How does I changed BPM? An overview on managing BPM through a mix

someone sent me a private message a while back asking me for some tips on changing BPMs of songs and between songs. I replied directly to him but realized that this might actually be a useful thread as well.

changing BPM is one of the primary aspects of DJing, and how you go about doing it is dependent on the songs you're mixing. as a DJ, your primary goal is to deliver a smooth and enjoyable song to the listeners. changing tempos or pitches in a pronounced and noticable way can sometimes kill a groove or generally sound rather off-putting.

you don't always have to change the BPM from one number to another. if two songs have a similar enough BPM, there's no harm in leaving a track play outside of it's original BPM. if you have a track A at 120 and track B at 124, you can slow track B to 120 before you bring it in and leave it there while it plays. you'll notice that most mixers (or software) will have 2 pitch adjustment modes: standard and keylock. standard will speed up or slow the track down and allow the pitch to lower or raise with it. if you slow a track down, the pitch will drop. speed it up, pitch will rise. more often than not, DJs use keylock, which keeps the pitch constant regardless of whether you speed up or slow down the track. the downside to this mode is that you usually can't go further than +/- 10% on your pitch slider before you start hearing artifacting in the sound.

if you want to actually move the BPM, there will be natural places within the songs where you can do it seamlessly. the easiest spots to change the BPM are in vocal breakdowns, or spaces in a song where the rhythm cuts out. without a heavy and persistent rhythm, a listener's ear won't notice you speeding up or slowing down a track. however, if you don't have keylock on, people will very easily hear the pitch change.

another point where you can change the BPM is at the end of a phrase. a phrase is a set of measures/frames in the song, usually a multiple of 4. most dance music has phrases, and learning to pick them out and count them is a huge benefit when DJing. changing the BPM at the end of a phrase will be noticeable though, so it's far more dependent on the song and whether a shifting BPM sounds fun or terrible.

you can also change the BPM between songs. some people call this "jamming it" or "slamming it", because it's a fairly abrupt sound. it can sound really good though, if the songs you're mixing have a good handoff.

BPM is a very important factor not only between two songs, but through your whole set. BPM will be a big contributor to the flow and the energy. speeding up the BPM will introduce energy into the music, while slow it down will pull the energy back. some DJs will even write a songs original BPM on the CD / binder cover / slipcover so they can know where they're going or where they're coming from with regards to the tempo.

it is always good to have an arsenal of songs that you can use to transition smoothly from one BPM to another as well. if you want to go from something at 105 BPM to 130 BPM, that could be fairly difficult with just some effects and a slider nudge. instead, having an intermediary track that starts slower and ends faster can do the job for you. just keep in mind that when you're beatmatching your next song, you need to match to the faster tempo at the end of the song instead of the slower tempo at the beginning.

or you could always kill the first track, blast some air horns, yell "WHO'S READY TO PARTY UP IN HURRRRR", then play the second track

please comment and add in your own tips and tricks, or correct me on anything I got wrong. also add in any questions you might have about BPM