We put an original ADR Compex F760x compressor/limiter up against its plug-in version to see if the levee breaks.
Review: Ted Howard
When I open a plug-in and see graphics perfectly matching the look of a piece of vintage hardware my scepticism meter hits the red. Sure it looks the same, but how does it sound? So given the opportunity to run a comparison between the Compex F760x compressor/limiter and the new Boz Digital Labs +10dB plug-in, I jumped at the chance.
The F760 has long been a favourite of mine during tracking — especially on drum room mics. It’s got power and wallop but with a clarity in the top end, even in serious gain reduction. Does the plug-in version follow suit?
The session I chose as a testing ground was a recent Ian Moss tracking gig at Rancom St. We have an AKG D109 omni dynamic hanging from the ceiling, affectionately known as the ‘Roof’ mic. I ran this through a Telefunken V76m then into an API 550b EQ, followed by the Compex. It’s a big, fat, When The Levee Breaks kinda sound. I also recorded an un-compressed split of the Roof mic post the API EQ for the test.
I opened the un-compressed Roof track and duplicated it in Pro Tools. On one track I patched the Compex F760x via a hardware insert, with settings to perfectly match the recorded track. And on the other I opened up the +10dB plug-in. With a little bit of fiddling at the input of the +10dB I had two tracks with the same amount of compression and identical output levels.
The main difference was the limiter function. On the Compex I like to run the compressor (with a fast .25ms attack) and limiter together on the Roof mic — I’m happy to let the close mics handle the drums’ transients and the Roof capture the smeared reflections. The super fast attack of the limiter clips off the peaks and helps minimise that ugly flamming effect that distant room mics can get.
The plug-in needed up to 12dB more input level to trigger the limiter and by then the compressor stage was in super slam mode, quite different from the Compex. The +10dB limiter sounds good (very similar envelope to the Compex) but for me is more useful as a stand-alone limiter rather than a part of an overall compressor/limiter chain.
The other difference was quite subtle; the +10dB had a very slight lack of HF clarity compared to the Compex when gain reduction reached about 8dB and over.
The stand out for me was that the signature power and meat of the original has been replicated. It really has that sound. After carefully matching all compressor parameters, I panned the two test tracks left and right (one with the Compex and the other with the +10dB). The two tracks sounded pretty much identical when soloed and when both were open and panned hard it was like listening to a mono source.
I tried replacing the +10dB with various other compressor plug-ins and all of them gave me a left/right pumping sensation when panned opposite the Compex’d track, even with the attacks and release numbers matching.
Boz Millar has matched the tone and envelope of the F760 compressor really well. In a way he’s improved it; who doesn’t love a wet/dry control for parallel compression? The EQ section, and the way it can be side-chained with the compressor stage is copied from the classic ADR Vocal Stressor; it’s functionally clever and sounds crisp and clean. I also ran a separate lot of tests on the expander stage and it also passed with flying colours.
Overall the +10dB is a really useful tool to add to the arsenal. I can’t wait to try it out next as a vocal channel strip!