[E-Dragon]

Simply put, a CBR of 256 in .m4r is more than good enough..
.m4R because you are talking about a ring tone, unless you have some app on your phone that lets you play mp3's or any other music format as a ring tone.

OK yes a higher bit rate does equate to higher quality, your ears (also the iPhones small speakers)
can not hear the difference between something recorded in a bit rate of 256 to one recorded in 320
So stick with 128 to 256 CBR any thing higher is a waste of space and will have NO real discernable effect and the quality of the ring tone you or others hear...

I would worry more about the db gain when recording, over-driving the recording will produce much far worse effects, of corse recording at a real low bit rate, say under 80 will also sound bad too...

As for your questions..

Encoding: use CBR - Constant Bit Rate. I phone requires a CBR (as far as I know the m4r is a CBR format) but if file size is not an issue save your mp3's in a VBR (depending on the original recording it could give you a higher quality resource)



Sample rate: In music the sample rate is measured in per second intervals, so you could say it is how much digital information is in one second. You could compare it to pixels in a picture.


Joint stereo is basically just something to make a file save in stereo a little bit smaller, it makes blank spots and certain frequencies mono. But this can also screw up some songs so just stick with stereo it will sound the best..