Hi to all of you ! I'm Piotr, I'm located in France and I'm sound engineering mostly in live music. I'm very often puzzled by some of the difficulties of an easy communication in our working environnement between the different locations. There are different solutions used, depending on the company, the festival and so on... mostly via small dedicated mixers, and two input powered speakers (https://www.behringer.com/Categories/Behringer/Loudspeaker-Systems/Portable/B205D/p/P0957#googtrans(en|en) for example). Maybe this is sufficient, maybe not, maybe there's a simpler way especially concerning the routing, inputing and outputting of utility signals as TALK mics etc... and sharing/providing them to incoming productions. So I've started a project, based on the usual setups on concert and festival stages, and discussions with my fellow colleagues in France and Switzerland, that intends to simplify the routing and mixing of the various sources needed: FOH talk, MONS talk, FOH shout, MONS shout, STAGE wireless talk, STAGE IEMs... Basically the idea is to have two 19" racks, one at FOH, one at MONS, that are dedicated mixes (5 sound sources to 3 mix busses), with 4 analog lines running (either/or XLR and CAT5 analog as in the RATCAT family http://soundtools.com/products/catfamily.php). I have a basic knowledge of electronics, I have successfully built a lot of projects (9K preamps, 1176, 51x 500 racks...), I'm learning KiCAD... At this point I need help !!! I'm not an electronics designer so there's a lot of things I need to clarify. The project calls for "basic blocks": MIC/LINE preamps (no 48v), MIC Splitting (easiest probably done with transformers ?), LINE Receivers to LINE OUTPUT, SUMMING stage (with mutes and level control probably) and LINE OUTPUT stage. I've investigated a simple INA217 based preamp as for example in: http://plchambert.ca...9/33836333.html https://www.diyaudio...-templates.html I've investigated basic mixer topologies as for example in: https://sound-au.com...udio-mixing.htm https://www.electro-...circuit.122073/ I'm trying to figure out which way to go and design then build this project, so before going further I'm hoping for some general wisdom !!! I clearly need a method to put it all together, so I would happily read your comments as to the steps you think I need to follow: general idea > basic synoptic > schematic > PCB design... I need to narrow down the building blocks to simple and easy to implement solutions: which MIC/LINE preamp, which SUMMING solution etc... And of course what are the bad ideas I need to throw away !!! As to clarify the general intention, here is a basic synoptic, which omits the local details of the racks (input connectivity and switching). The FOH rack is basically a passive input/output "patching" box, no mixing necessary, just connectivity. The MONS rack is where the mixing/summing/routing takes place so I guess active is the only solution. There are basically four different situations that need to be dealt with: Situation A : FOH with House desk / MONS with House desk Situation B : FOH with Production desk / MONS with House desk Situation C : FOH with House desk / MONS with Production desk Situation D : FOH with Production desk / MONS with Production desk (where the house communication system is generally not used but remains in use for the other shows.) That's it for the opening post !!! Tell me what you think. Tell me what to clarify. Looking forward to your insight and ideas, Thanks in advance !!! Regards, Piotr. https://www.icloud.com/iclouddrive/0oJRyb8MiqDE4rgSyom5BVOhg#FOH_MONS_Comms_General_Principle