FIG. 1: Waves Renaissance Bass with a moderate bass‑enhancing setting.
The three ingredients that are essential for creating a convincing synthesized-bass part are programming, playing, and mixing. I describe how to program a killer bass sound in this month's “Sound Design Workshop” column (see p. 70). Here, I'll discuss playing bass tracks and placing them properly in a mix.
I'll assume that you are playing or programming your bass line into a MIDI sequencer. If you have some keyboard chops, I highly recommend that you play the part yourself rather than step record or draw it in. There's nothing wrong with using both hands to play the part, and you can slow down the tempo of your sequencer to play more-difficult passages. Dance and industrial bass lines are exceptions, because they need to have the machinelike precision of a step-entered or quantized part.
First Things First
It's best to have your basic drum and keyboard parts before you record the bass line. If you also have a reference vocal, that's even better. A good bass line works around the vocal and pops through in the spaces between vocal phrases.
Once you have played your part into the sequencer, solo it and fix any obvious mistakes. Get rid of extraneous notes and spend the extra time necessary to ensure that the note lengths are just right; an undesired gap between notes can create an unsettling effect. When notes of the same pitch overlap, the second note will be stopped by the first note's MIDI Note Off message and will thus be truncated. That can happen, for example, when a bass line is quantized and the first note has been played early. If notes of differing pitches overlap, you may get a moment of mush as the two notes play together. To fix that, either shorten the duration of the offending notes or set your synth's keyboard mode to monophonic.
Whether to quantize, and by how much, is a matter of personal choice and differs by genre. With dance music, quantizing is the rule, whereas with hip-hop and rap, it isn't. If you are using a bass sound that has a strong attack, line it up with the kick drum, regardless of whether it is quantized. That will avoid a flamming effect in the low-middle range, which weakens the impact of bass and kick.
Experiment with portamento in your bass line and practice using your keyboard's pitch-bend wheel. Also experiment with the retrigger setting if your synth has that. With retriggering on, each note you play has a new attack; with retriggering off, notes that are overlapped do not have a new attack. That allows you to create gliding effects and to separate notes by changing your playing style. Portamento can often be set to kick in only when you play legato. You can program very expressive bass lines by alternating legato and staccato playing, by using the pitch-bend wheel, and by keeping a hand on the filter cutoff frequency.
Recording the Bass
If you are using a hardware synth, you need to find the best way to get its sound into your digital audio sequencer. The easiest way to do that is to plug the synth into one of your audio interface inputs and set that input at a -10 dB level; that may not give you the best possible sound, though. If you have a good standalone mic pre with a DI (direct injection) input, experiment with plugging the synth into it and running the mic pre output into a line-level (+4 dB) input of your sequencer.
I like to add a little hardware compression to the bass during tracking. Try 2 dB of gain reduction, hard-knee compression with a compression ratio in the 3:1 to 6:1 range, and a 20 to 40 ms attack. The slow attack allows the initial kick of the bass sound to come through, whereas the rest of the note is smoothed out and less woofy.
If you are using a software synth, bus the signal to your bass track and record it, leaving compression and EQ for the mix. Alternatively, you can run the sound out an analog output, through a hardware compressor, and back into an analog input of the audio interface. This gives you that analog sound, but you lose a little presence as a result of the digital-to-analog-to-digital conversion.
When setting up a compressor, set the gain so the volume is the same whether the bypass button is in or out. You can't tell if the sound is improved by the compressor unless the levels are matched.
I rarely use time-based effects such as chorus and delay with synth bass. Those effects might sound cool when the bass is soloed, but they make the bass sound mushy and can cause big problems in a mix. On the other hand, you might add some delay to a Jaco Pastorius — style bass sound. Pastorius used lots of delay, with pitch modulation, when he played flowing, melodic parts.
FIG. 2: Waves Renaissance Channel showing my favorite bass EQ and compression settings.
One of my favorite effects plug-ins is Ohm Force Frohmage, which you can download for free from www.ohmforce.com. It's a funky-looking filter plug-in with enigmatic markings. Without worrying about the details, I set the small knobs to around 12 o'clock and automate the large cutoff-frequency knob. Start with a bright, annoying bass sound; put Frohmage on the track; and automate the cutoff frequency to get a really expressive bass sound. This technique is most effective when the bass is in a featured role.
I've become very attached to using Waves Renaissance Bass (RBass) in my mixes; it's usually the first element in my bass signal chain. RBass boosts the first few overtones of the bass without boosting the fundamental. The ear infers the fundamental from those overtones, and you get a more apparent bass without adding a lot to the overall volume of the mix. It's also easier to find the best bass mix level with RBass (see Fig. 1).
Fig. 2 shows Waves Renaissance Channel with my favorite bass EQ and compression settings. I place this after the RBass. The 350 Hz dip in the EQ takes out the unclear part of a bass sound that lies between the bottom and the definition; the boost at 1 kHz increases that definition. Experiment with the frequency of the boost — different bass sounds will be defined by different frequencies. Be careful that the frequency you boost does not interfere with guitar and lower keyboard parts.
I use roughly the same compression settings for mixing as for tracking (see Fig. 2). Set the threshold so that the gain reduction is no more than 3 or 4 dB. Experiment with the attack time to see how it affects the attack portion of the bass sound. Experiment with EQ and compression while the whole mix is playing and with the bass soloed.
I often insert another compressor, Bomb Factory BF76, at the end of the signal chain (see Fig. 3) because it adds extra punch to the sound. Web Clip 1 is a Minimoog bass line without processing. Web Clip 2 is the same track with processing. The difference is subtle, but you can hear how the bass sits more evenly in the mix with effects processing.
FIG. 3: Bomb Factory BF76 showing my favorite second compressor setting.
Finally, for the bass to punch through a mix, you need to clear the other instruments out of its way. Put highpass filters that have 24- or 36-dB-per-octave slopes and cutoff frequencies that are around 100 Hz on any tracks other than the bass or kick that have a residual low end. The bass and the kick drum should be the only parts that have really low frequencies. My thanks to producer-engineer Carlos Alvarez for that tip.
The hardest part of creating a good mix is getting the vocal level right; the second-hardest part is getting the bass level right. Because rooms vary widely in their bass response and different areas of the same room will sound quite different from each other, it's important to check the mix in as many environments as possible: in the living room, the car, and, my favorite, through an iPod with Bose Noise Cancelling headphones. The bass response of earbuds varies depending on their position in your ears, so I don't like them for checking mixes.
A bass sound is ultimately measured by how it works in relation to the rest of the track. So pay careful attention to the rest of the mix along the way.
Steve Skinner has worked as an arranger-programmer for Celine Dion, Jewel, R. Kelly, Chaka Khan, Bette Midler, and Diana Ross. He arranged the musical Rent and coproduced the cast album.