40 Minute Mp3 disorted and lagging

[TeaTal]

Alright, I have audiobooks as MP3's in my library, and I don't want to turn them into Audiobooks. I use a program called Audacity to turn one chapter into my running routine (I add beeps to tell me when to run and walk right into the MP3), so I have one super long MP3 at a time in my library at a time.

Once I add tones to the song, turn them into a mp3 (I tried .wav too) and add them into my library, I sync my Ipod nano, 5th gen. The MP3 chapter, sounding absolutely fine on my computer, lags and is a bit distorted on my ipod. The last part of every word is choppy and computer sounding.

So, is it how I am syncing it to my ipod? Is it itunes or my ipod that is the culprit? I have reset the ipod and reinstalled itunes, and no other songs have this issue. This also didn't happen until recently; prior to that the mp3 file sounded fine.

Any idea's on how to fix this, or even what the problem is?

[cjmnews]

Guesses are:
1. The MP3 encoder settings in audacity are set too low. The computer is "improving" the sound by filtering. The iPod does not have those filters. Increase the quality and size of your file.
2. iPod is using Sound Check to equalize the volume. Turn it off.
3. The MP3 file is encoded with a Variable Bit Rate (VBR) that the iPod does not handle well. Try a different VBR or use a Constant Bit Rate (CBR).