Designing a Rolling Psytrance Bass in Spire: The Exact Patch, Step by Step

A psytrance bass either welds itself to the kick or it doesn’t. There’s no in-between, no “close enough” — the moment there’s phase smear, envelope bleed or a stereo image below 150 Hz, the whole track collapses into mud. Spire is one of the fastest synths in the world for nailing this sound, but almost every tutorial stops at “square wave into a lowpass” and hands you 20% of the patch. The rest lives in envelope timing, filter motion, mono discipline and how you carve the frequency handoff with the kick.

TL;DR

• One oscillator, square wave, one voice, no detune, no unison, no spread. Mono, glide off.
• Amp env: 0 attack, decay tuned to a 16th at your BPM (roughly 80–110 ms), 0 sustain, ~40 ms release.
• Filter env identical shape, driving a low base cutoff up into the note. This is what “breathes”.
• HPF the bass around 35–40 Hz, hard sidechain to the kick, hand the sub to the kick.
• Retune the envelopes and sidechain release every time the BPM or kick changes. There is no preset.

Strip the init patch back to one oscillator

Load Spire, hit Init, and immediately switch off Oscillators 2, 3 and 4 along with the sub and noise sections. A psytrance bass is a single-oscillator sound; every extra source you add brings phase relationships, stereo movement or low-end thickness you’ll then spend the rest of the session trying to compress away.

On Osc 1, set the mode to Classic and dial the shape control to a pure square (Spire’s Classic osc morphs between saw and pulse — you want the fully symmetrical pulse position). Voices: 1. Detune: 0. Pan spread: 0. In the voicing section at the top of the panel, switch polyphony to Mono and set Glide to zero — psytrance bass moves in fast semitone jumps, and any portamento smears the attack of every note.

Set Osc 1’s octave so a played A1 sounds where you want it. Most psy basslines are written around F1–A1; if your MIDI is up an octave, transpose the oscillator down instead of the MIDI so the project stays readable. Leave the analog drift low but not zero — a tiny amount of drift gives the top end of each note a bit of life without breaking the roll. Any per-note randomness beyond that (S&H on pitch, wide LFO on cutoff) is the enemy at this stage. The whole point is predictability: every note has to sound identical in attack and decay, or the roll wobbles.

The amp envelope is the roll

Open ENV 3 (Spire’s amp envelope). Attack all the way down, sustain all the way down, release around 40 ms. The one control that matters is decay, and it’s the single most important knob on the entire patch. Too long and successive notes bleed into each other and into the next kick. Too short and the bass sounds thin and clicky.

The decay has to be tuned to the 16th-note grid at your project tempo, then pulled a hair shorter so there’s audible space between notes:

• 138 BPM: a 16th note is ~109 ms. Try decay around 90–100 ms.
• 145 BPM: a 16th is ~103 ms. Try 85–95 ms.
• 148+ BPM: drop into the 70–85 ms region or the roll turns into a drone.

Now stop reading the numbers and use your ears. Solo the kick and bass, loop two bars, and shorten the decay until the kick’s transient punches through cleanly with no bass tail muddying it. When it locks, you’ll feel the pattern start to bounce — that hypnotic three-note lift between every kick that defines the genre.

If you hear a click on every note (common with attack at absolute zero on a square wave), nudge the attack to 2–4 ms. That’s enough to soften the transient without audibly slowing the note.

Filter motion: where a square wave stops sounding like a square wave

Route ENV 2 to filter cutoff with a positive modulation amount. Set the filter to LP24 for a rounder, darker bass, or LP12 if you want it to bark more in the mids — LP12 is more common on faster, harder tracks where the bass needs to cut through a dense top end.

Pull the base cutoff down until, with the envelope amount at zero, the bass is almost muted. Then shape ENV 2 the same way as the amp envelope — 0 attack, 0 sustain, decay in the 80–110 ms range, short release — and push the envelope amount up until each note opens the filter and snaps shut again. That opening motion is the “wow” inside every bass note. It’s the difference between a lifeless square and a bass that sounds like it’s talking.

Resonance is a taste call, but tread carefully. A quarter turn adds a bit of squelch and helps the bass find its own slot in a busy mix. Push it further and you’ll get whistling harmonics that fight leads and pads, and read very differently on club systems than they do on nearfields. When in doubt, less resonance and more envelope amount.

Mono discipline matters more than any plugin you’ll add later

Club sound systems sum the low end to mono. Any stereo width or detune sitting in the bass frequencies causes phase cancellation on the dancefloor, and the bass you spent hours mixing quietly disappears — or worse, only shows up in one half of the room. This isn’t theoretical. It’s why the checklist above is uncompromising about one voice, zero detune, zero spread, centred pan.

Put a utility with a mono button on your master and A/B constantly. If the bass drops in level when you flip to mono, something in the chain is stereo when it shouldn’t be — usually a chorus, a wide reverb, a ping-pong delay, or a stereo saturator that’s decorrelating harmonics. If you genuinely need ambience or motion on the bass, band-split it: send only the content above ~200 Hz to the stereo effect, and leave everything below it dry and centred.

Browse Psy Trance packs at Myloops →

Program the 16th-note roll

The pattern is deliberately dumb. Kick on every downbeat — 1, 2, 3, 4. Bass on the “e”, “and”, and “a” of each beat, filling the three 16ths between kicks. Over one bar: kick, bass, bass, bass, kick, bass, bass, bass, and so on.

Draw the bass notes at fixed velocity (110–120 is a good starting point) and a length just shorter than a 16th so MIDI note-off never overlaps the next note-on. Quantise hard. No swing, no humanise. Psytrance is machine-tight; any timing drift immediately reads as sloppy rather than expressive.

