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^^^

Sealed front speakers are about 4db less efficiency than ported front speakers, which is then X db less efficient than speakers with horn tweeters. If you have JTR or PSA front speakers, your -20 MV is more like -12 for another with sealed front speakers.
 

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Ultimately i want 2 subs and dual FV18's would put me over budget. Believe me I've thought about it though
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Believe me, a pair of FV15HPs has been my babies for years but I would opt for a pair of fv18s in your big room even if it means eating instant noodles for a month or two. They are so worth it though. The minute you turn them on, you will quickly forget about the instant noodles (you might still smell them). Rock on, you only live once :)
 

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@Rythmik,

Have you ever explored other cabinet form factors, such as cylinders?
Only as experiments. I did a ported sonotube long long time ago for my patent application. I didn't like the tube-y sound coloration. When I knocked the sonotube, there was a distinctive sound similar to the coloration sound I heard. I also realized a very large variation in terms of stiffness from one vendor to another. Basically they are construction grade, holding cement. There was a store in Anaheim selling cylinder plywoods for drum shells. I went there a couple of times. After I built my first sealed prototype, I became less interested in cylinder subs because I was so drawn to the clarity. When I sold my development reference sub which is a Velodyne ULD15-II, the guy bought it told me he liked the Velodyne sound when it was on its side and forward firing. Cylinder enclosure when placed as forward firing will dance a bit (and rattle against floor) and eventually I came to believe heavier enclosure is a plus. One of the cylinder sub selling point is "light weight". Hsu had a model called HRS-12V or something like that which is way bigger than an end table. I had one of those, again as a reference. In early days, Hsu specialized in cylinder subwoofers. But most companies no longer offer those. I think they have limited market acceptance.
 

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I did a ported sonotube long long time ago for my patent application. I didn't like the tube-y sound coloration.
Do you believe that all cylindrical subwoofer enclosures will have this tube-y sound coloration, regardless of their construction material, whether cardboard sonotube or plywood? In other words, does this tube-y sound coloration seem to be inherent to the round shape of the cylinder itself?
Do downward-firing subwoofers have less clarity than forward-firing subs?
 

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The fixed adjustment based on volume has been reverse engineered, but has the "adjustment based on the real-time estimation of loudness perception in the content" been documented in any detail? One of my problems with DEQ is that the specific way it adjusts volume is deliberately opaque, leaving it up to the user to test and effectively reverse engineer its algorithm.
Same here:)

In my room environment, DEQ do not work. Since it make all movies too bass heavy, at my normal listening of -10/-13dB. While some prefer having the option of DEQ to be set to On, I prefer having mine set to Off. Since it sound so much better to me in my room, proving once again that sound can be personal preference thing, and/or the room environment.


Darth
 

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Six months into our new house and i've finally decided i need to replace the inadequate sealed 8" Pinnacle subwoofer that i've been abusing for at least 10 years. We have a dedicated movie room that is 20x21x8 (3360 sqft). The current speaker setup is all Polk (RTiA7 towers L/R, CSiA4 Center, FXiA6 Rears, 265-RT sides) pushed by a Denon X3300W. Screen is a Sony XBR-85X900F and about 9.5ft from the MLP. Movie/Music mix is probably about 80/20. I do like hiphop and electronic music that hits or goes pretty low along side some alternative and rock.



Currently i'm settled on a single FV15HP and then adding a second later on. I guess I'm looking for a recommendation/confirmation that these subs will be a good match for this room. I'm just barely dipping my toes into the dedicated HT tuning world so I'm willing to work and learn to make these as awesome as possible. My budget goal is to keep it under $3k. I'm also partial to Rythmik because their servo direct technology is intriguing and they are just down the road from me.
I'd rate it on your bass listening habits. If you want the earth shaking bass, I'd calculate 3xFV15HP vs 2xFV18 for costs. The 2 FV15HP should be able to satisfy most people, but you might be limited to how much more it can do. For example purposes you might really start hitting compressions and distortions at higher volumes etc. The FV18 will also give you a lower frequency extension. Like someone once told my, "buy once, cry once". I asked you to calculate 3x 15HP so that in case 2 don't cut it, you'll supplement them with a third. That's what will haunt you for a long time. The "WHAT IF" that haunts most of the people on this forums. Sorry if i assume much, but it definitely hits me at times despite me being very pleased with my system and setup.

