7 Tips for More Expressive MIDI Bass Parts
by Craig Anderton
I’ve been playing electric bass for decades, but these days, most of the time I prefer keyboard bass on recordings. I’ve sampled so many basses it’s always possible to find a suitable bass sound within seconds—no plugging, unplugging, and tuning. And interestingly, many listeners have asked which bass I’m playing, because they like the sound. They’re always a little shocked when they find out I’ve been hitting keys, not strings, because the parts are quite realistic. (Note that I’ve released the three bass sample sets I use most here on craiganderton.org—the 5-String pack, Pop Bass pack, and Rock Bass pack.)
Here are 5 tips that will help make your keyboard bass parts more realistic.
1. Leave Spaces, Even Short Ones, Between Notes
Most bass lines are single notes, and because bassists lift fingers, mute strings, and pick, there’s going to be a space between notes. Go through your MIDI sequence note by note, and make sure that no note extends over another note’s attack. When the two play together, you get a momentary “note collision:” that not only doesn’t sound like a real bass, it can be pretty dissonant. I’ll even make the gap between notes a little longer if the notes are far apart. In the following screen shots, the gray notes have already been edited to add spaces, but all of the orange notes overhang into the next note.
2. Take Advantage of MIDI Velocity “Compression”
Really great bass players are known for their “touch”—the ability to play notes consistently, in terms of timing and dynamics. In some ways, it can be harder to play keyboard notes consistently than bass strings, which brings us to MIDI velocity “compression.”
Audio compression can give more consistent levels, but it doesn’t give a more consistent touch; that has to happen at the source. Some recording software programs have either MIDI FX or editing commands to compress data by raising low-level notes and/or or reducing high-level notes (the screen shot shows Studio One’s Transform function for MIDI data, which is applying velocity compression). But if your program doesn’t have velocity compression, there’s an easy solution: simply add a constant to all velocity values for “MIDI limiting.”
3. Bass Is Part of the Rhythm Section
Bass and drums need to be tight, and you don’t need to do a lot of notes on bass. I think of bass as the bridge between melody and rhythm, where it accentuates a chord progression while also accenting the beat. I often place the drum track (MIDI or audio) above the bass track, and move the bass notes to line up precisely with the drums, however as described next, this isn’t the only option…
4. Choose Whether to Prioritize Rhythm of Melody
If you slide the bass notes a few milliseconds behind the drums, then the drums will take priority and the sound will seem more rhythmic. Slide the bass notes a few milliseconds ahead of the drums to emphasize the melody. The difference shouldn’t be enough to hear an obvious delay effect; even a few milliseconds is enough, although the longer the delay (short of hearing an echo), the more pronounced the effect.
5. Use Synth Parameters to Shape the Bass Sound
When creating my own sampled bass instruments, rather than go through the hassle of multisampling different velocities, I sample each individual note plucked strongly, then tie sample start time, filter cutoff, and level to note velocity. Although the sound may arguably not be as realistic as something with four billion round-robin samples, I find this approach to be more expressive overall because the sound is smooth and continuous.
6. Add Slides Between Notes
Slides are an important bass technique—not just slides 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). Also, all my sampled bass instruments have sampled down and up/down slides for each string. Throw those in from time to time, and people swear it’s a real bass.
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. In the screen shot below, the first slide goes in half-steps from tonic to an octave higher. The second one slides from G to E and steps down over three semitones. The pitch bend then returns to 0 before the next E plays.
Even if they’re not exact half-steps, they go by fast enough to be perceived as non-continuous. For example, with a virtual instrument’s pitch bend set to +/-12 semitones, quantizing the bend to 1/32nd triplets will give exactly 12 steps in a one-beat octave slide up, while a 1/16th note triplet gives 12 steps over a two-beat octave slide. Make sure there’s no smoothing enabled for the pitch bend function.
7. Use the Mod Wheel Creatively
In Dubstep, the bass mod wheel usually doesn’t control vibrato, but instead controls amplitude (tremolo) or the filter cutoff frequency. For bass, I use the mod wheel for a variety of effects:
· Roll off treble as the wheel rolls further away to emulate a traditional bass tone control
· Mix in a suboctave for an octave-divided bass sound
· Alter tremolo depth
· Increase drive to an amp sim to give more “growl”
Above all—be creative! Although there’s nothing quite the sound of an electric bass, there’s also nothing quite like well-played, expressive keyboard bass. If you know how to do both, you can always choose the right tool for the right job.