Another Additive FPGA Synth

JovianPyx · Posted: Wed Mar 28, 2012 5:32 am Post subject: Another Additive FPGA Synth

I've modified an earlier additive (sine) synthesizer to do something a bit different.

My previous additive synth (32 sine oscillators) was designed to produce periodic waveforms and used the sine oscillators as harmonics, i.e., each oscillator has a frequency that is an integer multiple of the fundamental pitch.

Blue Hell suggested the use on inharmonic partials (not harmonics). These are calculated using multiplication factors other than integers to produce partials of higher frequency than the fundamental pitch. He also suggested that a scale might be constructed out of the partial frequencies (or lower octaves of them).

The result was interesting gong and bell like sounds, metallic sounds. I had been reading that gongs and bells can have inharmonic partial stucture and that because of this structure it can be difficult to hum the pitch of the gong because of the strong influence of partials above the fundamental. This seems true of the output of my synthesizer as well.

I will be working on some kind of a demo which I will post later today.

blue hell · Posted: Wed Mar 28, 2012 7:52 am Post subject:

Ah, lift off Cool

JovianPyx · Posted: Wed Mar 28, 2012 10:24 am Post subject:

Here's the first demo sample. I'll do more because settings affect the sound. This was just one setting. I played random notes (this is a monosynth) and let the DDR SDRAM echo/delay effect fill in.

InharmonicSynth_01.mp3

Description:

Inharmonic Additive Synth Demo 01

Filesize:

2.38 MB

Duration:

2:36

Viewed:

2014 Time(s)

JovianPyx · Posted: Wed Mar 28, 2012 11:27 am Post subject:

I will be adding more samples here in this reply as I create them.

InharmonicSynth_02.mp3

Description:

More Inharmonic Synth Bells

Filesize:

3.08 MB

Duration:

3:22

Viewed:

2062 Time(s)

InharmonicSynth_03.mp3

Description:

And another one

Filesize:

3.01 MB

Duration:

3:17

Viewed:

1958 Time(s)

InharmonicSynth_04.mp3

Description:

Too Many Clocks All Set to the Wrong Times

Filesize:

3.08 MB

Duration:

3:22

Viewed:

1967 Time(s)

blue hell · Posted: Wed Mar 28, 2012 12:49 pm Post subject:

Very nice bells Scott!

JovianPyx · Posted: Wed Mar 28, 2012 4:28 pm Post subject:

Here's a composition I call "Inharmonic Rag"

The scale used was created from the partials' frequencies.

Inharmonic_Rag.mp3

Description:

Inharmonic Rag

Filesize:

2.96 MB

Duration:

3:14

Viewed:

2039 Time(s)

JovianPyx · Posted: Mon Apr 02, 2012 4:07 pm Post subject:

This synthesizer was small enough that I was able to double up on the hardware and modify the MIDI controller to make a duophonic synthesizer. Basically, 2 monosynths each with 32 sine oscillators. The sample rate is still 250 kHz.

It sounds much better than the monophonic version because you can play 2 notes at once or in rapid succession and don't get a weird pitch burp sound.

The demo is bits of playing, pause, bits of playing, pause, etc. The pauses were actually a bit longer as I was changing the patch. Each of the segments have some settings different. There is also a 1 second echo effect.

Duophonic_Inharmonic_Additive_Synth_Demo.mp3

Description:

Duophonic Inharmonic Additive Synth Demo

Filesize:

3.73 MB

Duration:

4:04

Viewed:

1938 Time(s)

Cynosure · Posted: Mon Apr 02, 2012 4:23 pm Post subject:

It sounds awesome!

What kind of filtering do you do the the sine wave to give it the bell type of sound? Is it just the cross modulation from 32 oscillators?

JovianPyx · Posted: Mon Apr 02, 2012 4:35 pm Post subject:

Cynosure · Posted: Mon Apr 02, 2012 4:39 pm Post subject: