Week 164: The Case for Bass Multiband Compression Normally you don’t want to compress the daylights out of everything, but I feel bass is an exception, particularly if you’re miking it. Mics, speakers, and rooms tend to have really uneven responses in the bass range—and all those anomalies add up. Compression can help even out the response to give a smoother, rounder sound.
A lot of engineers will use an LA-2A type compressor (e.g., the ProChannel U-type compressor or CA-2A), but I prefer using the Sonitus Multiband compression because it serves simultaneously as a compressor, EQ, and limiter. Typically, I’ll apply a lot of compression to the lowest band (crossover below 200 Hz or so), very light compression to the low-mid bands (as well as reduce their levels in the overall mix), and medium compression to the high-mid band (from about 1.2kHz to 6kHz). I usually turn down everything above 6 kHz or so (there’s not a lot happening up there with bass), but sometimes will set a ratio below 1.0 so that the highest band turns into an expander. This can help bring down hiss if the very highest band is in play.
If you enable the Limiter under the Common tab, the Multiband compressor will also trap any transients, and you can “push” the individual bands to get a bit more compression without having to adjust the band’s compression parameter itself.
Another advantage of using the Multiband compressor is that you can quickly tweak the high and low ends to fit well with the rest of the tracks. I call the following preset "Tuned Thunder." There's heavy compression on the lowest two bands, but in the bottom window that shows gain for each band, note how the two lower bands have their levels brought up. Also, there's lots of attenuation on the higher frequencies. The result is a big, fat, round sound that sort of tunnels through a mix.
The next screen shot shows settings for extreme articulation when you need the bass to really "pop," and cut through a track. One of the secrets of a great bass sound is a significant treble boost so that the bass can hold its own against other track, because the ear/brain combination will fill in the lower frequencies. The only band that's compressed is Band 3, while the gain on Band 4 emphasizes pick noise and harmonics. To compensate for the extra highs, the low band below 100 Hz gets a little bit of gain. Finally, there's an overall boost of 3.4 dB to kick the signal into limiting from time to time.
When adjusting the Sonitus Multiband, the Solo and Bypass buttons on individual stages are fantastic for zeroing in on the exact effect you want for each band.
But wait!
There's more!! a little bit of distortion applied to bass can give a “growl” that helps the bass cut through a mix. The Bass Growl and Bass Rock CA-X bass amps offer built-in growl, but if you’re doing
à la carte signal processing, multiband compression will give a more even sound that benefits from a light amount of post-compression distortion.
Finally, in case you wonder if you should instead use the L-Phase Multiband, you certainly can but it’s not necessary to take the CPU hit when processing bass. The Sonitus does just fine, and the ability to limit peaks is just one more useful feature.