Rules regarding changing tempo mid-song?

[themattsmith]

I've recently started to record music and have no education or training in songwriting/music theory. Are there any rules regarding the tempo of a song?
Can you change the tempo at all? Only once? Back and forth many times?

[richiebee]

ALL rules in music are optional.

Songs can change tempo. Changes are more acceptable in some genres of music than others. The change should make sense.

In the context of tempo, I would recommend that you keep it simple. Otherwise you just confuse people, and they stop listening to your music!

Gradual tempo changes (upto about 5bpm) are practically unnoticable by a non-musician and can help project a song.

Sudden changes of a much more drastic nature can be very effective in the right song.

Doubling or halving the tempo makes life simple for the listener and can help them to continue to dance when the band has gone into a frenzy.

[thesilentdrummer]

It depends on the kind of music. For example, orchestral or choral music uses pushes and pulls very liberally (especially a Capella chamber choirs) to portray emotion. But since I am pretty sure thats not what you are talking about, usually solo-type pieces are good for liberal pushes and pulls. See billy Joel's "And So It Goes" for a real world example. However, in most full-band applications apart from what Richiebee said, one of the most common and useful tempo changes is to double or half the starting tempo. I believe Rush Halves "YYZ" in the middle of the song, and Lynyrd Skynyrd's "Free Bird" doubles the tempo for the fast part and guitar solos.

I would really avoid speedups of more than 5 BPM (that are not a double) over the course of the song. Songs tend to get out of control when the keep snowballing.

[EnSkorSang]

DO whatever the hell you want. If you think it sounds good jumping about all over, then do it! Its common in classical music (especially chopin) for tempo rubato to be applied, where the performer is given a slight freedom to adjust the tempo throughout the song as he feels necessary to help convey emotion...the very loose rule with this is if one bar is slowed down a little, another should be sped up to compensate. In pop music it isnt so common - but then try looking at some alternative bands and theres tempo changes all over the place! It matters not one bit what you do, so long as it sounds good.