Sudden distortion when recording

[Michaelk]

I am using 1.3.13 to transfer all my old records to FLAC. Quite often , i.e. once every 3 LPs or so, the recorded sound suddenly gets very distorted and “blubbery”. This situation continues until I stop the recording by pressing the STOP button. When I start recording again the problem is gone. I first experienced this on 1.3.12 and it is the same on 1.3.13.

I am using W7 64-bit with a 2GHz processor and 4GB RAM. The A/D is an external M-Audio FastTrack Pro. I record with a headroom of at least 6dB

Has anybody else experienced this problem? What can be done about it?

[kozikowski]

How are you transferring your LPs to Audacity? It's easy to get that wrong with a Windows Laptop. That and you might be suffering from Windows trying to "help" you.

Windows Enhanced Sound
http://forum.audacityteam.org/viewtopic ... 79&start=0

And last, do you like to record internet audio? Those are the exact opposite of the settings you need to record a record and can cause sound instability.

Koz

[Michaelk]

The M-Audio device is connected via USB. I have made the M-Audio device my default record and playback device. I have experimented with turning the Exclusive Mode in the Advanced Property menu on and off but the same error occurs irrespective of the settings. The error occurs at any time, sometimes after 3 minutes, sometimes after 20 minutes and sometimes never

And I have never recorded from the internet so I have not tampered with any of those settings (whatever they are)

[kozikowski]

And I have never recorded from the internet so I have not tampered with any of those settings (whatever they are)

Recording sound playing on your computer involves recursive sound pathways -- running the record and playback services of the computer at the same time. If you forget you did that, you can try to make a standard, plain recording and find you have echoes and talking-in-a-rain-barrel distortions. OK, so that's not you.

Does the work get very much louder, too, when it fails?

Did you keep any of it? It might be good to hear it.

Koz

[Michaelk]

the sound level is the same. No crescendos. I have a flac file of approx 4 MB that show the transition. can I mail it to you? What address?

[steve]

testing upload

[kozikowski]

Real Thing Upload.

Blurry_distortion.flac

(332.44 KiB) Downloaded 47 times

I can produce much more by linking, but I think this is enough. The digitizer is going nuts. That's not (IMHO) an analog error and Audacity cannot produce anything like that by straight recording, particularly in the middle of a note.

It doesn't sound like Windows conferencing processing, either.

You need to know that the original submitted clip has much lower levels than my submission. Mine is "amplified," the original had musical peaks at -25 or so. Not loud at all.

OK, let's go back up through the thread.....

Koz

[kozikowski]

I think your M-Audio isn't getting enough poop (technical term) from the computer's USB connection. The M-Audio is doing a powerful lot of work (generating phantom power, Headphones, etc.) and its operation may be constantly on the edge of failing.

Did you buy this?

============================================================
M-Audio FastTrack Pro
USB bus powered or works with external power supply (not included)
http://www.sweetwater.com/store/detail/TriggerFingPS
============================================================

That might not be a terribly awful purchase. We'll see what the other elves think.

Koz

[kozikowski]

The power supply is rated at 9 volts instead of the 5 volts that comes out of the USB connection and half an ampre is far and away higher than anything available from the computer. That's the power system that sounds much more appropriate.

Koz

[Michaelk]

It is certainly worth a try. I probably have a suitable PSU lying around somewhere. The funny thing is that I have been using the M-audio with this same computer for over a year now, partly for recording audio from a tape machine (using Audacity 1.2.6 I think) and partly as an audio measurement system, and it is only recently that this problem has turned up. It will be a couple of weeks until I get the time to try it out again. Will let you know. Thanks for your investigation.

/ Michael