Figured out a source of clicks when recording buffer to buffer

Elektron Gear Octatrack
41

Bpm with decimals aren’t exact :

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42

I also use a sinus wave.
At 120 bpm : 256.00 Hz (2s at 120 bpm)

Buy a Digitone. :wink:

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43

Yes you do. Moog.
Crank the fliter res all the way up. VCO levels down. Theres your sine wave

44

I’ll set that right to 918.75 Hz or whatever. lol.

45

Fair point. I have one, but it doesn’t get a lot of use.

46

Filled in some more and removed a decimal one that I verified didn’t work well.

Bad:
55, 61, 62, 65, 66, 67, 68, 82, 85, 86, 87, 88, 89, 95, 97, 104, 110, 122, 123, 124, 127, 128, 129, 130, 131, 132, 134, 136, 137, 138, 139, 141, 142, 145, 152, 153, 154, 155, 156, 165, 172, 173, 174

Good:
56, 60, 63, 64, 72, 75, 84, 96, 100, 105, 108, 112, 120, 125, 126, 135, 140, 143, 144, 150, 157, 160, 168, 175, 180

I haven’t been exhaustive and might have misclassified some.

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47

Free tuner app on your phone. Done.
Or use a tuner in logic.
Easy.

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48

2×2×3×3×5×5×7×7=44 100

49

Is that the secret? I don’t follow.

50

Issue is the finicky filter knob on the Moog, not the tuner.

51

Where Octatrack differs from a typical circular buffer type digital delay line setup (which are very well understood) is the restarting of the buffer’s playback. Your typical digital delay just keeps going - reading/writing perpetually. Octatrack introduces the playback trig that restarts the buffer. That’s why I attribute these clicks to the sequencer timing instead of the delay buffer itself.

52

These nunbers can be base multipliers to get tempos matching 44 100…

53

Another way to deal with clicks : hihats. :wink:

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54

That’s why some of the problematic BPMs are so surprising. Like 128 for example.

55

Bryan_T’s good=x & bad=o in a decimal table

# 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190
0 . . . x . . . x o x o x x x . x .
1 . . . o . . . . . . o o . . . . .
2 . . . o x o . . x o o o o . o . .
3 . . . x . . . . . o . x o . o . .
4 . . . x . x . o . o o x o . o . .
5 . . o o x o o x . x x o o o x . .
6 . . x o . o x . . x o . o . . . .
7 . . . o . o o . . o o . x . . . .
8 . . . o . o . x . o o . . x . . .
9 . . . . . o . . . o o . . . . . .

it basically shows that the phenomenon might be random, or triggered by factors that we did not think of yet. For a very brief moment i thought i see an :space_invader: just to mock us fair and square but then not… hmm!

56

I was playing with my OT last night.
128 BPM (which according to your findings is a bad one)

Couldnt hear any clicks in my loops (captured from external gear , electribe EMX1, fx tails and long sustained notes.

Im not saying the problem doesnt exist, just saying I couldnt hear anything in my scenario.

57

Very interesting. I get clicks starting right away I wonder what the difference is.

I’ll upload a clip I just did in a minute.

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58

Thanks for doing that. An interesting puzzle.

It is possible that I might have misclassified some. Or it could be the case that some BPMs are impacted to a lesser degree than others. One might only get one click every 23 repeats, while another gets a click more frequently.

59

We might need to conclude what the definition of a click actually is in case of the Octatrack.

I would understand such as a sudden wave jump from the running buffers sample (frame) amplitude to the start point amplitude, in particular one that jumps sharp enough to become audible.

In that sense some clicks might not become audible, they might be just not disturbing strong enough the continuous amplitude changes as interpreted wave.

Which is why the suggestion to use a special test frequency signal came up, that would make assumptions or rather predictions possible and then allow to compare what actually happens.

Also interesting with just those test cases the spread of the appearing clicks seems to be not following a tendency, it looks normal spread out on that decimal table. I’d expect the ‘audibility’ of clicks to appear more prominent in higher BPM simply for the sharper wave changes as of passing wave files faster… Which also tells us something.

Leaves me with a simple question, what is the actual buffer size in samples the machine shuffles data… 64samples, less? Does someone know more?

Well thats the technical side, but the actual challange is to formulate advice out of what we know to circumvent the audible clicks that can could happen.

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60

A click is normal if there is no audio continuity. So if source is not a seemless loop, a click can occur at any tempo.

I use plocks on start for tests.

Step 1 Start 0
Step 5 Start 32
Step 9 Start 64
Step 13 Start 96