Mixing distortion!

Hello guys!

I’m currently mixing together this audioplay in Audacity and I’ve encountered a bit of a problem.

I’m about 4 episodes into this thing and the first two were fine sound quality wise. After I edited together the third one, I noticed there was this audio warble in background. I thought it was because I had mixed mono tracks (the dialog) with stereo tracks (the background sounds). http://metalgearsolidcita.podbean.com/2009/03/22/chapter-overpoured-scene-3/

So for the next part, I made the dialog stereo tracks as well but that didn’t do anything and I still got that sound distortion.
http://metalgearsolidcita.podbean.com/2009/03/24/chapter-overpoured-scene-4/

I wrote a friend and he asked me to ask all my actors to send in their stuff @ 192 kbps and to export the audio at the same rate. Well, this gave me the idea to start importing the lines I already had at 128kbps (was doing it at 256) until my cast can make the changes for their next batch of lines. Doing that combined with doing the stereo tracks for the dialog seems to have helped a little bit but I can still here that distortion in the background.

I think the only difference between the first two parts and the second two is that I had panned the audio really far to each sides of the speakers for the dialog, to make it seem like the characters were on different sides of the room.

I have no idea what to do. I had the bit rate at “32-bit float” and I changed it to “24-bit”. Do I have to change anything else? I’m just pulling stuff out of thin air at this point. I would have looked around the forum and whatnot for answers but I don’t even know exactly what I’m looking for…weather it’s the audio or me. Is something too loud or is it just my crap computer? Please help someone!

–Amanda

You may be getting a little too complicated for everybody’s good.

I do serious production at 48000 and 16-bit Stereo. That is the AES/EBU television audio standard and everybody supports it. It makes beautiful podcasts, Audio CDs, MP3 and other compression type files (AAC, M4A, etc).

Some computers have trouble with 24-bit sound. There was a donnybrook a while back when somebody thought Audacity created damaged 24-bit sound tracks. Stay far away.

32-bit floating seems to be a delightful way to do production because of is extremely high quality, but there are documented cases of a WAV file recorded like that not making a stable MP3 file. Audacity does not convert well between standards.


So capture your performances live and Export them immediately as WAV files. Make backup copies to a separate drive and lock it up. When you’re done editing with the original WAV files, export the show as a Final.WAV. That’s The Show.

Then, way down here, reexport the show as an MP3 or other compressed format of your choice. The WAV export of the final show should sound crystal clear and perfect. The MP3 made from that should sound almost perfect depending on the settings you use. 192/256 should give you an almost perfect show no matter what else you do assuming you followed this formula.

If you exported MP3 anywhere in the middle or did other things to damage the show (Stereo/Mono?..maybe. Maybe not), then all bets are off because your master show is already compromised. We warn people MP3 and other compressors work by trying to preserve the original show quality. If you feed them already damaged master shows, then the damage will be preserved.

Koz

I guess I should have called it an “audio drama” since radioplay, in the most traditional sense, implies that it’s happening live or could possibly happen live. All my VAs live in different parts of the country so they send me their audio over the Internet and I mix it together.

So, I should ask them to record and save their lines as WAV files? That seems to be the next best thing to recording it live and saving it as a WAV file.

Yup, you should be working with WAVs in your production enviroments - as WAV files are lossless.

MP3 and other similar comressed formats are deliberately lossy, they throw away audio data - they are used at the end of the production chain to create delivery files (that are smaller than the equivalent WAVs).

WC

Having said all that, you are going to get two hits. The quality should be very, very good and oddball production problems should go away. The down side is the transmission and storage problem. Clear, perfect, uncompressed WAV files take up significant space. Be ready for a four or five times larger requirement everywhere to produce the show.

Depending on how you get the work across the world, the segments may no longer fit in a commercial email attachment or other shortcut.

You may encounter another problem associated with suddenly higher quality. One of the voice performers has a metrobus starting up in the distant background of her performance and nobody could hear it before.

Koz