MP3 Variable Bit Rate

Hello. I’ve noticed something that seems odd to me.
If I export an MP3 file at variable Bit Rate, Quality 7, and Joint Stereo, I get a Bit Rate that is much lower than if I do the same, but Quality 8. Shouldn’t Quality 8 have a lower Bit Rate than Quality 7?
I’ve done this with multiple files, and I always get similar results.

What version of Audacity are you using? See the pink panel at the top of the page.

In what application do you see the results you describe?


I’m using Audacity 2.1.3.

As I asked, what application says the Audacity-exported MP3 file at variable Bit Rate, Quality 7 and Joint Stereo shows a lower Bit Rate than Quality 8?

You can download “MediaInfo” from to see information about the two files.

Get the version without installer, because the installer may have malware or adware.

I find easy to encode repetitive material at a lowish level has a slightly lower bit rate at v8 than v7.

You could post the material.


For me, all else being the same, Quality 8 gives slightly lower bit-rate than Quality 7 (as expected). I’m using MediaInfo to tell me the overall bit-rate, and the result is confirmed by seeing a slightly smaller file size for the Quality 8 version.

Ah, that’s what you meant by ‘what application’. Windows Explorer. :slight_smile:
Since then, I’ve also come across instances where I did get a lower bit rate by using 8 instead of 7.

Check the file size. Unless one has massively more metadata (such as a big “Album art” picture) embedded, then smaller file size for the same duration = lower average bit-rate.
Windows Explorer may be calculating the average bit rate incorrectly.

Hm, perhaps I should reinstall Audacity.
I downloaded Want You Gone from Portal 2 to try, and when exported at Quality 8 from Audacity, it became 133kpbs, and when converted at Quality 8 from foobar2000, it became 77kbps. The latter seems more like what is intended…

I’m generally getting around 70 to 90 kbps with these settings:
Audacity uses LAME for encoding MP3. Did you download and install LAME as described in the manual:

Yes, I did.
I’m not sure what’s the issue, then… foobar2000 uses LAME too, right? So it’d seem logical for both to deliver the same results.
Well, thanks for trying to help, in each case. :slight_smile: