Recording - December 2009 - 26

A lot of musical styles rely on the low frequencies to add excitement to the sound or to carry the all-important beat. In the case of lots of dance music styles, it’s the whole point of the music. When this is the case, you want it to be loud and you don’t want to sacrifice sound quality for loudness. Lee “Scratch” Perry demands “Maximum bass at all frequencies!” How can you make him happy? 1. Mix bass and kick to the center This is a very simple thing to do, but it seems to escape a lot of people. If you pan something to the side, it comes out of one speaker, if you pan it to the center, it comes out of two. If you want a sound to be as loud as possible in the mix, pan it to the center. Don’t try any stereo tricks, like panning a mic on the bass cabinet to one place and panning a DI feed to another one, unless you’re willing to sacrifice loudness. These sorts of things can add space and definition to the low end, but most listeners won’t have sufficient playback quality to notice it anyway. They are out of place unless the bass is the centerpiece of the mix, and unless you’re recording Jaco Pastorius it probably isn’t. Hz tone at 50 dB. That’s a huge increase in perceived loudness, just from increasing the pitch two octaves! The amount of higher-frequency harmonics in the signal can dramatically increase the perceived loudness; in fact if you listen to a lot of commercial recordings you’ll find that there really isn’t any deep bass at all on the bass guitar, just harmonics. In general, if you get a DI feed, it will have a lot more of the fundamental and less high-frequency stuff than a miked cabinet. Adding a little distortion to a bass guitar will make a huge difference without changing the tone outrageously. While in the past I have railed against “fake tube” mic preamps which run vacuum tubes with very low plate voltages as silly effects devices, the one place where they really are useful is to dirty up direct bass tracks and add a little bit of higher-frequency definition to the tone. In the case of the open kick drum in modern rock music, most of the higher-frequency stuff actually comes from the nonlinearity of the microphone. If you put a B&K lab mic that is very accurate and does not overload into a kick drum, you’ll get a flat cardboardy sound that has a lot of low frequencies but nothing that a 6" speaker Boom, Muck Less BY SCOTT DORSEY More How to get loud bass—GOOD loud bass—on your recordings can reproduce. Because of this, the choice of the microphone and placement of the microphone can dramatically change the open kick sound sometimes moving the mic a few inches can make for a very different sound. Again, an effect device that adds a little bit of artificial distortion to the kick can make it a whole lot louder but it will not change the tone a lot. A “clicky” kick drum can be very audible in a dense mix but is obviously not appropriate for all kinds of music. Remember also that a lot of listeners might be listening on small speakers that really have no low end to them, and the high-frequency harmonics of the bass guitar come through on a small speaker even when nothing below 250 Hz does. Use an Auratone speaker or something similar and hear it for yourself. 4. Don’t rely on dynamic control You need a smooth and even track to start out with, before you can build the mix, so compression of bass and kick tracks can be a good thing. They bring average levels up and smooth them out. Limiting can also help; you can think of a limiter as a compressor that only acts on brief peaks above a certain sharp “knee” level. Limiting, though, is really something that does more to fix up problems with the bass sound than anything else. Think of dynamic control of the individual bass tracks as a thing you sometimes need to do in order to get the tracks smooth and even, Also, if you intend to release on vinyl this becomes even more critical because of the way the disc is recorded; any bass information that is not common to both channels makes needle tracking very difficult. If you’re mixing for LP, you need to make sure both channels are matched to within a fraction of a dB in level and you need a phase scope to make sure nothing you do is adding out-of-phase bass. Both of these things were very difficult in the analogue world, but today in the DAW world they’re both pretty easy. If you aren’t releasing on vinyl, being quite this picky about centering low frequencies isn’t so important, but it’s still a good habit to get into. 2. Think about the bass sound as two parts Instruments have a fundamental frequency to each note, and then a bunch of higher-frequency harmonics. In the case of bass instruments, most people, even at live shows, never hear the fundamental because they are listening through a system that cannot reproduce it. So think about the real bass (below 100 Hz) and the higher-frequency elements as being different sounds that come out of the same instrument at the same time—but which might need to be treated differently. 3. Add harmonics Remember the Fletcher-Munson curve? A 40 Hz tone at 80 dB sounds no louder than a 160RECORDING DECEMBER 2009

Recording - December 2009

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