Electric bass guitar is a very different animal than synth bass. If
you’re playing sampled bass from a keyboard or virtual instrument (see
Figure 1 above) and the goal is realism, then these tips—involving tone, MIDI,
and technique—will help you create compelling bass lines.
The Bass Signal Chain
Start with a dry, unprocessed sampled bass instrument,
then enhance it with suitable processing. This takes more work than
calling up a preset, but “baking” an effect into a sample isn’t how a
real bass works. Bass interacts with its environment.
Bass recording usually involves a direct box (DI) running
straight into your console or audio interface, a miked amp, or both. The
dry sound is essential for a DI emulation. An LA-2A or 1176-type
compressor, which can give a more “aggressive” sound for rock and
R&B than an SSL-type bus compressor, is typically next in the signal
chain. Bassists use compression for several reasons (sustain, even
response, touch) but because many playback systems and the human ear
lose response in the bass range, consistent bass levels have a better
chance of being heard. Some bassists prefer limiters over compressors
because taming only the peaks can give a more natural sound.
Regarding EQ, a significant high-end boost emphasizes pick
noise and overtones. Psycho-acoustically, the ear can fill in the
fundamental better if it receives this additional high-frequency
information. When mixing, this also leaves a little more room for the
kick. For the DI sound, I prefer EQ after compression (see Figure 2 at left).
For the miked-amp sound, run a bass amp simulation in
parallel with the dry track and blend them instead of using a sample
that incorporates an amp sound. The sampled bass will interact with the
simulation, so there will be less distortion when you play more softly.
Also, many amp sims let you vary virtual mic placement in relation to
the simulated cabinet’s speaker cone: centered gives fuller lows, to the
side gives a tighter sound, and off-axis makes the sound more diffuse.
As in real life, I generally place one mic close to the speaker and just
a bit off-center, with a second mic back, perpendicular to the cone’s
edge, and mixed lower. Reversing the second mic’s phase can also provide
useful effects. I almost never add room sound to bass.
Unlike guitars, bass sims don’t need to produce heavy
distortion—which is very difficult to get right. All the main players
(IK, Native Instruments, Softube, Waves, Line 6, Overloud, Studio Devil,
Peavey, etc.) make fine bass amp sims; IK’s SVX model in AmpliTube 3
(see Figure 3 below) nails several classic Ampeg bass amp sounds.
One of MIDI bass’s big advantages is being able to tweak
timing. Traditionally, kick and bass compete for the audio spectrum’s
low end, and because bass is non-directional on playback, they’re both
panned center—so they potentially obscure each other even more. Try
this: To emphasize the bass and the melody, move the bass a few ticks
ahead of the beat, but not enough to hear any kind of delay. To
emphasize the kick and rhythm, move the bass slightly late. The bass
actually sounds softer when late and louder when ahead.
Slides are an important bass technique—not just up or down
a string, but over a semitone or more when transitioning between notes.
For example, when going from A to C, you can extend the A MIDI note and use pitch-bend to slide it up to C (remember to add a pitch-bend of 0 after the note ends).
Unless you’re emulating a fretless bass, you want a
stepped, not continuous, slide to emulate sliding over frets. Quantizing
pitch-bend slide messages so they’re stepped is one solution (see
Figure 4 at left). Even if they’re not exact half-steps, they go by quickly
enough to be perceived as non-continuous. For example, with a virtual
instrument’s pitch-bend set to +/-12 semitones, quantizing the bend to
32nd-note triplets will give exactly 12 steps in a one-beat octave slide
up, while a sixteenth-note triplet gives 12 steps over a two-beat octave slide. Make sure there’s no smoothing enabled for the pitch bend function.
For precise slides, the following table shows the amount
of pitch-bend change per semitone. For example, if an octave is a
pitch-bend value of 8,191, and you want to start a slide three semitones
above the note where you want to “land,” start at a pitch-bend value of
+2,048 and add equally-spaced events at +1,366, +683, and just before
the final note, 0. This assumes your virtual instrument has a pitch-bend
range of +/- 12 semitones, which is what I use for bass to make these
kinds of slides possible. (Note that pitch-bend has a resolution of 14
bits with two bytes, which is why we’re dealing with these big numbers,
not the usual MIDI CC values of 0 to 127.)
Another option to add realism: Borrow a real bass, and
record slides (it’s not that hard) into a sampler or SFZ instrument (see
last month’s issue for my column on rolling your own samples). I
created several bass instruments for Cakewalk’s Dimension Pro around a
Gibson EB 5-string, and each one dedicated one octave to slides—five
downward, and five up/down. Occasionally adding these promotes a
realistic vibe—and you can download ten free EB slides online.
Mod Wheel Options
If your modulation wheel controls vibrato, reprogram it to one of these alternatives for more realistic performance control.
Drive amount. Tie the wheel to drive amount so that rolling the wheel forward adds “growl.”
Treble pullback. Pull down the highs by lowering a
lowpass filter cutoff or tone control frequency when the bass needs to
sit more demurely in a mix.
Hard picking. Roll the mod wheel forward to
increase amplitude of an envelope spiking a lowpass filter to give a
quick, bright transient. If you can control more than one parameter at
once, a very slight upward pitch bend from the same envelope can enhance
Sub-octave. Some bassists play higher on the neck
and use an octave divider for a huge “eight-string” bass. Roll the mod
wheel forward to add the sub-octave at dramatic moments. [This is a signature sound of renowned bassist Pino Palladino. —Ed.]
Wah. Create another layer with the wah, and overlay
the wah on top of your main layer. Addin wah to the main bass sound
dilutes its power.
There are bass fingerings that allow seamless transitions
between notes, but it often takes some time to lift a finger off a
string, push down on another string, and pluck it. To simulate this,
leave spaces between notes, especially when you want to emphasize a
Most importantly, remember that bass straddles the
rhythmic and melodic worlds, with different music emphasizing different
elements. Bass can do anything from acting like a melodic kick drum to
providing harmonic counterpoint—but a good bassist (or virtual bassist!)
never forgets that bass is part of the rhythm section.