Audacity Forum

Objective: Strike a balance between file size and quality

Recording Method: All vinyl records are imported via a USB turntable, cleaned up with various Audacity functions/settings, and then exported as 48KHz Stereo WAV files for archival purposes. The resulting WAV files are then rendered as MP3s to save space on laptop hard drives and portable devices like phones and iPods. (I have read elsewhere that stereo-recording is the best way to restore mono records – your comments are invited.)

Record Type 1: Monophonic Music recordings (Voice and instruments, and Instrumental-only)

I have used Fixed Bit Rate 192 Kbps with good results. I tried VBR2 and got a file that was significantly smaller with a nominal bit rate of 136 Kbps (Windows:Properties:Details tab). There doesn’t seem to be any quality difference. What bit rate settings do you experts use, and why?

Record Type 2: Monophonic Voice-Only recordings

I have several comedy albums from the 1960s that are monophonic voice-only recordings, e.g. "The Button Down Mind of Bob Newhart", that I want to render as MP3s.

I have tried various kinds of bit rates (Variable, Average, Fixed), various bit rate values (VBR2, VBR8, ABR 112, FBR 112 & 160), and both algorithm settings (Fast & Standard). I really can't discern much difference in reproduced sound quality. So in part, this is a technical question in search of a technical answer just so I know what the technical answer is.

Again, what settings do you use, and why?

Thanks, JP

pzkpfwvi wrote:I have read elsewhere that stereo-recording is the best way to restore mono records – your comments are invited

Difficult to give a definitive answer - it depends on the equipment, the software and exactly what restoration processes you are using. Probably best to make some test runs and see what works best for you. If you can't tell the difference then you may as well use mono for the smaller file size. Some (usually old) audio CD burning applications require that the source file is 44100 Hz 16 bit stereo.

"Preset: Standard" gives a good balance between file size and (good) quality for most material.
For very high quality (larger file size), I go up to Preset: Extreme.

The Preset values have been carefully tweaked (by experts) to give optimised trade-off between file size and sound quality for a wide range of material.
I have occasionally found marginally better settings than the presets for specific pieces of music, but it's a lot of time and effort and in my opinion not worth the effort (other than for the educational value). If I'm not happy with the "Standard" setting, I'll just "up it" to Extreme.

2 track mono files will be a little bigger than true (1 channel) mono files using these settings, so for the MP3 you will get slightly better size:quality if you convert to mono before converting to MP3.

True (2 channel) stereo will be roughly double the size of 1 channel mono files using these settings.

Personally (and this is purely a personal opinion) - I record in Audacity at 32-bit floating 44.1kHz. At final production step I export (downsampling with my ditther set to "Triangular" in my Preferences) to a set of 16-bit PCM stereo WAV files (these are my archive copies and are backed up onto two separate 1TB USB disks). I did think about highr quality for archive, but decided that for my old ears, and given the stae of soem of my much-played vinyl, that CD Red Book standard was sufficient.

I alos import a copy of the WAVS into my iTunes library and use iTunes to conver to AAC (iTunes converts to AAC nuch faster than Adacity) - I now use 256 VBR as I have a 160 gB iPod and a big-disk PC. When I started out I used 192 bitrate as a good compromise between space occupancy and quality - I now wish I'd started out at 256.

My son who is very finnicky insists on using 320 AAC on his iPod (and note that he has filled his 160 gB Classic, and is hoping that Bill will release even bigger iPods).

On good electrostatic speakers and on good studio headphones I can (still) hear the difference between 192 AAC and 256 AAC - I can't really hear the difference on going up to 320 or with WAV files. On those silly little Apple earbuds - 128 or above is ok ...

WC