Hi, I dont know if someone can help me with this. I would like to know if there is a formula to find out at what bpm to put a 4/4 track so that the quarter note triplet is equal to an eight note in a 6/8 at 140 bpm?
186.66666..., if I'm doing it right. If you change it to 141 instead of 140 you'll get 188.
Should just be 70 bpm? Three of those quarter-note triplets in 4/4 would span three eighth-notes in 6/8, which would require each quarter note to line up with the strong beats of the 6/8 on 1 2 3 4 5 6, since 6/8 is compound duple meter and such. Worse comes to worst, just test it with those bpms and keep pushing in one and the other direction until it sounds like you want it to sound.
You might could use some double modals.
I can show you how to work this out, you use the same formula as the one to caculate metric modulations. But before I can help you out what is the beat for the bpm of the 6/8. Is it a quaver = 140 or a dotted crotchet = 140?
This is a rare case where "notes per second" is a useful unit for something other than shred pissing contests (which I love, by the way).

NPS=(Notes per beat like 2 for 8th notes, etc)*(tempo=how many beats per minute)/60

You can now do some algebra to solve whatever conversion problem you have. Keep in mind that the dotted quarter note gets the beat in 6/8 time, usually.
Thanks to you all for your answer. I found out that by multiplying 140 by 66% I got the tempo that I wanted (which turned out to be 92). The last answer sure got me thinking though.
Quote by Floot
Hi, I dont know if someone can help me with this. I would like to know if there is a formula to find out at what bpm to put a 4/4 track so that the quarter note triplet is equal to an eight note in a 6/8 at 140 bpm?
Quote by Floot
Thanks to you all for your answer. I found out that by multiplying 140 by 66% I got the tempo that I wanted (which turned out to be 92). The last answer sure got me thinking though.

Well I'm glad you figured out the right bpm and it might be the bpm you were after, but it isn't the answer to the question you asked.
Si