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Discussion in 'Speakers & Subwoofers' started by MikaelG, May 11, 2003.
How much more SPL capability would they perform in
I think 12" drivers are the prefect compromise for subs. While enabling it to reproduce low end it also can response quicker to fast bass notes than a 15". I've heard some 15" drivers make a series of fast bass notes sound like one continuous note. Botton line, I think SVS shoots for a balanced sounding setup over simply SPL. BTW I own a 16-46 PCI
Not sure how this ended up in software- but this question belongs in Speakers/Subs
If anything the 15" drivers would have less output at lower frequencies, because they'd need a larger enclosure to get the same performance. If you dropped a typical 15" driver in one of the SVS cylinders, it would be way overdamped. Then there's also the issue of needing more amplifier power to take advantage of the extra displacement, in that size cylinder. There are good reasons SVS has stayed with 12" drivers..Tom could elaborate. What I just said might be one of them.
I really wish this 15" and 18" drivers aren't as fast as 12" drivers in bass frequencies myth would die. http://www.adireaudio.com/tech_papers/woofer_speed.htm There are 15" drivers that can do midrange duty as well or better than any 5.25" driver out there (and their efficiency leaves 5.25" drivers in the dust). It is however more difficult to make a 15" cone that doens't have break up modes in the midrange than it is a 5.25" driver, but it can and is done. Driver size also has no effect on how low a frequency the driver can play. A 1" tweeter could play 20hz, just can't move enough air to make it audible. How much air a driver can move is more or less directly correlated to how loud the driver can play a certain frequency though. And a 15" driver with the same travel ability of a 12" driver will be able to displace ~60% more air. Or put another way it has to move 60% less than the 12" driver to achieve the same output level. And in general the farther the driver travels the less linear its response becomes. The main reason you don't see 15" drivers in SVS products is enclosure size. 15" drivers in general require larger enclosures to work properly, and the added displacement ability will also require a larger enclosure to fit sufficient porting. People complain about the size of SVSubs now and 15" driver versions would be even bigger. Adds to material and shipping costs and reduces even further the number of people interested in the product.
Well put Dustin... Nice quick "basic" education, put in a easy to understand way for the masses that may not understand woofage & design. Cheers Geoff Edit: 15's SLOW, driver and cabinet designed Wrong=True! Designed correctly, every bit as (fast, quick, you pick the word) as Any Size Bass Drive, PERIOD...
Thanks for putting that straight Dustin. I was getting a little queasy and then you came along. Well said! :wink:
Dustin and I only agree on about 95% of stuff, and thankfully ( surely avoiding a lengthy debate) this falls under that 95% for the most part.. I have a room full of different 15s, been working with them for...man, must be going on two years now. All kinds of cool designs from Thilo (TC) and Scott (Destilj) and a few other companies looking for some feedback(or business). So it isn't that we haven't spent a good deal of time on that path...we just haven't found the right design combinations yet. Tom V. SVS
I third that Dustin,bravo. Being the proud owner of a pair AR1's (each tower containing a 15" 500 watt sub) I defini- -tely know that the "bigger means slower/sloppier" is noth- -ing but an old wives tale.
Tube based subwoofers with 15" drivers always end up far too big for my tastes. However, a 15" driver could probably work out quite nicely in the PB2-Plus enclosure. I imagine it would perform similarly to the twin 12" version, however be more affordable due to the cost of one driver vs. two.
It was a simple compromise Im sure. The cylinders would have to be big and W I D E. This isnt very practical for most folks. NOt me. I myself have a vented Tempest and it is the fastest sub I have ever heard. It is big and boxy but I dont care about that. rant/ Ugh. I hate it when people think anything bigger than 10" or 12" is going to have slow, sloppy bass. Where does all this bullshit come from? If it had any truth in it, it would just have something to do with moving mass. I think a bigger driver with less moving mass with a nice low Fs will play lower and "faster" than a heavier 12. /rant
Speed is all a factor of BL as the Adire article stated. BUT... Weight does play a factor in it.. It's kind of hard to say well this 15 has to be slower than this 12.. Etc.. You can't generalize without knowing the T/S Parameters. There are some 15's out there tha will outgun a 10" without breaking a sweat (as far as transient response is concerned).
What about the B4? I remember one of the fellas at SVS say something to the tune of, "We'll start using 15" drivers when they prove to be more beneficial than the 12"." [paraphrased!] Most SVS subs are flat through 20hz, so why the bigger driver? More spl maybe?
More surface area, more displacement, more extension. That is not always the case.
There are also definite advantages to using two 12's antipodally-mounted instead of a single 15" where negation of cabinet vibration is concerned. No point in building a rigid, nonresonant, heavy box if it's going to shake anyway.
What Jack said is what I think is why the PB2 is still using 12" drivers. This will probably fall in the 5% Tom mentioned above, but I think the reason the B4 isn't a B2 with two 15" drivers is the costs associated with getting a new 15" driver tooled up into their production deals. The dB12 was already being made and relatively inexpensive.
>>>This will probably fall in the 5% Tom mentioned above, but I think the reason the B4 isn't a B2 with two 15" drivers is the costs associated with getting a new 15" driver tooled up into their production deals. The dB12 was already being made and relatively inexpensive.
Hmm ok. I really don't understand the pessimism when it comes to 15 inch or more? What is all this BS about 15 inches won't work, because bla bla bla... ever heard of HGS-15 or B&W ASW4000? Do they shake? Are those bad subwoofers? Don't think so... If Velodyne can do a 18 inch monster, that can be blown away by two 12 inch SVSs, then isn't it interesting what a 18 inch SVS could do? I mean it's not like it's impossible. I'm not interested WHY SVS doesn't have 15 inch drivers in their subs, it's pretty obvious, they want to sell subs too, not be pioneers in having loudest SPL in lowest Hz. In order to do that, they must compromize. Now I wonder, if a 15 or 18 inch SVS driver would be placed in a equally larger enclosure, raising all parameters with equal amount of percentage, how much louder would it be? If 12x + 5y = 100z then I wan't to know how many z:s 18x + 7,5y equals to.