To Bridge or Not to Bridge...

[paolo137]

Hello everybody,
I'd like to know your mind about the setting of my new videoprojector room, currently a work-in-progress.
I already have the following:

- receiver: Cambridge Audio 540
- power amplifier: Rotel rb 965 (3/4/5/6 channels)
- front speakers: RCF Aithra 5 (massive vintage Italian speakers: 3 ways, 4 drivers, 8 Ohms, suggested power unknown, estimatated 150 w; sensitivity unknown, estimated above 90 dB)
- subwoofer: self made with Ciare PW 391 driver, a bass reflex washing machine with 700 w rms, sensitivity 93 dB, 8 ohms

(when done, it will be a 6.1 system; center and surround speakers still missing)


Now, I understand that the best thing will be to try the different settings and choose the best one based on the response of the room and the equipment, but, based on your experience, what would you do?:

1) bridge the 6 channels of the Rotel into 3 (150 watts each) and feed the 2 fronts and sub (receiver will drive everything else)
2) bridge 2 channels into 1 for the sub, and biamp the front speakers with the remaining 4 channels, rated at 60 w each
3) be gentle with the power amp and avoid bridging: 60 "rotel" watts will be enough to drive the speakers up to a reasonable volume

Please notice that I'm not a huge fan of very loud music/effects (the subwoofer was listed on the bay at a ridiculous price, otherwise I would have gone for a 100 w. unit, self-amplified), Furthermore, when listening to music, I will use only the two front speakers (true stereo). The room is roughly 180 sq. ft.

Thank you very much for your advice.

[Nuthed]

Anytime you bridge the sound gets a little gritty, in my opinion. Not bad, but not as pure as unbridged.

With that being said, why not give the 540 a try on it's own? It's supposed to be a decent performer and at 80 wpc it should suffice. You get 100 wpc when just driving the 2 mains.

[stuofsci02]

When you bridge you also need to treat it like your speakers are 1/2 the resistance... So 8 ohm speakers look like they are 4 ohms to a bridged amp. This can cause fits for the amp if the speakers have low impedances across their frequency..

[paolo137]

Thank you, guys: you have confirmed my concerns. Had not thought about amping the two fronts with the Cambridge audio, though. Might very well worth giving it a try. Could use the Rotel to power all the rest.
Will let you know!