Why Your FM Leads All Sound the Same and How to Fix the Rhythm

• Sound design
• Serum
• Psytrance leads
• 8 min video

You spent hours on an FM patch, and in the track it just comes and goes. Usually the problem is not the sound, it is how the sound is played. This lesson is about the note writing and cutoff performance that make an FM lead rhythmic, memorable and strong enough for the climax of a psytrance track, without an arpeggiator.

The video is in Persian. This article walks through every step in English.

Step 1: A simple, strong FM patch

KOOROW uses his favourite and simplest route in Serum:

1. Set Oscillator A to FM from B.
2. Tune Oscillator B two octaves down and raise the FM amount a little.
3. Test with a note an octave lower than you started.
4. Turn random phase off.

This style of FM suits tight, powerful leads.

Step 2: Sample-and-hold on the FM amount

Assign LFO 1 to the FM amount with a sensible depth, so the FM never pushes so far that the sound breaks. Set LFO 1 to sample and hold. A 1/16 rate is too fast here; something slower works better. Now the amount of FM, how much Oscillator B affects Oscillator A, keeps changing up and down.

Step 3: Band-pass filter on a MIDI knob

• Band-pass filter, 12 dB
• Some drive
• Resonance no higher than about 25%
• Map the cutoff to a knob on your MIDI controller

Step 4: Write the notes by hand

No arpeggiator this time. (A step sequencer, such as the one in Arturia Pigments, is another option for a future lesson.) Writing notes by hand gives the lead its hook:

1. Create a 1-bar clip.
2. Write a few notes and shorten some of them so they do not run into each other. Mix short and long notes.
3. Keep an idea in your head and experiment: write, delete, write again until you get closer to it.

Note length is everything in this method. Because of the sample-and-hold on the FM amount, the character of the FM changes with every note, so the lengths you choose shape the sound itself.

Step 5: Grow the phrase gradually

A 1-bar loop gets repetitive fast. Extend the loop to 2 bars, duplicate the phrase and vary the second half. Keep growing it the same way to 4 and then 8 bars. Do not open a 16-bar piano roll and try to write every detail at once. Start from one bar and keep adding branches.

Step 6: Record the cutoff as a performance

Turn on automation recording and play the cutoff while the clip loops. Moving the cutoff well takes practice, because it has to match the notes you wrote. For longer notes, KOOROW sweeps the cutoff just before the note arrives. Playing the cutoff matters as much as writing the notes.

Keep learning

• How to design an FM lead in Serum 2 for darkpsy and forest
• Psytrance lead disappears in the mix? Fix it with Ableton’s stock effects
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