Proper mixer settings for music playback, or hardware fixes?
timo.jyrinki at gmail.com
Sun Jul 20 11:49:52 CEST 2008
2008/7/18 Hans L <thehans at gmail.com>:
> Just a guess here since I haven't even had a chance to look at these
> settings yet, but maybe the second frequency(after the @ symbol)
> represents the sample rate? So depending on the sample rate you are
> playing, you can set a different bass frequency cutoff?
2008/7/18 Joerg Reisenweber <joerg at openmoko.org> wrote:
> Please refer to Wolfson WM8753 datasheet - link to be found on wiki
I checked the datasheet. Indeed it means sample rate, but one that
scales. There's a table specifying eg. that if you select 100Hz
cut-off @ 16kHz, it means that at 48kHz the cut-off is 300Hz. I guess
the names in alsamixer have been chosen according to even numbers, so
that they actually really scale from lowest setting to highest.
It's just that the scale seems to be opposite to reality, ie. the
highest cut-off frequency actually results in the lowest. Most
probably the setting I chose (200Hz @ 8kHz -> 1200Hz @ 48kHz) actually
represents 130Hz @ 48kHz, and the one named as such (130Hz @ 48kHz) is
in reality that 1200Hz @ 48kHz since it sounds so thinny.
Problem solved, the cut-off is 130Hz which is quite high for
headphones but ok for portable speakers.
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