Qu Separate Gain amd Trim control

[damcleanParticipant]

BTW I’ve emailed support to see if they can confirm what the behavior will be, I hope you are right.

[damcleanParticipant]

Hey all, I got confirmation from Allen and heath. As I feared, the qu treats the sq as if it were any other dsnake source (I.e. an audio rack) and sends control signals to change the SQ gain. However these control signals are ignored, so it does nothing. There is no way to control the trim in this way, here’s the email:

Hi Daniel,

With the SQ SLink port connected to the Qu dSnake port, the Qu will see this as if a dSnake expander is connected, so a gain control will be available on the Qu but it does not control the preamp on the SQ, the control messages are ignored. A trim control isn’t available on the Qu as there is no way for the Qu to know that there is an SQ connected and to change the gain control to a trim.

Sending the Qu Preamps to the SQ means that the gain control on the Qu does work, and there is a trim control available on the SQ. So if both gain/level controls are needed, this would be the best way to route it.

Thanks

Alex

[volounteerParticipant]

@damclean

did AH tell where in the documentation this could be found?
Or is this just more of their secret info that only they know.

[damcleanParticipant]

@volounteer

They did not. The documentation on page 29 seems pretty clear to me about the preamp gain setting with dsnake devices though. If you dont pay close attention to their being a digital trim in each channel processing cohort you likely wouldnt think anything of it.

The thing is, there is not QU based documentation that talks about the ability to connect to the SQ or any other mixer for that matter. Rather, there is only SQ documentation that talks about how to connect to the QU. The QU was not designed with this connection feature in mind. The SQ mixer came much later, and this particular feature came even later than that. They simply found a way to enable it by reusing the dsnake capability, hence we run into this particular issue as the dsnake feature bypassed the trim and forwarded preamp control signals.

I asked about potential future firmware updates… he just responded by saying essentially what I just wrote, that the SQ came much later and this feature was not considered when they did the initial QU hardware and software architecture. Although it may seem like a simple adjustment based on the block diagram, my guess is under the hood it would be a substantial change. Also I think they are end-of-lifeing the QU at some point in the near future, so it wouldn’t make sense for them to make further feature enhancements. Oh well.

We will want to upgrade to a 32 channel unit anyway at some point, so we may still do this which will still give us better control of our stream, and then maybe eventually we will get an additional SQ mixer just to give us this trim control, depending on how much of an issue it actually is for us.

Thank you everyone who engaged with me on this, and hopefully other people find this post helpful in future.

[volounteerParticipant]

@damclean

thanks for that update.

We do not use dsnake. But looking at the block diagram I can not see a way that AH could let you control the digital trim/pol. That would take some magical coding which is very unlikely they would try to do.

[damcleanParticipant]

I figured out a work around – use Dante.

It will add 10-20ms latency. For most that’s fine especially since it’s for audio streams outside of the room (although may be in ear shot).

So we’d get the SQ and get a Dante expansion card. Then connect a Dante enables computer to the QU usb and send the Dante channel through the usb.

With USB the qu gain long controls trim.

This also gives you Dante for anyone else on the network, which is a nice benifit. Gotta love network solutions.

Daniel

[Author]

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