Ya I have been going back and forth on the Sony 4k projector. It is pretty amazing. I have seen it in person at two theaters now, but the price point for a single one is high and I want 2 eventually. I would be much better served with 2 at 5k each. The FPS is fine for passive projection of most current movies, but for future growth 60 would be nice. Who knows how long that will take to land though. Could be 3-4 years.
If I did lower my projector then I would probably pick up separate amps simply because they last a long time and reduce the load on the receiver. Would you still go with the x4000 or are there better pre/pros? I am building on a system that hopefully I can keep in place for 10+ years. I know I will change out the receiver before then, but solid speakers and amps should last that long. I would rather add to them then replace entirely (9.2 etc). I value the little things. Subtle sound differences. I have exceptional hearing. I don't play things incredibly loud, but I want to hear everything a movie has to offer. Down to the buzzing of a street light or whistling breeze in an alley. The immersion is better like that then simply pounding gun fire for 2 hrs.
One other thought. Instead of getting a second sub. What about doing something like
buttkickers under each seat. Would this add to the effect or would you still need a 2nd sub with these to get the full immersion?
No doubt the Sony is an amazing projector, I haven't had the privilege of seeing it myself, but I bet you it will seem pretty long on the tooth in two or three years or so. I would just get a temporary projector, a good but not hugely expensive 1080p, until 4k technologies have matured a bit.
As for the x4000 with separate amps, something else you might consider is just using the X4000 as a temporary AVR and not worry about amps, but get amps for the AVR that you have to upgrade to when you upgrade the projectors. Remember, the x4000 can not handle HDMI 2.0 either, so I would consider it a temporary receiver for the route that you are thinking of here. That being the case, who cares if it doesn't last ten years because you will not be keeping it that long. Get your amps with your next AVR.
I definitely would not use buttkickers as a substitute for a second sub. A single sub is unlikely to achieve a flat frequency response in your room. If you are concerned about sound accuracy, get two subs, and make them good ones. Hell, get more than two if you can afford it. The more subs you get, the less hard they have to work, and the less hard they have to work, the longer they will last. Also the more subs you get, the flatter your room response becomes without equalization. If the Captivators are too much of an eyesore for you, you might think about some
Funk 18.0se subs. More expensive yes, but gorgeous and very high performers. They offer very low distortion even when pushed to the edge. The driver, cabinet, and amplifier are world class. As for buttkickers, they look pretty gimmicky, I haven't tried them but I don't think they would be immersive so much as distracting. Besides, they only shake your seat, but a good sub system can do that too, but nothing can replace that punch-in-the-chest feeling that you get from real bass. The buttkickers look like they could be fun though, for things like fighter sims and combat driving games, and since they are not expensive, I suppose there is no harm in giving them a try. Like I said though, they are not a serious substitute for high performance bass. If you want that buttkicker effect but with all the glory of serious bass, take a decent subwoofer and place it directly behind your seat, ie near-field placement.
