Originally Posted by
Spoon
Until you know what command line foobar is using you are just guessing to the difference. Also it is lame and the lame developers who decide to filter everything above 16KHz because they believe it gives higher overall quality when using CBR, to force 22KHz to be preserved goes against the knowledge of the lame developers who have spent 1000s of hours with 1000s of different types of file.
If you get rid of -b then it is not a CBR, it would be VBR, you can change the mode on the main encoder page.