A bass sound that holds up everywhere is a few choices done well: the right oscillator for the tone, a mono line kept in one register, the amp envelope and filter to shape it, saturation so it still reads on small speakers, and sidechaining so it fits with the kick. Here is each choice and how they fit together.
This is about the sound itself, on any synth or bass instrument, in any DAW. Which notes you play, the line and its rhythm, is a separate job with its own guide.
A good bass sound is one that stays solid and translates everywhere it is played. In practice that means a few things at once: it sits low without turning muddy, it plays one note at a time in mono so the low end is a single clear thing, it stays in about one register, and it carries enough harmonic content that you can still hear the pitch on a small speaker that cannot reproduce the deep sub. Build a patch that does those and it will hold up from a big system to a phone.
A bass patch is a short chain of choices. You pick an oscillator for the raw tone, shape its loudness with the amp envelope, tame or open it with a filter, add saturation for harmonics and weight, and often layer a clean low part under a more characterful one. Each of those is a separate decision, and the table below is the map for the rest of this page.
| Part | What it decides | Rule of thumb |
|---|---|---|
| Oscillator | The raw tone and how rich it is | Sine or triangle for a clean sub, saw or square for a fuller bass |
| Register | How solid and clear it sits | Mono, one note at a time, about one octave |
| Amp envelope | Whether it plucks or sustains | Short and plucky, or long and held |
| Filter | How bright or dark it is | Tame the buzzy top, or open it for edge |
| Saturation | Whether it reads on small speakers | Add harmonics so the pitch survives |
| Sidechain | How it shares space with the kick | Duck the bass where the kick hits |
One thing to separate early: this page is about the sound of the bass, the patch itself. Which notes you actually play, the rhythm and the movement of the part, is a different job. If that is what you are after, the how to make a bassline guide covers it. A good patch and a good line are two separate wins, and you can work on them one at a time.
For a clean, deep bass, start with a sine or a triangle, which are almost pure and put nearly all their energy right at the fundamental. For a fuller, harmonically rich bass that cuts through a mix, start with a sawtooth or a square, which are full of harmonics you can then filter down to taste. Many bass sounds use both ideas at once, a pure wave for the depth and a richer wave for the character, which is the layering covered further down.
| Waveform | Character | Good for |
|---|---|---|
| Sine | Pure and round, all energy at the fundamental, no harmonics | Deep sub bass, the clean low layer under everything |
| Triangle | Soft and mellow with a few faint harmonics, a touch brighter than a sine | Clean sub with a little more presence, rounded basses |
| Sawtooth | Bright and buzzy, every harmonic present, the fullest wave to filter | Rich, cutting basses; the classic synth workhorse |
| Square | Hollow and woody, odd harmonics only | Plucky and reedy basses, retro and game tones |
| Pulse | A square whose width you narrow, thinner and more nasal | Reedy, focused mid basses that sit above the sub |
Bass is almost always strongest in mono and in one register. Mono means the low end is a single, centred thing rather than a wide, phasey one, which keeps it solid and stops it from thinning out when a club rig or a phone sums the sound to mono. One register means the line stays inside about an octave, low but not so low it becomes rumble. Set the synth to play one note at a time, keep it centred, and you have closed off most of the ways a bass sound goes weak before you touch anything else.
The amp envelope decides whether the note plucks or sustains. A fast attack with a short decay gives a short, plucky bass that leaves space between notes, which suits busy, rhythmic parts. A fast attack with a long sustain gives a held, continuous bass that fills the bottom under a chord. Neither is right or wrong, but it is a real decision, and it changes the feel before you choose a single note. Decide whether the part should bounce or hold.
Raw saw and square waves are often too bright for a bass, so a low-pass filter is where you set how dark or how present it sits. Lower the cutoff to remove the buzzy top and leave a rounder, deeper tone; raise it to let more edge through so the bass cuts on small speakers. A little envelope on the cutoff, so the tone opens on the attack and closes as the note holds, gives that classic bass pluck. If the filter is new to you, the what is a filter guide covers cutoff and resonance in full.
Small speakers, laptops and phones cannot reproduce the deep sub at all, so a pure sub bass can vanish on them completely. The fix is to give the sound harmonics higher up that carry the same pitch, usually by adding saturation or distortion. Your ear then hears those harmonics and fills in the fundamental it cannot actually reproduce, so the bass still reads as low even on a speaker with no real bottom. This is why almost every bass that survives on phones has some grit on it.
Saturation and distortion add new harmonics above the fundamental, and those higher harmonics are what a small speaker can actually play. Start gentle: a little saturation warms the tone and adds weight, more of it turns into obvious distortion and edge. Push it until the bass is clearly audible on a laptop speaker, then ease back to taste. The goal is not to make it sound distorted, it is to make the pitch survive on a speaker that cannot reach the real low note.
A common and reliable approach is two layers. A clean sub layer, a sine or a triangle, carries the deep weight and stays untouched. A second, mid-character layer, a saw or a square, carries the harmonics and the bite. The important part is to split them: distort, saturate or widen only the upper layer, and leave the sub clean and mono underneath. That way you get grit and stereo interest on top without ever smearing or spreading the low end, which is the part that has to stay solid and centred. Widen the whole bass and the low end goes weak in mono; widen only the top layer and the bottom stays safe.
The kick and the bass live in the same low frequencies, so when both hit hard on the same instant they fight and the low end turns thick and undefined. The usual fix is sidechaining: you duck the bass a little each time the kick lands, so the kick gets a clear moment on its own and the bass fills the space around it. Keep the low end mono as well, and the two stop competing and start reading as one solid bottom.
Sidechain compression turns the bass down briefly whenever the kick plays, then lets it return. Set it so the dip is quick and mostly recovers before the next beat. A small amount is enough to stop the two masking each other; a large amount becomes the audible pumping used in a lot of dance music, which is a style choice rather than a fix. Either way, the kick keeps its punch and the bass keeps its weight, because they are no longer fighting for the same instant.
Sidechaining is not the only answer. You can also arrange the two so they simply do not land hard at the same time, placing bass notes in the gaps between kicks. Many solid low ends use both ideas: the parts are written to interlock, and a touch of sidechain cleans up whatever overlap is left. What does not work is a loud kick and a loud bass hitting the same instant at full level and hoping the low end stays clear.
Check the bass on the worst speaker you have, a phone or a laptop, not only on headphones or monitors. If you can still hear the pitch of the line there, the harmonics are doing their job. Then solo the kick and the bass together: if they feel like one steady low sound rather than two fighting ones, the patch and the sidechain are set right, and the rest of the mix has a solid foundation to sit on.
Everything above is about the bass sound: the oscillator, the register, the envelope, the filter, the grit. That is the half you have just built. The other half is the actual line, the notes and the rhythm, and it is a separate job you do not have to do by hand.
REHEAT is a writing tool. It generates the bassline itself, so once you have a bass sound you like you do not also have to labour over the notes. Pick a groove and it writes a line that follows your chords, and you either drag that line out as MIDI or play it live through your own bass synth with the REHEAT MIDI DRIVER. Either way the sound design stays yours and the part is handled. It runs as an Audio Unit, a VST3 and an AAX.
That split is the point of this page. The patch you build here is the sound; REHEAT supplies the notes to play through it, and the two stay separate, so you can change one without redoing the other.
Free to hear in the browser, no signup. Everything above still works by hand on any synth or bass instrument, which is rather the point of writing it down.
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