Digital Microphones: An evening with

beyerdynamic and Roger Nichols

Twenty-two members of the Boston Section AES attended a freewheel- ing and spirited presentation by Bob Lowig of beyerdynamic and "digital guru" Roger Nichols on the beyerdynamic MCD 100 series of "digital microphones."The microphones' premise is that if we're going to record, process, and edit in the digital domain, we should get our sounds into that domain as far upstream as possible. To beyerdynamic, this means the best possible capsule coupled to a dedicated, purpose-built a-to-d converter within the microphone's housing only a few centimeters from the capsule.

To set the scene, Bob Lowig began with some beyerdynamic history: Georg Neumann and Eugen Beyer had been close friends in college but pursued condenser and moving-coil microphones, respectively. A pact between the two men kept beyerdynamic out of the condenser-micro- phone business until Georg Neumann's death in 1973.

When, some years ago, beyerdynamic made the technical marketing decision to pursue a digital microphone, the first efforts were directed at novel transducer technologies, e.g., using a laser beam to track the diaphragm. The decision came down to this:"Let's use the best possible condenser capsule, one which is superior in the way it tracks sound pres- sure."The goal was noiseless transparency.

Next came the requirement to create a conversion which is matched to the microphone's element. The result was a 24-bit converter from StageTech, a firm with significant expertise in a-to-d technology, in collaboration with beyerdynamic. The A/D converter is not altering the sample to compensate for what may be anomalies in the transducer, but is only converting to PCM as accurately as possible. In fact, the intrinsic digital signal processing can be programmed by the manufacturer for whatever equalization the user may want. The conversion also uses a

(Continues p.2)