Audacity Forum

I have used Audacity 1.25 for a long time to edit our church's service each week. It is recorded via Tascam recorder onto a CD. I take it home, choose the tracks I need, import them into Audacity, do the editing needed on each track, string them together with an intro and closing, then export it as an mp3 file using the LAME plug-in before podcasting. Everything has worked well until I downloaded the newest version of Audacity, 1.3.13. I set up the preferences with exactly the same values as I had in version 1.25 and made sure that LAME had the same bit rate, but when I listened to the result in iTunes, the voices were all distorted. It sounded like the speakers each had their heads in a bucket with swirling water in it. The settings that I used for both Audacity 1.25 and 1.3.13 were
Sample Rate: 44100 Hz
Sample Format: 32-bit float
MP3 library version: LAME 3.98.2
Bit Rate: 48
I tried adjusting the sample format and the bit rate various ways but they gave me a file size that was at least twice as large in each case.
I am working on an iMac OS 10.5.8
Help!!

You should be in Audacity 1.3. 1.2 is becoming more and more unstable on modern computers and is no longer supported.

48 is barely enough for a mono show, but will destroy a stereo show. Did you mix down to mono and export that? That should sound passable. Audacity 1.3 has a Track tool that will mix down for you.

I don't trust 32-float. There have been reports of damaged MP3 files from that. I would be capturing the show at 16-bit and export that, but you can experiment.

Koz

You said you adjusted MP3 export in preferences. Audacity 1.3 adjusts MP3 export at the actual Export step. Did you mis-speak? Also, Audacity 1.3 default export is 128 which should give you a very nice presentation, just way too big.

Koz

I know that I can get a cleaner audio sound by using a variable bit rate in version 1.3.13 regardless of whether I use 32 bit float or 16 bit. But the file size becomes too large for a podcast. Regarding the adjustments, I adjusted version 1.25 in the preferences and 1.3.13 at the export step. Since I posted this, I have made further tests and it seems that when the volume was a bit too low in a section and I amplified that section that it really magnified the problem. Version 1.25 with bit rate of 48 handled the amplification just fine with no distortion regardless of whether I set it at 32 bit float or 16 bits. But version 1.3.13 couldn't handle the amplification at 48. But managed better with a variable bit rate at level 9. But even at that minimal level, the file size was half again as large as it was with 48. If I had short programs, file size wouldn't matter so much and I would raise the bit rate a little for a better sound. But a podcast an hour long is hard enough to download with the file size made as small as possible when the listener is in a less well to do country. I'm trying to keep them in mind. 80% of our subscribers live in China. Others live in African countries and various islands. To answer your question about mixing it down to mono. I have read that podcasts need to be in stereo because some players don't handle mono. So, no, I haven't mixed it down to mono. Thanks for your help.

I'm out of ideas. It's really scary when the example system didn't work right. That is, it did exactly what you wanted, but it was broken. Now you're trying to get a properly working system to replicate the old software and none of the results work as you want.

Traditionally, you couldn't force a stereo show at 32 to sound acceptable. It was seriously distorted. 64 was the absolute minimum. So you're somewhere in the middle. That's generally accepted as normal -- and it does it in multiple different audio programs. I did my initial experiments in Cool Edit and my boss had similar results using a different program. Audacity is following right along.

Let's see what the other elves have to say.

Just a note that "lame" is also a stand-alone software program -- not just a plugin -- and I think you can get a version to work under OS-X.

Koz

http://www.macupdate.com/app/mac/18882/lame

It's a command-line program, so you have to be comfortable in Mac Terminal.

Koz