If you're still looking for info on the AR2C, I have the Owner's Manual. In fact I also have the older model HO (High Output) series manual if you need any info about that line.
The Specs. in my manual are similar to what Terence posted except the lower Crossover frequency which is 300Hz (instead of 120Hz) and the woofer size which is 6 1/2" (instead of 6 1/4")...maybe I have a different version. My AR2C speaker would be at least 10 years old.
Here's the blurb about the switches on the back:
"On the back of the AR2C are two switches, one for Mid Frequencies and one for High Frequencies. This Voice Matching Equalization Circuit enables the AR2C centre channel speaker to be timbre matched to other speakers in the system or to compensate for frequency anomalies caused by the room environment. This type of frequency compensation is especially critical in multi-channel systems to ensure a seamless soundstage across the from channel.
Initially, each switch is set to flat ("0") which is the recommended factory setting. By moving either switch to the -1.5 setting, those frequencies will be attenuated or rolled-off. Fell free to experiment with each setting to determine the best switch position for your system and room acoustics."
I noticed Outlaw has a similar switch (among other switches) on their LCR speaker: [I don't have enough posts to specify the URL but look for the LCR under products/speakers and subwoofers on the outlawaudio website] You might find more detailed information on their forums on how people are using it.
Other that that the manual mostly describes how to care for your speakers finish, how to hook up speaker wire for bi-wiring or bi-amping and how to place them. PM me if you like and I can scan it in and send you the PDF, it's only about 6 pages for each language.
I have a pair of AR 310HO for fronts, the AR2C centre and a pair of AR 206HO speakers for surround. I have the switches set to flat and it sounds great to me
BTW, anyone have thoughts on a decent $1000ish or less AVR with hi-res audio/room correction/hdmi for this setup? I'm still running a non-hdmi receiver so am getting the itch to upgrade. Was leaning towards the Anthem MRX-300.