[Bug]KSP BPM timing is inaccurate

Step KeyStep Pro
#1

I noticed after recording a long jam into Ableton (same bpm on KSP and Ableton Live) that I needed to warp the recorded audio to keep it in time with the drum sequence within Ableton Live. The warping was not consistent and required many warp markers to be added. Simply adding a warp marker at the beginning and end was not enough, so there was some drift.

To investigate this I recorded a 1 minute 4/4 pulse. After recording I turned off warping, set the start marker accurately, and observed that after a minute the audio was out of sync by about 4ms. So I would assume the drift would become even greater for a longer recording.

I carried on the same test in Pro Tools are got a similar drift. So my conclusion would be the bpm is the KSP is not accurate.

Is this known behavior? Or even expected as the bpm on 2 devices might not always be 100% identical. Just wondering if I can troubleshoot this, or do I have to live with it?

Maybe a separate post, but when changing patterns has anyone noticed any timing issues, not within the KSP but against other external sync’d sequences (after correcting for latency).

#2

Hi @razzkazz

I do not use either a KSP or either of the DAWs you use, but are you using your DAW as a timing master and your KSP as a slave? If this is the case then this should not happen.

#3

I tried both ways. I don’t use Ableton Live as the master, but if I do the timing is tighter, but still drifts by around 2ms. Sometimes its bang on, other times not. But this is negligible. I use the KSP as the master, not the slave. What I am observing is that if you measured a piece of audio created in an Ableton, one minute long at 120bpm, and did the same from sequence coming from the KSP (both unwarped), they will be slightly different lengths, the one from the KSP will also drift, so I it means after recording, you first need to position the initial downbeat in the correct position, then warp it to stay in sync with an accompanying arrangement in Ableton Live.

As you don’t use the KSP with any DAW I’m not sure you can help, I was looking for user experience, sorry.

#4

Could the drifting be a ‘standard’ minimal MIDI delay? I think it slightly shifts the recorded audio over a period of time, if the generated audio is recorded as one take / track.

#5

To be honest, I don’t mind it not being in sync initially, but what I do mind is that it is globally off. As in, the unwarped audio, recorded at a particular bpm, does not sync/line up with the DAW timeline of the same bpm. If I recorded into a DAW with no warping functionality, there would be a major issue, and editing/arranging would be a pain. Also, if in your recorded audio has swing and offsets you are second-guessing where they should land on the grid. By setting the initial sound/beat to start at 0:00 I would expect the rest of the audio to be in sync, but it’s not.

#6

@razzkazz

This does sound like it could be a bug, after all if it’s drifting out of sync then it’s not properly in sync.

HTH and thanks for reporting it.

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#7

I had a different problem, but with a similar topic. When I use Ableton as master and Keystep as slave, a different bpm number was displayed in Keystep - in my case 3 bpm less. After editing the audio recordings, I noticed that they were running in sync, so they probably had the same bpm number. So keystep must display an incorrect bpm.