sample bpm/pitch rule?? sample professors look in here:)

[anode]

hi:)

ok say i Sample a 140bpm breakbeat and place on it on route key middle C.

when i play the sample back, up or down a key, is there a particular bpm it will drop/go up by? or would this be different with every single sample?

cheers
;)

[Evil G]

for each step up the scale, multiply the tempo by the coresponding value from this chart:

Minor Second = 1.05946
Major Second = 1.12246
Minor Third = 1.18921
Major Third = 1.25992
Fourth = 1.33483
Diminished Fifth = 1.41421
Fifth = 1.49831
Minor Sixth = 1.58740
Major Sixth = 1.68179
Minor Seventh = 1.78180
Major Seventh = 1.88775
Octave = 2.0000

got this from here:

http://www.phy.mtu.edu/~suits/scales.html

[Barely Human]

Well, logically -

1 Octave higher is twice as fast, so split it up into the 12 notes and you will get 8.3333333333333333r% increase in each note, so it deppends on your samples original bpm -

ie...

100 bpm loop

C = 100bpm
D = 116.66 bpm
E = 133.32 bpm
F = 141.65 bpm
G = 158.31 bpm
A = 174.97 bpm
B = 191.63 bpm
C = 200 Bpm

The maths will be a little off :cool: because of the recuring 3

[Evil G]

it's a log scale, not linear.

"For the equal temperament scale, the frequency of each note in the chromatic scale is related to the frequency of the notes next to it by a factor of the twelfth root of 2 (1.0594630944....). "

[Barely Human]

Yes, but we are talking about bpm. So each semi-tone has a bpm increase of 8.33333333r percent.

[Barely Human]

sorry, what am i thinking. Its just 8.3333333r Bpm increase per semi-tone :doh:

[Evil G]

no dude. tempo and pitch are identical concepts at different time scales, and the relation of frequency to chroma is exponential. each note is arrived at by multiplying the frequency of the previous note by the twelfth root of 2. obviously, using base 2, we get a natural convergence to a nice "round" number of 2 for an octave made of twelve steps. but you can't just mark two points at 0 and 2, and draw a straight line between them. the graph actually starts out shallow, and grows steeper towards the right.

a sampler speeds loops up and down by the same rules that it speeds sampled instrument hits up and down. there is now way it can tell the difference. it's all just a bunch of samples to it.

look at the frets on a guitar if you don't believe me. the 5th fret is exactly half way between the nut and the 12th, which it would not be according to your math.

[Evil G]

5.946% bpm increase, compounded per semti-tone.

[Barely Human]

Im lost now :doh:

I'll take your word for since you use bigger words than me ;)

So the scale starts of shallow and gets steeper towards the end??

[Evil G]

it's not that hard, and it's important to understand because this is what essentially makes music what it is.

20 hz to 40 hz = 1 octave gained with a 20 hz increase in frequency.
40 hz to 80 hz = 1 octave gained with a 40 hz increase in frequency.
80 hz to 160 hz = 1 octave gained with an 80 hz increase in frequency.
...
4 khz to 8 khz = 1 octave gained with a 4 khz increase in frequency.
8 khz to 16 khz = 1 octave gained with an 8 khz increase in frequency.

see how for each octave you go up, the frequency goes up by a bigger and bigger amount? that makes the graph curve instead of going in a straight line. when you make 12 equal steps between 0 and 2, you are in effect drawing a straight line, and your scale would not sound musical at all, and is not what happens inside a sampler.

[anode]

so if i multiply the bpm by 5.946% thats the correct bpm for each note? what do u mean compounded semi tone?

has the 8.33333333r percent been tested?

i dont have my sampler at the moment otherwise id try it.

[Evil G]

so if i multiply the bpm by 5.946% thats the correct bpm for each note? what do u mean compounded semi tone?

has the 8.33333333r percent been tested?

i dont have my sampler at the moment otherwise id try it.

if you are going up one step, multiply the tempo by 1.05946. two steps, multiply the tempo by 1.05946^2. three steps, multiply by 1.05946^3, etc.

going up by one octave, mulitply the tempo by 1.05946^12 (which happens to be 2.0 exactly).

[anode]

ok cool thanx Evil G ;)

[AcidTrash]

*stares blankly at screen and slowly slides off chair*

[Basil Rush]

Cute.

Pitch shifters suck sometimes.

Mine sounds great apart from transient detail which goes to shite and you're best off just speeding things up or slowing them down then ...

[RDR]

and of course recycle makes it all academic...

:lol:

[The Divide]

Im lost now :doh:

I'll take your word for since you use bigger words than me ;)

So the scale starts of shallow and gets steeper towards the end??
Amplitude is also in the Logarithmic Scale

http://www.ieer.org/log.gif

Starts shallow (large area slow incline) and higher up in the scale you go the faster the increase over distance. See above where each marking x10 left to right.

That’s why -6db half’s the amplitude of a sample - 6 again and it’s halved again

So say you have rock concert at 100db and you increase its amplitude to 106db you actually double the overall volume :shock: :shock: :shock:

Evil G you should get into teaching!

[auditory hallucinations]

wow thats some cool stuff

stupid question: the pitch controller on a technics deck - does it work in a linear or logarithmic way?

[Evil G]

wow thats some cool stuff

stupid question: the pitch controller on a technics deck - does it work in a linear or logarithmic way?

linear. the diff between 0 and +2 is the same as the diff between +4 and +6, because they are all referenced to zero.

in a log scale, each value is referenced to the previous value.