# Working out strums per second given beats per minute - using guitar tabs

Say I have a tune which has following strum pattern :

DownStrum * DownStrum * DownStrum,UpStrum,DownStrum,UpStrum

The `*` represents the end of a strum. So `DownStrum,UpStrum,DownStrum,UpStrum` in above pattern should take same amount of time as `DownStrum` at beginning of pattern.

I'm given the beats per minute of this pattern : 180bpm & will work out length of time for each strum. Is following correct ?

180bpm = 3bps(beats per second)

There are three strums in pattern `DownStrum*DownStrum*DownStrum,UpStrum,DownStrum,UpStrum`

So divide the number of strums by number of beats = 1 beat per strum and each beat is 1 second in length.

This gives :

DownStrum(1 sec)*DownStrum(1 sec)*DownStrum(.25 sec),UpStrum(.25 sec),DownStrum(.25 sec),UpStrum(.25 sec)

Please correct me on any of my terminology.

Update :

Image to describe strumming pattern :

Each arrow represents contact with strings and since each arrow covers the strings entirely every string will be strummed. After drawing this image can see now that

DownStrum(1 sec)*DownStrum(1 sec)*DownStrum(.25 sec),UpStrum(.25 sec),DownStrum(.25 sec),UpStrum(.25 sec)

Should be

DownStrum(.5 sec)*DownStrum(.5 sec)*DownStrum(.25 sec),UpStrum(.25 sec),DownStrum(.25 sec),UpStrum(.25 sec)

As for the first two strums there is an upstrum that will not make contact with strings, so first two downstrums should take 1 sec / 2 = .5 sec

At 180 bpm, this means that a metronome needs to be set at 180 and each click will represent one beat. Your rhythm pattern is (I hope) 1-2-3and -4and as in 2 crotchets(1/4) followed by 4 quavers (1/8) notes, or strums.If you count the 1,2,3,4 evenly, the 'and' will go between. The count is in time with the metronome.

After that, your theory goes awry. There are 3 bps, so a whole bar of 4/4 will take 1.33 secs. Divide by the 4 beats, and a downstrum will take 0.3325 of a second, except where there's an upstrum as well, where BOTH will take 0.3325s. So an upstrum will then be 0.166s long.I'm fascinated as to how you're going to measure this, though.

The bpm is there to establish a pulse. Imagine a band shouting "1,2,1234" at the start of a song. The 1234 is the count which can be quoted in bpm. The pulse of the song then goes at that tempo (hopefully!).

ON REFLECTION-

If, instead, there are 3 beats to the bar, it will look like 2 crotchets and 4 semiquavers.This is different, in that one bar will take exactly 1 sec., and the last four strums will take 0.08333sec each.

Whichever strum pattern it is, there's hardly any time to change chord at the end of a bar !

EDIT - it looks from your edit that there are 4 beats in the bar, and the strum consists of crotchet, crotchet, and four quavers.As in my first case scenario.

I'm a little bit confused by your explanation. Is it supposed to be:

1 2 3 e + a (pattern A, takes 1 second)

or

1 2 3 + 4 + (pattern B, takes 1 1/3 second)

The two downstrums in a row involve a motion where you move back up over the strings but don't strike them, as you mentioned, so if you're counting every movement of your arm, then for pattern A it will be 1/6 second for the quarter notes, with your arm moving eigths, and 1/12 second for the sixteenths, with your arm moving sixteenths as well.

For pattern B, it would be 1/6 for the quarter notes, with your arm moving eighths, and 1/6 also for the eight notes, with your arm moving eigths.

In either case, the subdivisions correspond to arm movements and NOT the actual strum.

Here's a list:

Arm movements at 180 BPM (3 beats per second)

Whole notes = 1 1/3 sec (At 2/3 sec, arm moves back up/down if playing two strums in the same direction)

Half notes = 2/3 sec (At 1/3 sec, arm moves if playing two strums in same direction)

Quarter notes = 1/3 sec (1/6 sec for same direction)

Eighth notes = 1/6 sec (1/12 for same direction)

Sixteenth notes = 1/12 sec (1/24 for same direction, wowzers)

and onwards to thirty-second notes, which I don't think will come into play at such a fast tempo.