Originally Posted by: hunter1801The song starts out by riding an A. I figured G is a whole step down, so can I just play the song a whole step down and it would be in G?

Yes, that is how transposition works. Play every note two frets lower.

Transposition on fretboard instruments is easy (& string instruments in general). Since guitars, bass, etc. do not distinguish between sharps & flats you simply play the same visual, graphic fretboard patterns but so many frets higher or lower.

Transposition on piano keyboards is harder. You can still see graphic patterns, but you have to distinguish between sharps & flats. So, sometimes when you have to "just play everything a whole step lower", this results in a completely different "set" of white & black keys.

Transposition on brass & wind instruments is harder still. First there is very little graphic, physical pattern symmetry. The embrochure (mouth positions) and fingerings do not easily show "shifting patterns" of key signatures. This is one reason orchestral players practice scales & sight reading from the beginning of their training. Unlike the guitar, there is virtually no way to "just look at the shapes & patterns & start to play something."

Before the invention of valves brass instruments were limited to one key by physical structure. In order to transpose at all (to a limited set of other keys), players had to slide a different length tube ("crook") in part of the horn! That way they could play the same physical motions, but the sound coming out of the horn would be higher or lower.

Hope this helps. That's a neat Cars song, enjoy. :)