Originally Posted by Alkaizer
It seems that my old 2007 Onkyo tx-sr805 has 5ch driven power of 162 watt at 0.1% and 7ch driven at 120 watt at 0.1%. (course: sound&vision)
Wow....how come old/cheap AVR have such power compared with new AVRs in the market?!
These will definitely drive KEF LS50 very easily, right?
It is quite simple--you don't NEED all 7 channels driven at once when using multi-channel surround.
Think about it realistically, say a 64 channel Dolby Digital theater and for fun, ignore the 4 to 8 channels for sub bass. What would happen if you blasted ALL the channels to maximum volume at the same time? Darkness! Kiss those breakers goodbye not to mention as you add more amplifier channels and speakers together in the same space, the SPL will skyrocket and smoke the audience. The sources are mixed according to Dolby specifications as the days of some guy just twisting pots by ear is long, long gone (thankfully) AI is a great application for that so things will get better moving forward.
An amplifier is a man made device using man made components that are manufacturered to certain tolernances. Amps don't grow on trees or are found in space. A black hole is a naturally occuring thing in space and science will be the first to tell you they don't know what is inside. Amps don't have that problem, they make small man made electrical signals larger and since they are made by humans, they are measured, tested and verified to fit within specific specifications. Give "science" a break, they have been screwing around with electrical signals far longer than you have been alive.
Then there are the audiologists that spend their lives with human hearing. They are aware of the limits of human hearing and combined with surgeons can make deaf people hear--they might know a thing or two. How accurate is human hearing? Well, it depends on the persons AGE and is indicated with hearing test results. You can't "teach" your ears to hear better to improve your hearing test results--but age will gradually make your hearing worse.
Back to amps, measure the things full bandwidth and get distortion readings from 0.0001 watts to whatever watts you chose to rate it and whatever impedance it was designed to operate within specifications. I can take an amp and rate it for 0.005% or rate it for 10%...same amplifier and it is up to the marketing and engineering department to specify the power level. You can get a chip amp from Texas Instruments that produces 0.005% distortion at 5 watts of output, it can punch around 50 watts at 0.01% and 130 watts at 10% distortion--same amp and it costs $5. The game of my amp does magical things because the maximum output at a certain level is meaningless because amplifiers don't operate that way. Their distortion is not linear so if you have a Denon AVR that produces 0.009% distortion at 10 watts and you use it at 10 watts---why would some audiophile amp the size of an AC unit sound different?
Look at speaker distortion next, amps create no sound without a speaker so.... what distortion do you get from speakers? Well, they measure that also! Voice coil (google it) they measure drivers at 105dB at one meter and the distortion even very finve, high power and very expensive drivers produce is at the 1% range. Subwoofer distortion is measured when it reaches 10 percent distortion. I don't know about you but worrying about fractional distortion levels when the speakers mask the amplifier distortion with much higher numbers is a waste of time. Sure, you can "claim" that your learned ears have the ability to ignore the speaker distortion and somehow pick out amplifier distortion but those medical people will negate that belief. Yes, masking of disotortion from louder sounds has been studied and verified.
I did some blind ABX testing with amps, CD players and so on back in the day--learned a lot. Much easier to do now, if you want to know at what levels of distortion your can detect with your own ears--the Audio Engineering Society has music you can download that has the error programmed in.... you can find at what levels things become noticeable and things that do not. So if you really want to know, they can hook you up! The other thing to do is learn how amplifiers work, what the measurements mean, what matters and what does not and then look at full measurements of amplifiers--the graphs not a single number. Just because an amp can do 2 ohms does not make it "better" than one that is limited to 4 ohms if you are using 8 ohm speakers. If it did, all the auddiophiles would be using Crown iTech and PowerSoft professional amplifiers because they are stable into 1 ohm loads.
Do amps "sound" warm? Sure, if they have a boost in the midrange power levels over the bass and treble. This is EASY to spot on a scope or output chart. Personally,. I would refuse to purchase any amplifier that has a warm, bright or whatever sound as a feature--I want my amplifiers accurate as I can make they sound any way I want to parametric EQ and processing. The amplifiers I use are accurate, they operate speakers that are generally 6 to 16 ohms, I don't clip them and they stay in their linear operating level. If you clip an amp, all bets are off but I learned many years ago that when the clip light hits--I screwed up!
Why do people hear things? That is a question for the medical people, they sure spent enough money trying to eliminate that (bias) For that reason, they double blind ABX testing was done so no outside things will skew the results. If you have ever done one, it is a learning experience not only to figure out what distortion levels effect you but damning proof you are a human with our natural biases at work. When I purchase amplifers and gear, I know what specifications I shoot for or better. Yes, I have an AVR and a chip amp--and a studio amp along with an arc welding PA amp with enough DSP to keep me amused for years. I go from "dumb brick" (studio amp) to spaceman spiff (PA amp and corrective AVR processing) Once any processors, EQ and so on is engaged, now the sound changes because of the processing--the amp has nothing to do with it. If you think AVR A sounds warmer than AVR B and they both have their corrective processing applied, the results you are hearing IS the corrective processing!
If you are a human, you have bias built in and be thankful that you do. Those weird biases kept your family tree alive and you can't turn them off. The McGurk effect explains why you hear with your eyes, they are higher prioority to the brain and if the ears disagree with the eyes, the eyes win automatically. You can take that test on Youtube--it is a lot of fun! How come we hear things in 7.1 channel surround that if flying over our heads but the speakers are to the side of you? Your eyes tell your brain where the sounds should be.... so if you think you have supernatural hearing, it is kicked to the curb by your eyes and brain.
Does it matter? Well, that is up to you! Say Amp A and Amp B sound the same but you like the features, looks, size, weight and so on of Amp B although it costs twice as much--go with Amp B. Not because of some "sound" it has but all the other factors you use when purchasing amplifiers. When I purchased my AVR, I went with features--there were specific things I wanted it to perform. My HT speakers are very efficient so never need more than 40 watts so power was not a factor. I prefer my amplifiers to run cool, be very reliable and tend towards a subtle look--not the gee-gaw million knobs and having a light show. I could of spent less on my AVR, a heck of a lot less for my other amps also if it was just "what it sounds like". There is plenty of audio equipment I would not use even if it was free--I am human and if it looks rediculoous, fadish gee-gaw fashion or if they speakers are finished highly reflective (I can't stand light reflecting off a speaker in the dark!) you can keep it no matter how good it is.
For decades I had my hearing, eyes, blood and everything else tested for my job. My hearing slowly got worse over the years, no matter how hard I tried it slowly trailed off. I would love to know how to "train your ears" to hear better, I want my 20 KHz back! Sure, you can learn how to listen for specific distortions and Harmon International will provide the video how to do just that. However, your hearing can't be more "accurate" .... I wish it could! The concept that people can hear something that is created by an electrical signal generator that is created by humans--and our creation creates unknown things that are not measureable is really stretching it--don't ya think? Considering the limits of human hearing are known, it would not seem to be unreasonable that humans would be smart enough to know how to match human hearing to what electrical signals can do. If those stupid science people can create a detector that can measure movement to one tenth of a proton to read gravitational waves (LIGO) they might, just might be able to measure a sound or electrical wave.
In summation, it would be much less confusing if the manufacturers just put out all the measurement charts which would prevent needless single point numbers. Back to my previous ponderings..."hair" on the surface of a black hole event horizon? ?????