MP3 file sounds normal, Audacity file v distorted! Why?

New user and voiceover, on a steep learning curve and could really use some advice!

Initially, made some demos and all worked fine. Using Windows 8.1 on a new lenovo laptop with Audacity 2.1.0 (.exe installer), and a Focusrite Scarlett Solo pre-amp.
When I listen to the MP3 files on mediaplayer they are normal, but when playing in Audacity they are distorted in various ways, it had been a constant flickering sound, now I just sound drunk!

Have attached an audacity file to give you an idea…

Any advice please?
wordpress sample.aup (1.98 KB)

Can you attach the problem MP3? It’s the MP3 that doesn’t sound right in Audacity, right?

We can’t listen to your AUP file… The AUP file itself doesn’t contain any audio. It’s just a list of instructions for Audacity.

well you’ve taught me something there for starters! :laughing:

the aup files and the mp3s are both distorting when played through audacity, whereas the mp3s are fine when I play it on mediaplayer.

what am I doing wrong?

much appreciated!

It may not be the problem you think it is. The clip you provided is pure and clear here. I performed a simple volume change and got it to pass ACX Audiobook conformance (attached, last sentence).

No clue why it’s appearing distorted or damaged there. Windows is famous for “helping you” with your audio whether or not you want the help. This may be a problem for the Windows elves. I’m a Mac elf.

Screen Shot 2015-06-09 at 10.26.01.png

The AUP file is a list of instructions of what Audacity should do with all that stuff inside the _DATA folder. That’s where the actual show is. You need them both and they both have to be in the same location or folder to work.

Don’t fall in love with MP3 files. Those are good for submission, posting and listening on your personal music device. They’re terrible for production. Do all production and archive work in WAV (Microsoft). Then, after everything is perfect, make the MP3. Each time you edit an MP3, the quality gets worse. You can go from a perfect WAV to any other format, but you can’t generally come back.


You may have found this already, but Audacity Projects (AUP) do not save UNDO. Once you save a project and exit, the UNDO system clears.


Wow - thanks a million for all that super helpful info Koz. Did not know about the UNDO thing! - eek so much to learn.

Especially happy about passing the ACX test-hallelujah! and that was totally raw. great. something’s going right at least!

Hmm…to sort out this baffling distortion.

Windows elves? any ideas?

They are going to ask you about your playback system. How are you listening to the work? Model numbers?

What are the settings in your Audacity Device Toolbar?

Does it misbehave when you listen on headphones? Earbuds may not be very helpful, but some in-ear earphones might be OK.


Just based on our experiences so far, the work probably sounds fine on other machines? That can help narrow it down. “It sounds fine on my mum’s machine and Koz’s, but not mine…”


Especially happy about passing the ACX test

If you have a reasonable microphone and recorder and a studio-ish quality room, there’s no reason not to produce audiobook quality material straight-away. Some people produce ratty work and then go through pages of effects and filters to “clean it up” in post production. ACX specifically tells us not to do that because it can make a voice sound funny and unreal.

When I get back I’ll tell you the steps I did to make it conform.


The short, bumper-sticker version is apply normalize to the clip you supplied to us.

Select the whole clip by clicking just above MUTE.
Effect > Normalize: [X]Remove DC, [X]Normalize to -3.2 > OK

The analysis program is a plugin written by flynwill (acx-check.ny, attached) Put that in your Audacity plugins folder just like an external effect or filter. Restart Audacity.

Select the whole clip by clicking just above MUTE.
Analyze > ACX Check > Wait.

Do you know what the ACX values are and what they mean?

acx-check.ny (5.6 KB)

I need to find out what these are! (model no’s).

I have just changed to MME - I had it on Windows Direct Sound previously, thinking that was the correct setting. This seems to have worked for most but not all of the tracks, the ones now giving trouble - a juddering effect like I had before the drunken one! - are audacity files!

yes, only listening via headphones.

Going through your other messages, many thanks again for all the help!

Bonnie, you’re in good hands. If you’d like to compare notes on submitting to ACX (which I’m about to do), please let me know.

Meantime, I have a quick, relevant question for Koz.

Does one use the ACX Check on the Audacity .aup work files (before exporting) or on the final MP3s? Because in my experience (and you mentioned this in the other thread), the MP3s’ noise levels get wonked around during export and don’t pass the tool’s requirements, even if the original work file did. Does the state of the MP3 not matter if the original was fine? Or should I be adjusting the original so that the MP3 ends up within parameters?

It’s a little more magic than that, although that would be magic enough. MP3 works by figuring out, magically, which sounds you need for your show and which it can throw away. As the MP3 quality settings get lower, it throws more and more away. You would think that the show would get quieter and quieter as pieces were deleted, but some delicate overtones and harmonics actually subtract from the show volume. So when MP3 deletes them, the volume goes up.

Right away, there’s storm clouds.

So it’s possible to set the blue wave peaks to -3.0dB as in the ACX specifications, but have the final MP3 come out over that, -2.9dB or -2.8dB. That’s why the final pass in almost all my tool lists is to apply Normalize at -3.2dB. The difference between -3.2dB and -3.0dB is the fuzzy zone where MP3 is allowed to do its work without losing conformance. If that’s too tight for you, by all means pick a different number, but also remember the values affect each other, so don’t wander too far away.

By all means do open up your MP3 in Audacity and re-apply the analysis tool. You don’t have to work in a vacuum (It hurts my ears when I do that).

I’ve never heard of MP3 affecting the noise level, but another thumby rule is never submit with borderline values. If your show noise comes in at -61dB and Anything At All goes wrong, you could fall out of compliance (-60dB).

We don’t have ACX blessing for our tools. We’re just going on their published specifications and our success rate.


That sounds great, though that may be a few weeks down the road for me, I’m just doing my first few takes in my new booth and trying to get to grips with the audacity machine, though hoping to be ACX-fit very soon, as I’ve an audiobook in the wings…

I’m still having sound distortion in playback.

Have switched between ‘MME’ and ‘Windows Direct Sound’ to see if this is the issue, but this is working sometimes (the track becomes perfect) but not all. I still get a flickering over the track, both the mp3s and the audacity files. Have been working through all relevant (I think!) suggestions of the manual to try and fix the problem but no go. Could ‘audio host’ be the issue here? I’m on windows 8 - the manual tells me that MME is usually the most compatible…


thanks :confused:

You may be in good hands, but you’d be in better hands if I was a Windows elf. I’m not. If you’re having Windows sound problems, we have no choice but to wait for someone who can speak Microsoft. Sorry.


Ok Koz, thanks anyway. Can I post a new topic on the forum? - as I have come some way since my original query and the question/issue has now changed slightly.

Yes, please do If the problem is with Windows audio, please describe what the issue is as clearly as you can.

Post the information from Help > Audio Device Info… top right of Audacity. Right-click in the Audio Device Info and choose “Select All”. Right-click again and choose “Copy”. Then paste into your post.


Hi again Koz - touching all wood as I write… I seem to have finally resolved my sound problems. Seemingly I had to install the latest driver for my pre-amp, a process which somehow didn’t happen when I bought it (I also recently changed PC). Don’t completely understand why, but hey, all is smooth as a millpond right now. Hallelujah. Many thanks to you for all the help and tips :stuck_out_tongue: . Especially for the ACX checker plug-in, it’s brilliant. Now I can finally get some work done :smiley: