MP3's are ringtones?

[grandkodiak]

How can I set my VX6700 to use an MP3 as its ringtone?

[AnswerDude]

Try copy the files to the /Windows/Rings folder on your device. Then, select the sound from the Ring tone list.

[grandkodiak]

I have tried and it lists it ok, but nothing plays. It seems to only take wavs

[AnswerDude]

Then you can just convert mp3 to wav files. There are many programs that can do it, here's one;
http://www.dbpoweramp.com/dmc.htm

[Biggboy]

Have you tired go to the file in "file explorer" and hold the button down and clicking set to ring tone?