I took a peek at the frequency response graphs for your two driver choices and I’m no expert but… I like ’em! The Corundum tweeter appears to be excellent with the ability to cross low, and the Epique 7″ driver — if it’s anything like the 5.5″ driver — is probably excellent as well.
My only hesitation is similar to what others have mentioned, the Epique is a very inefficient driver. We pad down tweeters to match the lower sensitivity of smaller woofers all the time and it’s no problem to do so… but in this case, I feel you’ll really need more watts than the Dayton tube amp at 50 per channel will provide. I built a subwoofer using the smaller 5.5″ Epique driver and it is literally a beast that moves so much air it’s hard to believe…. but it takes serious watts to get to that point.
Like you said, having such a nifty, high-excursion driver just loafing along with a few watts would probably somewhat disappointing in the end.
My thinking is… (and I’m going to spend some of your money here) Go with two 7″ Epique drivers per side (they’re almost $10 cheaper each once you go over 4 in quantity) and then go with the new Aiyima A07 Amps Preamps and Dacs (padlet.com) 300 watt per channel amp that Nick reviewed for your amp, then one of his tube amp DACS or preamps that he’s reviewed — if you just have to have that tube amp sound.
I think that setup or one similar will give you enough watts combined with the greater speaker output due to the ability to have a 4 ohm load for the woofer section on each speaker as opposed to 8 ohms which you’re really stuck with with a single woofer per side since most amps won’t like 2 ohms. I have a Nobsound 300 watt sub amplifier that uses the same chip that’s in the Aiyima A07 and it really is powerful… seriously.
Yes, it’s more money, but if you’re going to put some half-decent coin into this project, I say make sure it succeeds. That’s what I’d do… and… I don’t think you’d need a subwoofer if you tuned it right!
TomZ (Zarbo Audio Projects)