I can’t match carvernut’s 8 x IB15 drivers but I can share the details of my success in finding a subwoofer to match real pipe organs using only 4 AE IB15s.
My 2 x 2 opposed driver manifold has been a revelation in bass power, speed and subtlety. I have been listening to pipe organ music for 40 years but it is decades since I heard a large, live organ. So I have recently been seeking out recitals using different organs to make a realistic comparison with my IB at home. Ironically, each new organ provided yet more startling bass. The last organ was remarkable for the weight and clarity of its bass. After decades of straining to hear what was really happening on record and then CD I had no real reference to compare with my IB. My enjoyment of recitals at great English cathedrals in my youth were now a forgotten memory. My only visits to churches over the years had been to very occasional funerals with rather small organs. Now, finally, I had found an organ which sounded just like my IB. Capturing its same brutal power in a velvet glove. The subtlety of the way different pipes sounded. Their individual timbre. The leading edge as they spoke from the bottomless depths. The interplay of notes and harmonies at the threshold of hearing in the frequency range were suddenly laid completely bare. Just like my IB at home. I had tried a pair of 6th order series bandpass subs. They were nice but sounded too muddled and coloured compared with my next sub. The large SVS cylinder had the power but was just far too muddy. It conveyed no sense of the awe inspiring weight of the great organ pipes. My four AE IB15s can speak like a real organ. They sound just like an organ in every detail and nuance. They have the weight and they have the power. They are as articulate as one could hope for at the far end of the audible frequency spectrum and beyond. They can easily reproduce the beating and harmonies of the infrasonics and subharmonics of the largest pipe organs ever recorded. An IB housing a set of four AE IB15s is the subwoofer organists would use at home once they had heard such a phenomenal bass reproduction system.
Of course these drivers can do films and rock music too. They can do it with so much more grunt, speed and startling reality that you will wonder why you never owned a real subwoofer before. Can your subwoofer hurt your feet on sharp LFE impacts through the floor? Why make do with anything less? Can you hear the double basses and their timbre clearly when you are listening to classical orchestral music at home? No? Then isn’t it time you invested in a real subwoofer?
Inside the manifold:
The frequency response at the listening position using four AE IB15s:
More details below: