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Re: In the mood 4 sharing. My 4 VST as OSM's 4 U :)
Posted: Wed Sep 11, 2013 11:02 pm
by tester
Interesting thing about these oversampling methods. Tor - do you know how to implement these shaping methods to not oversampled signals? And do you know other noise shaping methods and how to implement them?
Re: In the mood 4 sharing. My 4 VST as OSM's 4 U :)
Posted: Wed Sep 11, 2013 11:44 pm
by tester
Oversample x4 inside. I must say that there are audible differences between OS4 and others, I hear them also on polyphase resampling.
Also found an interesting talk on dithering and some noise shaping:
http://synthmaker.co.uk/forum/viewtopic.php?f=4&t=6568
Re: In the mood 4 sharing. My 4 VST as OSM's 4 U :)
Posted: Wed Sep 11, 2013 11:57 pm
by tester
And one more thing. In peak filter, it seems that Q should be equal Q/4. Whatever comparisons I do with external filters - all SM/FS implementations of biquads have that difference in Q factor. Have no idea why.
Re: In the mood 4 sharing. My 4 VST as OSM's 4 U :)
Posted: Thu Sep 12, 2013 10:29 am
by tester
I wonder how will sound 8x oversampled monster.
I asume that the same type of cascading US/DS should follow?
Re: In the mood 4 sharing. My 4 VST as OSM's 4 U :)
Posted: Thu Sep 12, 2013 11:50 am
by tor
I never noticed the Q factor you mention but I will check it out. One more thing your 'e' limiter can be optimized a little.
Code: Select all
e = ((b-d)>=0)&(b-d)+((b-d)<0)&1e-10;
Code: Select all
bd=b-d;
e = ((bd)>=0)&(bd)+((bd)<0)&1e-10;
Re: In the mood 4 sharing. My 4 VST as OSM's 4 U :)
Posted: Thu Sep 12, 2013 12:29 pm
by tester
Unoptimized version of 8x oversampled filters. Can someone tell if this is correct setup?
As for optimization - the up/downsamplers can be pushed through mono4 in a different way. Right now - the 2nd pass of filtering just goes through all, but the up/down sampling can be processed separately, thus - I guess - saving some CPU I guess. Need to check that.
Meanwhile I think I add 16x oversampled version, to allow full tests.
Re: In the mood 4 sharing. My 4 VST as OSM's 4 U :)
Posted: Thu Sep 12, 2013 1:09 pm
by tor
looks all good to me. have not tested though.
Re: In the mood 4 sharing. My 4 VST as OSM's 4 U :)
Posted: Thu Sep 12, 2013 1:13 pm
by tor
Dozius made this one. Maybe used to save CPU
Re: In the mood 4 sharing. My 4 VST as OSM's 4 U :)
Posted: Thu Sep 12, 2013 2:18 pm
by tester
...and how to use it correctly in OS higher than 2?
I mean - how to get these all A,B,C... nodes for filter?
And more important - what comes out of these nodes? (in terms of spectral range? some sort of splits of spectra?)
Re: In the mood 4 sharing. My 4 VST as OSM's 4 U :)
Posted: Thu Sep 12, 2013 3:04 pm
by tor
There you have it
