If you're looking for an 'external analogue compressor with a reputation for attitude', you could do worse than the Dbx 566 dual-channel valve compressor.
Can you give me some compressor tips to make heavy guitars sound more full and even? For example, I want single-note melodies to sound as full as chords or power chords. Also I want to give palm-muted power chords more pump or bite. I'm using the built-in dynamic processors on a Yamaha 03D mixer.
Graham Day
Editor In Chief Paul White replies: Part of your problem is that the Yamaha 03D compressors are wonderfully transparent, so getting a pumpy sound isn't that easy! I'd recommend you try a fairly high ratio in hard-knee mode (around 8:1) and set the threshold so that the gain-reduction meter is showing just a dB or two of reduction on the single notes. Chords should then be brought down to a similar level. However, don't expect a huge improvement in evenness as overdriven guitar tends to to reach similar peak levels for chord and single notes anyway — with the waveform peaks all clipped flat, the average level becomes almost the same as the peak level, as with heavy limiting. Any remaining disparity can be smoothed out using your mixer automation.
You may be able to coax a bit of pumping from the 03D's compressors by using a longer attack than normal (100 to 250ms) and a short release time (50 to 100ms) but an external analogue compressor with a reputation for attitude may be the best solution. Check out the Dbx range, as their units are often favoured for beefing up rock sounds.
Publisher Dave Lockwood adds: If what you really want is for your single-note lines to achieve a similar subjective impression of power as chordal parts, one tried and tested method is to hit the front end of your amp or Pod-U-Like processor a bit harder using a compressor pedal in front of it. Use the minimum squash necessary to achieve a noticeable increase in sustain and then set the pedal's output level to something just above the level of the signal when the pedal is bypassed. The downside is that you will have less touch-sensitivity when playing, but there will certainly be more 'pump and bite' in palm-muted chords and low-string riffs, and a quite different subjective effect to applying compression after the distortion stage. Single-note high-string parts can often sound a bit thin when using a lot of distortion, due to the added harmonics, but when there is little or no fundamental in the signal, low-end EQ can't help much. It is room ambience and early reflections that tend to give any sound its sense of scale, so using a fairly dark, short ambience program, or adding a room mic if you are using a real speaker, can bring about a dramatic change in the apparent fullness of your single-note lines. Where EQ can help sometimes is in selectively notching out the more aggressive upper mid-range, 'presence' frequencies — start somewhere around 2kHz, cut no more than 3 to 4.5dB, with a bandwidth of only about an octave or so. This will significantly reduce the perceived level, allowing you to then turn up the signal a little to restore the same subjective loudness, thereby allowing a little more of the 'body' of the note to come through.