Audio freq response on various DVD speed settings? - HELP!

[will7370]

I've been contemplating recording some of the DirecTV radio channels to DVD (for later conversion to MP3---since my computer is nowhere near my satellite receiver). With the DVD record speed on my burner deck set to SLP, I can record 6 hours of audio (or 12 hours on dual layer discs), but what is the audio freq response for that low of a setting? The picture looks like crap, but isn't the audio at least within FM quality? I can do EP speeds and get 4 hours of recording, LP for 3 hours, and SP for 2, but what are the freq responses I am going to get here with these different speeds? Any advice or suggestions? HELP!

[MOVIEGEEK]

Most DVR's and recorders use 192 or 448Kbps AC3, the sample rate is 48KHz. Changing the recording setting won't effect audio quality.

[will7370]

So you're telling me that the audio fidelity on a DVD recorded at SLP speed is the same as one recorded at SP? I never would have thought so. Great! I'll grab me 6 hours worth of music overnight while I sleep.