As a matter of fact the BBB comes with a  24.576MHz  clock which allows
proper integer division on 48x samplerates.
And it also allows up to 384kbit samplerates! There's nothing to
believe. That's a fact. And it's better than what the PI offers.
The PI comes with 19.2Mhz, from an audio perspective not the preferred
choice. And it can't do more than 192kHz.
@HifiDuino you'll find all info you need.

The only way to get around these limitations on the PI with HAT dacs is
using the HifiBerry DAC+ Pro DAC. 
That's even better than the BBB default setup, since it also supports
the 44.1x family with a dedicated high quality clock.

Beside that I created for testing purposes a simple patch for the 4.4.x
kernel that let me run 384kHz on the PI2. 
I posted that one in the squeezelite thread.
And it works - a least at least when using sox as player. I havn't
managed yet to get my squeezelite working with 384kHz though.
Even that advantage of the BBB would be gone. 

Bottom line.
The rumor that the BBB has the edge over RPI with a master clock input,
thus can be slaved to an external  clock master, 
and also comes with audio compatible clock has been proved by now not to
be the full story. 
The HifiBerry DAC+ Pro very well feeds its clocks back to the PI and
covers all samplerate families with quality clocks.
But that's does not apply to all the other I2S PI dacs I'm aware of!
They have to live with that compromised clocking scheme, 
unless they'd have access to that "Integer-patch". At least for 48kHz
and 96kHz the situation would be improved. 
I'd assume and hope that we'll see more DACs with clocking scheme  like
the HifiBerry DAC+ Pro popping up sooner or later this year.

###

BTW. The newer 4.1.y and 4.4.y kernel versions also  include the 100%
volume control patch for the PCM51x DACs. 
Basically that setting of 81%=0db and above that facing distortions,
becomes obsolete.


#####

I2S-mmap

I think instead of waiting for backports that arrive -- who knows.
I consider it a no-brainer to add just that line  "dtoverlay=i2s-mmap"
to config.txt and add a 1 to the squeezelite buffer settings "80:4::1".
The overlay is available. We should eat what's on the table.



Enjoy.



::: ' Touch Toolbox and more' (http://soundcheck-audio.blogspot.com) :::
by soundcheck
------------------------------------------------------------------------
soundcheck's Profile: http://forums.slimdevices.com/member.php?userid=34383
View this thread: http://forums.slimdevices.com/showthread.php?t=105018

_______________________________________________
unix mailing list
[email protected]
http://lists.slimdevices.com/mailman/listinfo/unix

Reply via email to