I’m an aspiring electronic musician, and am hoping to create some stuff with real shaking low-end impact, but the interaction between kick and bass still puzzles me. In particular, a lot of the music I listen to has this kind of low boomy rumble that occurs every time the kick hits, which creates the impression that the headphones or speakers are shaking almost like they are made of jelly, even when the volume is turned down — you can hear this in tracks such as Clark’s ‘Outside Plume’ at 1:22 or Animal Collective’s ‘My Girls’ after 1:40, for example. Is that some sort of low sine wave with volume modulation or something? Also, I’ve heard about the idea of carving a space for the bass out of the kick, and adding some high to the bass to make sure it is heard, but I’m not sure whether that applies here. Which would get the low end here: the kick or the bass rumble? I am almost imagining that the kick may be getting a bit of the higher low end at about 160-240 Hz, whereas that low boom sound would get the real low 50-60 Hz area, but I really have no idea. Can someone help me figure out how I might replicate this sort of thing, since I’ve noticed that other amateur attempts tend to just sound like a muddy thump with a low, ‘blank’ sine wave on top.SOS Forum post
SOS contributor Mike Senior replies: I had a close listen to both the examples you mentioned, and the difficulty with trying to pick things apart after the fact is that the kick and bass always appear to be playing at the same time, so it’s a bit tricky to reverse-engineer the sound. Nevertheless, my best guess is that your general conclusion is correct, and that you need to concentrate your bass part primarily into the sub-70Hz region, so it stands to reason that focusing the kick drum further up the spectrum would be sensible from an arrangement/mixing perspective. Keeping the kick’s decay quite short (at least in the bottom couple of octaves) will also usually help avoid the low end of the mix getting muddy where there’s heavy-duty low end coming from the bass. However, there’s quite a bit more about these two commercial productions that might also be responsible for what you’re hearing, so let’s get down to some specifics.
Turning to the Clark track first, for a start the bass line itself seems to be a bit unusual on two counts. The first is that it appears to have quite a well-defined attack phase, so you get a real low-frequency pulse whenever the kick drum hits. As a result of this, I’m guessing that the kick drum would feel quite a lot less heavy if you heard it on its own, simply because you’re perceiving that bass pulse as an element of the kick-drum sound. That said, it seems to me that there are also some less prominent ‘static’ frequency peaks at around 50Hz and 100Hz which may well be on account of the kick drum itself. This makes a good deal of sense, given that in general I’d be loth to entirely filter out the kick’s sub-70Hz region in any club style, however much I might otherwise tailor its low-end frequency contour, simply because that helps keep the punchiness of the low end a bit more consistent if the bass line drops out or changes pitch.
The second unusual aspect of this line is the way the bass synth’s pitch can be heard sweeping around between about 35 and 90 Hz. This certainly helps to avoid it sounding like a simple sine wave, and I imagine it may also be the source of the subjectively ‘rubbery’ sound that you mention. The upper registers of the line should also be easily audible on a lot of smaller systems, but you’ll notice that if you stick a high-pass filter across the mix at 100Hz, precious little of the bass remains — so I don’t think its audibility is coming from any serious helping of mid-range or high-frequency energy. If the synth waveform isn’t a sine wave, then I’d suggest it has at least been very tightly filtered above its fundamental frequency.
Where the Animal Collective tune differs most clearly from Clark’s, to my ears at least, is that ‘My Girls’ has considerable harmonic information from the bass higher up the frequency spectrum, so the 100Hz high-pass filter test doesn’t kill it in the same kind of way. Otherwise, though, the two tracks have a lot in common: a bass line that, if not quite as wild, still provides a good deal of movement and the odd portamento; and a kick with tightly controlled, fast decaying low-end.
Finally, what’s also worth mentioning is that the kick/bass waveforms of these mixes appear to have been clipped (presumably at some point in the bus-processing or mastering chains), and this will also tend to make them a little more audible on smaller systems by virtue of the higher-frequency distortion products, albeit at the potential expense of a reduction in relative low-end power.