Q: How can I edit a song so that it is shorter?
A Audio Masterclass has a little problem...
"I would like some advice on editing. I have to cut a song from 7:45 to 4:00 because it is too long. Where should I start the editing process?"
Too long for what?
My first question here would be, "Too long for what?" If this is a song for commercial release then it is certainly too long. If you are going to write a song longer than Bohemian Rhapsody then it would really have to be something rather special.
If this is the purpose of the editing, then you need to think about what is it about the song that will make people buy it? All you have to do then is cut out the rest.
For instance, it might be that some of the duration is taken up by chorus repeats at the end. You could have the chorus once at the end and fade quickly at the start of the first repeat.
Some of the duration might be taken up by an instrumental solo. It's a rare solo that is the 'hook' of the song and the reason for purchase. Cut it out, throw it on the studio floor and trample it to death.
Some songs are burdened by too much introduction. Perhaps you can start straight in with the verse, or at least cut the introduction down.
If after all of these cuts the song is still too long, then you're going to have to lose a verse or two. Choose the verse or verses that say the least; that add the least value to a potential purchase.
Cutting for TV
It may be however that the song is to be used as part of a soundtrack for some kind of TV usage. For a commercial, trailer, program intro or drama soundtrack. In this case you have much more freedom. You should identify exactly what it is that makes this song unique; the reason why the producer chose it. You can now cut out pretty much everything else, and perhaps even repeat the good bits.
In this situation it is often not a good idea to try and keep a bit of each section of the song. For example, there is little point in keeping four bars of the middle eight. Just dump the whole thing.
However you approach editing the song, please don't think that editing is a mechanical process, or something to just 'get out of the way'. Think of editing as a process of 'recomposition'. The end result should sound, to a new listener, like the song was originally written that way. And if your edit is really good, it might be even better than the original recording!