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Old 18th July 2011, 10:05 PM   #11
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That's what it says:
Code:
  5:    1001726    XT-PIC-XT        RME96
The number you see is increasing 95 counts every second.

It just doesn't get lower. I set period_time as high as 100000000000 in mpd.conf
It does not get better than 43 counts with 16/44

Rüdiger
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Old 19th July 2011, 06:52 PM   #12
phofman is offline phofman  Czech Republic
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Quote:
Originally Posted by Onvinyl View Post
It does not get better than 43 counts with 16/44
OK. Perhaps MPD has some internal boundaries for ratio between buffer and period sizes. You can check the actual values set by the player in the file /proc/asound/card1/pcm0p/sub0/hw_params (provided your card has ID 1).
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Old 19th July 2011, 07:04 PM   #13
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I could only find periodsize which is said to be 8192 bytes
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Old 19th July 2011, 07:16 PM   #14
phofman is offline phofman  Czech Republic
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Quote:
Originally Posted by Onvinyl View Post
I could only find periodsize which is said to be 8192 bytes
And it perfectly fits the RME96_LARGE_BLOCK_SIZE in Considering old hardware for an audio player/recorder . This is the largest period your sound card allows. Let's see:

( 44100 Hz x 2 bytes x 2 channels ) / 8192 bytes = 21.5 IRQs (i.e. processed periods) per second


What format does that hw_params file list? If MPD sent S32_LE (i.e. 4 bytes instead of the 2 in the calculation above), we would get 43 IRQs/s which is your number.

Anyway, now you have verified that MPD is set up for both the largest buffer and period your card supports. That is the lowest CPU load you can achieve from your playback chain. Congratulations :-)
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Old 19th July 2011, 07:39 PM   #15
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Somehow youre right right now, it uses around 20 counts.

I spend quiet some time last year to get behind mpd.conf so I'm happy it proved right again now....

What I would really like to try is to do some tweaks with the psu. Are the power lines for drives, cpu, peripheral devices separate? So I could provide some voltages from a linear psu?

Rüdiger
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Old 19th July 2011, 08:21 PM   #16
phofman is offline phofman  Czech Republic
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Quote:
Originally Posted by Onvinyl View Post
Are the power lines for drives, cpu, peripheral devices separate? So I could provide some voltages from a linear psu?
Well, the PCI card is powered from the MB. It uses +12V, +5V, +3.3V, probably -12V too, all these voltages are available on the PCI bus. Theoretically you could cut the corresponding traces/remove the voltage regulators on your card and provide these voltages from different PSUs. Practically, it would be quite a chore

Well, you can power your HDs from a different PSU. I would doubt the effect though.
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Old 19th July 2011, 08:27 PM   #17
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My Q wasn't clear. The ATX Powerplug has 20 poles with multiple 3.3V, pathes. Are these seperate? and routed to different devices? Or are they multiples of the same line to enforce power capability of cables and contacts?

Rüdiger
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Old 19th July 2011, 08:31 PM   #18
phofman is offline phofman  Czech Republic
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Quote:
Originally Posted by Onvinyl View Post
My Q wasn't clear. The ATX Powerplug has 20 poles with multiple 3.3V, pathes. Are these seperate? and routed to different devices? Or are they multiples of the same line to enforce power capability of cables and contacts?

Rüdiger
I have disassembled many PSUs (mostly dead ones :-) ) and wires of the same color (i.e. voltage) have always been soldered to a single junction.
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Old 9th October 2011, 08:21 PM   #19
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Hi,
I could do with some help. My ancient fujitsu machine is dead. Since I'am a bit short at the moment, I swapped the RME Digi96 in another machine, which runs the same linux distro (Gentoo).

Amazingly, it does not work in 24bit mode here. I have to use 16 bit. If I try to call sox in 24bit, for instance, I get
Code:
sox FAIL formats: can't open input  `hw:0,0': select_format error: Operation not permitted
The driver is kernel built-in.

EDIT: Progress! I used to call sox by means of sox -b 32 -t alsa hw:0,0 (...)
That doesn't work no more. It works now if I type
sox -b 24 -t alsa plughw:PST ...
The only difference I can think of is, that I uninstalled dmix on the old machine, but forgot (about) it now.

Rüdiger
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Last edited by Onvinyl; 9th October 2011 at 08:45 PM. Reason: found something...
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Old 9th October 2011, 09:39 PM   #20
phofman is offline phofman  Czech Republic
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Look at the driver, method snd_rme96_capture_setformat git.alsa-project.org Git - alsa-kmirror.git/blob - pci/rme96.c . Only S16_LE and S32_LE formats are supported natively. If you want to use other formats, you have to use the plug plugin (plughw). Therefore, in sox you either have to specify -b32, or have to use the plughw:0 device. The result is equivalent - in the first case sox does the 32/24 bit conversion (no data is lost, the card uses only 24 bits of the 4 bytes anyways), in the second case the plug plugin does the conversion, feeding 3byte format to sox.

There is no reason to avoid/be afraid of the plug plugin, it does only the minimum conversions needed.
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