In the tradition of NPR’s Car Talk Puzzler but with a somewhat more practical application, I offer you this. I want to use BlogTalkRadio and POTS to bring remote callers into a live panel discussion for a live audience. The illustration below was drawn in a more optimistic era. Skype is not an option.
The Problem It requires mixing any number of microphones (or cell phones) in the live audience with the audio that is heard and generated by the remote callers. All of this gets sent back through an amp and speakers for the live audience. My first attempt looked like this:

First Test The result of this Rube Goldberg setup was intolerable feedback and reverb. Don’t get me wrong, I’m a fan of reverb but the inevitable delays that are inherent in Voip telephony are bothersome. On the other hand, there may be some submixing solutions.
Another Box 1?

Someone turned me on to some specialized hardware that may be useful. JK Audio’s REMOTEMIXERCPLUS might do the job. A poor product name, but potentially useful. With DSP chips that handle the audio streams discreetly, I suppose it can make up for the difference between analog and digital communications, but at $500 plus, it’s out of my budget.
Another Box 2?

Then there’s the Broadcast Host. “The digital hybrid connects audio signals to a standard analog telephone line without the transmit / receive crosstalk common to analog hybrids. The Digital Signal Processor (DSP) continuously monitors both the phone line and audio signals to deliver excellent separation. This proprietary, dual-convergence echo canceller algorithm can achieve excellent separation, typically exceeding 50 dB, without any setup and without sending a noise burst down the line.”
Simplify things

Maybe all I need is a Hybrid Audiocoupler and use that as an input to the mixer. Still, the live audience input needs to make it into the phone upstream. Hmmm….
Old School I had the pleasure of touring Palo Alto’s Media Center today. Their solution for hooking up a live audience with remote callers is an old studio solution called the Gensler. I can’t find any references to this online. Maybe I’m mispelling it. In any case, it takes land line input and mixes it with the studio mics. Not quite what I’m looking for, but it will do in a pinch.
I guess it’s always a case of making do. If you have anything to say leave a comment…