Ionic
Posts: 8
Joined: Sun Jun 04, 2017 4:56 pm

Audio HISS: disable_audio_dither or audio_pwm_mode???

Fri Jan 19, 2018 8:57 am

I don't understand which method I have to use for removing audio HISS on analog output.

I have to set disable_audio_dither=1 as stated here
https://www.raspberrypi.org/documentati ... t/audio.md

or audio_pwm_mode=2 from here?
viewtopic.php?f=29&t=195178

I have a RPi 3 and my system is updated with kernel 4.9.35-v7+, the latest official kernel from Raspbian.

Thanks

epoch1970
Posts: 1501
Joined: Thu May 05, 2016 9:33 am
Location: Paris, France

Re: Audio HISS: disable_audio_dither or audio_pwm_mode???

Sat Jan 20, 2018 3:12 pm

I’d recommend you add audio_pwm_mode=2 only.
This is a recent addition, AQ on analog out is truly good with this new driver.
It supports concurrent access, ie 2 (or more) separate programs outputting at the same time.
I’m not sure it is out of beta yet? For me, playing audio only with ALSA works a treat.

EDIT: As offered by jdb in his thread, I would recommend using SKIP_KERNEL=1 rpi-update if you don’t want to upgrade your kernel at the same time. I’ve used recent firmware with an older kernel (on piCore OS) and it just worked fine.
"S'il n'y a pas de solution, c'est qu'il n'y a pas de problème." Les Shadoks, J. Rouxel

Ionic
Posts: 8
Joined: Sun Jun 04, 2017 4:56 pm

Re: Audio HISS: disable_audio_dither or audio_pwm_mode???

Sat Jan 20, 2018 9:34 pm

epoch1970 wrote:
Sat Jan 20, 2018 3:12 pm
I’d recommend you add audio_pwm_mode=2 only.
This is a recent addition, AQ on analog out is truly good with this new driver.
It supports concurrent access, ie 2 (or more) separate programs outputting at the same time.
I’m not sure it is out of beta yet? For me, playing audio only with ALSA works a treat.

EDIT: As offered by jdb in his thread, I would recommend using SKIP_KERNEL=1 rpi-update if you don’t want to upgrade your kernel at the same time. I’ve used recent firmware with an older kernel (on piCore OS) and it just worked fine.
Thanks but If I use audio_pwm_mode=2 option I still hear "HISS" from speaker, so maybe this driver is not present on the latest kernel as I wrote here ;-)

P.S.: Can we use both options? By the way with both options "HISS" is present, so disable_audio_dither is not so good

epoch1970
Posts: 1501
Joined: Thu May 05, 2016 9:33 am
Location: Paris, France

Re: Audio HISS: disable_audio_dither or audio_pwm_mode???

Sun Jan 21, 2018 10:47 am

You should check AQ with headphones, too. Maybe the noise you're getting with speakers come from the amplifier or the line out cable.
"S'il n'y a pas de solution, c'est qu'il n'y a pas de problème." Les Shadoks, J. Rouxel

Return to “Advanced users”

Who is online

Users browsing this forum: No registered users and 7 guests