You seem like you could tell me the difference between *ambient* music (like that on the Hearts of Space broadcasts and website) and 'trance' music. Thanks.
I'm not an expert on this, but I'd say that a trance album will have a strong bass beat on at least some tracks, while an ambient album will not. I'd also characterize ambient music as "atmospheric," while trance is typically not. Ambient music is also often free of vocals, while trance may (or may not) have more vocals.
Check out the song "Hold You" by ATB; you can definitely tell that this is not an ambient song.
I'll note that in the albums I'm looking for, I'd prefer there to be at least some vocals. I'm pretty sure I won't enjoy a trance disc with no vocals, even if it's well recorded.