Nasty distortion when recording from USB -- Audacity works!

So I have a really weird problem recording via USB from my DJM 9000 Nexus mixer that I can’t crack. Despite not directly involving Audacity, I thought someone around here might be able to help me. I hope it’s reasonable that I ask here.

If I record via Audacity, the recording sounds fine! (This isn’t a solution for me, though, as I need to stream to a shoutcast server as well.)

I would always stream and record my mixes via a tool called Butt (http://butt.sourceforge.net/). It works fabulously. Well just the other day out of the blue, it started recording and streaming a really nasty version of my audio. It sounds fine from the mixer’s other outputs, but the USB stream as captured by both Butt and Traktor is a distorted mess. It sounds like a mismatch of sampling rate, if I had to guess.

The fact that TWO apps are suddenly not recording right has me thinking OS X is to blame somehow, but I haven’t even done an update recently!

What might Audacity be doing differently from these two apps? Any ideas regarding what I might try next? I’ve played around for 1-2 hours on this one and haven’t made any progress!

Here’s a couple second sample of this weirdness: http://threadbox.net/problem.wav

You did restart the Mac, right? From the “chong” on up.

Do you like to record internet audio? It sounds like you may be recording multiple sound feeds at the same time.

Apple (upper left) > System Preferences > Hardware > Sound > Input. What do you have selected there?

Past that I got nothing. Audacity doesn’t do anything in real time except Play, Record and some timers.

Koz

I’ve played with settings in “Audio MIDI Setup” and elsewhere… I’m really not sure what else to even try! I’m hoping someone with a little more knowledge of audio in Mac OS can hint me.

Btw, this is OS X v10.9 and there are no updates in the App Store. The Audacity that is recording fine is 2.0.3.

Thank you for the reply, Koz!

Yeah, I even tried shutting it down cold. It’s recording everything coming out of the mixer – which is just the one tune. Again, it sounds fine in my speakers.

I have the DJM-900nexus selected as the input device.

The clip really doesn’t tell us anything because we don’t know what normal is. Record a simple voice track. Use a very high quality MP3 rather than WAV. I don’t think the super quality of the WAV is going to tell us anything, whereas a longer, slightly lesser quality track might be useful.

Koz

Whoa! New information.

I don’t have a nice acapella handy, but I did record the same 2 measures with butt and audacity. What I noticed is that when I play them back in Vox like I have been, they sound all distorted and nasty. When I play them in VLC, though, they both sound fine!

This issue originally became known because the dnbradio.com folks were letting me know my stream sounded really bad. It was only then that I noticed my recording sounded garbled. What I’m finding now is that VLC plays it just fine… o,O

I need a little help connecting these dots… lol

Thank you so much for sharing your thoughts, Koz. It is uber appreciated.

http://threadbox.net/problem-butt.mp3
http://threadbox.net/problem-audacity.mp3

Well I was able to broadcast live without issue the other day, so that’s good. I’m not even sure now of the correlation between the bad audio my live listeners heard originally and the distortion I hear when I play back my recording in the new Vox from the app store. It’s generally a fantastic little player, but is seems to have trouble outputting though my DJM 900 USB interface. That’s right – I’ve since discovered that it actually has the same trouble with other files.

But this definitely seems to be entirely outside the scope of Audacity now. :slight_smile:

Thanks and sorry for the noise.