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post #1 of 8 Old 03-24-2009, 12:34 PM - Thread Starter
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I have a Harman Kardon AVR-254 which is rated at 50w/7 channels. Is is possible to redistribute the power output? The speakers I am looking at getting can handle up to 200 each and I will only have front speakers on this system. I think 175/175 would be ideal since I am doing a simple 2.1 setup but I have not dug in to see if I can do this.

Anyone know off the top of their head?
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post #2 of 8 Old 03-24-2009, 12:49 PM
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Receivers have a single power supply, so you generally get more power per channel with less channels driven. There's an upper limit to how much power it can put out per channel, and it's probably less than 175 watts.

If you really want a lot of power, you could add a power amp if the receiver has pre outs on it. It kind of depends on your needs. If you want to hit rock concert SPL of 110 to 120 dB, you may need a separate amp - but I don't suggest listening to such ear damaging levels.

"But this one goes up to 11"
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post #3 of 8 Old 03-24-2009, 01:10 PM - Thread Starter
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Thanks for the reply, Michael. I don't really want it rock concert loud, I just want enough to hit the sweet spot on the speakers (Energy FPS) and I didn't know if the stock 50 would do it. I had read that running too little could actually damage the speakers.
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post #4 of 8 Old 03-24-2009, 01:26 PM
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Quote:
Originally Posted by boutwell View Post

Thanks for the reply, Michael. I don't really want it rock concert loud, I just want enough to hit the sweet spot on the speakers (Energy FPS) and I didn't know if the stock 50 would do it. I had read that running too little could actually damage the speakers.

Your speakers can take any sort of wattage....you can give them a 10Watt amp and you can give them a 400Watt amp.

All that matters is what is the max SPL capabilities of your speakers so you do not destroy the drivers and what is the max watts out of an AVR before clipping which can hurt a speaker.

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post #5 of 8 Old 03-24-2009, 01:27 PM
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Speakers are damaged by exceeding their thermal or mechanical limits.

A common way of damaging speakers is to send them a clipped signal from an amplifier. Clipped signals resemble square waves, and square waves have higher than normal levels of high frequency energy. It is that energy which causes the tweeter's voice coils to heat up and possibly to damage them.

Which is why people will recommend you have more power on tap then is needed, so that clipping is avoided.

A hotly debated topic is how much power do you actually need? It depends on your speakers, your speaker placement, your room and your personal taste.

I did a recent test, that some people seem to disagree with, using a Kill A Watt meter. It measured a peak power draw of less than 300 watts total when I was driving seven speakers and playing the opening scene of the movie Iron Man. Personally, I think that says a lot about how much power is needed in real world listening. I think it says you don't need as much as people think. But that's just my opinion.

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post #6 of 8 Old 03-24-2009, 01:32 PM
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Your 254 is rated at 65wpc in stereo - 2 channel mode. That is a direct indication of the total power available to all channels together. Most good multichannel amps and receivers will give you somewhere around 1/3 more power when you are only using 2 channels. This ratio gives an indication of what the power supply is capable of. The lower the ratio the lower the power supply capabilities.

Harman Kardon typically are more conservative than many of the other manufacturers in their power ratings. Your 65wpc in 2 channel operation may achieve higher SPL than some makers ratings of 80-90wpc for their 7 channel amp when driven in 2 channel mode.

As for damaging your speakers, if you don't know what clipping sounds like find a way to hear it first hand. Having said that, I don't think you are in danger of harming your speakers unless you drive them to concert levels. If that is your goal, the 254 has preamp outputs, get a beefy amp and plug it in.

When all else fails - RTFM!

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post #7 of 8 Old 03-24-2009, 01:34 PM
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Quote:
Originally Posted by MichaelJHuman View Post

Speakers are damaged by exceeding their thermal or mechanical limits.

A common way of damaging speakers is to send them a clipped signal from an amplifier. Clipped signals resemble square waves, and square waves have higher than normal levels of high frequency energy. It is that energy which causes the tweeter's voice coils to heat up and possibly to damage them.

Which is why people will recommend you have more power on tap then is needed, so that clipping is avoided.

A hotly debated topic is how much power do you actually need? It depends on your speakers, your speaker placement, your room and your personal taste.

I did a recent test, that some people seem to disagree with, using a Kill A Watt meter. It measured a peak power draw of less than 300 watts total when I was driving seven speakers and playing the opening scene of the movie Iron Man. Personally, I think that says a lot about how much power is needed in real world listening. I think it says you don't need as much as people think. But that's just my opinion.

Hey now, I just posted that info

See other thread for more comments.

It is not "open-minded" to reject knowledge - Bob Lee
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post #8 of 8 Old 03-24-2009, 11:11 PM
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Yeah I saw the other thread.

"But this one goes up to 11"
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