Thanks for the new botic driver
Hi miero,
Thank you for opening this thread for the botic driver support and also for providing us the latest SD image with the new drivers.
After spending some hours for auditioning with this 3.15.1-botic1 kernel system, I'd like to report my experience with it, referring to your instruction and comments on the page from
http://bbb.ieero.com/.
> The distribution has integrated support for automatic shutdown of BBB
I enjoyed this. Thanks for this beautiful tweak. I also have my own history of damaging BBB a few month ago. ;-)
> By default the file is resampled if 44k1Hz frequency or multiples is being played. This might/will introduce hearable artifacts.
I confirmed it. After applying external clocks, playing the test_44k1_16b.flac file via MPD, that was heard with musicality under the built-in clock, became quite noisy and this was the case with all of my Red Book sources. Is there any way to avoid this problem?
> 1) using web MPC interface
The MPC interface is well designed and easy to use for a quick glance at the files.
> play FILENAME
The play command worked well and was more flexible in dealing with 44.1k sources than MPD in terms of noise-free play-back.
> 3) remotely form another linux machine by bbbplay
I enjoyed this hacking via a remote linux machine operating virtually on my Mac but how can I avoid entering my password requested by the BBB server before playing music?
> Notice: it does not support DSD
I hope this will be supported in the future.
> Installed clocks are configurable via:
- kernel option snd_soc_botic.ext_masterclk
For the temporary external clocks, I used either Amanero Combo384 DDC or I2SoverUSB DDC from jlsounds, both having MCLK outputs of 22.5792 and 24.5760 MHz, setting snd_soc_botic.ext_masterclk to 3. With this condition, I confirmed the sound files were played with its original SR.
> DSD format can be enabled via:
- kernel option snd_soc_botic.dsd_format_switch
First with this setting enabled, I failed to play the test DSD files provided under the /data, which caused severe signal drops, unable to complete the sequence.
However, to my surprise, the same setting went quite well with my personal collection of DSD sources, mostly DSD128 recorded from old vinyls, and, IMHO, the current botic driver appears quite well designed for this particular setting, that appears far superior to playing DSD by MPD with BBB connected to USB-DDC.
> The BBB has 4 serializers and each one is capable to generate:
- one stereo I2S channel
- one mono DSD channel
Here is a problem for me. By default playing PCM requires the LRCK pin to P9_29 header and the same pin must be moved to P9_41 header for 2-channel playing of DSD. I may be wrong with this understanding, but, if not, is there any way to move back and forth on the fly between these formats?
Anyway, I'd like to thank you, miero, for your great work. Cheers.
twluke