Guys , can i ask for some infos here? Nobody wants to get this clarified in my view!
1) Raspberry can not produce a jitter free MCLK to the I2s when on 44.1 (confirmed, as it has only on oscillator)
2) Raspberry can not produce 24 bit over I2S (statement not seen proven anywhere, but also not seen evidence that it works)
1) Raspberry can not produce a jitter free MCLK to the I2s when on 44.1 (confirmed, as it has only on oscillator)
2) Raspberry can not produce 24 bit over I2S (statement not seen proven anywhere, but also not seen evidence that it works)
I found this to be a very informative run through of the Pi's i2s clocking options, including slaving it to an external clock.
https://hifiduino.wordpress.com/2014/11/13/raspberry-pi-b-digital-audio/
https://hifiduino.wordpress.com/2014/11/13/raspberry-pi-b-digital-audio/
I describe my setup in the post linked below:
http://www.diyaudio.com/forums/pc-based/270908-raspberry-pi-cirruslogic-audio-card-fail.html#post4256393
After that I purchased the Raspberry Pi 2 and a Cirrus Logic board from MCM Electronics. With the new, faster CPU, playing back 24 bit 192KHz audio files is no longer a problem.
Mind you, I am not talking about theory. The Raspberry Pi 2 + audio card combo is in my music room connected to an Auralic DAC, which correctly displays the bit count and sample rate on the files mentioned above. I hope this helps.
http://www.diyaudio.com/forums/pc-based/270908-raspberry-pi-cirruslogic-audio-card-fail.html#post4256393
After that I purchased the Raspberry Pi 2 and a Cirrus Logic board from MCM Electronics. With the new, faster CPU, playing back 24 bit 192KHz audio files is no longer a problem.
Mind you, I am not talking about theory. The Raspberry Pi 2 + audio card combo is in my music room connected to an Auralic DAC, which correctly displays the bit count and sample rate on the files mentioned above. I hope this helps.
New hifi-berry dac+ pro with 2 separate clocks for 44.1/88.2/176.4 and 48/96/192kHz sample rates.
https://www.hifiberry.com/2015/09/new-product-releases-hifiberry-dac-light-and-dac-pro/
https://www.hifiberry.com/2015/09/new-product-releases-hifiberry-dac-light-and-dac-pro/
Cool product! This proves what i descibed in the initial post. You need to have 2 clocks
Yes, it looks good indeed. Maybe it would be nice to have an additional opamp as output driver. That would need a step up converter though. Maybe another stacked optional PCB for real pros...
I confirm that with volumio 1.51 on my RPI can't get 24 bit over I2S. I've check with logic analizer
My RPi 2/HiFiBerry Digi+ with Squeezeplug/Max2Play software plays 24bit/192kHz. At least as shown on my dCS Puccini and, as I've just verified, on my Chord Hugo.
I can imagine that the sample size can be faked by just adding '0', which you could only verify with a logic analyser. But the sample rate can't be faked, right?
I would be really keen to see some screenshots of your measurements. I don't have a logic analyser and would love to see some hard intel on the I2S output of the RPi I found my Squeezebox based setup to sound better than Volumio but could explain it of both would be bit/samplerate-perfect players. If they are not, then this would be a clear explanation.
Which I would still find weird considering Volumio/Rune/etc.. claims about audio quality
My RPi 2/HiFiBerry Digi+ with Squeezeplug/Max2Play software plays 24bit/192kHz. At least as shown on my dCS Puccini and, as I've just verified, on my Chord Hugo.
I can imagine that the sample size can be faked by just adding '0', which you could only verify with a logic analyser. But the sample rate can't be faked, right?
I would be really keen to see some screenshots of your measurements. I don't have a logic analyser and would love to see some hard intel on the I2S output of the RPi I found my Squeezebox based setup to sound better than Volumio but could explain it of both would be bit/samplerate-perfect players. If they are not, then this would be a clear explanation.
Which I would still find weird considering Volumio/Rune/etc.. claims about audio quality
It's hard to compare ! Did you benchmarked the SB and the Pi with a same usb DAC ? If yes it could tell more about layout and jitter issues than bit perfect issues (I hope they are both bit perfect).
Does anyone tried upsampled material on the I2S output of the Pi towards a reclocked DAC ? For instance : 16/380 ?
Maybe I've confused you: I run the Squeezebox software on the Pi. And I don't use a USB DAC anymore (see our discussion over at Ian's FIFO thread). I use a HifiBerry Digi+ to go S/PDIF to my dCS Puccini.
And I'm currently building the setup with RPi (running Squeezeplug) > Ian's FIFO > S/PDIF out > dCS Puccini.
If I could only find the time to finish this
I've switch to runeaudio alpha 0.3
Got working 16 and 24 bit music selecting HifyBerry dac and adding format "*:24:*" to /etc/mpd.conf.
then kill and restary mpd with
sudo mpd --kill
mpd
At reboot you will get only noise because rune overwrite mpd.conf, so you must re-edit manually it.
This force 24 Bit even on 16 Bit music so clock is always 64 fs leaving sample freq and channel as original
My output config is
audio_output {
name "snd_rpi_hifiberry_dac"
type "alsa"
device "hw:1,0"
auto_resample "no"
auto_format "no"
format "*:24:*"
enabled "yes"
}
Remember my dac is a pcm1794a NOS like dddac
Got working 16 and 24 bit music selecting HifyBerry dac and adding format "*:24:*" to /etc/mpd.conf.
then kill and restary mpd with
sudo mpd --kill
mpd
At reboot you will get only noise because rune overwrite mpd.conf, so you must re-edit manually it.
This force 24 Bit even on 16 Bit music so clock is always 64 fs leaving sample freq and channel as original
My output config is
audio_output {
name "snd_rpi_hifiberry_dac"
type "alsa"
device "hw:1,0"
auto_resample "no"
auto_format "no"
format "*:24:*"
enabled "yes"
}
Remember my dac is a pcm1794a NOS like dddac
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