This is a neat little trick, tempo-matched delay times. Works on guitars, vocals, even drums.

Fire up Cubase or whatever sequencer/drum machine you use and start a click track at, let's say 115 beats per minute. Now slide on over to your effects unit and add a delay time of 391ms. Play a few chords - it's tricky at first to keep in time with the click but you should start to sound a bit Dave Gilmour-ish. Now the clever bit, change to a multi-tap delay and add another tap 130ms after the first one. Oh yeah, how cool is THAT?

The trick is that the magic number 45000 divided by your tempo in bpm gives you the first tap time in milliseconds and the second tap is one third of the first time.

Here's a hellishly funky little calculator that does all the hard sums for you. It also works backwards so if you know your delay time then it'll tell you the bpm. Enjoy!