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PostPosted: Fri Sep 18, 2015 5:36 pm 

Joined: Sun Feb 03, 2013 2:39 pm
Posts: 333
Under some circumstances the multiband x-overs change depending on the sample rate used. I don't know if this is just the bands graph or actually affects the sound.

Reproduction: Factory reset, enable multiband, set it to 2 bands with 4167 Hz and 24 kHz (maximum);

Now look at the bands graph closely:
  1. Play some material with a 48 kHz sample rate. The bands cross exactly at 10 kHz as they should.
  2. Play some material with a 44.1 kHz sample rate. The bands cross at about 9.6 kHz. That's wrong!
I managed to reproduce this also with a different number of bands. The error seems to be about 4%.


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PostPosted: Tue Nov 03, 2015 3:30 pm 
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Joined: Mon Mar 17, 2008 1:40 am
Posts: 11185
Quote:
Under some circumstances the multiband x-overs change depending on the sample rate used. I don't know if this is just the bands graph or actually affects the sound.

Reproduction: Factory reset, enable multiband, set it to 2 bands with 4167 Hz and 24 kHz (maximum);

Now look at the bands graph closely:
  1. Play some material with a 48 kHz sample rate. The bands cross exactly at 10 kHz as they should.
  2. Play some material with a 44.1 kHz sample rate. The bands cross at about 9.6 kHz. That's wrong!
I managed to reproduce this also with a different number of bands. The error seems to be about 4%.
Ah. The problem is NOT in the calculation of the peaks (they are at the right spot, just try setting both to 10.000), but the crossover moves a bit.

Cause: At 44.1 kHz apparently the top frequency is reduced to 22050 instead of 24000, this explains the move.


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PostPosted: Tue Nov 03, 2015 6:07 pm 

Joined: Sun Feb 03, 2013 2:39 pm
Posts: 333
Ah, I see. I played some low quality audio at 22050 Hz and it moves the crossover from 10 kHz to below 7 kHz. That's more than a 30% error.


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PostPosted: Sun Nov 22, 2015 10:33 pm 
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Joined: Wed Aug 20, 2014 9:32 am
Posts: 231
Location: Poland
Since the switch in crossover actually happens in that scenario, shouldn't there be an information somewhere (like pop-up window) that sample rates below 48 kHz are not recommended (and why)?

Slawomir


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PostPosted: Mon Nov 23, 2015 12:12 pm 
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Posts: 11185
No, this is a bug that needs to be fixed.


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PostPosted: Mon Nov 23, 2015 1:15 pm 
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Joined: Wed Aug 20, 2014 9:32 am
Posts: 231
Location: Poland
Nice :) Thanks


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