Very interesting subject, Im kind of an audiophile myself and have tried experimenting with different kinds of music while going to sleep. Not much success yet, though. But Ive found that the smoothest, most chilled music to go to sleep to is either the soundtrack of Atlantis: lost tales (a game) or the soundtrack of Solaris (the new one, though the old one has some nice soundscapes too)

1. How often do you hear sounds in your dreams?

Pretty much always, but Im not sure that "hearing" is the right word. Since we dont use any physically real senses in dreams, sounds should be more mind-like, from inside the head. Always, since I was born, I can constantly, while dreaming, hear the sound of vacuum. Its not the sound of nothing (or maybe it is) because it somehow sounds. Imagine what a black hole would sound like (sorry, thats the best explanation Ive got). But it does not feel like any sounds are real, although they may seem very real. Au contraire, they may occur as very surreal and distorted, kind of like hearing on LSD. But its all in my head!

2. Do you ever hear people talk in your dreams?

Sometimes, and I have a feeling they sometimes are "outside" my body (in dreams)

3. When you hear sound, does it feel like the sound is being heard from your ears?

Redirect to answer #1

4. Have you ever used any other sences to hear sound (like seeing or feeling sound, a sixth sense isnt included)?

Yes, not so long ago I dreamt of a very strange device that was speaking for the dead. Imagine a Mystpuzzlemechanicssortof-thingie, a lot of rings, levers, buttons and some mechanical eyes and mouths. The sound of it kept sweeping between my "ears" and "eyes", I could hear the device moving and see it talking (of course you can hear somethin move or see it talking, but I mean it in that other, strange synesthesic way )

5. Have you ever heard a sound that was extremely high or extremely low in a dream?

No, not really, except for the vacuum (low)