How to Make Eerie FM Sounds

Frequency Modulation Synthesis is known for its metallic and clangorous character. It is easy to create these earth-shattering textures but challenging to predict and tame them (See Blog: FM Synthesis). Tastefully adding inharmonic sidebands is a difficult task that requires critical listening. Mastering this technique will reward you with a new bank of impressive sounds that you can use repeatedly in many different contexts. Below, I will walk you through some steps to create an exotic, attractive bed of FM sounds. This is what my eerie FM sounds like...

 

INSTRUMENT 1 - Big Bassy Bell

The Source - The design of this element is simple but strong. The key is long decays, detuning, and precise ratios. To bring out bell-like timbres, we need to set pretty specific C: M (M: C in some cases) ratios. For example, using irregular but related ratios like 1.666:1 (one and two-thirds) or 2.333:1 (two and one-third) will bring out the clang. Try using three carriers and three modulators - one for each carrier, all sine waves. Do not overdo the depth of modulation; keep it below 60. Ensure the decay times are at least 10 seconds for each carrier and 15 seconds for each modulator. The release times should be even longer - 25-40 seconds. The attack should be instant and should be 0 for each operator. Keeping these envelopes related is crucial for making a cohesive sound. However, you will want to detune individual operators to increase space and movement. Again, be precise - use related distances like multiples of 10 and permanently preserve the fundamental. Keep velocity sensitivity on. Lastly, try panning 2 of the carriers left and right about halfway. This is what my Big Bassy Bell patch looks like.

FX - Try adding a chorus. This is the most natural-sounding enhancement available. If you want to add reverb, go easy - since the decay time is already very long.

The Notes - You will want something drony and patient - nothing busy or complicated. Try to arrange notes such that each decay completes before the next trigger. ½ notes or whole notes will work well. Bring the tempo down to somewhere between 70 and 100 BPM. This is what my first instrument sounds like….

   

INSTRUMENT 2 - Evolving Stretched Bells

The Source - This patch has the same operators and ratios as the Big Bassy Bell patch. I modified the attack of the envelopes to about 5 seconds so that the sound sweeps in gradually (pictured below), added some global pitch modulation, and high-pass filtered it (no resonance because the sound is nearly pure resonance already).

FX - I used the same chorus effect from my first patch and a talk wah effect to add a little contrast.

The Notes - The notes should be legato and long. As with the first instrument, leave enough time for the sound to decay before the next trigger. Use tense counterpoint like 2nds and 6th, but nothing too dissonant.

Continuous Control - Use some long, subtle pitch bends and a bit of modulation like in the picture below (mod-wheel defaults to vibrato in FM8).

 

This is what my second instrument sounds like...

   

INSTRUMENT 3 - Little Bells

The Source - This sound will differ slightly from instruments 1 and 2. Start by opening a new sound. Enable two carriers and one modulator for each of them. Add a little feedback to each operator. Then, the operator modulates the first carrier, creating a chain setup (pictured below).

Here, you can use completely irregular ratios. Try listening for richness and sweet spots where tones pop out. Use shorter decay times (about 5 seconds). The decay on the modulators should be a little faster than the decay on the carriers. Experiment with the release times and modulation amounts until you find something you like. Finally, use the pitch envelope to make the sound bend down a little.

FX - Feel free to be coarse with effects here. I used a band pass filter, two delays, and a flanger. The first delay has the reverse function enabled.

The Notes - Play something that compliments the first instrument. They should seem to call and respond. This will help the second instrument cut through the mix more. This is what my third instrument sounds like...

 

INSTRUMENT 4 - Background Noise

The Source - For this last FM sound, enable three operators. Please make one of them the carrier, and the other two modulate it (pictured below). Use sine waves for the modulators and a soft triangle wave for the carrier. Give all the envelopes a slow attack (about 3 seconds) and a medium decay. Use 1.25 and 3.25 for the modulator ratios. The .25 decimal is a sweet spot for Erie, metallic robotic timbres. I sent it all to the filter (Z), making it a resonant high pass.

FX - I used a phaser and a little serial reverb.

The Notes - I drew in one long note for the whole section. This instrument is really about evolving automation and movement. 

Automation - “Read” a modulation amount and the filter cutoff to the XY plane. I assigned them to the X and Y axes and automated them together. 

Duplicate - Duplicate this track and its settings. Pan the original and the duplicate hard left and right. Detune one of them slightly. This is what my fourth instrument sounds like...

 

OUTPUT PROCESSING

Parallel Reverb - set up a reverb on a return track and listen for a good send amount on each channel. The instruments should sound like they’re in the same room - use the “coarse-to-fine” approach.

Imaging - Widen the stereo image using a plug-in like Ozone. Below is my full eerie FM sound bed. I added flair by bouncing the Big Bassy Bell to audio and reversing and inverting it. I also embellished it with a preset from FM8.