Emotiva separates or Yamaha AVR recommendation?

Bi-amping at this level never really works out good.  To do it right, you either need to do a y-splitter cable with an amplifier that has a very high input impedance, or you need to get an external active crossover.  The bi-amp features in receivers can severely affect sound quality.  It would be much better to just use a very high quality high current amp.  If you wanted separates, I would look for a really good 3 channel amp. 

What Emotiva processor are you looking at?  XMC-1?  or the lower model?  I would probably avoid their amps when combined with the Monitor Audio, which can be on the bright side.  Look for an amp that is slightly on the warm side of neutral.  Maybe Parasound? 

If you did the receiver route, I would maybe recommend the biggest Marantz receiver you can buy.  You can even go previous generation, such as SR7012 or SR7011 models.  Sound quality is the same as the newest SR7012 model.  The only difference would be features and bells and whistles.

What's your overall budget?

I had a lower end Yamaha Aventage AVR a few years ago and didn’t find any adverse effect bi-amping, before moving back to a 2 channel set-up, though I didn’t notice much sonic difference, just easier on the amp. Thanks for the heads up that Emotiva is bright sounding. I’ll look into Marantz. Late model used AVRs is where I’m heading, but would like to see if I could get more dynamics w/ separates.

Good to know.  If you had a Yamaha AVR and were running it with your Monitor Audio Silver, then you pretty much know what a new Yamaha receiver will sound like.  Another thing to think about -- if you are looking for dynamics, then the Marantz may not be for you.  It has excellent fullness of sound, but the high frequencies are rolled off and may lack in visceral impact and dynamics, depending on your taste.

For current multi-channel amps, I actually think that an Outlaw 7700 for $2499 would be good.  Another really good amp to look at is the Monoprice Monolith 5 channel for $1299.  The Monoprice is likely your best bet "for the money".  Now that I think about this, it would still be much better than any AV receiver you could buy.  Then spend the remaining budget on a processor of your choice. 

The Outlaw 976 for $929 would be an excellent processor for the money.  I would actually recommend this over the cheaper Emotiva MC-700 processor.  The 976 has linear power supply and much better analog stages.  You can always get better processors, but cost goes up of course.  Used Emotiva XMC-1 looks to go for about $1800 or so nowadays.

I don't think much matters until you have the same LCR speakers.  You might get better sound with just L&R with phantom center.  Mismatches ruin the soundstage.

You might also consider a higher quality AVR like those from Anthem.  Here's a used MRX 710 and a new MRX 520 just as examples...

https://www.ebay.com/itm/333311530070?ul_ref=https%253A%252F%252Frover.ebay.com%252Frover%252F1%252F...

https://www.ebay.com/itm/173981864776?ul_ref=https%253A%252F%252Frover.ebay.com%252Frover%252F1%252F...

I don't think much matters until you have the same LCR speakers. You might get better sound with just L&R with phantom center. Mismatches ruin the soundstage.

Very true.

I'm aware about the importance of similar LCR speakers but when I had a system years ago I liked the improved dialogue clarity and positioning w/ a high quality center even if it didn't match. I don't plan on changing speaker at present and plan to use what I have.

I should mention that I will use my current 2 channel tube system w/ TT somewhere else and I'm looking for convenience and improved dialogue for TV sports and other TV programing, plus the occasional movie.

Auxinput, I didn't have the MA speaker back then but still thought bi-amping was a plus w/ an AVRs extra amps for L&R highs.

A word about bi-amping from receivers.  In my experience, not every receiver will "bi-amp" in the same way.  Some receivers will output the same signal on both bi-amp outputs.  However, some other receivers will do a weird signal comparison. They will output full signal on the lower normal right/left.  It will then take the actual used signal from the speaker wire and run it through an op amp comparator circuit to remove those "used" frequencies from the main signal and then send the difference to the "hi bi-amp" output.  In this case, you lose massive resolution and sound quality. 

In the end, I'm never a fan of bi-amping because the amp will generally use a shared power supply anyways.  There are other considerations to keep in mind, such as the weird comparator circuits or having to use a Y-splitter cable which can affect signal quality due to input impedance of your amp.  You are better off just getting a really good high quality amp and run the channels full-range.  You can always use bi-wire speaker wire if the awg is large enough.  That is usually a benefit.