by Steve Cunningham
The current crop of high-end voice processors are mostly analog units that combine a microphone preamp, a compressor, some EQ, and perhaps a de-esser. But when Danish audio manufacturer TC Electronic decided to design a voice processor, they took a completely different approach. After all, TC is known for their hardware Digital Signal Processing products, and for software plug-ins that mimic their hardware products. All of these perform their magic using ones and zeros, so why not build a voice processor that also uses ones and zeros? The result is the Gold Channel Digitally Enhanced Mic Preamp.
The Gold Channel is a single space rack unit that combines two independent, high-end solid-state analog mic preamplifiers with a wide variety of digital processing blocks, including expanders, compressors, equalizers, gates, and more. The DSP blocks, many of which are from TC’s other award-winning products, are fully programmable and take full advantage of TC Electronic’s expertise in coding for digital audio applications.
The mic preamps come complete with pads, phantom power, and lots of other goodies. Each preamp directly feeds a 24-bit A/D converter, and all audio processing is digital from there on. The A/D converters in turn feed a chain of up to four processing blocks each. You can insert DSP functions into the chain in whatever order you wish, and the functions can be different per channel. There’s lots of flexibility here.
The unit’s analog input and output converters are all 24-bit as are its internal data paths, and it has I/O connections for just about any digital format you could want, including AES/EBU, S/PDIF (on either RCA or optical TOS link connectors), and ADAT Light Pipe.
The Gold Channel’s internal clock nominally runs at 44.1 and 48 kHz, but it will handle digital audio with sampling rates up to 96 kHz via the digital inputs with a couple of restrictions. When working with 88.2 kHz or 96 kHz digital audio, you can have either one processing block on each channel, or three processing blocks on channel one only, and digital word clock must come from the external source.
THE FRONT PANEL
The front panel is attractive but busy. Each of the two channels is served by a gain knob and a collection of buttons that control phantom power, phase, mute, pad, and other traditional preamp parameters. There are also four buttons per channel for switching in the various kinds of processing, and a nice horizontal fourteen-segment LED meter with clip indicator that can monitor either the input or the output.
Almost every button has one or more green LEDs associated with it, so it’s easy to tell at a glance what’s turned on. However, the buttons themselves and the legends are small, and those of us with less-than-perfect vision have to get close to see all the options.
But there are many options offered here, including pads at values of 20, 40, and 60 dB, low cut filters at 60, 80, and 120 Hz, and a digital “Softlimiter” that appears between the input selector and the low cut filter. This really is a “soft” limiter that appears to kick in at about -4 on the input meter, and in use its effect is transparent.
The right side of the Gold Channel has the black-on-green backlit LCD display, FUNCTION select buttons, and the large PARAMETER and VALUE knobs. These comprise the main programming interface for the Gold Channel. The four dedicated FUNCTION buttons to the right of the display let you work with and edit programs, set the master input and output levels, and set user preferences. Each of these pages has an onscreen menu bar with options you can select using the left and right MENU buttons.