Power requirements for Receivers and speakers

[vasanth]

Hello,

I wanted to ask one fundamental question about the output per channel from a receiver to the power that each individual speaker can handle. For example, for 7.1 system, the receiver is able to output 80W into an 8-ohm load. Now for the speaker description:

Center Channel: 20-125 W with an 8-ohm impedance
Front speakers: 20-100 W with an 8-ohm impedance
Surround speakers: 20-100 W with an 8-ohm impedance

I'm not using the rear back speakers, in other words, currently content with 5.1 setup.

My question is will the 80 W output from the receiver will be able to drive the speakers with the above numbers. I heard or am confused by the fact that if the total receiver output (80x7), 560 W is less than the total combined speaker power rating (the max, 125 + 100x4), 525 W + if I add the back speakers say, 50W each, in which case total speaker power rating will 625 W; will damage the receiver because its output power is less than the total power rating of the speaker (based on this confusion, I'm okay because my total speaker power rating would be 525 W as calculated above.), or in other words would I be undermining my receiver if I add the extra rear speakers (say 50W each).

All answers/responses are appreciated. Thank you.

 

[zumbo]

Over-thinking it.

If the speaker specs you listed are what you own, and you are currently seeking a receiver, then any decent receiver on the market will work with no issues.

More power is better, but any reputable brand (Yamaha/Denon/Marantz/Onkyo...) claiming 100x7 or better will be just fine.

 

[zumbo]

Hottest deal going, and should not be missed:
http://store.audioholics.com/product/3317/1/yamaha-rx-v3900-surround-receiver--yamaha-refurbished-/f3388d309b43fcef5f4a6bb4b79cb8b0

 

[zumbo]

If the 80W receiver you mention being an "example" is what you own, it is either out-of-date, or a very low-end model. It will work, but should be replaced for a more current piece.

Not based on it's ability to power your system, but based on the feeling that it is lacking current features.

 

[MDS]

I heard or am confused by the fact that if the total receiver output (80x7), 560 W is less than the total combined speaker power rating (the max, 125 + 100x4), 525 W + if I add the back speakers say, 50W each, in which case total speaker power rating will 625 W; will damage the receiver because its output power is less than the total power rating of the speaker (based on this confusion, I'm okay because my total speaker power rating would be 525 W as calculated above.), or in other words would I be undermining my receiver if I add the extra rear speakers (say 50W each).

I've heard some wacky things in my time, but never that one.

The receiver's power rating is per channel and is the maximum amount it can supply at any one time. Multiplying the number of channels by the per channel rating to get a big number like '560 watts' is misleading. You do not have a 560 watt receiver - you have an 80 watts per channel receiver (which is more than enough to create ear splitting levels in an average size room with reasonably sensitive speakers).

The speaker ratings are how much they can handle on a continuous basis and the max rating is the max it can sustain for short periods of time. It is nonsense to add up the max power ratings of the speakers and try to relate that to what power is necessary for a receiver/amp to drive them. Those speakers will be absolutely fine with the receiver.

If you add the two rear speakers, you'll have 7.1. Each channel will still be capable of 80 watts per. You will not have a 700 watt receiver.

 

[vasanth]

Thanks for reply, I'm getting the following configuration, being a first-time home theater buyer, I thought this was more than enough for my budget.

Receiver: Onkyo TXSR508
Center: Polk Audio TSi CS10
Front: Polk TSi100
Surround: Polk Audio OWM3
Sub: Polk Audio PSW111

What do you think about the above config?

 

[vasanth]

Since output for each channel from the receiver is 80 watts, I would think from your opinion, the receiver should be okay with pumping its 80 watts into the 100 watts (125 watts for center) for each of the speakers and not my opinion that receiver being lesser watts than each speaker would damage the receiver. Thanks again.

 

[zumbo]

Receiver has plenty of power for that system. It's a whole lot easier to answer an actual question than a general one.

Took 1 & 1/2 hours for you to reply to your general question with an actual one.

 

[vasanth]

Though the initial question was a general one, but that was what I wanted to understand, will one 80 watt channel of the amplifier (receiver) be inferior to a 100 watt (or 125 watt) speaker. The whole example was to put my clarify.

Once again, thanks for the many replies and clarifying.

 

[MDS]

Since output for each channel from the receiver is 80 watts, I would think from your opinion, the receiver should be okay with pumping its 80 watts into the 100 watts (125 watts for center) for each of the speakers and not my opinion that receiver being lesser watts than each speaker would damage the receiver. Thanks again.

I wonder if what you heard and is the source of confusion here is that an underpowered receiver can damage speakers. You hear that often but that is only if you drive that receiver way beyond its capabilities and it clips the waveform as it struggles to keep up. That can damage speakers but so can sending the speakers far more than they can handle.

The Onkyo 508 is not 'underpowered' for those Polk speakers.

Remember, the speaker specs are giving you a guideline for how much input power they can take and still work within their design limits without damage. The receiver will rarely be called upon to deliver its full power and even when it does, it is well within the limits of the speakers.

I see no problem with your chosen system.

 

[MDS]

Took 1 & 1/2 hours for you to reply to your general question with an actual one.

Maybe he was away painting as I was. Now I'm taking a break...anything to avoid work.

 

[zumbo]

Though the initial question was a general one, but that was what I wanted to understand, will one 80 watt channel of the amplifier (receiver) be inferior to a 100 watt (or 125 watt) speaker. The whole example was to put my clarify.

Once again, thanks for the many replies and clarifying.

Once again, you have made a general statement. It doesn't work that way, nor does it work the way you were thinking before.

The answer to your specific question is specific to your situation.

The Onkyo 508 is not 'underpowered' for those Polk speakers.

I see no problem with your chosen system.

 

[zumbo]

vasanth
The general clarification is this:

Remember, the speaker specs are giving you a guideline for how much input power they can take and still work within their design limits without damage. The receiver will rarely be called upon to deliver its full power and even when it does, it is well within the limits of the speakers.

Other variables include ohm load, sensitivity, and room size. This is the reason a general answer to a 80W receiver and 100W speaker is hard to answer.

 

[vasanth]

What conditions can a receiver be driven beyond its capabilities (possibly not with the above configuration)?

Thanks

 

[MDS]

What conditions can a receiver be driven beyond its capabilities (possibly not with the above configuration)?

Thanks

- Leaving the volume control at the max for some time while connected to low impedance speakers. That will tax the power supply of the receiver as it struggles to deliver the required current. That is the condition I mentioned under which people will say too little power can damage speakers and/or the receiver.

- Possibly the condition where the content being played has incredible dynamic range (think classical music) and using low sensitivity speakers. You'll turn up louder and louder to get the volume you want and when a dynamic peak occurs, it could require 10x the power in an instant. Low to mid-level receivers will struggle with that situation.

You're going to be fine with your system. I used to have an Onkyo 502 with older JBL speakers. The speakers were quite efficient (92 dB) but even loud volumes didn't stress the receiver. It did however stress my ears.

 

[lsiberian]

Though the initial question was a general one, but that was what I wanted to understand, will one 80 watt channel of the amplifier (receiver) be inferior to a 100 watt (or 125 watt) speaker. The whole example was to put my clarify.

Once again, thanks for the many replies and clarifying.

Just buy the Onkyo if you like it. It will do fine.

 

[cerwinmad]

Im driving CV VE-12 speakers that are 300w rated input, 6ohm, with my Onkyo 503 and it drives them beautifully, it takes a long LOUD session to get it stressed, based on what you have that receiver will be more than up to driving those speakers.