How to biamp my power hungry beasts! (1 Viewer)

[Girish]

I got a pair of Usher CP-8871 fronts. The manual says it needs 150 watts. I have two five channel amps. Lexicon CX-5(125 wpc), and a Rotel RMB-1075(120 wpc). I want to Biamp these speakers.(1). Using a Y connector from the processor feed it to the lexicons four channels and use two to each speaker( using four out of five) without using jumpers at the speaker(one from each channel to the two posts of each speaker).(2) Use one channel each from Lexicon and Rotel for each speaker without using jumpers at the speaker(one from each of the to amps to the two posts of each speaker). Use three out of the remaining six channels for center and surrounds.I have been told these are power hungry speakers!!

 

[schan1269]

Power hungry is BS.There is no way those "need" 150 watts.I'll look up their specs in a bit.

 

[schan1269]

Those are 4ohm, which means you can't use cheap amps.

They are also 90db efficient. Which means on 150watts...

They'd produce 111db. How deaf do you want to get?


The "150 continuous" rating means they'll take 150 watts all day long...and not fry. Does not mean they need 150 watts.

Anything over 10 watts is plenty(cause they are 90db efficient).

 

[Girish]

So I am ok using four out of five channels out of my Lexicon CX-5. Its a decent amp IMO.

 

[schan1269]

Only if you need to get deaf quicker than just using two channels.

There is no, none, nada reason to bi-amp these speakers.

Again.

These are 90db efficient. Granted you lose 3db per "yard"(meter) in distance(but you gain 3 having two speakers...not one).

So, if you are sitting 10 feet away...

1 watt is 83 db reaching your ears.
2 watts is 86
4 watts is 89
8 watts is 92
16 watts is 95 (already rocking)
32 watts is 98
64 watts is 101. Listen very long at this volume...you won't be listening very long.

So yeah...you need to bi-amp(sarcasm)

 

[schan1269]

Now, if you want greater headroom...

You could get an external crossover...run above X with 2 channels and run below X with 2 channels.

Have no idea what that X would be though. I would assume these speakers are wired inside for EQ bi-amp. Which is still relatively unnecessary.

But your bi-amp for "just more power" is nonsense.

 

[Girish]

Got it. So far the biggest speakers I have owned are Infinity intermezzo(4.1t) and ran with regular gear.. Wherever I have seen speakers these big(at audio stores), they had them hooked to super heavy expensive amps and cables(!!!). Just wanted to confirm with people like you who know what they are doing!!
BTW I picked these in your part of the woods(Howe Indiana).

 

[schan1269]

Awful big "neck of the woods"...ha.

(I had to search where Howe was. 135-ish miles)

But yeah. Hoighty toighty audio shops like mentioning godawful power amps that run 600 wpc and using $200/ft speaker wire.

I walked into a high end shop in Indy once and the speaker wire was 8awg cable that had to be wrestled cause it didn't bend(much). Top it off, they had the cable sitting on stands so it was "decoupled from the floor".

Some of this stuff is insane.

 

[Girish]

I have seen decoupling at a lot of stores! Also a subwoofer secretly hooked up in a corner to make speaker performance more impressive.

 

[Mr645]

Something like the Atma sphere SA-30, massive, expensive and 30 wpc, for $125,000 the Audio Note Souga rated at 8 watts per channel?

As stated above, if the speakers are not really designed to bi amp, it's not really needed. Either amp you have should be great to drive those speakers. There is a lot more then watts when it comes to volume and output. I use a Parasound 85 wpc amp between a Pioneer receiver rated at 110 wpc and the lower rated external Parasound delivers significantly more power and volume, as well as great control of the speakers. I also noticed that the 85x5 Parasound draws almost twice as much power from the wall as the Pioneer 110x7 receiver.