Tempo / BPM

[tony tony chopper]

Just wondering, is it only for legacy/cultural reasons that tempo selectors are always linear in BPM unit?
Normally you want your music "x% faster/slower" which would require a logarithmic control. I wouldn't dare to do this myself in an important tempo control as I'd expect users to complain about it, but IMHO it should be logarithmic - is any tool out there offering a logaritmic control? Maybe DJ tempo fine controls that have increments in "*/x speed" instead of "+-x BPM"?

[shankfiddle]

hahahaha
what you want is a metronome. like the one in the picture:
http://en.wikipedia.org/wiki/Metronome


pre-digital metronomes were indeed originally designed with a log scale. but that had more to do with pendulum physics than any inherent musical quality of tempo (IMHO).

EDIT:
After further consideration, tempo IS inherently logarithmic. tempo is a frequency- beats per minute and cycles per second are different units for the same measure. interesting that all modern controls are linear, hmmmm i hadn't thought of that

[Nystul]

EDIT:
After further consideration, tempo IS inherently logarithmic. tempo is a frequency- beats per minute and cycles per second are different units for the same measure. interesting that all modern controls are linear, hmmmm i hadn't thought of that

Are you thinking perhaps of how sound wave frequency in hz are scaled for things like EQ or a spectrum analyzer? But are useful audio content ranges from 20 hz to 20,000 hz, a factor of a thousand. Useful tempo range might be in the ballpark of 25 to 250, a factor of 10. For typical pop formats the factor is more like 3. It is no great hardship to dial in a tempo with linear controls for this reason.

[tony tony chopper]

Are you thinking perhaps of how sound wave frequency in hz are scaled for things like EQ or a spectrum analyzer?

Don't overthink this, it's about thinking "this should be x times faster/slower".

That said, I did find some info about DJ tempo nudge controls being in % (but still never saw a logarithmic knob for tempo control)

[Hink]

hahahaha
what you want is a metronome. like the one in the picture:
http://en.wikipedia.org/wiki/Metronome


pre-digital metronomes were indeed originally designed with a log scale. but that had more to do with pendulum physics than any inherent musical quality of tempo (IMHO).

EDIT:
After further consideration, tempo IS inherently logarithmic. tempo is a frequency- beats per minute and cycles per second are different units for the same measure. interesting that all modern controls are linear, hmmmm i hadn't thought of that

I can assure you that Tony knows what a metronome is...gotta love his tap tempo which is part of one hell of a host



The thing is he is an innovator who thinks outside the box and is not affraid to take a non-traditional approach to things to improve workflow

[shankfiddle]

Are you thinking perhaps of how sound wave frequency in hz are scaled for things like EQ or a spectrum analyzer? But are useful audio content ranges from 20 hz to 20,000 hz, a factor of a thousand. Useful tempo range might be in the ballpark of 25 to 250, a factor of 10. For typical pop formats the factor is more like 3. It is no great hardship to dial in a tempo with linear controls for this reason.

yes, that's exactly what I was thinking. it could be interesting to use a log tempo control, as the original poster mentioned. Of course, the real issue is that you'd sacrifice precision at one end of the range. so i guess that's the advantage(limitation?) of a linear scale: uniform precision over the whole range.

with a standard log scale, you would have more fine control between 25-35bpm than you would in the 240-250 range. I personally think if I were forced to choose, I would want the inverse: finer control over the faster tempos than the slower ones. maybe. I'd have to try

[tony tony chopper]

Of course, the real issue is that you'd sacrifice precision at one end of the range.

But that's the opposite. If you tweak your tempo in (fractional) BPM increments, you may go from 60 to 61BPM just like from 120 to 121BPM, while that 1BPM difference is 2x too large at 60BPM.
..which is why it makes more sense to use a logarithmic control, so that the result is linear in the (log) scale that normally interests us.

With a +-1BPM increment, the error will be +-1 beat per minute, whatever the tempo.. but we're not much interested in an error in fractions of beats, because that fraction of a beat is more meaningful at 60BPM than it is at 120BPM, and we're more interested in drifts in (linear) seconds, as we wanna align onsets.

[jancivil]

I only ever saw a % function of time in time-stretching samples. For me that's trial and error or I'd get a calculator out if I chart how much more or less time should be consumed, but I don't love it as a paradigm, percentages.

Cubase has ramps vs jumps in the tempo track. The ramps are gradual, I guess exponential...

Normally you want your music "x% faster/slower"

Normally I wouldn't, I don't think of tempo in a numbers-first ideation myself, I'm not leading with 'ok, this would be 75% of that' but I would have an idea that I may measure after the fact. I wouldn't be shocked if there are people that would be interested . It makes obvious sense to use logarithmic scale though. I guess there hasn't been demonstrated any great demand...