Transient Click at start of aplay audio?

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mrperrier
Posts: 4
Joined: Sat Sep 30, 2017 5:59 pm

Transient Click at start of aplay audio?

Post by mrperrier » Sat Sep 30, 2017 6:03 pm

Hi there,

Just got this Octo, pretty cool.

Would like to see if anyone has experienced a click at the beginning of aplay. It seems that if you play a short sound and another quickly afterwards there is not a click at the beginning but if you wait a time the click returns.

Any advice in dealing with this is appreciated.

Thanks.

flatmax
Posts: 609
Joined: Sat Jul 23, 2016 11:39 pm

Re: Transient Click at start of aplay audio?

Post by flatmax » Sun Oct 01, 2017 2:06 pm

Hi there,
There should be some alsa mixer settings to change these clicks ... not near an octo right at this point, will look for them soon.

Matt
Check out our audiophile quality crossovers : https://bit.ly/2kb1nzZ
Please review the Zero sound card on Amazon USA : https://www.amazon.com/dp/B075V1VNDD
---
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mrperrier
Posts: 4
Joined: Sat Sep 30, 2017 5:59 pm

Re: Transient Click at start of aplay audio?

Post by mrperrier » Mon Oct 02, 2017 4:26 pm

Hi Matt,

Thanks for the quick reply.

I just did a test, changing alsamixer settings on the DAC (immediate, zero cross, soft ramp, soft ramp w zero cross) and the behavior in aplay stays the same. Still a click at the beginning on playing a short sample with aplay, if the playback is repeated shortly after there is no click, waiting a few more seconds before playing the short sample again the click is back.

Any ideas?

Thanks!

flatmax
Posts: 609
Joined: Sat Jul 23, 2016 11:39 pm

Re: Transient Click at start of aplay audio?

Post by flatmax » Mon Oct 02, 2017 8:54 pm

OK - I have a feeling this has something to do with ALSA DAPM. Just to be clear, this is an output only issue - right ? Nothing to do with recording ?

Hmm ... I wonder if there is a way to turn off ALSA DAPM ... that would be the solution.

If you were to comment out DAPM widgets and routes here and recompile the audio module :
https://github.com/raspberrypi/linux/bl ... ard.c#L247

That would most likely remove DAPM and fix your problem, because the power would remain on all the time. NExt time I am fiddling with the driver, I will look into this for you.

Matt
Check out our audiophile quality crossovers : https://bit.ly/2kb1nzZ
Please review the Zero sound card on Amazon USA : https://www.amazon.com/dp/B075V1VNDD
---
Check out our new forum on github : https://github.com/Audio-Injector

mrperrier
Posts: 4
Joined: Sat Sep 30, 2017 5:59 pm

Re: Transient Click at start of aplay audio?

Post by mrperrier » Tue Oct 03, 2017 2:15 am

I am not sure if this problem exists in recording as my application is playback-only.

I will try recompiling this, commenting out the DAPM.

Interestingly omxplayer does not produce this clicking however I am using aplay because it's faster to playback.

I will keep you updated. I realize this problem is not unique to the octo, thanks for your help.

mrperrier
Posts: 4
Joined: Sat Sep 30, 2017 5:59 pm

Re: Transient Click at start of aplay audio?

Post by mrperrier » Tue Oct 03, 2017 4:37 pm

Having some trouble recompiling and installing this module, can you give me a rundown of how you'd do it?

flatmax
Posts: 609
Joined: Sat Jul 23, 2016 11:39 pm

Re: Transient Click at start of aplay audio?

Post by flatmax » Wed Oct 04, 2017 7:22 am

ok sure.

I decided to create a new post for a kernel hacking guide for the Pi :
http://forum.audioinjector.net/viewtopi ... 5226#p5226

Matt
Check out our audiophile quality crossovers : https://bit.ly/2kb1nzZ
Please review the Zero sound card on Amazon USA : https://www.amazon.com/dp/B075V1VNDD
---
Check out our new forum on github : https://github.com/Audio-Injector

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