Exported MP3 and .wav files are intermittently skipping

I am running Audacity 2.1.0 on an early 2011 MacBook Pro 13" with Yosemite 10.10.3. When I record the initial Audacity project and play it back, it sounds perfect, but when I export the file to either MP3 or .wav, the exported file will skip intermittently during playback. It appears that a few seconds of the recording is being skipped each time and it seems to happen all through the recording.

Please help!

Audacity > Preferences… then the Recording section. Set Audio to buffer to 10 milliseconds. If that does not record consistently, increase the setting to 20, then 30 until it records properly. That lower setting should fix the playback issue.

If that does not help, please say exactly what you are recording and what your recording and playback devices are.


But if it plays back fine BEFORE it’s exported to MP3 or WAV, doesn’t that mean that the skipping problem has something to do with the export process?

I am recording from multiple lavalier mics (Audio Technica Pro70’s) into a Shure M-367 Mixer, then from the mixer via stereo mini into the MacBook Pro.

The MP3’s (what I usually export to) are usually played back on a laptop (mine or someone else’s)

Do the clips play OK in Quick Time Player and/or iTunes? It’s not clear how you’re listening to the clips.

I play the clips in iTunes, but when I send the clips to others, they are usually played using windows media player. The problem is happening in both players.

But you also said:

So I assumed you were only spot-testing in Audacity but listening properly in some other app.

Can you state that you can play through the whole recording without problem in Audacity as soon as it’s finished? if yes, please import the exported file back into Audacity. How does that file sound in Audacity?

OK, but please tell us what the Audacity playback device is set to in Device Toolbar.

And what is the selected playback device in System Sound preferences in your MacBook Pro, which is the device that iTunes will be using? Is your own laptop on Mac or Windows?


when I wrote: “recording is being skipped each time and it seems to happen all through the recording”, I didn’t mean the Audacity file, I meant the exported MP3 or .wav file when it’s being played back. As I said earlier, the actual audacity recording plays back totally fine. It’s only when I export it to MP3 or WAV that it skips when being played back.

The MP3’s (what I usually export to) are usually played back on a laptop (mine or someone else’s)

I have no idea what the Audacity playback device is set to in Device Toolbar (I send the audio files to people in other locations, that play the files back on their windows computers using windows media player.

As I said in the first message of this post, I’m using an early 2011 MacBook Pro 13" with Yosemite 10.10.3. I’m importing the MP3 file into iTunes to play it back.

That does not answer the question. iTunes is an app, not a device. You could be using iTunes to play to your external speakers, to an external Firewire interface, or anything. You could be using a different playback device in Audacity. We don’t know if you won’t tell us what that device is.

Can you save the original recording as an Audacity project, then make a ZIP file of the AUP file and _data folder, then post the ZIP and the exported MP3 on Dropbox or similar and give us the download link.

If you can’t do that then please post a short MP3 that displays the problem. Please see here for how to attach files: https://forum.audacityteam.org/t/how-to-attach-files-to-forum-posts/24026/1


Hi folks, I realize this is an old thread. I am also having this strange bitrate issue and wanted to describe my experience: I export audio from Audacity in either Medium, Standard, or High quality mp3. The problem happens the same in all files that are downloaded to an iPhone and played back from its Files folder. The issue is only the first 10-20 seconds or so, where the audio skips intermittently a few times almost as if it’s buffering, then plays normal. The audio does NOT skip in audacity. I’m assuming it’s an issue with bitrate not matching that which the iPhone prefers. If the file is sent over signal, for example, then it does not skip when played IN the signal application, which means the file itself is fine and the iPhone is what’s having the issue. Likewise, playing the audio in iTunes also works fine. My buffer is set to 100 milliseconds in Audacity. Big thanks for any suggestions

In the MP3 export dialog, try setting the “Bit Rate Mode” to “Constant”.

Thank you billw58 that fixed the issue. One more question in case you have experience mastering for audio books. I got the ACX plugin running now thanks to the good instructions here and it’s telling me that my noise floor is too low along with a comment (dead silence sounds unnatural). I’ve used silence in between phrases in order to eliminate background noise and/or breathing etc that was getting in the way of the audio. Is there a way to add in a noise floor that passes ACX check to entire files? I have a hard time seeing how to produce an entire narration without silencing undesirable effects so I imagine there must be a setting that can reset the “dead silence” floor points back into range? Cheers!

Koz is the expert on audio book mastering. That said, what you need is a second or two of “room tone” - the sound of “silence” in the room you are recording in. No breathing, no smacking of lips, no trucks going by. Then, instead of using the “Silence” effect, you paste room tone into those areas.

Let’s talk absurd hypotheticals… Let’s say that someone was a complete beginner at using Audacity and went apesh*t on a massive project without researching much of anything except for basic presets to make the voice sound better. Let’s further say that person spent 5 months producing 11 hours of now-finished audio content, and figured (hypothetically) that the best way was to cut out ALL the silences between words in every chapter, making tens of thousands of unnecessary edits. Then let’s say they ran into the purely hypothetical problem that I laid out for you. Would this hypothetical person then have to cut hypothetical background silence room sound into all of those places, or could they hypothetically get away with somehow replacing silence via a mass edit? Or perhaps there’s some sort of setting that can be applied to kill dead silence? Asking for a friend, hypothetically… Also, how do I find this Koz you speak of? Thank you for your help

Record some room tone - the longer the better. Create a new track and paste the room tone into that track. Select the track and do Effect > Repeat with enough repeats to fill the track with room tone. Play it back. Audacity will mix the two tracks, putting room tone in the silences. Adjust the volume of the room tone track so the mix sounds as natural as possible. Mixing the two tracks will double the room tone under the words, and this may sound weird. If that is the case, investigate the Auto Duck effect (Auto Duck - Audacity Manual) and see if you can “duck” the room tone track whenever there is audio in the spoken word track. Alternatively you could listen carefully for regions where the extra room tone is intrusive under the words and manually “duck” the room tone track using the envelope tool in just those instances

I have no idea if this will work, but it is worth a try before going ahead with thousands of picky edits.

You are a gentleman and a scholar. I shall report the results of my upcoming misery in detail in due time