Beyerdynamic MCD-100
Beyerdynamic's bid to bring the microphone into the digital age - a condenser with a 24-bit converter inside the body.
Overview
The MCD-100 is a cardioid condenser microphone built to get rid of the analog cable run. Instead of sending a fragile low-level signal down dozens of feet of wire to a preamp, it puts a 24-bit A/D converter inside the microphone body and hands the console a digital bitstream. Beyerdynamic's stated goal, as laid out in the MCD Series introduction, was to bring the analog signal into the digital domain at the earliest possible stage of the signal chain - at the capsule itself.
The signal path starts with a large-diaphragm, gold-foil condenser element. The audio then passes through an impedance-conversion stage that also offers analog pre-attenuation, a −10 or −20 dB pad. That lets the mic handle sound pressure levels greater than 130 dB without overloading. The signal is then sampled at 48 kHz with 24-bit resolution inside the body. A minor modification can convert the sample rate to 44.1 kHz, and Beyerdynamic maintained the mic could be adapted in the future to a 96 kHz rate. The company advertised a total self-noise figure of −120 dB, built-in word-clock synchronization, and a linear frequency response.
Much of the MCD-100's cleverness is in its TrueMatch look-ahead DSP. It watches the incoming signal and keeps the A/D converter from overloading, so you can set levels and record without fear of digital clipping. The converter output can optionally be routed to that onboard DSP for gain control or filtering. The filter algorithm lives on an EPROM inside the microphone, and Beyerdynamic was capable of programming custom filter curves to a customer's specification. Output is AES/EBU digital over a two-conductor-plus-shield cable terminated with male and female XLRs. Beyerdynamic recommended AES3-certified cable at 110 ohms impedance, though it noted a high-quality low-impedance balanced mic cable would work for runs under roughly 20 meters. Unlike a conventional mic, the MCD-100 can be plugged straight into a tape machine or any digital processing device.
The catch is power. The mic needs an outboard supply, the MPD 100 or MPD 200 Digital Phantom Power unit, and it does not run off ordinary phantom. Period coverage noted one quirk: to run the mic in slave mode you have to open the power supply and move a jumper. Skip that step, or don't run the MCD-100 through a sample-rate converter, and you get digital clicks in your recording. The other friction is cabling and infrastructure. AES runs to the mic panel weren't something every studio had thought to install, so owners often found themselves running cable through the door.
EQ (August 1998, p.96) reported that the absolute dead quiet of the digital microphone made a conventional mic with a large heat sink sound like a raging wildfire by comparison. The reviewer described hearing the instrument rather than the microphone - no tube filaments rattling, no sputtering FETs, no phantom-power noise from marginal connections. The same review called the smooth frequency response and warm low end pleasing, the highs crystal clear, and single-mic captures three-dimensional enough that you could tell how far the instrument sat from the capsule. That reviewer used it on pianos, acoustic guitars, vocals, percussion, drum overhead, harp and more, and concluded the MCD-100 was the closest you could get to recording everything directly into a digital recorder without using a microphone at all.
Pricing was ambitious. Beyerdynamic's own 1999 advertising ran a $25 prepaid gas card promotion for buyers of an MCD-100 or MCD-101, a small sweetener on a very large purchase. The review's closing argument was that once you factor in what you'd otherwise spend on premium mic preamps, the MCD-100 effectively pays for itself.
The MCD-100 is a system, not just a microphone. You need the matching power supply, AES cabling, and a digital input, and the jumper and sample-rate housekeeping means you have to read the manual. Values and current availability are not well documented, so buyers should treat any listing as a project rather than a plug-and-play purchase.
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