Combining three 24 minute MP3 audio files

I am transcribing my professor’s lectures this semester. I am recording them on my iPhone and emailing them to myself. Unfortunately, I am unable to email the entire file and had to split each class lecture into three 24 minute segments. I then converted these segmented files to MP3s and did my transcription. Now, I would like to combine the three MP3 files back together and was hoping that I could use Audacity to help me do the job. I tried to stich two of the files together but I couldn’t do it. Using Time Shift Tool worked but seemed like it wouldn’t let me combine two 24 minute files – I could only add a piece of the second file to keep the time to less that 32 minutes. I was wondering if there is a 32 minute limit or am I doing something wrong.

I was wondering if there is a 32 minute limit or am I doing something wrong.

Sorry, I don’t have any idea what the problem is…

No… There’s an Audacity time limit (or file size limit) but it’s many hours. WAV files are limited to 2GB (or 4GB depending on which spec you read) but as far as I know, there’s no limit for MP3s. (I’ve made some concert MP3s that are around 4 hours long.)

Are you using the latest version of Audacity (2.0.6)?

If you don’t get a quick resolution, try [u]mp3DirectCut[/u]. It’s a special-purpose MP3 editor that can do (limited) editing without first decompressing the MP3 file. That’s an advantage if you are ever working with music (or other high-quality files) because you don’t go through a 2nd lossy MP3 compression step when you re-save (export) to MP3. Plus, it’s a little faster because you are working with smaller-compressed files and you don’t have to take the time to decompress & re-compress them.

Sometimes shorter segments or “chapters” might be preferred! Although, you’d want to split at appropriate times, not always every 24 minutes.

Have you tried zooming out (CTRL + 3)?

Instead of splitting the file so you can e-mail it, why not upload the file to “cloud” storage online, then go there to retrieve the file when you need it? Dropbox for example lets you upload files as large as 10 GB using their web site


I appreciate the suggestions. Turns out I am guilty of being a newbie to this impressive software. I was able to connect all three MP3 files and save it (saw it on you tube). Only problem I wasn’t able to stich them together properly. I tried to manually align the files and I got close but the overlap was obvious with the echo chamber effect. I would like to know if there is a stitch option where the files can find the overlap and join together at the proper point. Anyone know if that’s possible? If not, where (e.g., what other software package) should I look to obtain this function? Thanks in advance!

This should not be at all difficult. Are you sure you are using the latest Audacity 2.0.6 from

When you drag tracks to align them with tracks above or below, you should see a yellow Boundary Snap Guide that lights up as a yellow vertical line when you have an edge of one track aligned with the edge of another track.

Even easier, import the files. Make sure the top track is the first file, the second track the second file and the third track the third file. If not, click and drag above Mute / Solo (where it says “Hz”) on any track to move it up or down.

Then CTRL + A to Select All, then Tracks > Align Tracks > Align End to End, then Tracks > Mix and Render.

Now you have all three files joined together in one Audacity track. Is that what you want?


I want to eliminate the overlap in the files. These are lectures that were split into three MP3 files. Unfortunately, there was overlap in the files when they were split up. Now, I want to join them back together without repeating any of the text of the lecture that overlapped when the big file was cut into three little ones. It wasn’t a surgical cut, so there was a maybe 30 seconds overlap between the 3 little files.

If you just want to do a rough job, drag-select the overlap that exists in one of the files, press Z on your computer keyboard to find Zero Crossings, then press DELETE on your computer keyboard.

Repeat for the other overlap in one of the tracks.

Then if you want you can use the Tracks > Mix and Render item as described above, though export will render into one track for you.

If you want to do a more professional job, align the overlaps together exactly, then use Envelope Tool to fade out the overlapped area in the upper track and fade in the overlapped area in the lower track.

Repeat for the other overlap.

I am guessing you don’t need to use Envelope Tool for a lecture.