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Improving audio quality

Posted: Sun Nov 12, 2017 10:49 pm
by trawson
Hi all ...

I'm an old hand with computers but new to Pi. Current setup I'm testing is a Pi3 running MusicBox to drive a set of speakers in the kitchen. This is sort of proof of concept and if it works I will put more Pis and speakers around the house. This is just for streaming in each room, not trying (yet) to sync the rooms.

So I have the Pi3 all set up and I have been testing it with a tiny amount of content from NAS plus some via Airplay,. It all works but the noise level -- crackle, hiss, hum -- out of the speakers is bad, especially when nothing is playing. I know the current setup is not well-done but I'm not sure which issue to address first. Here are the questions:

  • Power supply -- do I need an EMI filtered supply? They seem pretty expensive.
  • Alternatively, are there in-line filters available for the USB power cable? I know I can build my own with capacitors and choke but I would rather have something packaged.
  • How much of the noise is likely to be due to using the on-board audio? I plan to add a DAC and I have a pimoroni PhatDAC here, but haven't installed it yet.
  • Any other suggestions?
Thanks for any help!

Tom

Re: Improving audio quality

Posted: Tue Nov 14, 2017 5:41 pm
by hitsware
If your ' phatdac ' has anywhere near the affect
as a ' hifiberry ' , you will jump up for happy !

Re: Improving audio quality

Posted: Tue Nov 14, 2017 6:34 pm
by FM81
If you mean this https://shop.pimoroni.com/products/phat-dac - yes, it has the same chip as the first hifiberry (over years lots of other versions was added) and there should be no significant difference in quality. It simply sounds good. But be aware that it is line-out-level only, means for driving speakers is an additional amplifier needed.

Greetings, FM_81

Re: Improving audio quality

Posted: Tue Nov 14, 2017 10:54 pm
by trawson
Thanks ... I believe that is the same board I have.

Do I need to do anything to filter the USB power?

Re: Improving audio quality

Posted: Fri Nov 17, 2017 10:43 am
by FM81
I assume NO! I've never needed such kind of filtering on my projects. But avoid ground-loops where ever you can ...

Greetings, FM_81