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Power Consumption confusion

Maraxx

Active Member
Hi guys,

I am in the process of buying real AV receiver for the first time, but I am very confused with all those Power Consumption values. For example I wanted to buy Denon AVR-1911 or 1611 then I saw that power consumption is about 460W, which looks huge for me since I watch TV a lot (few hours a day, and on the weekends really a lot).

So then I checked official power consumption value for Pioneer VSX920 which was about 245W which seems reasonable for me. Then I saw a review for the same receiver on the HCC web page: Review: Pioneer VSX-920 AV receiver | Home Cinema Choice: AV, surround sound and TV reviews

and they say that power consumption is 1500W for the same Pioneer VSX920 !!!

So what is going on ??? From where are they pulling those values official and unofficial. Does is matter if you listen stereo or surround, or does it matter if volume is low or high? Does a receiver consume power all the time 100% or what?

All that is huge confusion for me. I mean 245W is OK, but everything else is just huge for everyday use.

What do you thing guys? Does anybody have real values and infos.
 

Mark.Yudkin

Distinguished Member
Power consumption has two aspects:
1) the average power consumption under normal listening conditions,
2) the maximum average power consumption under load (maximal sustainable volume).

The figures you quoted are the second, and basically correspond to a precentage of the maximum power your speakers can consume without the amp's clipping. The magnitude of that percentage is dependent on the power amplification design, which in the case of the receivers you list with their class D amplification is fairly reasonable.

So for example the absolute theoretical maximum (100% efficiency) a 245W 7.1 amp can deliver is 245/7 = 35W continuous per channel. In practice, the limit is likely to be +/- 25W continuous. Peak can be higher (capacitors are a storage device).

The actual power consumption will depend on the efficiency of your speakers, the size of your room and your typical listening volume.

A more powerful amplifier (of the same class) will be able to go louder, that is deliver more power (current) to the speakers or equivalently consume more power. It does not mean that the more powerful amplifier (of the same class) will consumer more power for the same power draw. For this reason, many amps will also specify an average power consumption.

And yes, audio reproduction is a horrendously inefficient energy guzzler, mostly because domestic speakers are designed to be ludicrously inefficient transducers.
 

PSM1

Distinguished Member
The power any of the units consume will be limited by the power supply within the unit but will be dependent on volume and sensitivity of the speakers. Hence with the same volume and same speakers both the Pioneer and Denon will consume the same power give or take a little. Also amps will not be drawing the max power all the time since there are quiet and loud parts to any program. Buy an amp on the basis of the sound quality and features it has and not on the power consumption. If you buy an amp with a weedy power supply it means you have to run it harder which creates more distortion and hence a drop in sound quality (at its worst you can create clipping of the sound which can damage your speakers).
I use my amp (Arcam 350) for all my viewing and have not noticed a massive increase in energy bills. I believe the Gadget show did a bit on how much things cost to run and even a 50" plasma only costs around £60 or less for an entire year.
 

Maraxx

Active Member
Thanks for the answers, btw. I am planning to buy KEF 3005SE or 2005.3 surround package for my system.
 

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