[ChaNce]

Hi, I have a 6/8 part that I would like to put a 4/4 loop under. The 6/8 part is at 70 bpm. How do I figure out what tempo to play the 4/4 loop at?

[Gabe777]

same if your going for a progressive approach

if not, go with 95-100, it might match up

[ChaNce]

Right, but there has got to be an easy formula for figuring out where the bpm will fit together (meaning, how many beats of 6/8 do I have to count before some number of 4/4 beats will line up with it).

This must be easy, I just can't figure it out. There should be an equation that will get me there

C

[distressed_romeo]

Originally Posted by ChaNce

Right, but there has got to be an easy formula for figuring out where the bpm will fit together (meaning, how many beats of 6/8 do I have to count before some number of 4/4 beats will line up with it).

This must be easy, I just can't figure it out. There should be an equation that will get me there

C

I don't get what you're asking... Are you saying you want the barlines to match up, so that you're going for the King Crimson-polyrhythmic approach, where the pulses match up, but the barlines don't (in which case the bpm would be the same)?

Is this a guitar part you're planning on recording, or electronic loops, as one option would be to visualise the 6/8 part as quarter-note triplets at the tempo of the 4/4 part?

[distressed_romeo]

Wait, I have it...

Assuming you're counting the 6/8 part in quarter notes, rather than dotted quarter notes, putting a 4/4 part within the same space of time, will mean you're superimposing 4 quarter notes over the equivalent of three quarter notes, therefore the tempo of the 4/4 part will be 1/3 faster than the 6/8 part's tempo; to find that multiply the original tempo by 1.3333333333(recurring), or 1.33 if you wanna be practical. Unfortunately this means that the new tempo is likely to be a decimal that most metronomes won't do, and so the parts won't completely line up.

However, I drew this up to demonstrate how you could notate this idea in two different ways that most sequencers could manage. If you wanted to shift the emphasis between 4/4 and 6/8 while keeping the tempo constant, if you're treating each two notes in the 6/8 part as two eighth note triplets in the 4/4 part, then you could include a metric modulation symbol, for instance...

triplet eighth note = eighth note

...which would show the change in rhythmic emphasis without the need for BPM markers. There's a big article on this on Steve Vai's website in 'The Little Black Dots' section.

Hope that's useful and makes sense, as it took me ages to figure out...I suck at maths. If I'm wrong, then someone else with a better head for figures please correct me.

[ChaNce]

romeo, thanks, I think that is exactly what I need. Ill work on it and post what happens.