At 08:21 PM 1/6/2013, Josh Koffman wrote: >1. Radio - two way radio (walkie talkie) - half duplex >2. Production Intercom - a partyline style full duplex intercom system >3. In-ear monitors - a wireless stereo feed from the sound system >(with some things added that the audience doesn't get to hear) >The way I currently deal with this is to wear an in-ear monitor in one >ear, my intercom headset over the other ear, and have the radio >speaker/mic clipped somewhere nearby in the hopes that it will bleed >through enough that I can hear it. For the record, that rarely works. Hi there, Josh. What you describe is something that I do regularly. One of my hobby=20 jobs is doing live audio (at our local football stadium) as well as=20 doing RF (wireless mics & wireless intercom) *and* production=20 intercom for both live TV broadcasts and large live events. For=20 example, the last large Intercom job that I did (late last summer)=20 was for the film crew doing a 3D movie with the rock band Metallica -=20 that was an RTS Adam digital-matrix system with just shy of 100 users=20 on wired and wireless headsets plus an additional 45-50 users on two=20 channels of half-duplex 2-way radio on something like 18 channels of comm. Something that both myself and my users find very important is the=20 concept of spacial separation when monitoring multiple channels of=20 comm. One of my buddies does audio for live broadcast TV - he often=20 sets up several small (Fostex) speakers above and in front of him=20 (top left and right corners of the room) as well as at his feet and=20 behind him. This lets him identify which channel of comm=20 instructions are coming from - which lets him decide what to=20 ignore. He can't wear a headset when he is mixing live audio, which=20 makes the little comm speakers vitally important for him to do a good job. I regularly monitor 2 or 3 audio sources when I'm in front of my=20 intercom panel at the stadium - a walkie, the intercom headset and=20 program audio. But I cheat - I wear an IFB earbud from my 2-way=20 radio in my left ear, then have the intercom headset over top of that=20 ear. My right ear is either open (so that I can talk with people=20 coming into the audio booth) or has one side of Sony 7506 headphones=20 over it with program audio and/or monitor audio from the Wireless Mic=20 receiver racks. Both headsets get tossed when I have to go run and=20 deal with a problem but the radio earbud stays in my left ear. Can I suggest that you try using an IFB earbud in your ear for your=20 2-way radio? You might be pleasantly surprised at how well it=20 works. The earbuds that I use come from Audio Implements (USA) - 125=20 Ohm clarifiers with an air-tube to an accordion-style bud. Audio=20 from the intercom headset speaker has no problem getting past the=20 earbud into my ear. For what its worth, I'm using a Beyer-Dynamic=20 DT-108 single-muff headset when I'm sitting at that intercom panel. For Motorola radios, at least, you can get speaker-mics that have a=20 3.5mm earphone jack. That works well with the 125R Audio Implements=20 IFB earbuds. I would assume that Kenwood and Icom (and other 2-way=20 portable radios) have similar speaker-mics available. I mostly work=20 with Motorola HT-750 radios. If you find the earbud to be too uncomfortable for long periods of=20 time, I've recently started using a small headset instead of the=20 earbud. Unfortunately, I don't recall the names (manufacturer and=20 model) of the unit - but I can find out. Its small enough that the=20 Beyer headset fits right over top of it. This headset replaces both=20 the speaker-mic and IFB earpiece. I used it for the first time last=20 season and quite like it so far. You can try the mixer approach - I've got a small PCB that mixes 4=20 in-coming mono signals into a stereo output that I could send to you=20 (if I can find them - they were for Broadcast Talent boxes that I=20 built more than 20 years ago). These cards have individual dip=20 controls as well as pan controls - the dip controls dim each incoming=20 audio channel by an adjustable amount when that channel's dim control=20 signal is active. The card runs from a single +24V supply but will=20 probably work down to 12V. It uses TL072 and TL074 op-amps, which=20 limits how low the supply voltage can be. I hope this helps and I'd love to hear more about what you do. dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .