Latency Test........Help!!!

FIrst off, I’m a drummer and an Audacity noob.

I am having a latency issue during playback after recording a drum track to a song file in Audacity. I have reached and been directed to the Latency Test Page and THOUGHT I did it correctly, but I am still having a latency issue. I am using a Roland TD-27 as my audio interface into my MacBook PRO.

I think what I may be doing incorrectly when doing the Latency test is the arrangement of cables. This is where I need someone to “hold my hand” and let me know what exactly I need to do.

Which output do I place my cable in?

I’m assuming I’m placing the other cable to the headphone jack in my Mac

Thanks Everyone!!!

Nothing goes into the headphone jack of your Mac. That connection is always going to be “one computer late.”

Plug your headphones into your interface. Set Recording latency by playing a click or backing track to your interface and jam the headphones against your microphone.

Screen Shot 2021-07-27 at 09.14.49.png
Make an overdub recording.

The difference in timing between your new performance and the backing track is combined with the existing Audacity latency correction value. Don’t worry if you go the wrong way the first time. There’s no good way to describe how to do this.

When you get everything working, you can do this test and the backing track and the new track will come out exactly in time.

Then, when you actually perform, the backing track and all your performances will be exactly in time and play to your headphones in perfect theatrical time.

I make that sound so easy.

A super common error is recording your new performance and the backing track. That gives you two copies of the backing track and usually overload and clipping distortion. Make sure you are recording from your interface and not a software redirection program. Software redirection is really common. That’s what lets you record Youtube sound.


There’s a slightly less common cause of error. If you used one of the pre-baked Audacity click tracks, It’s possible to match up the wrong click. Instead of matching up Click One with Click One, you match up Click One with Click Four, which sounds the same, but is a whole second off.

That will give you lots of puzzled looks until you sort what happened. All the overdbbed music will be one whole phrase off.


I’m just now paying attention to the interface. Where is the digital connection to the computer? This doesn’t work with an analog interface.

Audacity can’t do production in MIDI.


That’s more better. USB printer cable. How old is this thing?

Do you have the adapter from USB-B to Mac Thunderbolt? Did you find an actual cable which will do that?


I took a lot of shortcuts in there. Stop me anywhere if you get lost.


Yes. I have an adapter that goes from the USB on the TD-27 to the Thunderbolt on my Mac.

Thanks for all your responses Koz!

Post back if you miss anything. I expect you to be able to do “Perfect Overdubbing” where you hear a theatrical mix of live performance and backing track in your headphones. Without digging in the Roland instructions, the knobs suggest this.

Big gushy headphones are good for performances like this.

I use the earbuds for the photos because they were small and I had them.


So the headphones coming out of my Roland module against the microphone on my Mac?

No. If you’re drumming, then that’s not going to work because there is no performance microphone.

That’s harder.

In all cases, after you perform an overdub, you can play both the backing track and the performance and push the performance track sooner or later with the Time Shift Tool (two sideways black arrows) until the two line up in time.

You can do that forever, but ideally, you adjust latency preferences until all the tracks line up automatically.

Try this. Generate > Rhythm Track.

That should give you a tick track with every fourth beat louder. TICK tick tick tick TICK tick tick tick TICK…

Use that as the backing track. Do an overdub and play your drum in time.

Play back both tracks and see if you can tell the difference between the two tracks.

Here’s a picture of what happens when they miss.

Drag-Select the miss as in the picture and read LENGTH from the little windows along the bottom. That’s the latency correction. You apply that number to the number already in the latency tool.

Audacity > Preferences > Devices > Latency > Latency.

Try the overdub again. See if it improved.

Yes, these adjustments are going to depend on your reaction time. That’s why the microphone technique is so handy. No reaction time.


There’s a performance hint. Always produce a lead-in before the actual song.

In real life, this is the drummer counting everybody down to a song. In this case, the backing track is counting you in.

Tick Tick Tick Tick Music.


Thanks for all your responses Koz!! SUPER helpful.

Curious. Once I’ve established my latency parameter and enter it into the Preferences section, will I not have to worry about it going forward or will it be required for every new track I record to?

Once I’ve established my latency parameter and enter it into the Preferences section

Not quite it. When you recorded your latency test, Audacity used the latency value already posted in Preferences. So your new latency value is the amount you missed plus the old value. And the old value is a negative number, so that’s what gives you the brain bleed.

Add the difference between the backing track and the new performance to the negative preference value.

… Whut?

That’s why I stopped trying to explain it. Just add the two numbers and see if the rhythm miss gets worse. If it does, then go back and subtract the two numbers.

And yes, the goal is to be able to overlay several passes of overdub and have everything—all the tracks—automatically come out in perfect time.

That sounds great, doesn’t it? That’s assuming your machine is in perfect working order, there’s tons of room on your SSD internal drive, you’re not using cloud drives, no Zoom settings, etc. etc. etc.