Sound quality of Raspberry PI 2+ I2S DAC - diyAudio
Go Back   Home > Forums > Source & Line > PC Based
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

PC Based Computer music servers, crossovers, and equalization

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 17th September 2015, 07:40 PM   #1
bading is offline bading  Italy
diyAudio Member
 
Join Date: Mar 2015
Location: Italy
Default Sound quality of Raspberry PI 2+ I2S DAC

Hi all
I want to buy a Raspberry PI 2 to play music (with volumio) but i have read and some say that 24bit are downscaled to 16 bit, when played through RPi.
It is true that 24bit / 96Khz FLAC file with the RPi and DAC are downscaled?
Thank's
  Reply With Quote
Old 18th September 2015, 03:16 AM   #2
diyAudio Member
 
Join Date: Mar 2007
Location: Bandung
It depend on your player software configuration. Try Moode http://moodeaudio.org , Moode Audio Player for Raspberry Pi
__________________
Didiet
WM8805+ESS9023 / SDHC Card I2S audio player + AK4430
  Reply With Quote
Old 18th September 2015, 04:36 AM   #3
diyAudio Member
 
timbarnes's Avatar
 
Join Date: Dec 2004
Location: Los Gatos
Quote:
Originally Posted by bading View Post
Hi all
I want to buy a Raspberry PI 2 to play music (with volumio) but i have read and some say that 24bit are downscaled to 16 bit, when played through RPi.
It is true that 24bit / 96Khz FLAC file with the RPi and DAC are downscaled?
Thank's
No - I use Volume with Raspberry Pi and a couple of different I2S DACs, and mpd seems happy to pass through the data unmodified. I think the HDMI output may be limited to 16 bit, but I don't believe there's any reason why the I2S output should be so limited.
__________________
Townshend Rock III, Hagerman Bugle 2, Naim CD5i, RPi Volumio, MiniDSP, Elliot P101, IRS2092, Parham Pi Sevens & Pi Three
RC Preamp (in progress), Pass BA-3 and F4, DIY Silver cables, Open Baffle BOFU, DIY subwoofer, GainClone, o2 Headphone Amp
  Reply With Quote
Old 18th September 2015, 12:15 PM   #4
Eldam is offline Eldam  France
diyAudio Member
 
Join Date: Sep 2012
Location: France
The problem of those boards is the quality of the I2S is not good enough : you need a MCLK to reclock the I2S output of the board not to waste the quality of those sources (bit perfect source).

But a MCLK, it seems easier and at least better for the sound to use a USB (with embeded MCLK) to I2S pcb between the nano PC board and the I2S DAC ! The asynchrone clock of the USB to I2S pcb saves you from the bad nano pc board clock !

There also some solutions to save the buy of a USB to I2S board, but it's not cheaper (e.g. a MCLK + buffered clock between the RasberryPi and the I2S DAC)

Last edited by Eldam; 18th September 2015 at 12:19 PM.
  Reply With Quote
Old 18th September 2015, 01:34 PM   #5
diyAudio Member
 
TimCurtis's Avatar
 
Join Date: Jan 2012
Location: Metro-Detroit
Quote:
Originally Posted by Eldam View Post
The problem of those boards is the quality of the I2S is not good enough : you need a MCLK to reclock the I2S output of the board not to waste the quality of those sources (bit perfect source).

But a MCLK, it seems easier and at least better for the sound to use a USB (with embeded MCLK) to I2S pcb between the nano PC board and the I2S DAC ! The asynchrone clock of the USB to I2S pcb saves you from the bad nano pc board clock !

There also some solutions to save the buy of a USB to I2S board, but it's not cheaper (e.g. a MCLK + buffered clock between the RasberryPi and the I2S DAC)
Hi,

According to NOTE #1 (below) in this HiFiDuino article, most i2s DAC's for Pi incorporate their own MCLK.
https://hifiduino.wordpress.com/2014...-pi-version-b/

"1. Notice that the DAC chips used are the ones that can cope without a Master Clock. RPi I2S does not Master Clock, so the DACs synch on bitclock and generate their own master clock."

Virtually all user feedback I get indicates excellent SQ from any of the i2s DAC's on the list in the article.

