Sound Quality Deterioted After Exporting Files For CD

I’m using Audicity 2.0.3; My operating system is Windows 7 Home Premium; My PC is an HP, Pentium processor dual-core CPU, E5300 @ 2.60 Hz; 2.60 G.Hz. I recorded our band one evening last year on a Tascam DR-07, at 24-bit 48,000 Hz .WAV file. I’ve done this before for years. When I recorded our band in the past, I would usually stop after each song we did, so it would later appear as a single file for each song, and usually I would subsequently edit the resulting recordings - one song at a time - in either SoundForge’s “Audio Studio” or Adobe Audition 3.0, and then export the selected edited songs to burn to CD using either of the software’s burning protocols or the HP resident CD/DVD CyberLink DVD Suite Delux. I’ve not encountered any problems before. However, this time, when I recorded our band, I recorded non-stop, ending up with a 1.5 hr single .WAV file. I imported the large, single file into Audacity, and followed the’s directions for “Splitting A Recording Into Separate Tracks”, a section in the Audacity Manual. And apparently, here’s where the problems started and where I need someone’s help/counsel. I split the tracks up by songs, edited them, and named them – using Audacity’s “.aup” project file format. However, I noticed afterward when I had saved the file, and re-imported it into Audacity, the project rate was 48,000 and the bit rate was identified as 32-float, not the 24-bit that I had originally recorded at. Actually, I hadn’t noticed it at all until I had save the file – and exported the .aup file to a PCM .WAV file. When I opened the .WAV file in Audacity, the file data indicated that again, the project rate was 48,000 Hz and the bit rate was 32-float…not the 24-bit I thought I had originally recorded the band with (??). Again, I went on to the the next step, e.g, to export the edited recording file to a CD-friendly Export Format. I clicked on File, selected the Export Format to be for CD burning, and chose 16-bit .WAV, 44100 hz project rate. I saved the file, and just to be sure prior to exporting, I listened to it as I usually would to insure there weren’t any glaring errors prior to burning. I was really freaked out (and clearly disappointed) with how different (bad) this 16-bit/44100 sounded! Like I said, when I’ve recorded songs before, in .wav file format, and burned to a CD without any problems – and certainly no discernible sound/tone variations. The new file was nowhere near sounding as clear – or even had the proper timing (I could tell from listening to the opening track’s drum intro) of the original .wav recording. What have I done wrong here? Is the .aup project file format the culprit? Did I miss a step – or more? This project is real important to members of our band and I don’t want to let them down. Thank you.

Converting from 24 bit to 32 bit is not a problem - the conversion is 100% lossless (perfect).
Audacity works internally in 32 bit float format (as used in most professional studios), so WAV files are automatically converted to 32 bit float format. This allows higher quality processing and avoids the risk of clipping while working on the project. 32 bit float format can handle signals over 0 dB without damaging them, but 16/24 bit formats cannot. Also, modern computers tend to work quicker with 32 bit float format due to the built-in “math coprocessor”.

16 bit is a “lower quality” format than 24 bit or 32 bit float, but it is still “CD quality” so I doubt that this is a format conversion problem, but from your description nothing jumps out as the obvious culprit.
Does the Audacity project sound OK?
Is there a noticeable difference between the sound of the Audacity project and the exported file?
Are you sure that you exported as a 16 bit WAV file?
Did you export as 44100 Hz sample rate? Doing so is a good idea as Audacity 2.0.3 has an exceptionally high quality sample rate converter, so it’s probably best to convert the sample rate in Audacity rather than leaving that to the CD burning program (standard audio CDs are always 44100 Hz sample rate). To set the sample rate of the exported file, set the “Project Rate” (bottom left corner of the main Audacity window) before exporting.
Did you mix down and normalize before exporting?

I split the tracks up by songs, edited them…

What kind of editing? Anything that might change the volume or sound “character”?

Do you have Audacity setup to show clipping? 32-bit floating point will never clip, but if the file goes over 0dB and you save-as 16-bit or 24-bit (integer) you can get clipping (distortion).

And Bob, your post would be a lot easier to read if you use paragraphs! :wink:

Hi Steve and DVDoug,
First of all…thanks for the thoughtful replies. Secondly…I think there was some “user error” on my part – including my reply here, probably, as I was trying to figure out what “post reply” box to hit so I could reply to both of you. I think I cocked it up, so apologies up front. Also, thanks to DVDoug for suggesting I break up single paragraphs into smaller ones for easier reading…which I’m going to do right now.

OK…I discovered when I tried another software approach that the original .wav file I imported was actually recorded at 48,000 16-bit. Prior to attempting to export any files, I tried to comp. and normalize the files…and they were distorted, and almost unlistenable. Which is when I first discovered I had mis-labeled the files. So when I was trying to save them, I also screwed up changing the sample and bit rate sampling.

When I have more time, I’m going to take both of your suggestions and re-do the whole process. In the meantime, on an eMusician forum, I followed the suggestion to import the original files into to Sound Forge Audio Studio (which has a drop drown window that details the files’ bit and sample data – which tipped me to my own “brain-fever-esq” errors in the first place. The SF file was converted to 44100 at 16-bits and came out sounding clean as the original. I haven’t used the files to burn the CDs yet, but I was just happy to have the sound come out the way it was supposed to.

To DVDoug specifically, I think you were also onto something as this recording was pushing 0 db the entire 20 songs…and I believe several of the sections were clipping, which, as you point out, could also negatively impact the resulting sound quality – which I think happened to my files as well.

Finally, this is the first time I’ve used the Forum…and hope to improve for any future posts…and maybe not be so quick to pull the trigger to post something until I’ve spent a lot more time troubleshooting on my end. Regardless…both of your prompt replies are extremely helpful, and I will incorporate suggestions when I retry to export Audacity .wav files to 44,100K/16-bit for CD burning.

For what it’s worth, it was confusing to me to try and save a file and determine what the file components were in .wav, following edits in .aup files. Drop down windows for Sound Forge and Adobe Audition seem to have a more user-friendly format, and make it very easy to understand what file elements are existing and what elements you can select prior to saving. It’s all personal preference, I guess…and with the wild success of Audacity, I’m sure others haven’t had any issues. So, I think it’s up to me to do some more manual reading! Thanks again guys. Much appreciated.