Sample rate or codec issue causing 'ragged' audio quality?

[theavguy99]

What a wonderful DIY project, thanks Jeff for sharing this!

I've had fun making this project work and have learned a few things along the way too!

I've noticed that the audio playback quality is somewhat 'ragged' as I'd describe it. I've tried changing the sample rate between 44.1k and 48k but there wasn't any change in the quality of playback- the only difference was when I first loaded and tried the player I think it defaulted to 44.1k sample rate and I noticed that the songs played a bit fast and that the overall pitch was slightly higher than normal. Changing to 48k solved the faster playback/pitch issue, but I still notice that piano or horn notes in a song have a digital edgy-ness or ragged character that does not exist if I take the same usb interface and play the same stream using a pc. Sounds a bit like what I remember old 8 bit audio devices sounded like.

My settings in /etc/mpd.conf "audio output" section are exactly as you show them in part 5, with the exception of changing 44100 to 48000 as described above.

I'm using a fairly good quality sound blaster external usb interface, that I use regularly on a pc and works very well. The only thing I notice is rfi leaking into the audio path if it's too close to the asus antenna, but moving it a few inches away solves this.

The 'raggedness' I'm hearing is not mp3 compression artifacts nor do I believe it's choppy network playback performance as the stream plays fine.

So is this just a limitation of the linux audio codec or is it a hardware/config setting that I've just missed?

Thanks!

[mightyohm]

Hmm. I haven't experienced the ragged quality with the SYBA adapter and the settings given in the tutorial. I wonder if the sample rate of the stream you are listening to doesn't match your audio adapter, and the router is doing some crude resampling that is causing the problem? I would try picking up a SYBA USB-audio adapter (they are cheap) and see if that solves the problem.

I have definitely seen RFI issues, and in fact my finished radio suffers from some RFI coming in through the audio adapter. Fixing this is on my long term to-do list, but it's not bad enough to warrant ripping the radio apart to fix it just yet.