Regards,
moodeaudio.org
https://twitter.com/MoodeAudio
Tim Curtis
  Reply With Quote
Old 18th September 2015, 01:48 PM   #6
diyAudio Member
 
TimCurtis's Avatar
 
Join Date: Jan 2012
Location: Metro-Detroit
Quote:
Originally Posted by bading View Post
Hi all
I want to buy a Raspberry PI 2 to play music (with volumio) but i have read and some say that 24bit are downscaled to 16 bit, when played through RPi.
It is true that 24bit / 96Khz FLAC file with the RPi and DAC are downscaled?
Thank's
Hi,

Not true when Linux and MPD are configured for bit-perfect audio i.e., source sample rate passes through the the audio pipeline without any sample rate conversion. Moode and many other MPD based players are configured in this way.

On the hardware side, the Pi HDMI, USB and I2S interfaces support up to 24/192 and I believe up to 32/384 over USB and I2S but I would have to look back in my notes to confirm this.

Can you provide the link(s) where this information came from?
"but i have read and some say that 24bit are downscaled to 16 bit, when played through RPi."

Regards,
moodeaudio.org
https://twitter.com/MoodeAudio
Tim Curtis
  Reply With Quote
Old 18th September 2015, 05:48 PM   #7
Eldam is offline Eldam  France
diyAudio Member
 
Join Date: Sep 2012
Location: France
Quote:
Originally Posted by tppc View Post
Hi,

According to NOTE #1 (below) in this HiFiDuino article, most i2s DAC's for Pi incorporate their own MCLK.
https://hifiduino.wordpress.com/2014...-pi-version-b/

"1. Notice that the DAC chips used are the ones that can cope without a Master Clock. RPi I2S does not Master Clock, so the DACs synch on bitclock and generate their own master clock."

Virtually all user feedback I get indicates excellent SQ from any of the i2s DAC's on the list in the article.

Regards,
moodeaudio.org
https://twitter.com/MoodeAudio
Tim Curtis
To swap a SqueezeBox, those cheapy dac boards for Rasberry are good enough ! I talked in the spirit of something better than those plug& play boards ! Certainly a good SQ/P. In my mind a nano board is just a commodity, what ever its outputs : I will use async reclock and better : fifo buffer with its own Crystal signal and isolator !
  Reply With Quote
Old 18th September 2015, 07:11 PM   #8
bading is offline bading  Italy
diyAudio Member
 
Join Date: Mar 2015
Location: Italy
[QUOTE=tppc;4455746]Hi,

Can you provide the link(s) where this information came from?
"but i have read and some say that 24bit are downscaled to 16 bit, when played through RPi."

Comments in this article:
https://volumio.org/raspberry-pi-i2s...ounds-so-good/

Thank's for all
  Reply With Quote
Old 19th September 2015, 12:32 AM   #9
diyAudio Member
 
TimCurtis's Avatar
 
Join Date: Jan 2012
Location: Metro-Detroit
Quote:
Originally Posted by bading View Post
Quote:
Originally Posted by tppc View Post
Hi,

Can you provide the link(s) where this information came from?
"but i have read and some say that 24bit are downscaled to 16 bit, when played through RPi."
Comments in this article:
https://volumio.org/raspberry-pi-i2s...ounds-so-good/

Thank's for all
Hi,

I'm not sure whats going on in that blog but I could not find a reference link in the posts made by user "ralf" claiming that there is some sort of i2s truncation issue. That seems very odd.

I did a bit of searching on Github and was unable to find a bug report about "i2s 24 16 bit truncation". For further investigation, maybe ask question on one of the Github threads that the Linux i2s guy (Florian Meier aka "koalo") is on.

Regards,
Tim
  Reply With Quote
Old 20th September 2015, 04:10 PM   #10
diyAudio Member
 
Join Date: Dec 2014
I have not tried with i2s and the considerations above should be taken into account, but I have used it with a USB DAC (MusicStreamer Pro) with excellent results. It is my main music source in my setup for months now.
I have used Volumio but preferred Runeaudio (better performance). I plan to try Moode soon as it looks promising.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
My DAC for the Raspberry Pi usul27 Digital Source 147 8th November 2015 04:53 PM
Raspberry Pi DAC options recommendations?? JonesySA Digital Line Level 11 1st May 2015 12:14 PM
Opus DAC with Raspberry Pi Type B kinku Digital Line Level 8 11th April 2015 01:11 AM
Raspberry Pi: external I2S master clock (PCM_MCLK) wutzke Digital Source 25 17th January 2015 06:02 PM
Raspberry Pi I2S output as Asynchronous USB-to-I2S Tinco Digital Line Level 26 27th September 2013 03:18 AM


New To Site? Need Help?

All times are GMT. The time now is 07:38 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
Copyright 1999-2016 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki