Originally Posted by beastaudio
I would assume the subs were tested from the same location, all things being equal? Were there measurements taken or decay times run or is that what the graphs above were dictating? The FV18 with the two vents open mode's response almost mimics that of a traditional sealed subwoofer with a shallow rolloff through the bass region...even well before port tune. That would totally explain the behavior of a"Snappier" sound. The JTR 14/24/4000 is tuned more like the fv18 looks with all ports open, a dead-flat response groundplane, even slightly rising. That by itself will create the two very different sonic signatures. I'd love to see some graphs of the day you tested both if they are available.
, there are in room measurements that I now have. I just need to parse through.
JTR's dead flat response is with LFA at max. The LFA control has differed over the years (
can fill in some gaps). I believe the Cap 4000ULF and 2400ULF featured an LFA control with 12dB of range (looks like a high-pass filter centered at 20Hz). At the end of 2017 JTR Increased the range to 18dB to allow a -18dB cut specifically to accommodate smaller, sealed rooms with cabin vessel gain. All Cap 1400/2400/4000 subs shipped since Jan 1, 2018 feature the -18dB cut.
Just a few anecdotes (I have the luxury [at the moment at least] to own both the Cap 2400ULF and Rythmik FV18):
My neighbor has a room almost the same size as
's, however it's on a concrete slab. He now has 3 2400ULFs installed without the issues
experienced. We tested with my 2400ULF in his room before placing the order.
My downstairs space is on a slab and wide open to just to adjacent rooms but upstairs as well (25' ceiling in living room & entry). The FV18 (aluminum driver) just gets swallowed up and doesn't produce enough TR to be impactful with movies. Dual Seaton F18s actually produced more. Meanwhile the 2400ULF and 4000ULF are simply the best I've experienced in the space hands down. Move the FV18 upstairs and it's a whole different ballgame. Great TR and SQ better than any other ported sub I've heard. What I haven't done is cart the 2400ULF upstairs. These subs are simply widgets to determine the right solution based on a user's listening preferences and their room.
In regards to
I believe I am batting 1,000 in my recommendations for their rooms.
I believe I mentioned before that I built the RPI TR meter. I just haven't been able to produce any repeatable results outdoor GP as of yet. The waterfall looks to be an accurate predicter so far.
I probably left out several details so ask away. I'm also all ears to hear hypotheses, suggestions for testing, etc.