Hi Franin,
I've sort of been in your situation in that I've been looking at getting new subs. Twin F112's have been recommended to me but I didn't like that idea
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I'm currently running a Single Velodyne DD-18 lol
After a LOT of research these last few months, I've finally settled on getting a pair of Seaton Submersives. I'm a Sydney sider, so am only a bit closer than you are to the US
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I'm actually not worried at all about the warranty as I've had a long chat with Mark Seaton, and he is really a top down to earth bloke (he's an avid skier too and just about all the snow people are top blokes). If stuff does go wrong, sure it may be a bit expensive with freight charges, but I am sure, Mark WILL get the problem sorted. Subs really aren't that difficult. There are a few screws holding the driver in and a few holding the amp in. Unless UPS or FedEx drops the box HARD, nothing's going to go wrong with the cabinet. Both the driver and the amp are easy enough to swap out if they ever need. However, Mark's designed these puppies to be pretty much bullet proof. If you do drive them hard enough to failure, the protection circuitry does kick in.
Other options I looked at were a pair of JL Audio F212's. I originally wanted these, but just couldn't justify the Australian prices. I thought I might be able to get them in from the states for about $10k AUS, but that fell through as they are usually shipped direct from the JL Factory. The next option was a pair of F113's. I seriously considered this option and even had a single F113 in my home for a day. I can get these shipped in from the US for a landed price of about $7.5k AUD which isn't too bad considering RRP on them now is $5600 AUD. However, after auditioning the single F113 and comparing it to the DD18, I didn't think it really would give what I wanted. The F113 was much more impressive through the 30hz-80hz range than the DD-18 having much more 'punch' to it. However, below 30hz, I felt that the output became quite strained as the 13.5inch woofer really had to start moving quite a bit to be able to keep output levels going below the 30hz range. Compared to the DD-18, I felt that distortion levels on the F113 were audibly higher, but I never got round to checking with Fuzzmeasure.
Anyway, I've been seriously looking at the F113 when I came across the SVS PB13-Ultra. On paper, according to Ilkka's measurements and Craigsub's rankings, this sub 'outperforms' the F113 especially in the sub 30hz range. I mainly use my subs for HT use and the aim in replacing the DD-18 was to get more of the sub 20hz action happening. This is what ultimately steered me away from the F113. The way it does the 18hz -3b measured spec is with HUGE Xmax driven by HUGE amplification. It really is pushed to its limits down there which is why its distortion levels go up. Whereas, the PB13-Ultra being ported and tuned to 20hz or 15hz (those are the best tunes), does those frequencies fairly comfortably and just goes crazy exponentially below its tuning frequency. Peter of Deephzaudio is the Australian importer of SVS and seems like a nice guy. He is currently running a promotion on the PB13-Ultra at $2599 which I think is pretty good value. However, I still didn't bite as I've always had and built sealed subs personally and hesitate to purchase a ported sub without first auditioning. It just seems easier to get good 'impulse response' with sealed subs. I am sure that with all the glowing reviews floating around of the PB13-Ultra, it must be a pretty damn good sub though.
So now, onto the Seaton SubMersive. From trolling the forums, it does look like many former F113 owners and SVS PB13-Ultra owners (and many who've suffered from major Upgradetitis having owned BOTH the F113's and PB13's) have jumped onto the Seaton bandwagon. I can understand why too. The sub does seem to offer the best of both worlds. It offers the advantages of the impulse response of the F113 in the upper sub register being a good sealed design with a low frequency extension 'on par' with the PB13-Ultra (yes, yes the PB13 will have more output near the tuning frequency of course but the SubMersive quickly catches up as the content drops below that tuning frequency). Being a twin 15 inch driver offers quite a significant cone area advantage vs a single 13.5inch or in your case a 12 inch driver and as you know, air displacement is cone area x Xmax. The twin 15 inch driver, really doesn't have to work very hard to keep up with the 13.5 inch air movements and this should help keep distortion levels low. Amplification on the unit is also not puny utilising a 1000w ICEpower based amplifier. This is more than the 750w unit used on the SVS sub and probably just a bit less then the '2500w peak' unit used on the JL Audio.
So anyway, rather than seeking out another 2 F112's, I'd probably sit back and ask yourself what you really are seeking to do with your home theatre. If sub 20hz performance is what you are after, you can just keep the F112's (they ARE really great subs for the upper bass registers) and reinforce the lower bass with a different type of sub like Gene did - I'm thinking Seaton Terraform XL or Danley Labs DTS-20
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. Or you could sell the F112's and get a pair of SVS PB13-Ultra's for an Aussie importer with easy access to support solution. Or you could take a plunge like me and put your faith in Mark's design skills and integrity and get a pair of Submersives
Hope this helps and Merry Christmas BTW!