I generally don't have a problem transposing songs, and understand the music theory required to pretty much transpose anything. My question is - if we transpose a song too far, might it end up less recognizable for an audience, or might it hinder the song as much as it improves it? Most of the time, I think not, but my dance/top 40 cover band has recently realized that we have a deficiency in our selection of 90s & classic rock songs, and I'm coming across a few that just don't sound right to me when you transpose them too far.. For example, our singer has requested that we move "Under the Bridge" by the Red Hot Chili Peppers to Bb (originally in E). She does sound better in this key, but in doing so, the whole introduction, which is just the guitar by itself, ends up being really high and you loose (imo) the instant recognition that the song might otherwise have. It may just be me, as I'm a guitarist, and grew up loving the guitar in some of these songs... so I'm not sure if the average person would really notice whether something sounds a little "off". Some seem to suggest that people can't hear the difference between keys, and we can transpose anytime we want... meanwhile, a prime feature of music during the baroque era was a belief that different keys had their own character and changing the key completely changed the intent & meaning of a song (of course they weren't dealing with equal temperament, so there's more truth to that than today!). Maybe the truth lies somewhere in between? So I ask - to you, is it worth transposing a song by a huge amount (like a tritone, as suggested above) to make it easier to sing, or are there cases where it is better to just not do the song?