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Distorted exported MP3 tracks

Posted: Sun May 03, 2009 3:22 pm
by julia63
I have looked in all the written information and can not find the answer to this problem. After I edit a aup track I export it to MP3. The MP3 file sound is distorted. It may have clipping or may not. Sometimes this happens and sometimes it doesn't. I also am getting distorted aup tracks after I save and reopen. I have tried I/O sliding without results. Is there a feature on audacity I haven't discovered that can restore these tracks to the original sound? I am editing talks not music. :cry: I am using 1.25 Audacity. I couldn't figure out how to export to MP3 in 1.3x version. Thanks for any help!

Re: Distorted exported MP3 tracks

Posted: Mon May 04, 2009 5:30 am
by kozikowski
<<<After I edit a aup track I export it to MP3.>>>

An AUP file is an Audacity Project Manager. It's job is to keep track of all the editing you did and where all the parts of your show are. It's not a track or a sound file.

Audacity will try to add up all your active tracks when you Export. If that sum comes out to over 100%, then you will get a distorted Export. If you sense the Exported show getting crunchy or harsh, apply the amplify tool to all the tracks equally and reduce the level of everything 3dB. More if the crunchy is severe.

I bet you're asking yourself if there is any way to catch this ahead of time. I'm wondering that myself. You're not the first poster to get burned with this.

Koz

Re: Distorted exported MP3 tracks

Posted: Fri May 07, 2010 10:13 pm
by Udo
Hi,
I have been using Audacity 1.3.6 up to now. Since I installed the latest version (1.3.12), I have sever quality problems exporting to mp3 with 128kbs.
It seems to be a problem related to Lame. 1.3.7 upwards requirers Lame 3.98.

I have done some testing. Please listen to the mp3s attached, it speaks for itself.
Regards
Udo

P.S.: can I only upload 3 files?

Re: Distorted exported MP3 tracks

Posted: Fri May 07, 2010 10:15 pm
by Udo
Here are the other 2 files
Regards
Udo

Re: Distorted exported MP3 tracks

Posted: Sat May 08, 2010 9:56 am
by steve
The recommended version of Lame for Audacity 1.3.12 is version 3.98.2 which is available from the link on this page: http://audacityteam.org/help/faq?s=inst ... m=lame-mp3

Re: Distorted exported MP3 tracks

Posted: Sat May 08, 2010 6:14 pm
by billw58
Udo:
I downloaded the fifth file (1.3.12 with Lame 3.98) and the levels are extremely low. I was able to amplify it by 23.8 dB. I don't hear distortion so much as intermodulation of the piano and the noise, particularly a spike at around 100 Hz.

Try doing Effect > Amplify before you export and see if that helps. Better still is to get the levels right when recording.

What is your setup? What machine, what OS, how are you getting sound into the machine, and what external equipment are you using?

-- Bill

Re: Distorted exported MP3 tracks

Posted: Sun May 09, 2010 2:46 am
by Udo
Hi Bill (and stevethefiddle),
I am aware that the original recording is at low a level (and one of the microphones has a slight hissing problem). My point is that the lame 3.98.2 (which I was referring to when indicating 3.98) is remarkably distorted when compressing to mp3 128kbs (constant) compared to the 3.39 version. Just download the file "Test 1.3.6 Lame 3.3.9" and compare for yourself.

I have tested it on Windows 7, Vista and Windows XP; all the same result. Hence, I reverted back to 1.3.6 in order to be able to use the old Lame version. I was just wondering why nobody seems to bother and just increase the kbs. 128 works fine for me. I would like to see that the development team considers this so that we can all enjoy better quality at 128kbs in newer versions of Audacity.

Regards
Udo

Re: Distorted exported MP3 tracks

Posted: Sun May 09, 2010 2:49 am
by Udo
By the way, I am recording using an external Lexicon Lamda sound device. All original recordings are of good quaity; only when I export to mp3 the diminissed quality becomes an issue.
Regards
Udo

Re: Distorted exported MP3 tracks

Posted: Sun May 09, 2010 1:30 pm
by steve
Could you upload the same recording as a WAV file so that we can run a comparison.

Re: Distorted exported MP3 tracks

Posted: Sun May 09, 2010 9:20 pm
by Udo
Hi Steve,
Here it is (I had to cut it down to below 1MB).

Regards
Udo