Recordings play back at slower speed

[Peter S]

Thanks alatham for advice.

Changed the rate to 48000 as you suggested. Sadly this didn’t fix the problem immediately.

I recorded one side of a vinyl LP which I timed at 19 min 55sec. Audacity’s readout showed it at 21 min 38sec, which I make around 8.6% slow. The music was audibly slow on playback.

I changed the rate back to 44100 and immediately tried again. This time it worked perfectly. So did several subsequent recordings. Maybe simply changing and resetting the sample rate did something?

I can’t claim my estimate of slow running to be accurate to the last percentage point, but it has never run slow by as little as 5% or more that 10%. Whenever Audacity has run slow, it has done so in the region of 8-9%, so your theory seems persuasive.

Any further thoughts?

[steve]

Soundcards generally use their own clock to time the sample rate and keep it at a consistent speed. It sounds like the clock on your sound card is playing up. Do you have an alternative sound card to try?

[Peter S]

'Fraid not. Only what's inside my computer! I wouldn't know a sound card if it bit me on the ankle!

I've been doing some more recording today. First LP side - 8.6% slow as before. Flipped it over, and without changing any settings, side 2 recorded perfectly. 2 further LP sides recorded fine. Baffling!

If I was going to get into digital recording in a big way, I would consider upgrading my sound card (my PC's 4 years old). This is pretty much a one-off session to digitise some old analogue recordings. So long as Audacity manages to stagger through that, I'm content!

Thanks for your comments.

[steve]

I can understand you not wanting to make any huge financial (or learning curve) investment, but it may be worth trying a Behringer UCA202. They're cheap and I have one permanently connected to my turntable (via a phono pre-amp) and I'm very happy with the results.

http://www.behringer.com/UCA202/index.cfm?lang=eng

Some people have had problems with USB audio devices, but far less so with this one than some others. For the price and ease of use it may be worth trying.

[Peter S]

Many thanks stevethefiddlefor the tip and for being tolerant of the less technically knowledgable! (When you mentioned "new sound card", I envisaged having to crawl around inside my PC case with a circuit board in my hand!)

I read up a bit on the Behringer unit online, and this supports your recommendation. I decided to order one. Maybe a bit OTT just to record a few LPs, but sounds a useful bit of kit to have. Might even inspire me to do some more creative recording - get my old mic and guitar out!

I'll post another bulletin once I have got this unit up and running.

PS By a strange coincidence, I opened the local freebie paper and the UCA202 was mentioned in an article about DJ gear. I'd never heard of it until yesterday!

[Peter S]

Report back on using the ACA202

I'm now the proud possessor of one of these units. Pleased to say that my first couple of recordings are free of the slow playback I have been whinging on about here. Hope it's fixed the problem.

Audacity recognised the Behringer unit immediately - there was no need to select it as the input source from the drop-down menu. (In fact this box was 'greyed out' - no options were available.)

The input level appears to set itself - the recording level was unaffected by the slider input control. Setting it at 0.1 or 1 made no difference to the amplitude of the waveform. I'm surprised by this. Unless I'm missing something?

A minor inconvenience is that I can't monitor via my PC's speakers (though I can through the UCA202's headphone socket). I would have to connect the speakers to the UCA's outputs if I wanted to do that.

So far, so good!

[waxcylinder]

The probable reason that you can't monitor through your speakes because the USB device has hijacked the entire audio on your PC, both input and out (they mostly all do that) - and as your USB device does not have speakers you won't hear anything (unless, as you say, you connect your headphones to the UCA202). What you need to do to fix this is go to Control Panel>Sounds and Audio device properties>Audio and reset the output device to be your PC/s soundcard. It may also help to rest the output device in Audacity Edit>Preferences>Audio I/O - and set this output device too to your PC soundcard.

However it is generally thought to be better to monoitor on headphones as this minimizes the chance of aural feedback from the sound waves from the speakers to the record deck.

WC

[Peter S]

Thanks WC.

I changed both the settings as you suggested. The USB device had indeed imposed itself as the default in both places. But for some reason my speakers are still silent when recording.

Point taken about using headphones to avoid any form of feedback between speakers and deck. I would do this for any ultra-important material. For practical purposes though I found monitoring through speakers at modest levels worked well, without any audible ill effects - and my head wasn't attached to cans for hours at a time!