PAUL WHITE tries out a compressor that looks like a cross between a portable CD player and a Stealth soap dish, but discoversthe sound is much bigger than the package.
Dbx have been making compressors for a long time, and they can be seen in professional and project studios everywhere, but the MC6 Mini Comp under review here is the company's attempt to take a larger share of the desktop studio market, where not everyone wants to splash out on rackmount processors. Instead, they're offering traditional dbx technology in a plastic desktop package with faders instead of knobs. Optimised to work with line-level signals of -10dBv, the MC6 can handle levels up to +16dBu, so it can be used in the insert points of a professional console or multitracker with equal ease, but it also has a -20dBv input instrument setting for live performance use. The bypass footswitch jack on the rear panel is also provided for the benefit of the live musician. Power comes from a supplied mains adaptor, and all connections are on the rear panel. Also included is a metal clip that can be used to secure the unit to the strap of a guitar amp, and a set of adhesive rubber feet for tabletop use.
Inside this deceptively small package is a full-featured stereo compressor based on the circuitry used in the dbx 160, and though the inputs and outputs are on jacks only, these are TRS types that can accept balanced or unbalanced connections. It's possible to use the compressor in mono mode, but in this case only one channel is usable as the side-chain circuitry is common to both channels. Perhaps surprisingly on a unit of this price, the side-chain uses a separate RMS detector for each channel, the outputs of which are fed into a summing circuit. This is far better than summing the audio and then using a single detector, where phase cancellations between the left and right channels can cause the detected level to be lower than the actual level of the individual channel signals.
The OverEasy approach to soft-knee compression is something dbx are famous for, and the MC6 can be switched between OverEasy and conventional hard ratio modes. Five sliders provide full control over Threshold, Ratio, Attack, Release and Output Gain, but for those who'd rather let the compressor do the thinking, there are two auto modes, for Vocal and Instrument use respectively, that override the Attack and Release sliders and optimise these parameters automatically, depending on the input signal characteristics.
Many budget compressors suffer from poor metering, but the MC6 doesn't fall into this trap, with two 8-section LED meters to show gain reduction and I/O levels. The I/O meter can be switched to monitor the compressor input or output, depending on the front-panel I/O button setting, and another nice touch is that all the buttons have status LEDs. Curiously, the top level shown on the I/O meter is -3dB, which seems a little low when you consider that the unit can handle levels of up to +16dBu without distorting.
Compressor activity is monitored by three LEDs that show green for below-threshold signals, Yellow for levels within the OverEasy or soft-knee range, and red for levels above the threshold. In hard-knee mode (OverEasy off), the yellow LED remains unlit, as there's a prompt transition from uncompressed to compressed when the signal hits the threshold.