Custom or Purchased Ringtones Sound Muffled in 6.0.1

Custom ringtones sound muffled when used as ringtones, yet sound perfect when used as text tone or any other alert. This was fixed in IOS 5.1 but is now back. This is easily tested by going to sounds and listening to the custom ringtone in Ringtone then go to Text Tone and listen to the same file. There is a marked difference. The Ringtone sounds muffled and narrow-no bass, not much treble, the Text Tone sounds perfect, as it should.