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RP-260: Receiver Power vs Speaker Continuous Power


Thaneian

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Hello,

 

I am new to all this and I just bought 2 RP-260F and a RP-450C for black friday. My plan is to run 3.0 for HT and 2.0 for music to start off and slowly as my budget allows, start adding more speakers for a proper HT setup. I am trying to now buy a receiver but I am confused to what kind of power I should be looking at?

 

For context here are the following stats:

- I sit 9 feet or 3 meters away from the front

- Current living room is 9ft high, 17ft long 17ft wide = 2600 cubic feet. This does not include openings to a hallway, kitchen and den. (It's a condo)

- RP-260 sensitivity is 97db at 1 meter

- 6db is lost for every doubling of distance from the speaker. Therefore, if I sit 3 meters away, I lose 9db in volume

 

88db @ 1w
91db @ 2w
94db @ 4w
97db @ 8w
100db @16w
103db @ 32w
106db @ 64w
109db @ 128w

 

It's my understanding reading around that the reference peak level you want your speakers to be able to hit is 105db at the listening position. Based on that it looks like I should be perfectly fine with an receiver that can deliver at least 64w. What I don't understand is why everyone is pushing for expensive $800+ receivers and in some cases, adding an amp as well to power their speakers? Unless they are sitting more than 3 meters away from the front, why would you need that much power?

 

And how does the 125w continuous power handling spec fit into all this? I can't find the link link anymore, it was an article from Klipsch recommending that you don't go below 80% of the continuous power rating. Which in the case of the RP-260 is 100w = 125x.8, which is much higher than the 64 watts it seems I only need.

 

What am I missing here, do I need a receiver capable of 100w or 64w for my needs?

Edited by Thaneian
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It's because, generally speaking, the more speakers a receiver powers the less power per channel it will put out.  Power output is usually measured with one or two channels in use, many times at 1kHz instead of a full 20Hz-20kHz range.

 

If you want the output you describe you'll have to get a massively powerful top of the line receiver, or get a receiver that has the features you need ( including pre-amp outputs) and a separate amplifier that can handle the output you want.  That's because, generally speaking, standalone power amplifiers will have components to allow for higher output.

 

If you buy a receiver simply based on rated wattage you won't end up with what you're looking for.

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I looked at test benches from Sound and Vision for the Pioneer VSX-832 (CAD$389.95) and the Sony STRDN1080 (CAD$599.99) and the power test ratings seemed pretty adequate.

Pioneer VSX-832 (bench)

2 Channels driven (8ohm)

106w @ 0.1%THD and 122.5w @ 1%THD
5 Channels driven (8ohm)

70.4w @ 0.1% THD and 81.9w @ 1% THD

 

Sony STRDN1080 (bench)

2 Channels driven (8ohm)

98.9w @ 0.1%THD and 121w @ 1%THD
5 Channels driven (8ohm)

66.2w @ 0.1% THD and 90w @ 1% THD 

7 Channels driven (8ohm)

64.4w @ 0.1% THD and 75.5w @ 1% THD 

 

Compared to a Denon X3400H (bench)

2 Channels driven (8ohm)

123w @ 0.1%THD and 147w @ 1%THD
5 Channels driven (8ohm)

97.6w @ 0.1% THD and 106.1w @ 1% THD 

7 Channels driven (8ohm)

72.7w @ 0.1% THD and 80.8w @ 1% THD 

 

Looks like the Sony or Pioneer would be adequate for my needs vs the more expensive Denon?

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There's another factor to consider:  headroom.  Do you want to have a receiver that will give you the output you want while stressing the power supply to the maximum power output it has?  If those receivers seem to work for you, the best way to do it is try one out for a while.  You can always add an amp later if you choose to.

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1 hour ago, K5SS said:

Condo = You will be fine with any of those receivers.

 

I’d get the Denon for the room correction software though. 

