High-pitched noise with RR group XFades with low buffer sizes

[Christoph Hart]

... And it's gone.

It was in fact an issue with a too low threshold (60dB) for detecting whether to use the full modulation signal or just a single value for performance reasons. I upped it up to -80dB and now it's basically inaudible.

Let me know if that problem persists with your real-world project, then I'll add a custom preprocessor where you can define a threshold for the detection - it's used in a few other places, just search the codebase for 0.001 and look for comparisons.

There was another related thread a few weeks ago about the AHDSR silence threshold so maybe it might be a good thing if this was customizable without hacking in the HISE Source code.

[tomekslesicki]

@Christoph-Hart thanks so much, I'm going to check this later today!

And I'm all-in for customizeable silence thresholds!!!

[tomekslesicki]

@Christoph-Hart I noticed you just added the HISE_SILENCE_THRESHOLD_DB preprocessor, thanks! :-) Could you please tell me about the value logic? For example, if I'll build HISE with:

HISE_SILENCE_THRESHOLD_DB=100

the threshold will be set at -100db, or should I rather build with

HISE_SILENCE_THRESHOLD_DB=-100

instead?

[d.healey]

[Christoph Hart]

This is in the comment of the preprocessor:

but you can override this (as a positive value, it will calculate the gain factor by taking the
number as negative dB value and convert it to a gain factor)

But it doesn't use this value for the crossfade detection (I've still hardcoded the -80dB) there, so you don't need to change this preprocessor to fix your issue.

Edit: Dave was faster :)

[tomekslesicki]

@Christoph-Hart @d-healey thank you!

I just tested the latest commit and it's indeed way better, but I'm still getting a bit of the buzz when the envelope gets to the curved part (so when the modulation slows down). Could you please bring it down a little bit more, or add the xfade threshold as a preprocessor so I can experiment with this myself?

[Christoph Hart]

@tomekslesicki you can just change the location I modified in the commit and use an even smaller number above zero, then let me know what you end up with :)

[tomekslesicki]

@Christoph-Hart well, that was a logical answer :D I built a couple of versions with different values and 0.00000000001f works prefect for all buffer sizes.

[d.healey]

@tomekslesicki said in High-pitched noise with RR group XFades with low buffer sizes:

0.00000000001f

That's some precision!

[Christoph Hart]

0.00000000001f

haha this is basically zero with the single precision resolution of seven digits... You're effectively just deactivating the logic that will save you CPU cycles when there is nothing going on in the modulation signal.

I guess I'll rather make a preprocessor like HISE_ENABLE_CROSSFADE_MODULATION_THRESHOLD and if that is set to true, it uses the -80dB threshold that gets rid of most artifacts and if that's not enough for your particular project you can disable it entirely by setting this to zero.

[tomekslesicki]

@Christoph-Hart sounds like a good plan! ;-) By setting it to 0, you mean something like this?

HISE_ENABLE_CROSSFADE_MODULATION_THRESHOLD=0

[Christoph Hart]

@tomekslesicki yes. Also you then can just leave it as default in HISE and just add that to your project definitions (if you can live with the low artifacts at -80dB during development), this way you don't have to edit the source code at all.

[tomekslesicki]

@Christoph-Hart epic, thank you!

[tomekslesicki]

@Christoph-Hart we don't have this HISE_ENABLE_CROSSFADE_MODULATION_THRESHOLD yet, right?

[Christoph Hart]

@tomekslesicki ah yes my goldfish brain with its limited attention span moved on to the next fancy thing…

[tomekslesicki]

@Christoph-Hart if I could then send a little wish to that goldfish, I'd say that HISE_ENABLE_CROSSFADE_MODULATION_THRESHOLD would make me very happy ;-)

[d.healey]

@tomekslesicki If the goldfish can grant wishes then I wish for more goldfish!

[Christoph Hart]

@tomekslesicki There you go...