Multi-Surface Mode – Global Input Channels Preamp Option Changes Both Surfaces

[OrionX]

Yesterday working in the shop after consulting the “Understanding Multi-Surface Mode” document we setup (2) C2500 Surfaces with a CDM48 Mixrack, with a GigaAce card in the mix rack option slot to do some testing of Multi-Surface mode for an upcoming gig that’s a few weeks out. After recalling the MultiSurface-FoH and MultiSurface-Mon shows on the respective Surfaces, we noted that both Surfaces had the Gains on the surface (1-64 on the FoH C2500, 65-128 on the Mon C2500), even though each surface was set to their proper role.

On the FoH C2500, I used the Global Input Channels Preamp screen (hit select on a channel, then hold setup, tap, the preamp section), selected channels 1-64, and tapped “Disable Preamp on Surface”, which switched all the strips on the FoH Surface to have trim. However, doing that on the FoH C2500 also changed all the strips on the Mon C2500 to have trim on the surface instead of Gain.

Is this expected behavior? Is there no other way other than one by one tapping the Preamp option on each channel individually to switch this without affecting the other Surface, or am I missing something?

[SteffenR]

if you select the option “Disable Preamp on Surface” you get the message

Disable Preamp On Surface for all Input channels. Continue?

So what do you expect?

The idea is… after the sound check (or setup) you switch all channels to “trim” enable Gain Tracking and you need to touch the gain only if a channel is not properly set…
For normal operation you have the trim control.

In the case of the need for changing the gain of an input you can still access the gain in the preamp screen.

[OrionX]

What did I expect? I expected it to take the pre-amp gain off the Surface that I executed it on (the FoH C2500), not both Surfaces that are configured for different roles.

The idea is that during sound check, the Monitor Surface sets the pre-amp gain, the FoH Surface uses Trim. At the end of sound check, the FoH Surface sets Gain Tracking to “on” so if the Monitor person makes a gain adjustment for the monitors the FoH trim is adjusted proportionally to so it doesn’t affect the FoH mix. Only one person ever adjusts pre-amp gain itself in this mode (monitor engineer in the scenario I am working in).

So again, is it really expected that this affects both Surfaces connected to the system regardless of their assigned roles? This smells like a bug, honestly.

[SteffenR]

it is expected that it affects the whole system…
That’s just the way it works.

After setup you disable the gain completely from the encoders
you can still access the gain within the preamp screen
and with gain tracking enabled, every gain change will reflect on both strips trim control

if you need it different
then you have to setup what you need by yourself
store it to a scene and you can recall it whenever you need it

[OrionX]

I understand how you access pre-amp gain when you have the Trim on the surface. This is not the issue.

The issue is that a Global Surface option (setting either the pre-amp gain, or the trim on the Surface using the setup button on the surface and tapping the pre-amp area), instead of affecting the Surface it’s set on only, affecting all Surfaces in the system.

I also expect it to only affect the channel range selected. If I select channels 1-64, which are the FoH channels (with channel sources Rack 1-64), why would it change channels 65-128 (also channel sources Rack 1-64) on the other Surface? This is a setting of what the Surface controls (pre-amp or Tirm), and should be individual to the Surface.

The only way to disable the pre-amp on the Surface and have trim only, without it affecting the other Surface, seems to be you have to set it one channel at a time.

I would note this behavior is not called out in the Multi-Surface document, hence why I am asking if this is really the intended behavior (have Surface options on one Surface in a system overwrite option on another)

[OrionX]

I also expect it to only affect the channel range selected. If I select channels 1-64, which are the FoH channels (with channel sources Rack 1-64), why would it change channels 65-128 (also channel sources Rack 1-64) on the other Surface? This is a setting of what the Surface controls (pre-amp or Tirm), and should be individual to the Surface.

Correction here – the channel start and end on that screen is labeled specifically for Gain Tracking, so a poor assumption that it would limit the effect of the buttons above it (Enable Preamp on Surface & Disable Preamp on Surface). However, I stand by my thought that these buttons should only affect the local Surface, not all Surfaces connected to a system.

[SteffenR]

However, I stand by my thought that these buttons should only affect the local Surface, not all Surfaces connected to a system.

It works not that way… again… the idea is to have both (all) surfaces on trim during the show, even the director instances should switch to trim in this case…

[OrionX]

It works not that way… again… the idea is to have both (all) surfaces on trim during the show, even the director instances should switch to trim in this case…

Why would I want my monitor engineer, who is supposed to be controlling the pre-amp gain in this scenario to switch to trim for show? The *entire* point of Gain Tracking is so that whoever has the head amp gain control (in this case, the monitor engineer) can make adjustments to the pre-amp gain, and the other engineer’s trim automatically compensates. Having the monitor engineer have to make an extra step to get to the pre-amp gain during show is just silly.

One could try and make the argument that “whatever adjustments need to be made during show can be made in Trim for all concerned”, but that’s a preference.

And honestly, the core issue is a setting that should be relative to one Surface (Surface Role: FoH) and its channels (1-64) should not be forced on another Surface in a different Role (Surface Role: Monitors) using channels 65-128. This behavior nuance is certainly not intuitive, and after a read through the Firmware Reference Guide, The Understanding Multi-Surface Mode document, and a scrub through the knowledge base, does not seem to be actually documented anywhere.

It would be great for Allen & Heath to chime in here with the -official perspective- – @nicola @keith @ben et al – care to weigh in here?

[MJCElectronics]

I’ve not used multi surface much and it’s been about 18 months since I last touched it but I do remember the switch over being simple and only 1 surface of the 2 I was using switched to trim (which is what I expected and wanted).
I’ve always used 1 surface on gain and 1 on trim with compensation as Orion is saying above and I agree the whole point of compensation is to leave 1 surface controlling gain but gain changes not impacting others.

[SteffenR]

the whole point of compensation is to leave 1 surface controlling gain but gain changes not impacting others

You can change the gain from all surfaces or Director instances (with the user rights to do so) or even from other controllers in the network
and gain compensation on will compensate on all channels where it’s on…

I don’t understand why this is a problem, since you can set it up as you want…
it takes a bit time. but if someone is used to the way it works now (broadcast console, FOH, monitor)
they have to do one extra step for each surface (and can’t do it for the complete system)… so it’s just a matter of taste

[MJCElectronics]

I’ve never really though about it that way, just followed the setup instructions which when I read them said gain on one surface trim on the rest.
Didn’t realise you could have gain on all surfaces and it would still trim the others when you make a change even though the trim is not “in your face”
I guess if it works that way with compensation on then it matters little whether gain or trim are on surface and like you say it’s just personal preference.
I need to go play with multi surface again.
Every day’s a learning day 🙂

[OrionX]

I’ll have both Surfaces back out for testing before long and will be working with it more. There are numerous other things still to sort with this mode before we roll into a live gig with it.

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