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radulescu_paul_mircea

New SVS Ultra 16"

61 posts in this topic

Eh.   You'd get more SPL and better response with two PB-13 Ultras.  

 

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

 

:\

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Could anyone chime in on why SVS Ultra drivers do so poorly in maximum upper bass SPL? It must be a very inefficient driver, but why throw away so much sensitivity? JTR's Captivator clearly shows you can achieve exceptionally high maximum SPL both down low and up high with a low Mms "high-ish" sensitivity driver.  What's the advantage gained with such a low sensitivity driver? They clearly chose to do this to maximize low bass output, but if that's the only reason, it seems to be a rather big sacrifice, especially when looking at what the Cap is capable of. 

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SVS typically tailors their subwoofers response to be flat anechoic.

 

I'm sure they slice out any rising response if the driver has it with internal DSP shaping. Had these been passive systems where Ricci could dump a larger amp worth of CEA burst...it might look different.

 

 

They like to publish nice pretty lines that are flat. :)

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They tend to use drivers with lowish sensitivity so they have a flatter more extended natural response. The tradeoff is the upper bass headroom is lower than with a more efficient driver.

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Inductance could come into play here, but I'm not sure it does.  I've noted already that in sealed systems, mass doesn't do much to response except cut the high end.  It improves sensitivity and efficiency down low only slightly.  It may also have some slight benefit as far as distortion is concerned.

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Inductance may be a factor on the 16 drivers even with shorting rings in the motor. An 8" coil is a large amount of wire even if it is only a 2 layer or a shallow wind height. The Tymphany driver Kyle linked is the platform they are based on that seems clear, but I'm sure SVS 's version are modified for their specific apps. They do say one is an overhung and the other is underhung for example. It's probable that SVS developed that driver with them as the build house and now Tymphany is offering their own version.  A few things pop out off of the Tymphany spec sheet though. The frame OD is 15" even on the spec sheet so I wonder why list it as a 16"? Also the former ID is listed at 7.4" so it seems like a 7.5" coil not 8". Still huge for sure. MMS is listed at 538g on the T driver which is heavy but honestly lighter than I would've imagined with such a large diameter former and coil. Motor efficiency is about 160. 1w/1m sens is rated at 83dB. That's pretty low. The gap height is very large at 36mm and xmax is only listed at 10.5mm. I'd assume that's a very basic coil overhang figure with no adder. That would be very conservative with such a large gap height and 57mm overhung coil wind. Using a calculation that adds 1/3rd gap height to the overhang would put Xmax 22.5mm and assuming I'm correct the coil wouldn't leave the gap completely until 46.5mm one way. I'd expect that driver to exhibit a very broad BL curve with shallow reduction in force as the coil moves away from centered in the gap so it should certainly be capable of a ton of excursion with distortion increasing relatively slowly as excursion increases. Again SVS's units could be substantially different so I'm just speculating most of this off of the T driver data sheet.

 

Found a cutaway...Looks like they are using a bucking mag up top to get a bit more flux through the gap. Also 2 big aluminum sleeves.

post-5-0-32572900-1485969963_thumb.jpg

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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 :D

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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 :D

 

I've got a PB2/Plus, which I think was later renamed to the PB12-Plus/2 - not quite the same model but a similar design :P

 

It's been gathering dust since my PPSL build!

 

I need to sell it TBH, at the moment it's just a convenient table for dumping things on  lol

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The Plus/2 was awesome too, I loved that sub.

 

Old school subs for the win :)

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Found a cutaway...Looks like they are using a bucking mag up top to get a bit more flux through the gap. Also 2 big aluminum sleeves.

attachicon.gifSTW350cutaway.jpg

 

There is so little spider left in that basket compared to the coil, I would think that would severely limit the travel.  I wonder what guided them down these design decisions.

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