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daoki

Add more speakers lose power ?

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Hey guys my setup is pair of Polk audio rti a7 speakers powered by a Yamaha PC2002M 240 watts per channel and a Yamaha cx2 preamplifier. My dad gave me some Bose Acoustimass 5 series 3 cube speakers not including the subwoofer. 4 cubes in total. So what I decided to do was run some speaker cables from behind the Polk A7s because behind them they have 2 sets of red and white terminals, 1 set is already been used from the speaker to the power amplifier, leaving the other set free to biwire speakers, but I am not biwiring them I think? What I have done is used the other set of remaining terminals on the A7s and plugged in speaker cable and ran them behind my couch where I have floor stands on each side essentially rear left and rear right and I have 2 Bose cubes on each side. My question is if my A7s are 300 watts into 8ohms and the Bose cubes are 135 watts. But the way I have set them up does it mean my polks are losing power because the Bose cubes are taking the power from them theM? Because the way the Bose cubes are connected behind the A7s? Does that make my A7s lose power going down to only 165 watts?What do you guys think of my setup is it worth doing ? Any issues ? Or does it mean if the Bose cubes are using 135 watts from the polks the Polk will just grab more power from the power amplifier to replace power used from polks? So essentially still staying at 300 watts and the Bose cubes 135 watts no power loss in any speaker ?

Cheers

 

Tony

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You are doing things wrong! Tony.

 

Those terminals on the rear  of the Polk's are not intended for that use.

 

The wattage rating of passive speakers are not important, It's impedance that will be the thing that is a factor in what you are doing.

 

If you want a multi channel set up get a multi channel amp.

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What will happen if I set them up like that ?

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Tony, I just re-read your original post, and will say don't do it!

 

You are as I read it wanting to run 2x Bose speakers off the back of each Polk?

 

I'm back to suggesting that you do not use the Bose speakers in that set up.

Edited by Muon N'

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8 hours ago, daoki said:

Hey guys my setup is pair of Polk audio rti a7 speakers powered by a Yamaha PC2002M 240 watts per channel and a Yamaha cx2 preamplifier. My dad gave me some Bose Acoustimass 5 series 3 cube speakers not including the subwoofer. 4 cubes in total. So what I decided to do was run some speaker cables from behind the Polk A7s because behind them they have 2 sets of red and white terminals, 1 set is already been used from the speaker to the power amplifier, leaving the other set free to biwire speakers, but I am not biwiring them I think?

What you are doing (if I understand it correctly) is very, VERY stupid. Don't do it. The Bose cubes are designed, SPECIFICALLY, to operate via the subwoofer. The subwoofer rolls off the low bass so the cubes will not be destroyed. 

 

8 hours ago, daoki said:

 

What I have done is used the other set of remaining terminals on the A7s and plugged in speaker cable and ran them behind my couch where I have floor stands on each side essentially rear left and rear right and I have 2 Bose cubes on each side. My question is if my A7s are 300 watts into 8ohms and the Bose cubes are 135 watts. But the way I have set them up does it mean my polks are losing power because the Bose cubes are taking the power from them theM?

No. You'll just destroy the Bose cubes. It may take awhile, or it may take a few seconds. Ultimately, however, they will be destroyed. The Bose cubes are not designed to deal with frequencies much lower than 300Hz. 

 

8 hours ago, daoki said:

 

 Because the way the Bose cubes are connected behind the A7s? Does that make my A7s lose power going down to only 165 watts?

No. The Bose cubes will be destroyed and all the power will then be routed to the Polks. All good. 

 

8 hours ago, daoki said:

 

What do you guys think of my setup is it worth doing ?

No. It's stupid.

 

8 hours ago, daoki said:

 

Any issues ?

Apart from sounding horrible and that you will needlessly destroy the Bose cubes, nope. 

 

8 hours ago, daoki said:

 

Or does it mean if the Bose cubes are using 135 watts from the polks the Polk will just grab more power from the power amplifier to replace power used from polks?

Speakers do not 'grab more power'. 

 

8 hours ago, daoki said:

 

So essentially still staying at 300 watts and the Bose cubes 135 watts no power loss in any speaker ?

Cheers

 

Tony

Just don't do it. It's a really dumb idea and you'll just destroy the Bose cubes. BTW: I want you to think on this for a bit. Have you ever felt how hot a 100 Watt incandescent light globe gets? Do it sometime. Even a 60 Watt, or 40 Watt one. Maybe a 50 Watt downlight. Do so, then you'll have an idea of just how much power 135 Watts is. Do you REALLY think those dinky little Bose cubes can handle 135 Watts, without melting into a blob, or catching fire? Those little Bose cubes can REALLY handle about 10 Watts, NOT 135 Watts. I know this may surprise you, but manufacturers often tell fibs about the ratings of their products. Shocking, I know. 

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7 minutes ago, Zaphod Beeblebrox said:

Do you REALLY think those dinky little Bose cubes can handle 135 Watts,

I know the OP’s idea is risky, but why would the Bose cubes be getting 135 W?

For the vast majority of the time the amp is almost certainly putting out far less than its full rated output 

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Just now, Sir Sanders Zingmore said:

I know the OP’s idea is risky, but why would the Bose cubes be getting 135 W?

For the vast majority of the time the amp is almost certainly putting out far less than its full rated output 

Of course, but I was trying to make a point about the absurdity of relying on ONE number in isolation. The reality is that the Bose cubes are designed to deal with NOTHING below 300Hz. When serious bass is applied to the Bose cubes, both their excursion limits and power handling limits (which is around 10 Watts) will be exceeded and the cubes will be destroyed. 

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Plus, I am guessing the Bose will be in parallel with the polks and that will change the impedance that the amp is seeing.

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Yeah, the impedance would possibly be below 2ohms, maybe well below with 2x Bose hanging off each Polk.

 

I looked for those specs for the Bose without any result.

 

The rest is covered by ZB, and nicely.

Edited by Muon N'
typo

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4 minutes ago, Batty said:

Plus, I am guessing the Bose will be in parallel with the polks and that will change the impedance that the amp is seeing.

Correct, but, as I already stated, only for a short time, until the Bose cubes are turned into smoking hulks. I'd give it 2 ~ 3 minutes. Tops.

 

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