I just puit this in another post (acoustic guitars and effect) in this forum - it goes like this
"delay is a common effect - but it must be in time with the track. If you don't know the tempo as it relates to time try this. - get a stop watch with 100's displayed i.e.
0000.00
The start beating the fours - 1, 2 , 3, 4, and start the stop watch on a down beat - now count 11 beats stopping in the eleventh. The stop watch will now read milliseconds like so 0004.50 which is a 450msec delay - other delays at this tempo are 225 and 112.5 etc. If you put the eights delay (225) on the guitar it really livens it up - just a touch!
cheers"
I've got a program called Beatcalc - you can tap a tempo into it as well as type a tempo. Plus you can put in a one bar sample and it will tell you the tempo.
Divide 60 by the tempo of your tune as expressed in Beats Per Minute (BPM).For example: 60 divided by 120= .500 (milliseconds).That will give you 1/4 note delay.To get 1/8 notes,divide by 2 (250 milliseconds).Cheers!