Starting from scratch ..need advice from you

I'm using a custom built set of Tannoy HPD 315's ca (1975). They have been updated with newer surrounds, crossovers, and massive 150 liter bass-reflex cabinets.

They are used in my 34' X 16.5' (w/cathedral ceilings) room in a combined surround capable, two-channel centric system.

I can listen to vinyl using a tube preamp and SET 300B amp, or switch to Class D power amps that put out as much as 500 Wpc.

I'm also using a 15" Tannoy passive sub, powered by a Crown XTi 2002 power amp, bridged to mono, that provides 1600 Watts into 8 ohms, along with a 12" sub I rebuilt using after-market parts.

The Tannoys have had no problem with having the available power, I generally don't listen very loud anymore, but the sound is all I could ever hope for, and the speakers and subs are able to create a very pleasurable amount of pressurization in my large room.

You may consider looking into Tannoys. I used vintage drivers and custom-built stuff (and DIY) to save money, but Tannoy's newer stuff is nice, too. Some of it though, is quite expensive.

Just my 2 cents worth. Hope everthing works out to your satisfaction.

Enjoy.
Dan

Why would you want two sets of main speakers?

As a general principle, I prefer quality over quantity. I also run my bluray dvd player through my integrated amp to watch movies, though I take the purist approach and stick to 2 channel music which is my priority. Keeping it simple and focusing on 2 channel music has allowed me to buy better speakers and upstream gear, and invest more in isolation products, cables & AC power such as an audiophile wpo. Running multiple channels and mixing different speakers and subs can have a deleterious effect on coherency and musicality.

In my system, I aim for a sound which is natural, coherent, engaging, musical & non-fatiguing. By "musical" I mean that music sounds lifelike in a word. I run a small, but very powerful Vitus integrated amp, Magico S5's and a Vitus cdp as my main source. But you don't need to spend anything like that money to achieve similar goals.

Though admittedly this is quite a departure from your stated plans, FWIW I would stick to a 2 channel setup, sell your Focal 836 speakers & look for a 2nd hand pair of Legacy Audio Focus SE speakers, 2nd hand Modwright KWA-150 amp & 2nd hand Modwright LS-100 preamp. If you're patient, for about $14-15k you would have an awesome setup.

The Legacy Focus SE speakers are great value high end speakers. They have awesome bass which digs down to 18Hz & thanks to its sealed box design, bass is tight and accurate. The SE's run 2 x 12" long throw low bass drivers & 2 x 7" mid-bass couplers, so definitely no subs required! The KWA-150 would be delivering 250 watts @4ohms into the Focus SE's which are very efficient (95.4db), so that is *plenty* of power.

Also fyi, Dan Wright from Modwright offers a Dac and Phono option for the LS100 preamp, so you could later get the dac option and run it as a dac-preamp to stream music from a laptop or HDD. If you wanted to later take the sound up a notch further, you could upgrade the tubes to something like a Genalex Gold Lion (GZ34 rectifier) & Shuguang Black Treasures (6SN7). There is also an upgrade path for the KWA-150 which can be factory-upgraded to 'SE' spec. I am a fan of Modwright who offer the best customer service and back up support in the industry.

The above options imho would massively improve the sound of your system & offer great value. That gear will hold it's 2nd hand value well, so even if you later had a change of direction it is very unlikely you'd lose much/any money. They are keepers for sure. Hope that helps.

I am also curious as to the reason for using two sets of front speakers.

Two pairs of front speakers and 40 year old amps? I got nuthin'. Good luck with that.