Why are the Infinity IRS, Reference 1b, Beta ect speakers passive on the mids and highs?

@bdp24 
"The Emit and Emin drivers were good, but the way they were employed left something to be desired; different frequency ranges appeared at different heights, for one thing".
This is corrected when you hand match the drivers for exact output and hardwired the pad. The pots were poor.

The pots were poor.

Pots are always a problem when old in any speaker, you replace the pots with appropriate resistor L pad power resistors of the same values for your preferred setting.

Cheers George

I am learning here. Timlub, it sounds like you have experience on the RS1B. Is there anywhere I can get specifics on what to do to improve the RS1b. What made me start the thread was an experiment I did with the RS1B's I have. I disconnected the crossover and tri-amped the system. I know a lot changed because all of the EMIM's went to a midrange whereas passively 6 are 150-700 and 1 is 700-3500 but I did not like the sound as a simple 3 way. I have another system where I have 10 EMIM's and a ribbon tweeter from a magnepan 20.7 where the tri amp works pretty well but falls short in some ways to the RS1B. I am trying to figure it out.
Marc

Partroysound
When you tri amped them what crossover points did you use?

I have not triamped these, I've never owned them.  I worked for Marcof/SpeakerCraft, we did alot of custom work and I got these to work on years later because of my time there. I worked on the crossovers only... Measured each ribbons output individually, then customized the pads within the crossover.  So without having complete driver measurements, that's why the basic design wasn't changed... better caps and coil or 2 and hand matched pads. 
For me, as long as your amps can handle driving ribbons (some cannot) and you have a very good crossover, this is a no brainer. 
It will take a bit to get these matched, but I would expect excellent results.