So after hooking up my dual A7S-450s, I thought I'd move my Cambridge Soundworks PSW1 (1997 sub, 12in driver, 140watts) somewhere else in the house. After all, what can that sub add when I have TWO 1300watt 18in drivers in my theater???
Just for kicks and giggles, I thought I might as well hook it up to see if it could add anything. I placed it directly behind my listening position, calibrated it to 69db because I didn't want to 'muddy' the sound of my A7Ss (calibrated at 75db each), and gave it a go. WOW! I swear these things are the little engines that could. For whatever reason, it really opened up my A7Ss!!! Bass was much more detailed, and VERY tactile. They literally felt like I had hooked up buttshakers (transducers) to my HT seating. It was unbelievable the difference it made.
So I got out the SPL meter and test tone disc to figure out what the heck was going on. My upper bass really opened up because of that PSW1 (compare the yellow and red curves below)! I don't know if it did this because that's where the PSW1 shines, or it canceled out some frequencies that let my A7Ss open up...whatever the reason, there was no way I was taking out the PSW1 from my HT room.
The only problem was that I had a VERY nasty null at 71hz. I could live with it though because it really sounded so much better compared to the A7Ss alone. So, I was happy for a whole day...and then decided to see what my other listening positions sounded like. All were great except one. For some reason, the left most LP seemed to have less effect of the subs compared to the other positions. Did some quick thinking, and decide to hunt for another PSW1 to fill in any gaps. Unbelievably, found 1 locally on craigslist, and I swooped it up.
I placed it right behind the position that I felt was lacking, and viola! That seat now had the visceral feel like the other ones! I plotted my curves again, and also found out that the 4th sub removed my null!!! (blue curve)
I absolutely love these PSW1s....
So below is my graphs starting with Duals (A7Ss), then Trips (A7Ss + PSW1), then my final curve, Quads (Duals A7Ss + Dual PSW1s).
My A7S are tuned to 75db each, and my PSW1s are set to 63db each (combined for 69db). My A7S do the majority of the work while the PSW1s complement them and shake the HT seating. I have 1 eq2 for both PSW1s to apply the subsonic filter to them to make sure they don't distort on scenes outside their tuning....
You can check out my Quads and HT gallery here.
This, hands down, is the best my HT room as ever sounded and the best FR curve I've achieved. The bass is effortless and bottomless and completely shakes my seating. Not sure if I got lucky with my room combined with the A7Ss and PSW1s, but it certainly should give you second thoughts about what to do with the subwoofer(s) that are being replaced with the eD's that you bought!