Sequencer bpm issue with keyboard

[MarkPAmanParticipant]

Ah delays….. maybe not tempo changes?

Maybe You’ve set the desk up with the keys feeding through an inserted effects unit, which could introduce a delay. Or you can add a small, <85ms, delay at the input of each channel, so check that too.

[ZecureParticipant]

Just to confirm. He meant tempo changes not delays.

[[XAP]BobParticipant]

The QU can’t produce tempo changes – it doesn’t have enough memory to do the serious buffering required.

Changes in delay are generally accompanied by digital clicks since the QU has to throw away or insert samples to move from one delay period to another.

A recording of this would be appreciated.

I’d also suggest trying it again with a fully reset desk, and plugging into two channels on different PCBs – cahnnel 1 & 10 maybe…

[DavidCoParticipant]

I’d just like to reiterate my original point that it is *impossible* for the Qu to control BPM via an audio signal going the other way. Qu doesn’t even generate a MIDI timing clock (0xF8) which would be responsible for mastering a BPM. I don’t see how you came to such solid conclusions based upon circumstance alone. I suggest you make the recordings as requested above, and clearly explain what the symptom is that is apparent in the recording.

DC

[janwParticipant]

Below is a link to a sequence recording without A&H but just connected to an active speaker.
The lights on the iPad (app=”tempo”) indicate the bpm=126 ; as you can see perfectly in sync, no issues at all.
[video src="https://dl.dropboxusercontent.com/u/5518126/Sequence.mp4" /]
Later this week we’ll do a recording on the A&H to compare the difference.

[DavidCoParticipant]

Okay, so is the sequencer an app running on the iPad? If so, it could be possible that another process (such as QuPad) is taking a share of the CPU resource, and the sequencer app isn’t written in a way that compensates for sharing that CPU resource, and instead accumulates a time error?

DC

[janwParticipant]

The sequence is run on the synth = Korg M50 which is connected to the active speaker through a DI box (radial)
There is NO link with the ipad ; the latter is just used as a convenient way to measure & show BPM

[DavidCoParticipant]

Okay, in which case my above theory isn’t relevant. I await the next video.

DC

[janwParticipant]

thank you very much. I really appreciate you want to help looking into this.
We will do the tests on our QU-24 this Wednesday
Below is a live recording of our last gig where we also used A&H equipment (but not ours). I referred to it in my initial explication. As you can hear, there is no tempo change/delay whatever so my conviction is it has to do with the settings on our A&H

[DavidCoParticipant]

So the above video is connected to an A&H desk and there was no BPM change, and wasn’t supposed to be one?

DC

[janwParticipant]

that’s correct, the above is a connection to an A&H (not ours but the one of the organizer of the event) that shows that there are no BPM changes introduced by the synth

[janwParticipant]

We tried to record the problem yesterday but believe it or not : we were not able to reproduce it…
What did we change ?
Nothing…expect for a USB stick we formatted on the QU-24 and kept in the system for a while. But even if we detached it from the QU we could not reproduce the problem anymore. This might sound “good” but we feel very unsecure as that it might pop up again just like that during our next GIG. I will keep trying to reproduce/record it.

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