LATENCY

[natureboy]

Finally i found the solution! The new Audacity version(1.3.3) has at the preferences section and in the "audio I/O" field, two keyes about latency. There i put 10 millisec. in both (just for trial-without knowing anything). And that's it! All the latency disappears! No skips, no lag, no delay! But if there is someone expert that can tell to us what exactly we must put at the latency field of Audacity 1.3.3 it will be very usefull. Thanks.

[alatham]

I would leave the Audio to Buffer field alone. Mine defaulted to 100msec. I'm not certain of what it does, but I think it's a playback delay. If you set it too low, Audacity has trouble playing files. I think this number will need to be higher for people making multi-track recordings, since Audacity needs time to add each sample up before sending it to the sound card.

Once that's set, you can do this to find the Latency Correction number.
1) First, set Latency Correction to 0.

2) Import a file (or record one) with a small bit of silence followed by some percussive sound followed by a few more seconds of silence. I have a recording of two drum sticks being smacked together that I used to do this.

3) Set Audacity up to record the output. Either set it up for Streaming Media, or run a cable from Line Out to Line In. Then highlight that first track and click record.

4) You should have two tracks now. If you zoom in enough, you should be able to see the time difference between the two tracks (since it's a percussive sound, this will be easy to see). Use the cursor tool to measure the time difference. Personally, my second track occurs .143 seconds after the first track.

If you're not sure how to measure the audio, take a look at those three time displays at the bottom of the screen. You can change the display format by clicking the drop down menu to show 'hh:mm:ss + milliseconds'. Then click the Length button (instead of End). Now highlight the portion between the very beginning of the two sounds. The second display at the bottom will tell you how much audio you have selected, this is the time difference you want.

5) Since my time delay was .143 seconds, I enter -143 milliseconds (remember the negative sign) in the Latency Correction field. Now I try recording again and it works.

I'll upload a screenshot at the end of the final step. The first track is the original one, the second is the uncorrected track, and the third is the track recorded with the -143 millisecond Latency Correction.

[natureboy]

You're right Alatham! That's why my Audacity playback was distorted. I'll do more trials... Thanks.

[Bradlee]

This is good stuff. I'm going to experiment with the suggestions below tonight. I do have some questions and any ideas will help....

I have a newly built pc (built by a prof computer tech for the purposes of recording....) and I just got a presonus firebox. I would like to record at 44100 and 24 bit. I'm having subtle clicking and popping and then I'm getting delay when multi-tracking. I did a huge project last year using audacity with a 3 year old Dell and external sound card and I was do 50 tracks in a 7 minute song and had no problem at all with clicking or delay. What could be the problem this year and what setting(s) should I go with? I'm using audacity 1.3.4 and though it can be unstable I like it better than the relatively limited 1.2. I'm actually about to pull my hair with this b/c I would like to already be recording. It seems like with the better equipment I have this year, I shouldn't be having so many problems. I've recently considered sending the Firebox back and going with another external soundcard. But, I would rather keep ther Firebox b/c what I'm recording with it sounds so, so good.

[richardash1981]

I think the clicks are down to a driver problem if you are running Windows, unless the machine is overloaded by other applications running in the background (Virus checker?), or has IRQ configuration issues. I'm afraid I don't put a lot of store by the fact that it was built for audio - was it benchmarked and tested with the OS installed after being built?

[kozikowski]

And everybody missed one. It takes time for the speakers or headphones to generate the sound and you to respond to it plus the microphone overhead. I'm perfectly clear those are tiny numbers, but you're making adjustments in the microsecond range. I did it by creating a click track and playing along with it. If I was constantly behind, adjust forward. A couple of passes and the overall average of my performance matched the click track.

MIDI control starts sixteen instruments one after the other. They're not all perfectly in sync with the downbeat.

Koz