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44khz vs 48khz
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daark
IsraTrance Full Member
Started Topics :
58
Posts :
1397
Posted : Jul 20, 2010 08:18
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Maine Coon
IsraTrance Junior Member
Started Topics :
12
Posts :
1659
Posted : Jul 20, 2010 20:17
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Wow!
Pitch went up and so did filter cutoffs.
But not the speed?.. 
I am guessing that it’s your host (DAW) that screws things up. I have not seen anything like this in Ableton. In fact, Ableton up-samples all audio internally to a floating-point format to avoid clipping. So, all your 44 audio is processed as 48 (or maybe even 96 - don't rememnber) anyway.
I am not a technical person, but it seems like your DAW thinks in terms of samples instead of real milliseconds. So, it keeps all the settings constant in terms of the number of samples, which leads to smaller time periods at higher resolutions, so all the frequency cut-offs go up.
It’s like in Photoshop, when you apply a filter with a kernel of a certain size in pixels. Let’s say you have a 100x100 pixel picture at 100 PPI. You smooth it with a Gaussian blur filter (the graphical version of low pass) to your taste. Let’s say the “radius” setting on the filter you liked was 10 pixels. If you load the exact same picture but as 200x200 at 200 PPI and apply the same filter, it’s not going to look the same as the first picture. You are going to have twice as much detail there that escaped blurring because 10 pixels are not 0.1 of an inch anymore but 0.05. So, it looks like your low pass filter just shifted up its cutoff.
The low pass filter in sound is exactly the same as Photoshop blur filter. The high pass filter is exactly the same as a sharpening filter. Same math. Only instead of pixels they process samples. So, if the settings are remembered in samples instead of milliseconds, the results are going to depend on the resolution, just like in that Photoshop example.
If I am right, it’s a bug. You can work around it by re-calculating all the cut-offs every time. But it’s probably easier to switch to something that already does it for you automatically.
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Maine Coon
IsraTrance Junior Member
Started Topics :
12
Posts :
1659
Posted : Jul 20, 2010 20:21
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I think I know why pitch goes up but the speed does not. Most (or all?) the sounds in this track are synthesized. The synthesizer's pitch (and probably all other settings) is affected by the time resolution problem. The timing of notes, though, is not because it's triggered with MIDI messages, which work in real milliseconds, rather than samples. Ha! I think mystery is solved.  |
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