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Do you believe that all cylindrical subwoofer enclosures will have this tube-y sound coloration, regardless of their construction material, whether cardboard sonotube or plywood? In other words, does this tube-y sound coloration seem to be inherent to the round shape of the cylinder itself?
After some thought I think it all broils down to the length of cylindrical enclosure. The shorter the better. But I know some customers are happy with their cylindrical subs. The issue I see is that tube is very effective in transmit sound. To see that, let us put all the magic sound absorbing material on the cylinder wall and it will not have much effect because the sound wave travel direction. Only the end cap can have any effect. The Hsu end table style HRW-V12(?) that I have for 2 years were pretty good. It is ported downfiring. When I did the measurement (with close mic and driver face up), I noticed one thing. For those who did bassbox simulation for ported subs and have to enter the loss for the enclosures which will affect the port output at port tuning frequency, that enclosure has the least "loss" I have measured, which means it can gain 1db or so extra output at the port tuning frequency.

Do downward-firing subwoofers have less clarity than forward-firing subs?
My view is it depends on the crossover frequency.
 

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You guys were just supposed to say dual FV15HPs were all you would ever need, not recommend the biggest sub they sell. But I've lurked around this forum long enough that I should know better. haha


In all honesty, when I started this thought process, I was dead set on the 12" sealed Monolith. I guess if the FV18 is the answer to my question, do I go paper or aluminum cone? Paper was recommended by pn56Matt (thx), but I'm not sure I fully understand the why. What's the "real-world" benefit of the paper cone?
 

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You guys were just supposed to say dual FV15HPs were all you would ever need, not recommend the biggest sub they sell. But I've lurked around this forum long enough that I should know better. haha


In all honesty, when I started this thought process, I was dead set on the 12" sealed Monolith. I guess if the FV18 is the answer to my question, do I go paper or aluminum cone? Paper was recommended by pn56Matt (thx), but I'm not sure I fully understand the why. What's the "real-world" benefit of the paper cone?
Sorry mate. You've swam into the shark tank. I barely make things work with a dual FVX12 in my theater (3000 cuft), but since I'm on rent and I don't expect to get such a big dedicated room ever, I went for the smallest ones which could fill this room and then later if I shift again they won't be small.
Dual FV15HP would be about right, but you yourself need to decide how much louder do you wanna go. I'm left with barely 3db overhead at about 40-60Hz frequency, so that's how I live. It's awfully close to compression and I have seen the amp light blink a couple of times. Not unsafe though as noted by many people here, but still I don't like it.
I'm however able to run most Bass EQ settings coz j have a lot of headroom from 10-30 Hz. Almost 25db at 30Hz and 15db (maybe 10) at 10 Hz. It's nothing I've done, it's just how the room is. My MLP is about 14ft and the subs are below the FL/FR Speakers. They sound superb. I do have the "what if" moment for the FV15HP, but who knows the next lease will maybe make the FVX12 look too big in the room.

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You guys were just supposed to say dual FV15HPs were all you would ever need, not recommend the biggest sub they sell. But I've lurked around this forum long enough that I should know better. haha


In all honesty, when I started this thought process, I was dead set on the 12" sealed Monolith. I guess if the FV18 is the answer to my question, do I go paper or aluminum cone? Paper was recommended by pn56Matt (thx), but I'm not sure I fully understand the why. What's the "real-world" benefit of the paper cone?
Haha. It really does depend on you taste and listening levels like others have mention. My space is a huge L shaped open concept living room probably 7500 cubic feet, but I feel 2 fv15hps are plenty fine. I feel some minor chest kicks and my walls will shake. They are accurate as hell though which I appreciate. Sorry, probably didnt help you.

