Receiver Too Weak?

OP, this very issue is what set me on the road to upgrading from a so-so HT system to what I like to think is a fairly decent hi-fi system that allows for TV intergration via  HDMI or Optical, depending on what I’m looking at ( for instance, multichannel movies/streaming shows or 2 Chanel YouTube music videos like “Tiny Desk, etc).  I too found my AVR wasn’t cutting it, however I did have a pre-out and started with using a powerful 2 or 3 channel amps for the LCR (Used Acurus, Emotiva, etc) and let the AVR (Denon) handle the surrounds and subs (x2).  I made sure to use the room correction ( Audyssey) to get the multichannel mixes right (very important for HT!).  That made a HUGE improvement for HT.  I used DEFTECH flagships (9080s) for all the speakers, including the CC which all rated at 95db sensitivity, so everything played with power and ease. Keep that in mind as you consider any change in your speaker/receiver/amp upgrades: make sure you get high sensitivity speakers so your power amps or receiver have plenty of head room to power your listening space.  I now have a low sensitivity setup with Maggie’s so I use a lot of power (Parasound A21+) that match-up pretty well.  I believe your bookshelf B&Ws are 89db, which is ok, but will definitely struggle with high peaks in action sequences and have your turning up the center channel volume for quiet dialogue with your Yamy’s 95w/per.  It is pushing up to 7 amps in a cramped box w/ likely a pretty noisy transformer. I learned the hard way how important it is to match the speaker/amp setup.Your Yamy is a solid AVR, just not strong enough to push all those lower sensitivity speakers.  If it’s for HT exclusively I recommend getting high sensitivity 3-way floor standing speakers and leave the B&Ws for 2 channel music. Upgrade your AVR to one that has a pre-out and get an external power amp (there’s plenty of good powerful older models on EBay or Reverb to try-out until you find what you like). Whatever you do, remember it’s the matchup bw the sensitivities and power. Good luck!

It’s not the power, it’s the Speakers. I’m using a Denon AVR 650H and it doesn’t have huge power, but I’m using some Klispch floor standers and a matching center channel and an SVS 2000Pro subwoofer and I rarely need the sub.

Sadly, I think you need more receiver, it's under 100w @ 2 ch, usually if you drive more channels the power will be even less. Your speakers have low sensitivity, so they need more power to sing. 

You didn't really say if it's music or movies that are the issue. If you are only running 3 speakers, or something else. 

Setting up a HT system is a ton of work, you have several speakers to place, a ton of wires to run, some of them are LONG runs. Setting all the individual speaker levels, each speaker crossover, subs, etc.....

It's a serious process that takes a lot of time, effort and skill. A good starting point is to measure out the listing room, place the speakers, measure them to the listing area, try to get them all square. Then run your room correction. Listen to it for a bit, adjust as needed. For the center speaker, try to keep in inline with the front L/R, make sure it is open to the room, no reflections on top or below. As in a shelf, or cabinet. If it is, pull it out, so the drivers are in front or at least flush with it. Is there a coffee table also in between you and the center? Move it, and see how it sounds, or put a blanket over it. Seriously it will sound very different. Then adjust all the levels to suit you. 

Than rinse and repeat. Different sources, different services sound so different. My HT receiver has a couple pre-set stores for settings, I adjust them a bit for the source. Like Netflix's usually needs more bass, and center ch. Amazon needs less bass, and center, also dynamic compensation. That is unless I want the room to shake. 

We didn't even get into cables, subs, room treatments, etc...

FWIW, I have a 9.4.2 setup, sadly I fiddle with it almost every time a movie starts. 

The dialog in video can challenge even a very high end HT or 2 channel system.  I improved it by upping the output put from the center channel in the settings of the AVR.  Since center channels are mainly for speech and not much involved with music, it doesn’t alter the musical content.

Op,

Here's my short list to solve what I'll call your HT amplification problem: Can't hear details (dialogue, or otherwise), (plus, maybe weak soundstage?): 

1. Mostly HT: high sensitivity speakers for sure (95db or more)

2. Size of your room?  Sm/Med (Your speakers w/ subs (+ AVR/amp of 200w or more); Large Rm: floor standing 3-way speakers (DefTechs are great for movies, not so great for music) + Sub/s   with almost any AVR not less than  100w/ch for ALL surrounds (which really means you'll need an AVR or amp pushing 200w/per anyway).

3. Subs ALWAYS for HT.  I recommend 2, but you have a large SVS, so may be fine.