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brummer10 / guitarix

guitarix virtual versatile amplification for Jack/Linux
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GxBigMuffPi has a 12 kHz tone #73

Open magnetophon opened 3 years ago

magnetophon commented 3 years ago

When I use this plugin in ardour, I get a 12 kHz tone, not matter if the transport is running.

gitterdude commented 3 years ago

I can confirm that; at least in the 0.42.1-18-g0789a662 version. I don't think it's audible under normal gain staging but it is there.

brummer10 commented 3 years ago

Hi I can't reproduce that here. But, I've implement a 12kHz filter which should remove this. Let me know if that works.

magnetophon commented 3 years ago

I later found out that the frequency is not constant, so you cannot notch it out.

brummer10 commented 3 years ago

Which sample frequency do you use? Is is above 48kHz?

magnetophon commented 3 years ago

No, I think it was 48k, but it might have been 44.1k. For sure nothing else.

gitterdude commented 3 years ago

I'm seeing it both with 44 and 48kHz

But I only see it on my really old i5-650 PC. It's not there on a slightly newer i7-4710MQ one. The i5 is running Ubuntu 18.04 and the i7 openSUSE 15.3. They're both have gcc-7.5.0

I thought it could be the -O3 optimization but changing it to -O2 made no difference.

magnetophon commented 3 years ago

I never thought CPU would matter, but here we are.

I'm using a fairly recent Intel i5-10310U (8) @ 4.400GHz, if that helps.

magnetophon commented 3 years ago

To be clear, I agree with @gitterdude

I don't think it's audible under normal gain staging but it is there.

So it's not high priority issue, imho. Just wanted to let you know.

gitterdude commented 3 years ago

It could be some difference in the distros, rather than the CPUs; that was just an initial guess. openSUSE uses a newer libboost for instance: 1.75 vs 1.65 in Ubuntu

The signal is at -65dB with the volume and tone on the Muff at max.