My master bus typically runs through the Waves SSL Comp and then into the Waves L2 Ultramaximizer. I always have the output on the L2 set to -1.0. I usually tap it a bit with the SSL and for final mix have the L2 with typically less than 3db average reduction, often less. Both the compression and limiting have always sounded natural with no distortion or artifacts.
I’ve recently been working on a live project where I’m mixing individual tracks for bass, drums and keyboards. What I’ve discovered is that a clean bass guitar and low frequencies synths in the bass range start becoming fuzz pedal distorted as I get close to the -1 db output mark on the L2. Because I’ve never noticed artifacts before, I went through a number of tests to try to isolate it. Here’s the highlights.
- I first muted everything but the bass to simplify testing
- Used headphones to verify it wasn’t my speakers (it actually sounds like a bit like a blown speaker)
- Same distortion through the headphones
- Verify I’m not overloading the inputs of my audio interface (coming in at -18 into a Yamaha TF5)
- Verify no other processing on the TF mixer
- Verify no other processing in signal path in Cubase
- Removed SSL and L2 from the master bus (no other inserts)
- Tried the Cubase limiter with the same results
- Removed Cubase limiter from master bus
After removing all the master bus inserts, I then brought up the volume to approach 0db on the stereo out. I did this several ways, increasing channel input gain, increasing channel volume fader, increasing stereo gain, increasing stereo fader. In all cases, before I got to 0db (usually around -1 to - 2), I would begin to hear the distortion.
So, it’s not the compressors or limiters that had been on the master bus inserts. There’s something in the output of the audio engine itself that’s resulting in the distortion. I tested this across a number of projects.
I would naturally expect clipping distortion if I hit 0db, but I’m not. And when I’m using the L2, which is certainly a quality product, the output is set to -1 for exactly this reason - to prevent clipping. Same results with L3 and Cubase limiters.
In my normal song mixes I’ve tested absolutely slamming the SSL (needle pegged at -20) and the L2 (as much as -20 average reduction) just for testing. With bass guitar in, I get the distortion. If I mute the bass, the drums naturally sound compressed, but the kick is crisp and clean (EZ Drummer, Modern Vintage kit). There’s something weird going on with bass guitar & synth tracks that are clipping or otherwise distorting before I’m hitting 0db.
At this point I’m running out of ideas on what to test next. If anyone has suggestions on how I can further track and isolate this problem I’d be most grateful.