Audacity Forum

OS: W7
Audacity V 2.1.1

Before I get shouted at for not doing my homework, let me explain that I've just spent the last hour on youtube watching tutorials for seamlessly looping a track. What I gathered from these tutorials (and indeed what they proved) is that the process is as simple as downloading a loop and importing it into Audacity before using the 'repeat' function to create a loop to your desired length. So what am I doing wrong?

When I try this, the transition between loops sticks out like a sore thumb. Either there's an ugly audible hiccup of some sort (millisecond of silence or a 'click' sound), or the loop starts in the wrong place.

Is the problem that I'm simply using loops that, while they profess to be, haven't been produced accurately? And if this is so, how do I ensure I am using samples that will in fact loop seamlessly?

For the record, I use freesounds.org and simply searched for 'loops'.

OurJud wrote: ↑

Tue Sep 04, 2018 8:52 pm

What I gathered from these tutorials (and indeed what they proved) is that the process is as simple as downloading a loop and importing it into Audacity before using the 'repeat' function to create a loop to your desired length.

That will work fine, provided that it's a good quality / well made loop, and it is in an appropriate format.
(MP3 is a terrible format for loops because MP3s always have a bit of "padding" at the start due to a limitation of the format.)

I just picked a loop from freesound.org at random: https://freesound.org/people/DragonTran ... ds/388268/
It can be downloaded as a WAV file, which is good as it avoids the headaches of MP3.
As it is, it loops "not too badly", the length is right so it maintains a steady rhythm when looped, but it is not exactly "seamless".

In order to avoid clicks at the join, the person that made this loop just applied fades at the ends, but when looped, this is certainly noticeable as a drop in volume. This is possibly usable as is, provided that there is other stuff going on, but it can be improved.


As the first chord repeats almost identically several times at the beginning, I decided to replace the first "stab" with the second occurrence, so that I could avoid the problematic fade-in.
In this screenshot, the selected area is approximately the part that I duplicated (Edit menu > Duplicate) into the second track, and then carefully lined up with the first stab:
I then trimmed a bit off the end of the second track, and crossfaded it with the first track, using the "Crossfade Tracks" effect.
Then I trimmed the start of the second track so that it started at exactly the same time as the start of the first track
(Edit menu > Remove Special > Split Delete)
Then "Tracks > Mix > Mix and Render" to mix the two tracks into one:
Then it's time to do the same for the end of the track.
In this case, it was a bit tricky to line up the duplicated 2nd to last stab with the final stab in the first track, so I switched to the track spectrogram view so I could see the accent more easily.
Trimming and selecting for the crossfade
Final trim:
and final mix:
Then just a very short fade-in / fade-out at the ends so as to ensure no clicks, and the resulting file: (also uploaded to freesound.org and credited the original creator of the loop)

If you don't want to go through the trouble of carefully editing loops to make them seamless, the alternative is to buy commercial loops from a reputable company, or search through lots and lots of free ones to pick out the ones that work best.

In the long run, if you are interested in making sampled / looping music, learning the skills and techniques of precise editing is invaluable.

Thank you, Steve. I really appreciate the lengths and trouble you've gone to in order to answer this question.

Coincidently that was the exact sample I used when I was trying to get it to work.

I won't pretend I'm able to follow your instructions on first read-through, but I will study it closely and do my best to replicate your results.

That said, when I download and listen to your edit I'm still hearing the transition when I loop-play it or use the repeat function. Maybe it's not the best example to be playing around with, as it starts with a fade-in and I think it is this I'm hearing.

Actually, are you sure you uploaded the right track, as the profile when imported into Audacity looks nothing like that in your screenshot of the final mix?

OurJud wrote: ↑

Tue Sep 04, 2018 10:55 pm

Actually, are you sure you uploaded the right track, as the profile when imported into Audacity looks nothing like that in your screenshot of the final mix?

Yes, that's the right file.
Note that it has an unusual rhythm - it's not the usual count of :
"1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4"
it's got a count of:
"1, 2, 3, 4, 5, 1, 2, 3, 1, 2, 3, 4, 5, 1, 2, 3"

steve wrote: ↑

Tue Sep 04, 2018 11:07 pm

OurJud wrote: ↑

Tue Sep 04, 2018 10:55 pm

Actually, are you sure you uploaded the right track, as the profile when imported into Audacity looks nothing like that in your screenshot of the final mix?

Yes, that's the right file.

My mistake. Very sorry. I tried your finished edit again, opening it direct into Audacity and the loop sounds flawless to my ears! I must have been trying the original when I tested it before.

Once again thank you for this detailed tutorial.