I’ve noticed that the channel direct outputs and the bus outputs to multitrack recording are not time aligned (I don’t recall if this was on 1.5 or 1.6 FW), resulting in comb filtering if the 2 are combined in a mix without delay compensation. It would be very helpful if the amount of required delay compensation were documented somewhere
Hi @RobT
Latency depends on the Mix Source and Ip Direct Out point, and may also change slightly between firmware versions.
More details are available here - https://support.allen-heath.com/hc/en-gb/articles/4402940899857-SQ-Phase-coherent-mixing-in-SQ
Thanks,
Keith.
Multitrack recordings generally use the audio directly from the source (ie your channel direct outs). This ensures a “clean” signal is recorded to be played back for VSC or mixed down further if you want a “produced” sound. This is exactly what you are doing with your individual audio sources.
It’s not strange that you would also want to record some buss outputs as it’s a great way to check individual mixes after the show, record the stereo mix, etc. However I do find it strange that you would want to add those buss outputs with your clean direct outs. In my mind, you would use one or the other - clean tracks for VSC or mixing down the show and busses for a quick stereo mix or for spot checking individual busses.
If you aren’t going to combine them together, then the audio timing really doesn’t matter. Furthermore, you can always record them normally (without any timing corrections) and then “fix” it in post production if you really need to combine the two signals. This could be done via a DAW, or even in the console if you are bringing the audio back into the console for some reason.
That article does a good job articulating the problem I have, but not answering the question I was asking. I’m looking for the latency (samples, us, whatever) between the pickoff points, specifically between an input direct out and a bus output (in this case, it’s a matrix but the bus [LR/post-fade aux/group] to matrix offset is given in that article). And if it’s firmware dependent, that also needs to be captured in the documentation, since wrong information here is as useless as no information since it cannot replace determining the latency manually.
I’m well aware of how multitrack recordings are normally used. In this case, in addition to providing the client with individual tracks, I was also providing a scratch mix in the form of the house mix. But since this was a primarily acoustic performance and I was using a mix of solo inputs and a stereo ensemble mic, the house mix was a bit light on the ensemble. So I was adding some of the ensemble mics back into the scratch mix to better represent the sound in the room. If you’ve got a better way to do this without burning another bus pair (when I already have the ensemble mics multitracked individually) or redoing the complete mix from the multitracks, I’d love to hear it so I can improve my workflow.
Honestly the best solution is to measure it yourself. I would want to do that anyway if I had a situation that required perfect time alignment.
Open Sound Meter is free to use and can produce this type of measurement easily.