Fat stacked oscillators

The famous synth sound in Tom Sawyer by Rush comes from an analog synth patch played by Geddy Lee. It was created on an Oberheim OB-X (later sometimes OB-Xa live).

The sound is often called a sync-lead or OB brass lead.

The “Tom Sawyer” Synth Patch

Here are the basic ingredients of the patch.

Oscillators

Two oscillators slightly detuned.

• Oscillator 1: Sawtooth

• Oscillator 2: Sawtooth (slightly detuned)

Detuning creates the thick analog sound.

Filter

A key part of the tone.

• Low-pass filter

• Medium resonance

• Filter envelope opening quickly

This gives the bright attack then mellow sustain.

Envelope

Fast attack, medium decay.

Typical shape:

• Attack: fast

• Decay: medium

• Sustain: medium

• Release: short

This creates that punchy lead articulation.

Modulation

A little modulation adds movement.

• slight LFO to pitch or filter

• small vibrato from mod wheel

Why the sound is so recognizable

The Oberheim filters had a very distinctive character — big and brassy.

They were used heavily in early-80s rock alongside synths like the:

• Moog Minimoog

• Sequential Circuits Prophet-5

But the OB-X had the fattest stacked oscillators, perfect for Rush’s arena sound.

How to recreate it on your Arturia keyboard

Since you’re using an Arturia controller with GarageBand, try this:

1. Open a Mini V or OB-style analog synth patch.

2. Set:

   
   

   • 2 saw oscillators

   • slight detune

3. 
   

4. Low-pass filter around 60–70% open.

5. Filter envelope amount around 40–50%.

6. Fast attack, medium decay.

7. Add slight portamento if available.

You’ll get very close to the Tom Sawyer lead.

🎹 Interesting musical fact:

The synth solo in Tom Sawyer was not originally planned — the band left space for improvisation and Geddy Lee recorded several takes before choosing the final one.

If you’d like, I can also show you something fascinating:

the exact synth rig Rush used around 1981 (it was enormous) — and why they needed foot pedals just to switch patches live. It was one of the most complicated live keyboard setups in rock history.