Export Quality Problem

[R&RJ60]

When I record, the sound of my recording is fine. But when I export, it exports in a way that makes the exported file sound echo-y or like it's overdubbed whenever I re-open the file with Audacity or iTunes. Don't know if this makes any sense, but the wave picture of my recording looks normal and solid, but when I export to my folder of sound recordings, then when I re-open the file from that folder in Audacity, the re-opened recording looks all feathery, rather than sold and well defined. Not sure if I'm exporting incorrectly or there's something wrong with my preferences or there's a problem with whatever stuff I had to download to be able to export in a mp3 format.

[steve]

Encoding to MP3 format always reduces the sound quality. In order to make the file smaller, some of the audio information is discarded, so there is a trade-off between file size and sound quality. The loss of sound quality is irreversible and each time the file is re-encoded a bit more quality is lost.

To minimise the damage, you should use uncompressed file formats (such as WAV) throughout the production. If you require the final audio file to be in MP3 format, then exporting as MP3 should be the final step. (It is also advisable to keep a back-up copy in WAV format in case you wish to re-edit the file in the future). The minimum setting for reasonable quality stereo MP3 music is generally considered to be 128 kbps. Higher numbers produce better quality but larger file size. Audacity offers some useful presets for MP3 quality - "Preset = Standard" is good for stereo music. "Preset = Extreme" is very good quality.

To change the MP3 quality, when you get to the dialogue for entering the file name, click on the "Options" button.

[R&RJ60]

Thanks so much. But any idea why this is an issue for me in 1.3 but not in prior versions of Audacity? Certainly with the first Audacity version, I could export, re-open in Audacity or iTunes from the exported version in my files, edit (or just listen), and re-export with no apparent change in quality. This seems to be something specifically related to 1.3.

[steve]

What are you current MP3 encoding settings? What settings did you use in your previous version?

[R&RJ60]

I was using Audacity 1.2.4. Not sure what my settings were cause there doesn't seem to be that "Options" box. What I was able to locate in preferences in File Formats was a Bit Rate of 128, and in Spectograms an FFT size of 256. Are either of those relevant? Otherwise, where should I be looking for the info you've requested.

In 1.3, under Quality it was 128 Kbps, the Bit Rate Mode was Constant, and the Variable Speed was Fast.

Thanks so, so much for helping me out with this. Much appreciated.

[bgravato]

In Audacity 1.2.x there was no "options" button in the export dialog. Those options were set in the Preferences, I'm not sure in which section.

In Audacity 1.3.x export options can be accessed from the export dialog.

128kbps is considered to be the minimum acceptable bitrate for stereo music. More demanding users say that bitrates of 192kbps or higher should be used.

Variable bitrate can add a slight improvement in quality for the same file size (or smaller file size for the same quality), but the difference will be marginal.

[steve]

Variable bitrate can add a slight improvement in quality for the same file size (or smaller file size for the same quality), but the difference will be marginal.

That depends on the type of audio. In some cases it can make a considerable difference. I agree that more commonly the difference is not that big, but the preset VBR options are very well optimised for stereo music and will generally give some degree of improved sound quality over CBR.

[kozikowski]

If you were exporting MP3 successfully with the old Audacity, then you got lucky. MP3 creates sound damage at all settings and you can't stop it. Sometimes it can seem you have no damage, but by the third edit and export of the same work, distortions creep in.

It's very subtle and the damage is intended to sound natural. I have to do this once: Directly compare the off-air quality of a radio show with the compressed podcast. You can listen to either one all day long, but they don't compare at all side by side. The podcast sounds restricted and squeezed compared to the air show.

MP3, AAC, and M4A are delivery formats intended as dead ends. They all have tradeoffs for sound quality versus filesize.

Koz