[strophlex]

Hi

I am making some noise with my SammichFM.

I modulate op4 with op3, both sine and apply a slow attack to op3 with the envelope and I hear some pretty nasty distortion. It sounds like zipper noise. The same happens if I make the attack of op3 faster and modulate it with an LFO with sine shape. Did I do something wrong or is it a common problem I just have to live with? Is there some methods to minimize it?

I know FM can cause aliasing if to many operators modulate each outher, but do I also have to keep track of levels to avoid digital overflow (amplitude)?

I will upload audio sample soon.

[strophlex]

Listen on Soundcloud.com

This post has been edited by strophlex: 21 November 2011 - 16:10

[jojjelito]

If it walks like zipper and quacks like zipper it is a duck? Sounds very much like zipper noise, or when I change waveforms on the fly with the data slider on my Prophet VS...

This post has been edited by jojjelito: 21 November 2011 - 17:06

[strophlex]

Cmon... Can anybody with an FM comment on this? Did you make the same observation? If so did you find a way to minimize it? If not, do you have any idea what I did wrong?

This post has been edited by strophlex: 25 November 2011 - 09:00

[toneburst]

Did you get to the bottom of this, in the end?
I haven't used my SammichFM for a while, but I didn't notice anything like this last I checked. On the other hand, I did get some pretty nasty digital distortion artifacts when I first put the thing together. They were solved by re-melting the solder on the SMD chips. You could try that, if you haven't already.

Just a thought.

a|x

[strophlex]

toneburst, on 29 March 2012 - 10:32, said:

Did you get to the bottom of this, in the end?
I haven't used my sammichFM for a while, but I didn't notice anything like this last I checked. On the other hand, I did get some pretty nasty digital distortion artifacts when I first put the thing together. They were solved by re-melting the solder on the SMD chips. You could try that, if you haven't already.

Just a thought.

a|x

Thanks for the reply. I haven't managed to solve this. Thought it was just the way the chip worked since nobody had a solution. Did you listen to the audio samples? Is it the kind of artifacts you experienced.

[Thomasch]

strophlex, on 29 March 2012 - 10:51, said:

Thanks for the reply. I haven't managed to solve this. Thought it was just the way the chip worked since nobody had a solution. Did you listen to the audio samples? Is it the kind of artifacts you experienced.

This would be my first checklist:
- maybe the audiodriver from your soundcard runs nuts, change buffersize, or deactivate other Plugins if to free CPU and RAM
- if possible change to another soundcard or a different input.
- try different Outputs on your MBFM
- reduce the volume in MBFM Menu

[strophlex]

I will double check the other outputs and try the volume.

The synth is not connected to a computer, so that rules out all sound card issues.

Thanks.

[Imp]

I can recreate this behaviour, my sammich does that too.
It happens with too high volume of the modulating OP.
You can reduce the volume (of op3 in your case) and use a higher multi instead, to get almost similar overtones.

[strophlex]

Thanks Imp. I will try that.

[strophlex]

Imp, on 30 March 2012 - 09:20, said:

It happens with too high volume of the modulating OP.
You can reduce the volume (of op3 in your case) and use a higher multi instead, to get almost similar overtones.

Thanks! This did the trick! I am just not good enough with FM yet, but this was a good lesson to learn.