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The FV18 will also give you a lower frequency extension.
The FV18 and FV15 both have the exact same frequency extension at their lowest frequency settings. The FV18 has 2 ports advantage over the 1 port FV15 in the lowest extension mode.
 

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What's the "real-world" benefit of the paper cone?
Check here for common FAQ regarding 15" vs 18".

As far as the paper cone, you gain up to 3 dB (which normally requires a doubling of input wattage) in the higher (low) frequencies, i.e. above 50 Hz. I believe this is a main reason the FV18 is so darned good for both HT and music. Also, the PC introduces slightly higher distortion, which can make the bass seem/feel "heavier," which lots of folks seem to like a lot.

I don't own a Rythmik (I hope to, some day, own dual FV18 Rev2 PC's, but that's a LONG ways off due to budget issues!), but if I were you, I'd buy a single FV18 PC now and save up for a second later, if there's any doubt in your mind!
 

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After some thought I think it all broils down to the length of cylindrical enclosure. The shorter the better. But I know some customers are happy with their cylindrical subs. The issue I see is that tube is very effective in transmit sound. To see that, let us put all the magic sound absorbing material on the cylinder wall and it will not have much effect because the sound wave travel direction. Only the end cap can have any effect. The Hsu end table style HRW-V12(?) that I have for 2 years were pretty good. It is ported downfiring. When I did the measurement (with close mic and driver face up), I noticed one thing. For those who did bassbox simulation for ported subs and have to enter the loss for the enclosures which will affect the port output at port tuning frequency, that enclosure has the least "loss" I have measured, which means it can gain 1db or so extra output at the port tuning frequency.
Since cylinders came up, I guess it's time to jump in this thread. I have a single old SVS 20-39+ from around 2002 that I've been using. I've always thought it was good, but I do feel like something is missing sometimes. My room is about 2700cf and is undergoing a big overhaul right now. When it gets done in a couple of months, I've decided I'm going to upgrade the sub. I keep going back and forth between the FV18 and FV15HP. I'm not a crazy (in a good way!) basshead like most are on here and my goal is to have excellent sound for movies (I'm just not a music guy at all). Has anybody made the jump from one of the old SVS cylinders to one of the bigger Rhythmic subs like that? I suspect it's a big upgrade, but how big of an upgrade will it be?
 

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^^ I went from a cylinder Hsu TN1220 500W version (their best version) to the FV15. The TN1220 was crazy good back in its day but the FV15 bests it in ALL departments (extension, output, sound and build quality). The FV15 costs more however. Regarding the big upgrade over your svs 20-39, I know it will be, how big? everyone is different so I won't be able to answer that.
 

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The FV18 and FV15 both have the exact same frequency extension at their lowest frequency settings. The FV18 has 2 ports advantage over the 1 port FV15 in the lowest extension mode.
Won't the SPL vary then?
edit: Oh but ofcourse I'm guessing the overall SPL of fv18 is higher than FV15HP.

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You guys were just supposed to say dual FV15HPs were all you would ever need, not recommend the biggest sub they sell. But I've lurked around this forum long enough that I should know better. haha


In all honesty, when I started this thought process, I was dead set on the 12" sealed Monolith. I guess if the FV18 is the answer to my question, do I go paper or aluminum cone? Paper was recommended by pn56Matt (thx), but I'm not sure I fully understand the why. What's the "real-world" benefit of the paper cone?
I still feel that the FV15HPs in that dedicated space would work well. The FV18 would offer more headroom. @BhootZ is correct about the lower extension of the subs. I should have said the FV18 should have more output in lower frequencies than the FV15HP. IMO, the aluminum cone really nice looking. The paper cone has more output in the chest thump region. I think it’s around +1.5dB in the 40Hz range. Somebody please fact check me.
 
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It might be more correct to say "potential output" from the FV18 paper cone. Because if room EQ flattens your sub (it better, or it isn't worth much), relative output will be the same but headroom will increase.
 
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