Way back in the late 1970s early 1980s, I was using a pair of rear speakers in my audio system. They were configured in such a way, that they reproduced the 'acoustic' of the venue in which a given recording was made.....in those days the source was mostly vinyl, but I also used a reel to reel tape deck.
This configuration was/is know as a Hafler Circuit. The system worked like this: a pair of (small) rear speakers were positioned high up on the side walls, approximately in line with (or just behind) the optimal listening position. The rear speakers I used were small Kenwood bookshelfs and the front of each speaker sloped down (and in) towards the floor, so they were angled to project the sound down to the listener sitting below. These speakers were wired in such a way they they reproduced the 'echo' or 'acoustic' of the recording venue....information which is apparently embedded in all two channel recordings, but is not normally accessible in a conventional two channel set up.
The rear speakers I used, had their woofers disconnected, so that only the tweeter was active. In later years, I used both the woofer and tweeter in the rears. The circuit was volume controlled by a potentiometer, which could be positioned anywhere in the circuit, but I chose to position it (out of sight) behind the amplifier. I found this system to be a very useful tweak, especially for setups operating in confined spaces.....in larger rooms, I found that a Hafler circuit could confuse the stereo image, so for that reason, I discontinued its use.
I'm now listening in a confined space once again, so I'm contemplating reintroducing a Hafler circuit.
Does anyone know whether this system is still used and if so, have there been any refinements to it, over the years? If I'm going to use it again, I would like to use the most advanced and up to date version there is out there.
Here are some explanations, discussions and examples of a Hafler Circuit: http://www.sa-cd.net/showthread.php?page=1
