature transducer for detecting clogged heart arteries. I was awarded dozens of patents, and I traveled the world giving lectures to cardiologists and other medical professionals about innovations relating to sonics, ultrasonics and also optics. We both are avid music and audio fans.
We also knew that we both liked manufacturing real products, coming up with new and better materials and processes, and the creative possibilities. We had enjoyed very successful careers, but, after the company became too big, innovation slowed, and the sheer bureaucracy and politics annoyed us. So we escaped.
Scoping Out the Field
Still relatively young (by our own standards!) we realized that a second career focused on our interests was the ticket. After looking at fields with technology needs we already knew about, in acoustics, sound and transducers, it became apparent that the microphone world was ready for innovation. We brought in accomplished musician and highly entrepreneurial business person, Chris Regan, to get the ball rolling. He came back with positive news, and we could hardly control our enthusiasm as we learned how musicians, producers, engineers and other innovators “saw the possibilities” with us, and shared our views on the need to improve sound recording devices.
Out with the Old–Almost
It looked like an entire era of advancement in materials and acoustics had been ignored; plenty of reissues of old designs, while everything else around the microphone field had changed fundamentally. Recording techniques, new music delivery channels, and the democratization of music production by PCs and affordable software were changing recording, and music making.
About the only thing that needed an update was the microphone–in fact, the reverse was happening–users were clutching old, vintage designs, but they were hearing, often for the first time, the limitations of noise, distortion, hash, “tizz” and other artifacts that are exacerbated by the dispassionate reproducibility of digital recording, which keeps everything, good or bad. Meanwhile, cheap reproductions of classic designs were flooding the marketplace, and some of them were usable, at least by vintage standards.
Over to one side of this scene was a resurgence of interest in ribbon microphones. Ribbons had a mixed rap sheet. I won’t repeat the oft-mentioned myths surrounding the vaunted but mysterious ribbon transducer microphone, except to say that some people were willing to use them, under certain conditions. A few manufacturers were starting to sell reworked versions of the older ribbon mics and finding a very enthusiastic customer who seemed to be genuinely relieved by the smooth and relatively uncluttered sound of ribbon mics, and the “dose of analog” they put back into the mix. But these old designs were limited: They tended to be very dark sounding. They had relatively low output levels, and they were all made using the same old “foil” technology that had been used, and cursed at, since day one.
A Series of Improvements
So we set out to improve all of these things, one by one. First, we had to understand tone options. All mics have timbre, no matter how “accurate” or “neutral” they are said to be. Anyone in recording knows this, but there haven’t been many attempts we know of to organize it into a library or palette of colors for mic designers to work with. Our work in medical acoustics was a huge help in finding the tone options. Curves and measurements only tell part of the story. It is the same in medical ultrasound: We can specify a certain bandwidth and slope very precisely, but that doesn’t mean that the image of, say, a diseased artery, will look any clearer or be more meaningful.
On the contrary, it seemed that the more we relied on specs and processing, and not our eyes, the worse the images got. It didn’t take long to confirm that analogy to music recording. In our early days, we made dozens of differently voiced ribbon microphones, some traditional sounding, some intentionally very bright, and others with highly asymmetrical patterns. The result is the ability to expand the gamut of ribbon microphone characteristics for specific jobs or generalized use, from vocals, to acoustic and electric instruments and percussion–many that were once the exclusive province of condenser microphones.
Output was another consideration. The use of some good engineering design techniques and the philosophy that “every fraction of a decibel adds” propelled us beyond the output level of the typical stage dynamic right away. A hot output meant that not only preamps, but also things like field recorders and remote Blumlein setups were now much more practical. The other side of output is noise, and we beat that down using the most aggressive shielding and design techniques available. Did you know that the noise floor of a properly designed modern ribbon microphone is near the so-called “theoretical limit” defined by the terminal impedance? It is, and that’s a good thing.
Three Down, One to Go
That left the last remaining bugaboo–the famous, infamous, mysterious, persnickety, fragile, delicate, impossibly thin, ribbon element. This one part, so essential to the operation of all ribbon microphones, hadn’t changed at all since the very first BBC, RCA and Beyer microphones, and it has always been the weakest link. The perfect ribbon, according to the important early innovators such as Harry F. Olson of RCA, would have zero mass, perfect conductivity and be strong enough to use as a trampoline, something that foils certainly do not do!
So ribbon mics were left to the few who dared to live with a certain danger, for the sake of sound. And lately– by which I mean in the past 10 years–it has been possible to double the toughness of the ribbon by making it thicker, reducing the paranoia somewhat. But that wasn’t sufficient to make a ribbon mic strong enough for kick drums, to use on stage, or, perhaps most importantly, to stop the obsessive worrying that has gone on too long.
Nanomaterials to the Rescue!
Hugh Tripp and I had been in the same predicament before: How can we get something small and light to act like something big and strong?
Medical devices that go into the heart can’t break, or else! That experience was key: Our work in nanofilms, carbon nanotubes, thin film deposition, superelastic and shape-memory materials allowed us to envision ribbon performance closer to the ideal set forth by Harry Olson. We were already making and selling ribbon microphones, and things were going well. The new material was going to be expensive and take a lot of time. A large check out of the checkbook, the hiring of an additional materials scientist (we are grateful to you, Kevin!) and months of experiments yielded an entirely new class of materials, some that act much like an ideal ribbon should, and after some process development, kept the pure acoustic qualities admired in the old ribbons.
What Do You Call It?
Secret prototypes were circulating, and rumors, too. What was this new nanomaterial? Would it really stand up? As we did alpha and beta rounds and focused on “severe” applications such as miking kick drums with our colleagues at Mercenary, we began calling it, “Acoustic Nanofilm,” which didn’t mean a darn thing to anybody but us.
I remember having the new material still under cover at a trade show, imagining how I would explain it: “Roswellite” popped into my head–a bit wacky, but telling. Hard to forget. I immediately picked up the phone and called my one expert on all things named, my wife, Pat, who incidentally works in aerospace and satellite components. “If I told you something was made of Roswellite, what would you imagine it is?” I asked her. “Something that is super-light, tough and metallic,” she instantly responded.
The Roswellite Advantage
I’ve been asked to not write an advertisement. This is an account of new material developments that enable better ribbon microphones such as el Diablo and Naked Eye Roswellite. We also want to use Roswellite (ahem, “acoustic nanofilm”) in new medical devices, also. Like anything new and unfamiliar, people are naturally curious, but skeptical. We’re enthused about the sound, the performance and the extreme durability of Roswellite-equipped ribbon mics. We will know we have succeeded when the ribbon microphone takes its proper place among the many, and becomes not just a “nice-to-have,” but the best pick for the best sound, in virtually any circumstance.
Bob Crowley is president of Soundwave Research Laboratories, makers of Crowley and Tripp Microphones. He plays the Japanese end-blown flute, also known as the shakuhachi, and is an inventor with more than 100 U.S. and foreign patents. Crowley and Tripp manufacture all of their microphones in their Ashland, MA lab.