better audio quality for Raspberry Pi on audio jack

c64emu · May 27, 2016 at 3:21 PM

Available with rpi-update firmware is an experimental audio driver for the Raspberry Pi that should significantly increase the quality of sound produced by the 3.5mm audio jack.
The OP has reimplemented the original PWM-based 11-bit audio @48kHz as 7-bit 2nd-order Sigma-Delta modulated at 781.25kHz. The effective noise floor with this scheme approximates that of CD-quality audio DACs.
For more details see the following thread:
https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=136445

Implementation in LibreELEC is very simple:

There has to be the latest firmware. The latest firmware does adress some problems with KODI. vcgencmd version tells me, that the Version on LibreELEC is older and has still this bugs.
and two parameters in /boot/config.txt:

Code

dtparam=audio=on
audio_pwm_mode=2

**chewitt** · May 29, 2016 at 3:01 AM Official Post

This is on our radar but we're advised there are some issues (as well as fixes) with the newer firmware. When pi Foundation folks tell us it's a safe/good point to bump the default firmware we ship; we'll update.

**popcornmix** · May 29, 2016 at 1:29 PM

Note:
dtparam=audio=on is not required for kodi usage. It may be needed if you run external apps (e.g. emulators) that require alsa.
audio_pwm_mode=2 is sufficient for kodi.

You can manually update the firmware (http://start.elf/fixup.dat) to get bug fixes that aren't in Jarvis release.
You can use a Milhouse nightly build which does have latest firmware.

envagyok · October 31, 2016 at 11:59 AM

In libreelec 7.0.2 is it already embedded, and enabled?