Noise added to file

[Pyrocles]

Whenever I re-open or import a file on which I have been working for any significant length of time, a great deal of ambient noise is added to it. This is occurring now in "Build 24.2.0.83," but it has always happened with every version of the program I have ever used.  Is there a solution?

I have found a work-around: To save the file under a new name every 5 or 10 minutes and then re-open it to see if the noise has been added and if so, to trash that file and open an earlier one, redoing the work done since it was saved. Pathetic!

[SteveG_AudioMasters_]

What format are you saving your work in? Especially, what is the bit depth?

[Pyrocles]

I'm saving the files in .wav format (Wave Uncompressed), 44100 Hz Mono, 8-bit.

[SteveG_AudioMasters_]

Well as I suspected, that's the source of your noise! If you save a file as 8-bit, you've only got about 48dB of dynamic range available to you (think cheap cassette recorder). If you don't want noise like that, save your files as 16-bit.

[Pyrocles]

I'll do so. I'll also inform LibriVox that they may want to let their readers know about this problem.

[SteveG_AudioMasters_]

They will probably reply that you ought to read their tech specification more carefully... this is what it actually says:

"Please submit final contributions with the following parameters:

• Sample Frequency: 44.1 kHz (44,100 Hz)
• File format: MP3 (MPEG-1 Audio Layer III)
• Bit rate: 128 Kbps constant bit rate
• Recording Mode: Mono (make sure completed file is audible in BOTH EARS when heard through headphones)
• Volume: around 89 dB (-16 to -21 LUFS)"

They are saying that the final submission should be an MP3 file, but that's just their distribution format. You create that file from your master file, which should be 44.1k 16-bit mono. You record in this format, and from that you do a Save As, and that's where you select MP3 and the appropriate bit rate. So you'll have a master file you can retain, and you submit the MP3 file to them.

[Pyrocles]

I notice that any new files that I make automatically default to 8-bit. I have not found any way of changing this setting except in the "Save As" function. What am I missing?

I have never had trouble with the final files submitted because they are made by Audacity, not Audition.

[SteveG_AudioMasters_]

When you select New File, you should change the bit depth in the settings box that opens. It should remember this the next time you open it. Can't see why you need to use Audacity either - you could more easily do the whole job in Audition.

[Pyrocles]

Many, many thanks.