This article originally appeared in the January 2021 issue of Pro Sound News. Innovations is a monthly column in which different pro audio manufacturers are invited to discuss the thought process behind creating their products of note.
Recently we extended our Synergy family of microphones to include the LS-308, which is a microphone expressly designed for recording situations where isolation is essential but nearly impossible to achieve. It is the first large-diaphragm condenser in history to offer a full 270 degrees of off-axis rejection, reducing sounds from nearby sources by up to 25 dB. While the design and development of the LS-308 were fraught with challenges, we are proud to have created a microphone that is a true “problem solver” in the studio, and the first of its kind.
The original idea for this microphone came from a conversation I had with an engineer and friend named Fab Dupont. He was experimenting with a “lip microphone,” an old radio microphone that you put right on your mouth. It rejects everything except what it’s pointed directly at, but the bandwidth is almost non-existent. Fab asked me if we could do a microphone with similar rejection, but with a large-diaphragm condenser kind of sound. I didn’t think it was possible, but I ran the idea by our chief engineer and physicist, Charles Chen, Ph.D. Charles confirmed my assumption, but I couldn’t get the idea out of my head.
After a good bit of back and forth, I had a “what if” moment: What if we used the principles of a shotgun microphone, but made it purpose-built to close-mic loud sound sources like kick drums, toms and guitar amps? Charles began exploring designs based on this idea, but as great engineers often do, he came back with something completely different: a concept involving a second-order cardioid pattern that resembles the flame from a lighter, but is actually an ultra-narrow cardioid pattern.
At this point, you may be asking yourself, “Why even try to achieve such a severe degree of isolation in a studio microphone?” The answer is that we wanted musicians to be able to record with each other in the same room live, while isolating individual sound sources for recording. There is a life and energy that comes with recording this way, but it is extremely difficult to do well—and microphone bleed is a nightmare. Our belief was that if we could achieve this level of isolation with a mic that could also handle high SPL, we would have something truly unique that solved a really big problem.
After proving that the polar pattern could be achieved, we needed to take a much closer look at the circuit design. This is where things got complicated. Our original prototypes were really rough. We tried numerous design options, including small-diaphragm capsules because we thought they might be easier to deal with. (They weren’t.) At the end of the day, we just couldn’t get the timbre or response we wanted because of the physics involved in the design.
The pivotal moment for us turned out to be mastering a double bias circuit, which places two identical microphones into one. It sounds easy enough, but each circuit has to be matched perfectly. If a single resistor is slightly out of spec on one of the circuit boards, it will be unbalanced and introduce phasing issues. You also have to hand-tune two large-diaphragm condenser capsules that are moving around in the same microphone exactly, which is easier said than done.
There were other inherent limitations we had to work with as well, all of which were dictated by physics. For instance, we could only reject 25 dB in sounds below 7–8 kHz. This is why the microphone is sonically more akin to a ribbon than a condenser. This timbre works wonders on intended sound sources, but the mic also takes EQ exceptionally well if you need more top end on a sound.
An unexpected challenge turned out to be how directional this mic is. Most microphones have a wide sweet spot that allows them to be placed similarly with positive results—but not the 308. It hears like a laser, which can be very confusing or even frustrating in terms of mic placement if it’s your first time using the mic. The difference in timbre you achieve just by moving the microphone in half-inch increments straight across a woofer, for example, is significant. We tell users that you have to forget everything you know about mic placement because it doesn’t apply here. When you embrace that, you begin to realize that you have the ability to capture some truly unique sounds that you weren’t able to in the past.
The LS-308 is the most unique microphone we’ve ever made. It’s not going to work on everything, but it’s a problem-solver that does what no other microphone can. Want to track electric guitars in front of a live drum kit or the beater of a kick drum with almost no bleed? No problem. Want the perfect vocal mic? This probably isn’t it. Lauten Audio is a tiny, family-owned company that crafts unique microphones to solve problems. We hope you enjoy the 308 as much as we do.
Brian Loudenslager is the founder of Lauten Audio.
Lauten Audio • www.lautenaudio.com