Review: Buzz Audio DBC-M compressor

The Buzz Audio DBC-M diode bridge mastering compressor is 1 rack unit high in a 250mm/10” deep case. Build quality is confidence-inspiringly sturdy, and the front panel features two identical compression channels. 

The controls are, from left: Gain – for post-compression gain makeup in 0.5dB steps; next is Compress, which controls the amount of gain reduction: both this and Gain are high quality Elma rotary switches – all controls are switched on the unit, aiding audio quality and making recalls easier. 

Next are two smaller six-position rotaries, Attack and Release, both offering a variety of speeds – Attack includes a Fast (less than 0.5ms) setting handy for taming transients, and Release features an Auto position, where faster elements are allowed through but slower operation applies on more constant signals.

To the right of the control knobs are three toggle switches: firstly, Hard/Soft. Diode bridge compressors typically have no ratio control; instead, as here, ratio changes with gain reduction so at small amounts the ratio in the DBC-M starts at about 2:1, rising to around 10:1. 

In the Hard position the self-adjusting ratio works normally, whereas in Soft mode some dynamics are retained when only light compression is required. The next switch is Flat/ Bass: when Bass is engaged, a high-pass filter is added to the side chain to reduce the sensitivity of the compressor at low frequencies – this can be useful when mastering bass-heavy music to retain low-end dynamics and avoid LF elements pumping the whole track. The final toggle of the three is Bypass/Engage, a ‘proper’ hard-relay bypass. 

 To round up front panel components, there’s an LED gain reduction meter above the switches mentioned above, then to the right a switch to link the two channels for stereo operation. Finally, on the extreme right I was pleased to see a power switch: lack of these at the front of a piece of gear – or at all – is something of a pet hate of mine, so having one is always a plus point for me. 

In Use When the review unit arrived it was plumbed into the mastering console here at Lowland Masters, and listening tests took place over a period of about a week. As I already own a diode bridge compressor from another manufacturer, I started by taking existing mastering projects, substituting the DBC-M and comparing results. 

While I’m not about to rush out and sell my unit (yet!), the Buzz did extremely well: among the first things I noticed was how good the on-board steel transformers sounded – although they had a colouration of their own, it was clear and tight, a good fit for much music in the pop, rock and dance/urban genres although surprisingly good on acoustic material as well. 

The sidechain bass rolloff really came into its own on electronic dance music: I don’t have this on my own diode bridge unit, so it was refreshing to be able to have more control over how the lows were presented. 

The warm and musical compression action of the DBC-M was largely as I expected in a compressor with this kind of gain control element, but I appreciated the variation I could achieve using the Bass and Hard/ Soft switches. 

After a while with the unit, unlike some compressors I found that for any given program material there would usually be a range of settings that worked, something to be welcomed: while too much choice in mastering isn’t always a good thing, in this case I felt it put control firmly in my hands to create the dynamics that best fitted the project. 

My only comment with the Buzz concerned the gain reduction meter: it measures up to 20dB, which I’d be unlikely to use in mastering; also, the smallest amount indicated is 1dB, but I regularly use a fraction of that. Fortunately, ‘ears before eyes’ did the trick during the review period, the onset of compression being clearly audible. 

If I was to buy a DBC-M, I might ask for a meter scale modification, as Tim Farrant is known for being receptive to user requests. Conclusion The Buzz DBC-M is a fine compressor, well suited to the mastering environment and more. While it might not be your only compression choice, it’s surprisingly versatile and can get great results in a range of musical situations. 

  • Maximum input level; +27dBu
  • Maximum output level; +27dBu
  • Noise -80dBu (measured A Weighted with 10dB gain applied) 
  • Gain: variable -2.0 to +10dB in 0.5 dB steps RRP: £1,910 ($2,517) + VAT