Something I've been thinking about lately and thought I'd get some forum input on this. Consistency in how AVR manufacturer's market their power ratings seems to be woefully inadequate, which lends itself to a bit of confusion in determining just what a given AVR's power output may be. It is understandable that many manufacturer's may exaggerate their claims or publish specs that suggest more power than what they are actually capable of at RMS levels and also with the recent addition of multiple new features such as wifi, Atmos/DTS: X, bluetooth, 4k, etc., it seems possible if not even likely that in order to keep costs contained they may choose to make sacrifices in the amplifier stages. Would this be a reasonable assumption?
As someone who's been formally trained and schooled in electronics, I am intuitively familiar with the principles of Ohm's law and even the Kirchoff laws as they relate to current and voltage drops. One would think this would give me a greater ability to understand these AVR specifications, but in reality the way they are often published or marketed often makes little sense and likewise only leads to more questions. That combined with my lack of in-depth or similarly intuitive knowledge on just how a typical modern AVR routes its power to its output channels has me more than a bit confused. Seems like opinions and answers in the greater online community beyond this forum are about as varied as the AVR specs themselves. Also maybe I'm overthinking this, and I'm trying to apply standard circuitry calculations to AVR technology and maybe there's more to it than that.
The reason I ask is that I've begun to consider my recent purchase of the Marantz SR-6011 and its power output relative to my previous AVR. That one, an older Pioneer was rated at 770W total (7.1), and published specs of 110W per channel. That makes sense to me and is easy math. I also realize that these specs are indicative of peak power output and not factoring in RMS, so average power output will typically fall around a value less than listed peak power levels. The Marantz website lists specs on the SR-6011 as 110W for 8-ohm loads at a 2 channel drive. It's a 9.2 capable receiver. It lists power output for 6 and 4 ohm loads as well, but I have 8 ohm speakers so I'll focus on that. Yet Best Buy (where I bought it from) lists a total power spec of 1540 Watts and I can't figure out how in the world they came up with this. Are they just full of it? Last time I checked, 110w x 9 = 990w. Also from the Marantz site I'm not sure what exactly the "2 channel drive" bit means relative to the 7 other discrete output channels. The Marantz site lists higher power output levels for lower impedance loads and varying THD, but none of the numbers they list make Best Buy's spec add up. The math just doesn't work.
I'm basically trying to figure out exactly what kind of power I'm getting to my speakers and just last night discovered a rather sobering fact. The SVS SCS-01's and SBS-01's I've been running are actually rated at a 84.5db sensitivity and not the 87db or so I had previously thought. I'm a little embarrassed to admit this, but I've ran these speakers a long time with no issues at all so guess it was just something I never needed to check. But it's right there on the label plate on the back of the speakers.
So, having a (allegedly) similarly powered AVR as my old one at 110W per channel one would think nothing should be any different right? Except my repeated runs through Audyssey's calibration have yielded a great sound at lower volumes but if I crank it up for maybe a good action flick I have noticed that the sound begins to sort of fall apart and get a little thin (think action sounds, lots of crashing sound FX, glass breaking, metal crunching, etc.). Even maybe some detectable distortion, but I often can't tell if it's that or just part of the actual sound effects being used. I guess not all power is created equal. It still sounds good, but its an anomaly I certainly never noticed before.
True to my theory above, in looking at the Marantz website for the SR-6011, they focus a HUGE amount of their descriptive text on the fancy bells and whistles (only some of which I actually care about) and their power section is written almost as an afterthought.
I mean, I've got basically the 2nd in the Marantz line from their $2200 flagship model, one would think these issues should be absolutely non-existent even for speakers of a lower sensitivity.
Also, certainly not a quantitative, scientific evaluation of it's capabilities but its overall weight is about 11 pounds less than the old Pioneer. Which to me suggests they skimped a bit on the amplifier section, or maybe here, 8-9 years later they've just been able to make those transformers and amplifier stages smaller and more efficient without reducing quality. *Shrug*.
Sorry, long winded post I know. I'm supercharged on strong coffee and these thoughts have been burning a hole in my brain this weekend.. I went way over budget on this purchase and am already having to cut back elsewhere to sort of bring things back into balance with my finances so I want to undoubtedly know I made the right choice with this receiver one, and two, what the hell is up with all these wildly different power specs? And where does Best Buy get that 1540w rating from? I don't see it listed anywhere else. Most other online retailers simply copy the exact specs as they are listed on the Marantz website. Best Buy's rated spec seems like pure bunk to me from what I can see.
One last question, I promise: What happens to the excess power ability of an AVR that has 9 output channels, but you're only running 5 channels for a 5.1 setup? Does that just sit in reserve, or is the AVR able to provide a little more juice though the actual connected outputs?
