Kyle

awe

Sorry if this was asked, but how do you mount the drivers? Does that rear access hole allow you to get screws all around or does the top come off some how?

Ya maybe the saying should be: there is no replacement for [sensitivity]

Hello! I'm the lurker of this forum, lol. Indeed, very good points. I'm often amazed how bad a subwoofer can sound with a sinwave at full volume (capability) around port tuning, but put music into it and it just seems to work and the distortion seems to subside The real question is how many more db can you get out of a driver + amp if you increase the box and or port port and the art of the whole process becomes the design trade offs. The double 18 box I spoke of is very huge and very impracticable. A few dB loss here and there for a subwoofer half the size might add a lot of value to most people.

One could write a phd thesis on modeling flow of a fluid -- this simply comes down to FEA, and any other modeling is just an approximation. But lets face it, this is not rocket science, its just a speaker I will say there was only one subwoofer I have seen that did not have port issues and it was a twin 18" box with a single 18" port - no curves. Very low velocity, extremely capable. When you see ports with high air velocity then that's normally an indication of being undersized. There are reasons to do this (extension, size etc) but it does mean the port it exhibiting its limits.

The Plus/2 was awesome too, I loved that sub. Old school subs for the win

I'm starting to wonder if the Old PB12-Ultra/2 could compare to this thing. Does anyone have one? Its going to have a power disadvantage with that 1k bash amp, but I think it could be a cool battle

I never like giving up sensitivity, even in sealed tbh

I'd like to see the PB13 with that new 1.5k amp :\

Similar OEM counter part. Tymphany makes the SVS drivers so this is probably more similar than not to the ultra driver. STW-350F188PR01-04.pdf

That's why I came up with my alternate theory Its a plot against neodymium!

I posted this on the AVS forum, but I'll re-say it here. I think the 8" coil is a move to retain a high B ceramic motor but avoid going with the super wide-style magnets like the LMS Ultra or others like it or change to an even more costly neodymium motor. An 8" ceramic t-yoke magnet would generate a lot of B but still end up being a smaller motor than something like the LMS Ultra. At the retail $2500 price point, a high power neo motor is probably out of the question. This is a bold and cleaver way to side step that issue but still have a very powerful and not-too-heavy motor. I think the power handling, coil centering and structural advantages of an 8" coil are secondary despite SVS's nomenclature and also not without opposing considerations -- added weight & potential spider throw limitations.

^ Sure, I understand. Normally I do the 25% gap rule. Its pretty close to 70% BL in most cases I have seen. For example, the Pro 5100 is 25% out of the gap at 28mm. It's true FEA'ed 70% orignal BL value comes in at 31mm -- pretty darn close. But like I said, as long as you have WW and gap size, you can pretty much get a good ball park of the motor stroke. What SVS has done is thrown out p2p values with no coil WW or gap height. I understand that the underhung 16" Ultra has more p2p throw than it's overhung sibling but is that a function of motor clearance or real xmax? We don't know :\

Ya, it would be best to know the gap height and coil winding width. That's all we really spec here at data-bass.com anyway. You can nearly derive everything else form that with reasonable accuracy.

Yes, I believe you should always go for maximum BL no matter what and use EQ to fix things if you need to. If you have more motor you reduce the current demand of the amp for the same output and that has huge benefits. Of course BL and xmax counter each other in all practical applications so these are the real trade offs. The highest BL you can get from a motor is even hung , or depending on fringe field distribution, very slightly overhung. This would really reduce linear BL curve and you would have higher distortion at high displacement.

Good questions! Motor power is not really what the right factor it, its a contributor to the Q and its the Q that's what matters for system design. That's a big topic... In general, underhung usually has less motor force, but not always. A lot of things can effect this. Another big topic, but the primary reason underhung cuts BL is because you're reducing the coil across the effective gap so you're leaving B directly uncoupling with wire at all times to create the xmax geometry. It is true as you reduce the size of the coil you reduce the relative Re so you also gain BL^2/Re that way, and you reduce moving mass too (but only a little). Those two things sound like a big gain, but generally not as much as the BL loss you already incurred. This is all of course assuming the same motor for both coils options.

The ported probably needs more motor because its driving a port. You typically want a lower Q driver in a ported box to keep things flat or tilted downward. What you want to avoid is a high Q hump. Sealed drivers on the other hand can sound thin if the Q is too low and thus would require extra EQ to boost the low end. Having a little less motor force is a natural way to deal with that and keep the response flat. I believe one of these drivers is under hung and the other is overhung. Different variants for different systems.

lol, you mean to tell me you're not caught up in how you like or dislike the front LCD panel like they are over on avs?

exactly correct. I would also add one more interesting feature. A disc magnet like this generally yields a 2x fold advantage in B captured in the motor compared to an outside ring. Typically you would jump on that, but because of the surface area limitations of the coil ID, disc magnets need to be neo. And even then they have very quick limits with 4" or even 5" coil constraints. An 8" coil opens up that diameter quite a bit and seems to even allow an ordinary ceramic magnet to be useful. This magnet stack may only be ~7.9"" or so in diam., but it might be similar to a 10 or 11" ring magnet. something similar to the LMS Ultra in terms of B. Its just a rough guess...

The nomenclature is still a little silly... "Groundbreaking smartphone app"

if it was an 18, they would list 18. I don't get the logic of that. And 18" frame is about 18.5" OD.

Yes interesting indeed, excited to see how they perform. The sub looks damn good too!

8" coil... wow. My main concerns with big coils is they cut into overall spider displacement. going forma 3" to 8" coil, one would need to increase the spider by 5" OD to maintain that capability. So if you had a 10" spider, you would need a 15" spider. I don't see how that fits on a 16" speaker. Perhaps they have a special long throw spider that works more like a surround? Very cool. Is this driver neo by chance? I know back before Steve left SVS he was working on the new 16" driver but it was radial neo I think. Not sure if this driver inherits any of that idea or not. With an 8" coil, I'm guessing not... it might be a good fit for a neo t-yoke disc magnet.

I have a similar problem. For some reason my speakers get more quite only after 2-3min of turning them on. I mean it seems to be 10 to 15dB drop without fail. The other interesting piece of information in my room is that my wife often walks over to the stereo right before it gets quite. I'm wondering if these two facts are related in some way.. hmmm.

haha Ya. me wonders about the cheap liquid cooling options for PCs these days and how they might work on motors... they are probably not nearly big enough but the idea seems interesting