Originally Posted by velocci
can you give me an example of one?
This is just a example I found quickly so others exist cheaper.
My brother just picked up a used one for 100 bucks that does the same thing.
High-Power Simultaneous Multi-Channel Drive
With Class AB amplifiers, driving all channels at full power is only possible for a short time, at around 300 W to 400 W power output. The SC-LX901’s Class D3 Amplifier has the ability to simultaneously drive 11-channels at 850 W power output, while efficiently delivering dynamic content.
For example my receiver is 135 watts per channel into 2 channels , so 270 or so watts max divided into its 7 channels or 38 watts per channel with all channels driven max.
In the linked example it would be 850 into 11 channels at 77 watts per channel.
So just for easy math consider it to have double the watts per channel as mine, which is not a big deal as pointed out that equates into 3db louder......which is little to no difference really.
Mine which can only put out a max of 38 watts per channel with all channels driven runs my system to ear blistering levels.
3 front large 15 inch woofered 3 ways and 4 additional dual 6.5 inch woofered speakers. , so 7 speakers total.
The fronts are rated at 225 watts rms and the other 4 are 175 watts rms .
So I could feed them 1250 watts rms or 178 watts per channel , instead of the 38 they get now, which would only result in approx. 6 db more volume.
Take your current receiver if it has a volume dial that starts in the negative and goes up towards 0 as it gets louder and adjust it up and down 6 to get a idea of what little of a difference 6 db is.
Say your speakers at 90db at one watt .....2 watts would be 93, 4 watts 96, 8 watts 99, 16 watts 102, 32 watts 105db, 64 watts 108 db, 128 watts 111db , 256 watts 114db, 512 watts 117db..........which has far exceeded my speaker ratings at 225 watts per channel and at only 32 watts per channel in this approx. example is already at reference volume, which is crazy loud in a small house sized room.
I have my system calibrated for reference at 0 on the volume, I listen at -12 to -16 most of the time, which is still pretty loud. So -12 from reference of 105 db is 93 db which takes 2 watts on a 90 db per watt speaker. So for example purposes I would be using 2 watts most of the time to watch a movie pretty loud out of a available 38 watts for each speaker.
Moral of the story....
Most normal 100 watt per channel into 2 channels at 8ohms and abover recivers will power most speakers well above normal listening levels. Unless you have horrible speakers and like it as loud as a rock concert, then the AVR will be fine for most situations.
In my room at -12 on the AVR playing a bluray it is pretty loud, like most sane people would tell you to turn it down please
which is reached using a couple of watts .
The subject goes way deeper than this, but for a teaching example this covers the basics when applied to how many watts do I need.
My receiver which is capable of a max of 270 watts will play louder than most people can tolerate and well into the permanent hearing damage levels .....my speakers are rated at a max of 116db which is way louder than ever needed in my room..........db also drops with distance, so if I were max powering these at 116db on 175 watts, then it would fill a rather large room where one might get at distances of up to 50 feet away or no one would be closer than 25 feet or so to the speakers. In small sized home room not many would tolerate 116 db for long, it sounds like the music is inside your head at that level and not being heard.
Sound that is radiated from a point source drops in level at 6dB per doubling of distance. If you start at 50 feet from the source and move to 100 feet from the source you will have a 6dB drop in level. If you move from 500 feet to 1000 feet, you will have a 6dB drop in level.
So in our AVR example if we apply distance to it, most speakers are rated at one meter or 3 feet....so we lose 6db at 6 feet and another 6 db at 12 feet etc etc. I sit approx. 9 feet from the speakers , in my example or my room it is 93 db at 3 feet from the speaker and 87 db at 6 feet and 81 db at 12 feet. So I am getting approx. 82.5 db at my ears off of a couple watts, which as mentioned is pretty loud.
In a full distance example as above at reference of 105 db which is 32 watts on a 90db per watt speaker, we are at 99db at 6 feet from the speaker and 93 db at 12 feet from the speaker, or 94.5 db 9 feet away in my room and at reference , which I probably like levels way louder than one should or most will listen at, and I can not take reference for a entire movie and a lot of guests still want me to turn it down when listening at 12 db below reference.
This information above is for example purposes and is ruff and leaves out many aspects which effect things such as driver sizes, what hz numbers it is measured out etc etc etc.............but should give you a fairly basic concept of how many watts do I need and why 20 watts per channel difference on a AVR receiver is pretty much meaningless....100....120....135 per channel amounts to pretty much nothing difference wise in a AVRs wattage performance . Even a large difference of say doubling the power from 135 to 270 watts per channel only gets a 3db difference.
Move your AVR`s volume up and down 3 numbers and see what that amounts to, so even a 270 watt VS a 135 watt per channel receiver is still fairly meaningless, which is why recievers in the 100 to 135 watt range are for all wattage/volume comparisons no different.