 

Yes!  Get the Denon because it has Audyssey room correction software.  Marantz has it, too.  IMO people with some patience get good results with Audyssey.  My Klipschorns and center channel Belle Klipsch, in my room, have never sounded better!

See: "Audyssey FAQ Linked Here" While not quite perfect, it is better than any Denon or Marantz manual I've seen.  If you read this you won't need the now outdated Denon to English translator that is floating around online.

 

You probably won't lose a full 6 dB for every doubling of distance.  People who use that figure usually add a little back in for room gain and boundary gain.  The figure is for in the great outdoors on top of the proverbial flagpole.  Really.  Paul W. Klipsch, in one of the factory listening rooms, for 3 doublings of distance measured a loss of about 9 or 10 dB, through the whole frequency range.  That's about 3 dB per doubling.  If your room is quite dead with wall to wall carpet, overstuffed furniture, tapestries on the walls (or too many commercial absorbers), you might lose an intermediate number of dB per doubling, like 4, 5, or conceivably 6.

64 watts is probably enough, BUT most fairly good or better AVRs are 100 watts per channel or more, nominal.*   If you are not yet using a subwoofer (with its independent power) and you set up the AVR for no subwoofer (subwoofer yes / no switch on no) your AVR may channel the LFE into the front speakers.  You don't want that to clip your AVR, so it might be helpful to either get a sub right away, or get a more powerful AVR (and keep the volume down a bit on outrageous special sound effects.

 

Klipsch started adding a almost microscopic footnote to their sensitivity specs: "1. In an average listening room."  I don't know if this applies to the RP-260 or not, but if it does, it means you should figure the sensitivity at about 3 or 4 dB lower than stated.  I forgive them, because they make such good speakers.

 

* i.e., fraudulent.  AFAIK, all AVR manufacturers have built a deceptive fudge factor into their power specs.  They are more honest with their separate power amps, but even then ... the FTC thought they had this licked about about 40 years ago, but when AVRs came in, the companies reverted to their evil ways, using "alternative facts."  And, in this case, they really are alternative facts; when they say 10% THD at 1K Hz, 4 ohms, 1 channel operating, they probably being quite truthful, but highly misleading.  The power spec that counts is with ALL channels operating, 8 ohms, 20 to 20K Hz.  Try to find THAT spec anywhere but in a bench test report!

 

For someone "new to all this"  you are quite thorough and organized.  You're off to a great start!

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8 hours ago, Rivernuggets said:

Another thing to consider is do you listen to movies and music with 105db peaks?

For me I hover around 80db with peaks around 90. I'm content without much concern for damaging my hearing.

 

Or peaks around 100.  Unless a limiter or compressor has been used, loud passages at around 80 dB are conventionally thought to have peaks with leading edges 20 or more dB higher, depending on the instruments that are playing.  SPL meters won't necessarily show the true magnitude of these, particularly meters with needles only.  PWK said these meters lag about 13 dB below sharp peaks, because of needle ballistics.  Peak reading meters, with LEDs come closer to reading these.  Classical and Jazz are best recorded without compression, and almost always used to be.  Now, who knows? 

 

Still, an amplifier that delivers 100 w.p.c., all channels operating, would probably be enough.

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On 12/2/2018 at 8:09 PM, garyrc said:

The power spec that counts is with ALL channels operating, 8 ohms, 20 to 20K Hz. 

Yes!

15 hours ago, garyrc said:

Unless a limiter or compressor has been used, loud passages at around 80 dB are conventionally thought to have peaks with leading edges 20 or more dB higher, depending on the instruments that are playing.  SPL meters won't necessarily show the true magnitude of these, particularly meters with needles only.  PWK said these meters lag about 13 dB below sharp peaks, because of needle ballistics.  Peak reading meters, with LEDs come closer to reading these.

I have a digital Radio Shack db meter. Just checked and you're right, the peaks are around 100.

Rat Shack decibel_reader.jpg

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