How to Design a Reese Bass in Serum 2 (With the Fundamental Removal Trick)
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The reese bass is the backbone of hard techno. That thick, warbling, detuned low end that fills the bottom of your mix and makes everything feel massive. But here's what most producers get wrong: they detune a saw wave, call it a day, and then wonder why their sub sounds inconsistent on a big system.
The problem is the fundamental frequency. When you detune multiple voices, they create beating and comb-filtering effects) — the slightly out-of-tune copies interfere with each other, causing amplitude fluctuations at every harmonic, including the fundamental. And that first harmonic is your sub bass. If it's phasing, your low end is literally getting louder and quieter constantly, sometimes swinging 10 to 15 dB. On a club system, that means your sub is pumping in and out unpredictably. It feels weak, unstable, and wrong.
The fix is a technique that separates the sub from the harmonics so each can do its job perfectly. This is part of our Wall of Sound series — the reese bass is where the whole thing starts.
What You'll Need
All of this happens inside Serum 2 with a spectrum analyzer running alongside it. Prism (free from Surge) or any frequency analyzer plugin works. Having the visual feedback is important because you need to see the phasing to understand why we're fixing it.
Step 1: Start with a Saw Wave
Open Serum 2 and load the default preset. You should have a basic saw wave on Oscillator A. Drop your MIDI down so the fundamental is sitting around 50 Hz — this is the sweet spot for hard techno sub bass. You want to be in that 30–85 Hz range.
A saw wave is the starting point because it contains both odd and even harmonics, giving you the richest possible frequency content. If you started with a sine or triangle, you'd have a cleaner sound but way less harmonic material to work with.
Step 2: Detune It
Add voices to Oscillator A and start turning up the detune. You'll hear the sound go from a clean saw wave to that classic thick, buzzing reese texture. The more you detune, the wider and more aggressive it sounds — but also the faster the phasing happens.
Now pull the width down to zero first. This keeps everything mono so you can hear exactly what the detuning is doing without stereo imaging confusing things. You can widen it later.
Here's where the problem shows up. Open your spectrum analyzer and watch the fundamental frequency — that very first, lowest peak. See how it's bouncing up and down? That's the phasing. Every time those detuned voices align, the fundamental gets louder. Every time they misalign, it gets quieter. On a subwoofer in a club, this would sound like the bass is pulsing randomly.
Step 3: Remove the Fundamental
This is the trick that changes everything. In Serum 2, click the pencil icon on the wavetable editor for Oscillator A. You'll see the harmonic series laid out — the first bar is harmonic 1 (your fundamental), the second is harmonic 2, and so on.
Drag that first harmonic all the way down to zero. You've just removed the fundamental from the oscillator.
Play the note again and check your analyzer. That bouncing low-frequency peak is gone. The sound is very similar — you still hear all the richness and movement — but the very bottom of the frequency spectrum is now empty and stable.
Step 4: Replace It with the Sub Oscillator
With the fundamental removed from Oscillator A, turn on Serum 2's sub oscillator. Set it to a sine wave and drop it down two octaves so it sits in the same range as the fundamental you just removed.
Now look at your analyzer. You have a rock-solid peak at the sub frequency — perfectly still, no phasing, no movement. And above it, all the detuned harmonics are doing their thing, phasing and warbling and creating that reese character.
This is the key: your sub bass is now completely independent from the detuning. Harmonic 1 is perfectly in tune, not phasing at all. Harmonics 2 through 128 are phasing, warbling, and doing all the cool stuff that makes a reese sound like a reese.
How To Hear the Difference
Here's a quick A/B test you can do in your session. Duplicate the synth track and set one to the default detuned saw (with the fundamental still in), and the other to the fundamental-removed version with the sub oscillator.
Put an EQ on each one and solo just the low end — everything below about 100 Hz. On the default version, you'll hear and see the sub bouncing all over the place. On the fixed version, it's dead steady.
Now imagine that going through a festival PA system. One version has a sub that's jumping 10–15 dB. The other is consistent and strong. That's the difference this technique makes.
Step 5: Add Filtered White Noise
With the fundamental and sub handled, you can start layering in texture. Turn on the noise oscillator in Serum and set it to white noise. You don't need much — just enough to add some air and presence to the upper harmonics.
But you don't want the white noise interfering with your pristine sub. Put a filter on the noise oscillator path and high-pass it so it stays out of the low end entirely. Now you have clean sub, rich detuned harmonics, and a subtle noise layer on top.
Step 6: Key Tracking on Filters
Here's a detail that makes a big difference: turn on key tracking for your filter cutoff. Without key tracking, your filter sits at a fixed frequency. If you set the resonance to accent the third harmonic at 150 Hz, it will always accent 150 Hz — even when you play a different note where the third harmonic is at a completely different frequency.
With key tracking on, the filter cutoff moves with the note. So if you set it to accent the third harmonic, it will always accent the third harmonic, no matter what note you're playing. This keeps the tonal character of your bass consistent across the entire range.
Step 7: Mono and Glide
Turn on mono mode. You don't want your bass playing two notes at once — it'll create conflicting fundamentals and mess up your low end. Add a small amount of glide for that smooth pitch slide between notes, which is a classic reese bass characteristic.
With mono mode on and key tracking active, your filter cutoff will also glide smoothly between notes, keeping everything locked together.
The Finished Signal Chain
Here's what you end up with from bottom to top:
The sub oscillator provides a pure, rock-solid sine wave in the sub frequency range. Oscillator A runs a detuned saw wave with the first harmonic removed, providing all the rich, phasing mid and upper harmonics. The noise oscillator adds filtered white noise for texture and presence. A key-tracked filter accents specific harmonics consistently across all notes. And saturation or distortion can be added on top of all of this to further shape the character.
It's like building a house. The sub oscillator is the foundation — steady, reliable, isn't going anywhere. Everything on top of it can be as wild and creative as you want because the foundation is solid. You literally can't mess it up.
What's Next
The reese bass is just the starting point for a full wall of sound. From here, you'll want to build out your mids, highs, and drum layers to fill the rest of the frequency spectrum. Check out the other guides in this series:
- How to Build a Wall of Sound in Hard Techno — The complete picture of how everything fits together.
- Understanding Harmonics — The theory behind why this technique works.
- Why White Noise is the Secret Weapon for Louder Mixes — How adding noise helps your mix handle saturation.
- EQ Into Saturator: The Classic Chain — Processing your bass through drive without it falling apart.
- How to Install Serum 2 Presets — Get preset packs loaded into Serum 2 so you can start producing immediately.
Want reese bass presets that already have this technique built in? Check out our Serum preset packs — designed for hard techno and ready to drop into your session.
References
- Beat (Acoustics) — Constructive and Destructive Interference) — The physics behind why detuned oscillators cause amplitude fluctuations.
- Fourier Series: Sawtooth Wave — Why saw waves contain all harmonics and are ideal starting points for bass design.
- Mixing Secrets for the Small Studio by Mike Senior (Routledge) — Comprehensive reference on low-end management and frequency balance.
