It was explained to me that the EQ would allow a JBL calibrator to come and do all the manual fine tuning to get things just right... and I'd then have a "Synthesis Certified" theater. Does that make any real difference, or is it just a bunch of hooey?
I'm not much of a tinkerer myself, and would prefer to just get things done once and then be done with it. I'm definitely in way over my head on all this stuff!
If you want the Synthesis certified, then you’ll need the EQ abs JBL amps and subs. I have a good friend whose home theater is Synthesis certified. I really like his system (and really the 4367’s for lcr), but overall I like mine a little more (SCL-2/SCL-4/C763L). I use Dirac and have acoustic treatments, an Arcam AV40, and have a lot more, and more capable, subs. I spent less, we both enjoy equally, I spent more time tweaking and optimizing.
In regards to in-wall subs, I haven’t heard many. The one I have heard have been bettered by less costly but physically larger floor space subs.
If you don’t want to tweak, just write a check and really enjoy, the Synthesis certified all JBL/Arcam/Mark Levinson/Revel system is the way to go. They sound great. It’s just quite a bit more money. My friend and his wife are both surgeons, time was more valuable than money. It made perfect sense for them.
I like to experiment with placement, enjoy tweaking, and change out equipment more. Sysnthesis certification didn’t add up for me.
Like I said, we are both happy with the route we went and the end results.
Concerning subs: they are finicky on where they will perform best. Especially for seat-to-seat performance. I have 6 subs, so be in each corner, and because my floor is carpet and pad over concrete, two right behind the seating. In-walls really wouldn’t have worked as I didn’t have a 100% idea of where everything in the room would be (and I like even yet impactful bass). If you go with in-wall subs I’d start the room plan well before buying anything and consult with JBL about the best placement. Be honest with how you will want the room, how it will be used, what compromises you’re ok with and what you’re not. In-walls are more of a commitment as it is much harder to install and/or move, patch, rerun wires.
You may want to look at a variety of options besides inwalls. These could be other, floor sitting, JBL or Revel subs. The Revels come with a variety of finish options that may make them easier to live with. Other brands I like are Deep Sea Sounds (I have 4 Marianna 18S’s), Seaton Sound (I have two SubMersive HP’s near field), JTR Speakers (I don’t own but have heard many and Jeff the owner is great to talk to, and from what I’ve heard, great to work with), Rythmik, and JL Audio ( I own two fathoms and use them in a separate 2.2 music only system).
JTR, Deep Sea, and Seaton have all done custom designs for people, including many here on the forums. One design that may make large subs easier is a tall column sub with a veneer you and your spouse like.
A word of warning, Mark Seaton can be hard to reach at times. Read the Seaton thread in the sub forum to see how others are getting along to make sure you’re comfortable and everything is smooth before you order. I’ve never had that problem personally, and Mark is a wealth of knowledge, but I felt it prudent to put the disclaimer on.
If you aren’t going Synthesis certified, no need to go with their amps. Their amps are fine, but so are my ATI’s which cost less and have more options for channel count per amp.
Best of luck and enjoy the journey.