Audacity Forum

Hello,

I've just been given a new computer by my employer which runs windows XP. I have previously had quite a bit of experience using Audacity 1.2 on an XP machine and 1.3 betas on a windows 7 machine. Now I'm running Audacity 1.3.14 on the new xp machine and am encountering a problem I've never seen before. I use Audacity to record music from a traditional turntable through an ARTcessories USB Phono Plus digitizing pre-amp and into my computer. The amp is a plug-n-play USB amp, so no drivers. Again none of this has caused any problem until now.

Now for the problem: At random points while recording, the audacity track appears entirely red (click detector on). The music, which I am monitoring through the pre-amp sounds fine and there is no indication of a change coming from the turntable. However, when I play the red (or all-blue) part back, all I get it static. So, since I've checked the head shell on the turntable and changed the USB cable (to one right out of the box) and there are no possible driver problems, I'm at a loss as to what to change next, as the problem continues. I record primarily classical music, so I aim for a high quality recording, usually using the 32-bit float option. If possible I would like to fix this without lowering recording quality.

Any suggestions would be greatly appreciated!

Topic moved to the Audacity 1.3.x part of the forum.

It sounds like you have the pre-amp level set a bit too high. When setting the level aim for a maximum peak level of about half the track height (minus 6 dB). That level should allow sufficient headroom to avoid distortion while still providing plenty of dynamic range.

I know the rules on that one. It's not about gain or anything like that. It will record for 4 minutes or 40 minutes without any trouble at all, then all static all of a sudden. No changes to the music, no sudden movements or shifts in my chair, it just seems arbitrary. I just tried a recording on Audacity 1.2.6, which I also have installed, and it did the same thing. It got through 50 minutes of a record before going all static, so I don't think it's specific to the build. It must have something to do with the hardware or settings of this new computer. As I said, on other machines everything has worked perfectly. This computer is the only variable it seems. Could any settings be causing this problem?

I've been through most of the obvious stuff already with Erich when he wrote to [email protected]

You could look in Device Manager in the Windows Control Panel to see if there are any yellow exclamation marks for USB Controllers.

Is this XP Media Center Edition? A lot of hardware is not compatible with that.

Using a different length of USB cable could help. Shorter cables are less noisy in my experience, if they are long enough to prevent interference between computer and equipment.

Does the computer have a line-in? Can you connect the line out of the ART Pro to that, so avoid the USB connection?



Gale

Are you going through a USB hub? Audio doesn't much like that.
Koz

Thanks again for the feedback everyone. I'm definitely not going through a hub. The device manager says USB controllers are fine. It's XP pro. The USB cable is only 3 feet long. I'm not sure they get much shorter than that! So, I think that leaves the line-in option, which I had definitely never considered. Would that affect the quality of the audio input? I'll definitely give it a try tomorrow morning. Here's one question that may make me seem stupid, but I'll survive: If I'm going with the line-in option, can't I bypass the middle-man? In other words, why go through the USB amp at all? I have the right type of cable to send it straight from my stereo amp into the line-input. Do I need one of those USB pre-amps if I'm not using it for USB?

Thanks again for all the feedback!

Is your new computer a Windows Laptop? They tend to be missing the Stereo Line-In option.

This is a desktop sound card with the traditional three connections. The green socket is where you put your earbuds or headphones. The blue socket is the Stereo Line-In where you would plug your music system, mixer or stereo cassette machine, and the pink one is the super sensitive mono connection for a special purpose computer microphone.

http://www.kozco.com/tech/audacity/pix/ ... Final2.jpg

Windows Laptops are generally missing one...

http://www.kozco.com/tech/audacity/pix/ ... pSound.jpg

..and guess which one.

Koz

anevsky wrote:I have the right type of cable to send it straight from my stereo amp into the line-input. Do I need one of those USB pre-amps if I'm not using it for USB?

If you have an amp with a phono input for the turntable and a headphones out or line/tape/aux out, then no, you don't need the ART phono... assuming you have a line-in on the computer (or a mic input switchable to line in).

Something like the ART Pro should (in principle) give better quality than an inbuilt sound device, and probably does until the noise sets in.



Gale

Hey guys,

Back in the office, and you're right, there is no line-in option on this laptop. This is the third laptop I've had from them and it's the only one without it. There is only a headphone jack, although there is a microphone button on the f-keys and I can get it to record my voice. I just don't know where the mic is and it doesn't seem to be related to the jack (I tried using the jack as a line-in to see if it would make a difference, but still the only thing it picked up my the noise of me moving around the room). Ugh, so that option's out. By the way, I've tried a couple more times today. Even tried with a the USB/eSATA port instead of the traditional USB ports I've been plugging it into, just to see if it would make a difference. Also set the gain down low enough to where the audio never passed -9 before the static set in. I'm at a loss with this thing. I've also tried everything I can think of with the sound settings on the computer--recording with the speakers muted, recording with them unmuted... Not that those should make a difference, but nothing seems to make a difference. I could record a whole record without the static or just 5 minutes, but the problem never goes away.

The problem appears to be in the chain where the digitized audio is sent from the USB driver to Audacity. Are you running any tasks other than Audacity? Is there an anti-virus scanner running in the background. If Audacity is not given the CPU time to grab the digitized audio, it will lose bits of it and the result may sound like static, but could actually be chopped up bits of what you are trying to record. When the static happens, what is the actual recording time as indicated in Audacity versus the actual time of the LP you are recording? If you watch the recording cursor during a burst of static, does it move smoothly, or is it jerky? Are you zoomed in to the recording, so that the waveform display has to constantly scroll and refresh?

-- Bill