Insert phase coherency and latency

[Carl N]

Hi all!

I’ve just bought an SQ-6 and 2x DX-168 stageboxes. Very happy with them. Seriously good, well designed and thought out products. Well done A+H 🙂

I noticed a comment from Kieth in another thread saying that part of the reason these desks sound so good is that they are phase coherent. Makes sense to me and I’m happy that they were designed that way. But it got me thinking…

I have a lunchbox and make good use of analog inserts all the time. So if I use the channel inserts on my SQ, is everything still in phase? i.e. is the rest of the audio delayed to match the latency of the insert? How about analog vs digital inserts on different channels? Keeping all of that in phase would get complicated quickly! My guess would be that using an insert will break the phase coherency, not a big deal, but I’m curious what happens. 🙂

[Andre S]

Hi Carl,

on page 31 of the 1.5 manual you´ll find a note, that “insert send and return is not latency compensated”.

Cheers

[SteffenR]

So if I use the channel inserts on my SQ, is everything still in phase?

no this could not be in phase anymore
the inserts add some delay to the signal path
since the desk doesn’t know what you have inserted,
there could be no automated compensation for that

you have to do this by yourself

another “weird” solution could be to use an insert on all channels with the same delay 😉

[Carl N]

Thanks Andre, I missed that! 🙂

[Carl N]

Yep, I understand that Steffen, I was reffering to the known quantity of the insert itself, not whatever is plugged in to it. Cheers.

[ianhind]

@Carl

Because the console is unaware what you have inserted, it’s impossible for it to know the round-trip latency involved.

You’ll need to do a measurement using Smaart or an audio delay finder and calculate how much time the insert is creating (if analog hardware this will be very low, probably 1-2ms).

Once you have your latency calculated, you’ll then have to delay all your channels to that number except the insert channel. This will line up the insert latency to everything else.

You could probably gang channels together and set the gang to delay only and make this much quicker.

[Author]

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