About BPM and BPM Calculations...

BPM is only one factor when selecting songs for mixing. Other elements such as key, rhythm pattern, vocal renderings, and distinctive chordings and melodies are as important. Experience and instinct are developed through listening to and working with your music. Some people have a natural instinct, others have to work hard to develop it. If you know your music, you will probably have a pretty good feel for its tempo and will find that knowing the BPM is actually least important. Your ear should always be your guide when blending songs.

The BPM presented in D.J. Rhythms are calculated with a stop watch. The watch needs to be accurate to 1/100th of a second. For a standard 4 beats per measure dance track, count 1,2,3 and start the watch on the 4th beat. On the next beat begin your count, 1,2,3,4,5...etc. and stop the watch wherever. 8 or 16 beats will give you about a 1 bpm accuracy (based on human performance), 64 beats is probably around 1/4 to 1/2 bpm accurancy and 100 beats is at accurate to 1/4 bpm. I've been doing 50 beat counts, but recently switched to 32 or 64 beat counts as this matches the measure patterns of most songs.

To figure the BPM multiply the # of beats counted by 60 and divide by the time on the watch.
(#beats)*(60sec/min)/(# seconds)=#beats/min
[Off course you may also do it this way: (#beats/#seconds)*(60sec/min)]
E.g.:
Count 64 beats in 32 seconds: 64 X 60 =3840 3840/32.00= 120.0 bpm
Count 32 beats in 14.65 seconds: 32 X 60 = 1920 1920/14.65 = 131.05802 = 131.1 bpm
Count 8 beats in 3.5 seconds: 8 X 60 / 3.5 = 137.1 bpm

Given # beats & # secs, my MusiLog software will make this calculation, but it doesn't currently have a timer/counter built in because I have not found my computers to be particularly accurate. I do intend to tweak MusiLog and see if I can improve this aspect.

Speaking of accuracy, it's really a waste of time to figure BPM to 1/4 beat accuracy. A BPM accuracy within 1 or perhaps 2 BPM is close enough for getting an idea of how to adjust the pitch for mixing and which songs might be within BPM proximity.

It's important to realize that many songs, especially the older disco songs, do not have steady BPM. These tempo changes are in my PC database but are not yet visible in the DJ Rhythms Dance Music Database and charts.

There are several commercial BPM counters available. The December 1995 issue of DMA (Dance Music Authority) reviews a manual one ("The Time Machine") and the January 1996 issue of Mobile Beat Magazine reviews an electronic one. You can find these mags at larger record and book stores. There is also a link in the DJ'ing resources section of the D.J. Rhythms Links Catalog to a MS-Windows program, WinBPM, for manually calculating BPM on a computer. The BPM Counting section of In Tune also provides tips on BPM counting and links to available software.