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Tom7777 ·
I always get confused when it comes to time and maths stuff, i was just wondering how does tempo relate to samples, say you had a standard delay module and had it set to something like 44100 samples how would you tempo sync it? Is 44100 the same as 120bpm ect?
dreamkeeper ·
At 120bpm, 1 beat = 0.5 seconds (60/bpm)
0.5 sec at 44100kHz = 22050 samples (0.5 x samplerate)
--> 1 beat = (60/bpm x samplerate) samples
Shifrin ·
Forgive any obvious errors:
The sample rate, i.e. 44100 is the number of samples per second so if your delay is 44100 samples in size and you're running your soundcard/host at 44100 then you'll get a 1 second delay.
BPM is obviously beats per minute, e.g. 120. If we have a BPM of 120, we can work out the number of beats per second by dividing by 60 (60 seconds in a minute). So for 120 BPM we get 2 beats per second.
Now, from the above we can see that in 44100 samples we have 2 beats (for the given sample rate and BPM). To get the number of samples per beat we divide through by the number of beats per second.
44100 samples = 2 beats (divide both sides by 2) 22050 samples = 1 beat
So a delay of 1 beat would be 22050 samples, now you can multiply each side of this with whatever delay you want i.e. a 3/16th delay would be :-
22050 samples = 1 beat (multiply both sides by 3/16) 4134.375 samples = 3/16th of a beat
HTH (and hope I got that right - not used my brain in a long time!) Also, I am sure this had been answered in detail (along with schematics by myself and others on here already - try a search!)
Shif.
[edit]Trust me to be verbose![/edit]
dreamkeeper ·
[edit]Trust me to be verbose![/edit]
Hehe! Usually I'm the one who's late. Seems you typed out what I was thinking before posting - nice!
Hey, mods! Can we have a second-accurate display of the posting time? 😉
Tom7777 ·
Thanks guys, im still a bit confused to be honest but that information helps alot, I think there should be a load of tempo/sample rate convertions and maths modules added. 🙂
Shifrin ·
Tom7777 wrote: Thanks guys, im still a bit confused to be honest but that information helps alot,
I'll give another example, just for reference 😉
Lets say you have a BPM of 149 and the sample rate is 44100 - a delay with the length of 1 beat would be :-
(60/149) * 44100 = 17758.39
Now the number of samples the delay needs to be set to for the following tempo-sync'd delay times would be :-
1/1 = 17758.39 = 17758 samples 1/2 = 0.5 * 17758.39 = 8879 samples 1/4 = 0.25 * 17758.39 = 4440 samples 1/8 = 0.125 * 17758.39 = 2220 samples
Obviously if you're using a fractional delay there's no need to round to the nearest sample - but I rounded them as SM's built in Delay needs an integer for the sample number.
Shif.
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