More changes to the HT room. I added two more JL Audio Fathom subs for a quad sub config. Last Fall I had an audio get together at the house and we torture tested my F113 pair along with a pair of SVS PB13's. We were able to drive these very capable subs into distress with some of the more intense movie LFE content by running them slightly hot and within 5db or so of reference level (total SPL). In the case of the F113's, the noise was apparently by design and was a limiter kicking in to avoid over excursion and damage to the driver. It seems that more and more big budget Hollywood movies are containing LFE content that really pushes the envelop of what these commercial subs are capable of handling.
Subsequent to the GTG, I tried several alternate positions to see if I could get rid of the limiter induced distress, but no luck. So, after reading a Harmon study on multiple subwoofer placement (http://www.harman.com/wp/pdf/multsubs.pdf
), I decided to go with a quad sub configuaration in the HT. I purchased two Fathom F112 units and installed them last Thursday.
After a quick setup, I ran through the DVD demos that were causing the distress with the dual subs and heard nothing but clean and intense bass. I cranked the volume up a bit and still nothing but very intense LFE pressure in the room. This past weekend we re watched much of the Cloverfield DVD that has some big LFE as well as The Golden Compass BR DVD with it's DTS MA HD audio track. All I can say is the bass energy the quad Fathoms creates in my 3600cf HT is incredible. There is a scene in Golden Compass where an Airship does a fly over and that is the single most intense LFE segment I have ever heard. It pressurized the room so much that my ears popped and did it without the afore mentioned distress.
Since the initial setup I have re-run the Audyssey room correction EQ multiple times (8 positions) and tweaked the SMS-1 settings. I now can run my level balanced system at a lower overall volume and achieve even more palpable LFE.
Needless to say I am very happy with the quad sub config. If you are crazy for LFE like I am and have the space/budget to do it, the quad config might do the same for you. Here are some pictures and a graph from my SMS-1 that pretty clearly illustrates the headroom the quad Fathoms provide. All it took was 500 lbs of subwoofer.
Size Comparo F113 & F112
F113's in the back of the room
F112's up front