Originally Posted by: Mike_x1xIf the music is 4/4 thats 4 beats to a measure yes?

Yes, if the time signature is 4/4, there are 4 beats in every measure. 120 BPM stands for "120 Beats Per Minute", which means you will simply be playing 120 beats in one minute, or 120/4 measures in one minute = 30 measures.

If the tempo was 100 BPM, you would be playing 100 beats in one minute, meaning there's more space between each beat. You would be playing slower than 120 BPM. Each measure would last longer.

If the time signature is 3/4, there are 3 beats in each measure. If the tempo was 120 BPM, we would still play 120 beats in one minute, meaning the space between each beat is the same.

However, we would be playing more measures, since we only have 3 beats in each one here (120/3 = 40 measures).

/Ben