BPM in file name with OT samples

Elektron Gear Octatrack
#2

Hi, (Bolide305 from french AF?)

I would write the tempo at the beginning of the file name to be sure. Maybe you talk about this :

• The tempo guessing algorithm analyzes the sample filename for tempo figures, checking if the initial guess is off by a factor 0.5 or 2.0. The ”normal” BPM range the Octatrack uses to make its initial BPM guess is 85 BPM-170 BPM. If you have loops with tempos outside this range, it might be a good idea to put the BPM value in the filename. Typically, a 70 BPM loop is initially loaded as 140 BPM loop, but if the number 70 is found anywhere in the filename, the octatrack will use 70 BPM instead. Similarly, if 280 is found in the filename, the BPM of the sample will be 280.

Willow

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#3

Hello,
do you know if this will actually work without doubts?
Because I remember, a couple years ago, I renamed all the files (full songs) with bpm in the filename, but at the end of the file name (e.g. “Diff Star_92”)

But this technique never worked…

thanks

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#4

Tu as vu, je suis partout :smiley:
Octaflood !

J’ai à relire ton paragraphe quelques fois, déjà qu’en français je suis une grosse nouille :relaxed:
Haha
On prend possession du site ?

#5

this never worked for me either…
I actually have to put in the wrong bpm in the attribute setting in order to get the right bpm… really annoying. having my OT project set to 123 bpm, all my files run normal when I set the original tempo to 113 bpm in the attribute window.
Since I mostly use prepared loops at a multiple of 48, I can calculate and see if the bpm is set right, which doesnt really work for full tracks.

#6

That is not really cool… ^^

#7

I’ve got to try this for myself.
Wasn’t the Octa sort of aimed at DJ’s a bit when it first came out, focusing on showing off the timestretch function. And the fact the volume knob is for cuing tracks in headphones and not a master output volume control, like on all other Elektron boxes (my only real bugaboo with OT).

#8

? You can mix or choose what you listen with headphones on the Mixer page.

#9

I wish it was a master output volume like on all other boxes. Not headphone volume.
But I supose in the Octatracks case, headphone vol makes sense.
How many times do you reach for it to adjust volume and it does nothing.

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#10

I see what you mean.

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#11

Please, can we have some Elektron HQ’s mate to chime in and confirm that actually, putting the BPM in the filename, won’t provide an expected result?

I am speaking of random length full songs…
Thanks!!

#12

What is the best method to write the sample name to get correct bpm detection…

I’ve been labelling them…

01-125 BPM BASS - Cm
Etc…

I have read the manual about it and looked it up on here
but still unsure about where to put the bpm…
Would this be correct or will the numbering at the front cause problems
does anyone know the correct way?

Thanks

#13

Yep. It’s best to name your samples so that the only occurance of numeral relates to the BPM.
Example : bass.Cm.134

You can use spaces or underscore instead of dot. This works reliably for me.

Having any other numeral in the file name may cause issues. Obviously the biggest obstacle here is, how do I name 16 basslines without calling them, bass 1 bass 2 etc. Erm, your’re on your own there… get creative!

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#14

Cheers… yeah thought might not be best being like that,
I haven’t had too many issues yet but might try another way then if could cause conflict.

#15

Could use letters a-z and if you need more than 26 in one folder use za, zb, zc, or something like that?
Not sure how OT sorts files in such a case.

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#16

Yea as stated, making sure that the only number in the filename is the bpm works for me (90% of the time)

So:

NineHats 125

Rather than

909Hats 125

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#17

Ok, this is good info, but what if my audio file is not in an integer BPM? How to get the OT to identify a 126.47 BPM loop correctly? I don’t think a filename with “126.47” will be correctly identified (?)

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#18

Good question. Give it a try, as you can adjust to .xx of a bpm in the file name within the attributes section. So it may well calculate it exactly.

If not it may well round up/down, and in that case if you have the correct tempo in the file name you can then adjust it manually in the attributes section if needed.

#19

but only in increments of 0.04 and sometimes 0.05 when it feels like it

#20

1/24=0.04166666 to be more precise.
With explains 0.05 values you found, this not random.

I listed all values (see Attributes on post bottom)
The Untold Truth About Octatrack Tempo

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#21

Or more precise the OT stores and works with tempo multiplied by 24, makes sense because of MIDIs amount of ticks per Beat. Why multiply? It allows to work with Integers only which is CPU friendly.
No Float values at all in that regard.

Examples:
120,02 bpm = 120,02 * 24 == 2.880,48 which results in 2.880 == 2880 / 24 = 120bpm
120,03 bpm = 120,03 * 24 == 2.880,72 which results in 2.881 == 2881 / 24 = 120,0416666667bpm

there is your tiny difference.
For those who might think that makes things difficult, that is still much more precise than Abletons Midi Clock introduces Jitter by pure math compared to clock ticks of CPU’s

for the nerds in C it looks like…

#include <stdio.h>

uint16_t dspFriendly_x24(double audioFileBpm) {
    double bpmDouble = audioFileBpm * 24.0f; //user assumed bpm
    uint16_t bpmInteger = (uint16_t)bpmDouble; //casting cuts the commata
    if (bpmDouble - bpmInteger >= 0.5f) bpmInteger++; //round up if needed
    return bpmInteger;
}
double machineAlignedBPM(double audioFileBpm) {
    return (double)dspFriendly_x24(audioFileBpm) / 24.0f;
}
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