Sure, no probs mate
I know how frustrating these choices are, as we all hear and value things differently. And of course, the industry is putting it's spin on the PR everywhere... just listen and enjoy the hype arond the X brand I am not going to menton now. You will know what I mean if you demo some popular £800 speakers on your own, as I know at least one that sounds "ish-ish"
During my dozens of DEMOS, I followed the following cherry-picking logic, in the order of importance that I expected from each component to deliver
1, Choose good speakers first, with matching centre. I demoed about 8-10 pairs of speakers, with MA coming out on the top, but that's for my taste. To me this is the best in my budget, although it is true that in case of the RS and RX, you may need to overdrive the centre for a good lively dialogue, which is a no brainer for most amps -> tick in the box.
2, Pick the rears, this should be relatively easi(er) at least it was for me, as 5.1
3, Find a good sub, that will work well with your speakers. This is a tricky one, as most floorstanders in this range will sound excellent and detailed above 100 or so, whereas most subs often deliver best in the 25-75 range, often leaving you with a crossover gap to fill with good settings, and paring of speakers (look at the thousands of thread on this topic, and you'll see what I mean) It took me more than a few weekends, and plenty of evenings to demo at least 10 subs, and I can tell you form experience that for movies 8 out of 10 will do a great job (look at the RELs for budget, or the SVS for high end, but for gods sake, avoid MA's RSW12 uness you are really good in overing it up with a good amp. 8 out of 10 will sound fine for compressed pop (stuff you hear in music clubs, loud and overdriven) so if that's your thing, you'll get good mid level subs no probs. However, if you're an audiophile and enjoy quality acoustic music, this is where it really matters. For these recordings, you will quicly hear the limitations in the lower-mid range (and don't think sthng over-sophisticated, a simple mainstream acoutsic guitar recording will often go into the crossover range, as well as good quality rock). You will quickly hear that it is not just a 'barely noticeable' for 'audiophiles' but the gap sometimes can be really striking. I actually found only 2 out of 10 which I found satisfactory for my type of music, and only 1 within my budget
4, Find your amp. You're perfectly right, a good pro can fiddle around with equalisation (esp if he knows his stuff) in seconds to make a brighter amp sound smoother, and vice versa. So if you know the amp has good EQ features, and works well (in in the £500+ range this can be taken for granted) then simply use direct feed and see what's what (it's very much like carl zeiss versus canon lenses in a digital camera: you can photoshop any to your tastes, but the basic tones will nevertheless be given by the lenses)
To my liking, the Denon and Marantz sounded very close, ie. the difference amongst these brands is barely noticeable. But with RX speakers, if I was pushed to choose, I'd go for the Denon due to soundstage which the RX needs. But you won't make a mistake with the Yammy either, it will also sound great.
5, Choose your blue-ray player. This is perhaps the last one to pick, as it is unlikely to ruin your experience, unless you are really detailed and wish to see Arnold's growing chest hair in slow motion in the opening scene of T2
Yes it's possible, as it was pointed out to me during one of the demos!
Good luck, and enjoy
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