Complicated question Silvermesa. There are people on both sides of the
Do all receivers sound the same? bomb. In theory, if they do their job
correctly they will not have any "sound" of their own, instead they will faithfully reproduce whatever source material they are fed in a completely neutral manner to which it was originally produced. There are many different kinds of EQ out there, and each manufacture has their favorite form(s) of it, so when comparing any actual "house sound" or even the sound from one model to the next, you must make sure that
none of those sound enhancing, equalizing, or altering features are engaged.
Getting each receiver and setting it in your room with your speakers would be the best way to compare the raw "sound" of the receivers. You can then make up your own mind if there is any difference from brand to brand, or through a model line. This is a very expensive, and
very time consuming proposition.
If you are using an external power amp, then there is a whole other can of worms concerning the "sound" of the amp, and synergy with the pre/pro or receiver... but yes, that would be a good way to compare the sound of just the pre-amp sections of the receivers.
I haven't personally compared any receivers side by side, and think there are very few people out there who actually
have compared them with proper comparison control mechanisms in place (the
only variable would be the receiver or pre-pro).
All that said, what most people are looking for with a modern receiver is exactly what must be eliminated for a proper comparison of the actual inherent "sound" of the piece. Everybody wants room correction, EQ, and bass management. That is great... and very beneficial... for movies. I really don't want any of that stuff to taint my music though, if you are of like mind and want faithful music reproduction, and will be using the receiver for both music and for movies, then you should make sure that there is a "pure direct" mode, or "flat" mode, or something similar that will easily defeat all the EQ that you will want for movies, and provide you with pure unadulterated music. (Really, like Nuance mentioned, the best way to do this is through use of a separate 2 channel pre-amp with a HT bypass feature so that you can "share" the front L/R speakers with your HT system) Short of getting a separate pre-amp just for music this is a must have feature, and fortunately many modern receivers include such a feature.
Another feature that I think is important these days (and even more-so in the future) is a networking function. Right now connecting to your network will allow firmware updates, internet radio, streaming music and/or photos from your computer. Yes, there are other devices that do even more than that via a network connection, but for the firmware updates alone I think it is a worthwhile feature.
One more example... I wanted the ability to have everything plugged into the receiver via HDMI and still be able to watch cable TV, or play a game on my PS3, without turning the receiver on. Sounds simple, right? Nope. Until this year, only one brand offered that feature. Now I know of two brands that will do it, and the receiver must be in "standby" to accomplish this passthrough. Many receivers must be fully powered on for any signal to be passed through. Some people don't care about this, but I do because I am somewhat energy conscious and do not always want to play a game or watch TV with full surround sound, when just the TV speakers will suffice.
That's the kind of stuff to look for. Decide what features you want/need, then pick the least expensive AVR that offers them. Factor in the amp section if you are going to use it. If you are using an external power amp for your fronts I wouldn't worry about this part at all. Anything available right now with pre-outs has an adequate built in power amp to handle most surrounds.
Wow, didn't expect to write all this, but I just picked a receiver myself (strictly for HT use), it will serve as an amp for surrounds when I add them eventually but for now all it has to do is act as a switch and provide a 3.0 soundtrack for movies!
Search the web for answers (well at least opinions) to your question about how each brand sounds. some will say
Denon sounds thin, some say Denon sounds warm.... Yamaha sounds too clinical and lifeless... Yamaha gives me way better sound than anything, and I've tried them all... Onkyo drives hard and reveals all kinds of detail... Onkyo sounds horrible, I'm returning it... Pioneer is warm and lush... Pioneer is lacking in dynamics... For everything that is out there, there is someone that will love it, and someone that will hate it.
Good luck sorting it all out.