For pitch, start with the root on every position, then introduce movement sparingly:

• Root on every note — pure drone, great for breakdowns and full-on peaks.
• Root, root, root, octave-up on the last 16th — motion without breaking the trance.
• Root, minor third, root, fifth — more melodic, common in progressive psy.
• Semitone jumps (root down to the leading tone) at the end of a phrase to build tension.

Write 8 bars, then change one note every 4 bars so the ear stays engaged without the pattern losing its hypnosis. The bassline is a rhythmic engine, not a melody — any note that jumps too far will fight whatever lead sits above it.

Sidechain: surgical, not pumping

Route the kick to a sidechain input on a compressor across the bass. Fast attack (around 1 ms), ratio between 4:1 and 8:1, threshold set so every kick pulls 6–10 dB of gain reduction. Release is the one to tune by ear — start around 80 ms and adjust until the bass comes back exactly as the kick’s transient finishes but before the next bass note hits. Too slow and the roll sounds gappy; too fast and the kick’s punch gets swallowed.

The goal here is nothing like the audible pumping of progressive house. It’s a clean window for the kick, then the bass snapping back into place fast enough to feel continuous. A fast VCA-style compressor (Ableton’s Glue, FabFilter Pro-C 2 in “Punch” mode, the Waves API 2500) handles this cleanly. Opto-style compressors are too slow.

Many psytrance producers prefer a volume-shaper like LFOTool or Kickstart over a compressor because you can draw the exact duck curve — full attenuation for the first 20 ms, then a shaped ramp back over the next 70–90 ms. If you’re new to psy, start there. It removes an entire layer of guesswork and gives you a curve you can copy from track to track.

EQ handoff: hand the sub to the kick

Kick and bass are fighting for the same low-end real estate. The fix is a clean division of labour, not louder EQ moves.

On the bass channel, high-pass around 40 Hz at 24 or 48 dB/octave. You’re giving the deepest sub to the kick and stopping the master from wasting headroom on frequencies most club systems can’t reproduce cleanly anyway. On the kick, roll off the low mids from around 150 Hz with a shelf so the kick lives from roughly 40–120 Hz and the bass owns 100 Hz upward. There’s a narrow overlap zone around 100 Hz — that’s what the sidechain is refereeing.

Additional moves that consistently help:

• A gentle bump around 200–400 Hz on the bass for body.
• A narrow cut somewhere in 300–500 Hz if the bass sounds boxy.
• A presence lift between 1–3 kHz so the bass reads on laptops and phones.
• A low-pass on the bass around 10 kHz — a square-wave bass has nothing useful above that, and cutting it stops the bass masking hi-hats.

Reference on multiple systems. If the bass sounds huge on your monitors but vanishes on earbuds, you’re leaning too hard on sub content and not enough on mids.

Add drive without wrecking the low end

A raw Spire bass is clean, which in psytrance is a problem — you want harmonic density so the bass reads on small systems and cuts through a dense mix. But almost every saturator on the market adds low-end weight, and that’s exactly what you don’t want fighting the kick.

The disciplined approach: split the bass with a multiband tool or a simple crossover. Below ~150 Hz stays completely dry. Above 150 Hz gets the saturation. Any of these work on the upper band:

• Tube-style saturation (Softube Saturation Knob, FabFilter Saturn 2) for warmth — subtle, not fuzz.
• A waveshaper or transistor stage for aggressive harmonics.
• Bitcrushing at a high sample rate for a gritty digital edge that suits darker psy.
• A guitar amp sim on a parallel send at 10–20% wet.

After any saturation stage, re-check the low end on a spectrum analyser. Even band-split saturation can push intermodulation energy back down into the sub range. If your low-end meter reads hotter after the saturator, either back off or add a second HPF post-saturation.

Browse Psy Trance packs at Myloops →

Layering: usually a mistake, occasionally the answer

One patch is almost always enough. Psytrance thrives on low-end simplicity, and most layering attempts end in phase problems the producer then spends hours undoing. But there’s one layering move that works: a clean sine sub underneath the main bass.

Load a second Spire, initialise, set Osc 1 to sine, one voice, mono, no filter movement. Give it the same amp envelope as the main bass so it tracks the same rhythm, and drive it from the same MIDI clip. Sidechain it even harder than the main bass — you want the sine to duck almost fully under every kick, since it’s living right in the kick’s territory. Bus both to a bass group and mix from there.

What doesn’t work: stacking two mid-range basses. They’ll phase against each other and the fix will be worse than the original problem. If you want more mid character, use an effect (extra saturation, a resonant filter automation, a bandpass with a slow LFO on cutoff) on the single main bass rather than a second sound source.

Troubleshooting the roll

Most problems on this patch come down to the same handful of causes. Loop the kick and bass together — never troubleshoot bass in a full mix — and work through the table.

The bottom line

There is no secret Spire patch. There’s one oscillator, two envelopes with the same shape, a hard mono signal path, and a signal chain designed around a single job: making the space between the kick and the bass do the work. Every decision on this patch either serves that interlock or fights it.

Once the core is built, the real work is context. The same patch will sound completely different at 138 BPM under a tribal one-shot kick versus 146 BPM under a layered modern kick, or in a full-on drop versus a progressive breakdown. The envelope decay, the sidechain release, and the EQ handoff around 100 Hz all need to be retuned every time. Save the patch as a template, then treat every new project as a fresh tuning exercise. That’s how the producers whose basslines you’re chasing actually work — not a magic preset, just relentless attention to how the bass and the kick share one bar.