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[Mark McFarlane]

I'm reworking a coordination at a small church campus that has 2 sanctuaries that are in seperate brick-clad buildings.


FOH ~200' apart and
stages ~300' apart


I've been using WWB for the past decade and am doing the new coordination with Soundbase COORD (which is pretty awesome).


I have historically put each room in its own zone.


My question: can I safely ignore IMD between these two rooms and set up the coordination to

• only consider channel spacing between rooms and
• consider channel spacing and IMD within each room

What are the considerations here, e.g. for adjacent rooms you would always consider IMD,...

[Brian Jojade]

You should consider ALL RF sources within the range that they can effectively transmit signals.  The mics don't know that they are in different rooms or different systems. Different buildings doesn't much matter.

A way to test if you should be concerned would be to take a mic into the other building.  Can you still get audio signal?  If so, RF is getting there.  Yeah, it may have dropouts and whatnot, but it's still there.

Consider yourself lucky that you have the information about the RF frequencies in both locations.  It's so fun when working in a building where everyone brings their own wireless stuff and problems start to crop up out of nowhere.

[Scott Helmke]

Intermod is a local issue, so yes you can put separate rooms into separate zones and generally ignore intermod between them.

[Mark McFarlane]

You should consider ALL RF sources within the range that they can effectively transmit signals.  The mics don't know that they are in different rooms or different systems. Different buildings doesn't much matter.

A way to test if you should be concerned would be to take a mic into the other building.  Can you still get audio signal?  If so, RF is getting there.  Yeah, it may have dropouts and whatnot, but it's still there.

Consider yourself lucky that you have the information about the RF frequencies in both locations.  It's so fun when working in a building where everyone brings their own wireless stuff and problems start to crop up out of nowhere.

Thans Brian. I am coordinating the transmitter frequencies in all rooms as a single system.  Specifically what I was asking (sorry if I wasn't clear) is whether I need to consider IMD in devices between rooms.  WWB and Soundbase COORD both allow me to ignore IMD between zones (in my case, zone=building).

[Mark McFarlane]

Intermod is a local issue, so yes you can put separate rooms into separate zones and generally ignore intermod between them.

Thank you Scott, that is what I was expecting (or at least hoping for).

[Brad Harris]

All of the above is correct (and even contradictory to eachother in some ways)...


Coordination is a bit of an art ...

On the technical side, there shouldn't be an Intermod between the locations as described with the transmit powers that we use, but that doesn't stop someone from bringing over a transmitter from the 'other side' ...

As mentioned above, direct hits are a very valid consideration regardless of "zoning" scheme. IM's and its varieties are a slightly different story.


When I'm doing coordinations, Ideally (...not always...) I start out with the most robust way I can ... Everything in one ZONE, 3TX3 (or whatever the software nomenclature is for 3 transmitters 3rd order) and every other calculation enabled and go with that.

If I can't get any more frequencies that I need, then we start to compromise.....


What happens if the Easter production, or Christmas production gets large enough that bringing over some wireless from one location to the other. Easiest way is to have it already ready to play nice with each other without changing frequencies....


Brad

[Mark McFarlane]

All of the above is correct (and even contradictory to eachother in some ways)...


Coordination is a bit of an art ...

On the technical side, there shouldn't be an Intermod between the locations as described with the transmit powers that we use, but that doesn't stop someone from bringing over a transmitter from the 'other side' ...

As mentioned above, direct hits are a very valid consideration regardless of "zoning" scheme. IM's and its varieties are a slightly different story.


When I'm doing coordinations, Ideally (...not always...) I start out with the most robust way I can ... Everything in one ZONE, 3TX3 (or whatever the software nomenclature is for 3 transmitters 3rd order) and every other calculation enabled and go with that.

If I can't get any more frequencies that I need, then we start to compromise.....


What happens if the Easter production, or Christmas production gets large enough that bringing over some wireless from one location to the other. Easiest way is to have it already ready to play nice with each other without changing frequencies....


Brad

Great considerations I hadn't thought through Brad, thanks for chiming in. 

...I did run an event last month where we had some "10 minutes before show start" equipment mis-behaviors and I grabbed a wireless mic TX/RX from the other zone.  That probably would not have worked without re-coordinating if I hadn't previously been using IMD between zones.

I was hoping to turn off IMD between zones/rooms but I'll go back to using 2T30 and 3T30 between zones/rooms as my default and only turn off between-zone IMD calcs if I can't find enough clear frequencies (and maybe mark that gear as 'do not move').

[Jordan Wolf]

I don’t have it with me, but Shure recommended certain zone-to-zone interaction settings based on approximate RF levels picked up from one space to the next. I’ll try to follow up on Monday 6/26 when I’m back in the office and have access to the Post-It I wrote it down on (but did not take a picture of/type in my phone), lol.

My usual venue has spaces on the 2nd floor and 2nd Mezzanine that I consider far enough to make IMD a non-issue, but channel-to-channel and direct-frequency interference an issue. Likewise on the 3rd and 4th floors. The 33rd floor is basically it’s own building, so I allow for the 2nd/2M  and 3/4 zone freqs. to be completely unaccounted for and have had no issues in my years of doing so with dozens and dozens of RF kits weekly.

[Jordan Wolf]

Wanted to follow up about the Shure-recommended parameters regarding zones and interactions in WWB:

-85dBm or below: “Separate Zone” (no Ch.-to-Ch. or IMD)
-70dBm — -85dBm: “Related Zone” (IMD-only)
Greater than -70dBm: “Same Zone” (Ch.-to-Ch. & IMD)

I forget exactly where I heard/saw it, but it was likely one of Shure’s advanced RF webinars.

[Mark McFarlane]

Wanted to follow up about the Shure-recommended parameters regarding zones and interactions in WWB:

-85dBm or below: “Separate Zone” (no Ch.-to-Ch. or IMD)
-70dBm — -85dBm: “Related Zone” (IMD-only)
Greater than -70dBm: “Same Zone” (Ch.-to-Ch. & IMD)

I forget exactly where I heard/saw it, but it was likely one of Shure’s advanced RF webinars.

Thanks Jordan. I assume these numbers are simply absolute scanner measurements and not the difference between the remote zone's TX level and the current zone's TX level.

[Jordan Wolf]

Thanks Jordan…

You’re welcome.

I did find a video that had the numbers I wrote down in it, but it was not where I originally got them from.

It basically describes what you said: power up a transmitter in one zone and scan using a receiver in each other zone, then see how much RF spills into each of the other zone(s).

[ProSoundWeb Community]