Chiff and Fipple Forums

Since I play flute I decided to post this here. Sorry if I am in the wrong place. I have been trying to record myself playing along to tracks I have laid down using Audacity and am having trouble getting the tracks to align properly. It seems that I am in time while recording when I am listening through the headphones, but when I play the two tracks back they are out of sync. Am I missing something? Any help would be greatly appreciated.
Arbo

latency

realign after you've recorded
(select one of them and move it a bit)

I never seemed to have that Issue with Garage band. There must be a setting I am missing, or it's just a delay with the head phones...
Arbo

Yep, latency. There are some latency settings you can play around with in the Audacity options.

I also find it helps to first put down a click track as a steady reference for lining up multiple tracks later. It's tricky to slide stuff around, but the results can be pretty good.

I find that when aligning (there's a alignment tool - select the whole track and then use the alignment tool to move it back and forth) I get best results if I zoom in on a section in the middle of the tracks and slide around using that. Especially if there as spot where I take a breath or otherwise have a blatant element to align on because I can see the wave form(s) and align visually too. At the beginning I'm just a tad off sometimes until I steady up on the beat. Click track helps as MT says.

It might be what MTGuru meant, but in my limited attempt to do that (bodhran + flute) I added a click track on the end of what I would listen to in the headphones, then, just after finishing playing for the second track, put the headphones against the microphone to pick up the clicks in the second track. Tried doing it with the clicks at the start but it all got too exciting.

david_h wrote:It might be what MTGuru meant

I don't think so, that sounds too complicated ...

Audacity lets you generate a click track before you start recording. Make it long enough to cover your recording, plus a few extra bars at the beginning and end.

Record your first track against the click track, then adjust it so everything lines up. Subsequent tracks you can record against the click, or against the previous recorded track(s), or a combination of those. Again, line everything up after recording each track. Finally, double check the alignments and mix down.

At the time I was mindful that there are places in this (cyber) world where people get a bit funny about click tracks and the like (but me, I'm a metronome user). Although I think I was playing the bodhran to a commercial recording, then playing the flute to the bodhran. Checking out my general ability to play in time with things.

Playing rounds was another thing to try

I guess for all this to work the latency has to be constant ?

[edited the bit about rounds back in because I had edited it out - to stay on topic - it before MTguru posted !]

Yes, a click track can be a bit of a strait jacket. But once you record your first track against the click, you can, if you like, ignore the click and record the rest against the music tracks. And if you regard the first track as a "scratch track", you can re-record that, too. This approach helps to keep the results from sounding too mechanical. And in the end you still have the click track to help line everything up aurally and visually.

I agree, rounds can be a fun way to start exploring multitracking!

david_h wrote:I guess for all this to work the latency has to be constant ?

Yes, that's right. Pick a reference point in the track, and line it up with the corresponding click by sliding the track over. The rest of the track should then line up.

I wonder how fancier dedicated multi-tracking software (eg Cubase) gets around the latency problem? Perhaps measures it and automatically provides the needed offset? Anyone happen to know?

I wonder if you record a click (just a click, not a click track), replay it from track one while recording it (through the microphone) on track two, and then measure the offset (in mSec) between the two, can you use that offset number to realign actual music tracks? Even if it got you pretty close it might be handy.

I wonder if as you add tracks the latency increases due to more load on the computer's brains, or if it's a fixed value due to delays in processing, etc? That would become obvious with a few measurements.

Alternatively, record some extra click track before starting playing. When recording subsequent tracks, have the speakers unmuted for the first few seconds. That will put a few seconds of click on each subsequent track. Use these clicks to align the tracks?

Haven't tried any of this, but might have something to offer.

Terry

Thanks all for the suggestions. In the meantime I have gone back to Garage Band, as I seem to have no problem creating multiple tracks (in sync w/ themselves) using it. When I have some time to play around I'll revisit Audacity.
Arbo

Arbo,

Get a Zoom H4. They're great for multitracking.

Michael

Terry McGee wrote:I wonder how fancier dedicated multi-tracking software (eg Cubase) gets around the latency problem? Perhaps measures it and automatically provides the needed offset? Anyone happen to know?

usually the audio device driver software can report back what the input and output latencies are more or less accurately. Audacity seems a bit primitive in this regard, but version 1.3+ does have a way to manually set compensation for latency. here is the relevant section of the online Audacity manual. and here is a forum discussion that includes a post on how to use a click track to determine the best compensation amount, much like Terry suggests above. otoh, Reaper is powerful, complicated, cheap, and handles latency automatically.

fwiw, dan

bang wrote:Reaper is powerful, complicated, cheap, and handles latency automatically.

Yes, a good reminder. Also recommended by Peter Laban. Thanks.

bang wrote:

Terry McGee wrote:I wonder how fancier dedicated multi-tracking software (eg Cubase) gets around the latency problem? Perhaps measures it and automatically provides the needed offset? Anyone happen to know?

usually the audio device driver software can report back what the input and output latencies are more or less accurately. Audacity seems a bit primitive in this regard, but version 1.3+ does have a way to manually set compensation for latency. here is the relevant section of the online Audacity manual. and here is a forum discussion that includes a post on how to use a click track to determine the best compensation amount, much like Terry suggests above. otoh, Reaper is powerful, complicated, cheap, and handles latency automatically.

fwiw, dan

Latency happens both in the computer and also in whatever recording interface you have. For example the latency can be set a fair bit smaller if I record through my external box than if I use the built in hardware for the job. Nowadays though most modern machines are good enough to pass. Latency is set in number of samples and can be as little as 32 samples IE about as I remember 500th of a second, or thereabouts. Mine is fine at 64 samples.
It's astonishing that the damn thing records your note adds whatever effects you fancy "Set the reverb to Grand Canyon Scottie!" and then gets the whole lot back to your shell like so quickly that you don't notice any lag between playing and hearing... either it is really fast or we are really slow.