masterngc Posted July 4, 2005 Share Posted July 4, 2005 Hi, I want to make a dual 18" Throated Bass Bin... You see, were doing some home reno, and i want to obliterate the wall behind my HT... Klipsch doesn't have any 18", I know the 15" Kick ***! So Where Can I Get 18"'s and Which ones are the best??? Quote Link to comment Share on other sites More sharing options...
BS Button Posted July 4, 2005 Share Posted July 4, 2005 Interesting that you ask. Look for the Eminence 4 ohm 18" at parts express. I believe it has the same everything as the 15" K33. Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted July 5, 2005 Share Posted July 5, 2005 Carefull taht you get what you want going to an 18" .. lotsa 15" drivers really offer better performance than a cheap 18 .. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted July 5, 2005 Share Posted July 5, 2005 Check out Ascendantaudio. Their Avalanche 18's work great in Home applications. I have some in an IB. Quote Link to comment Share on other sites More sharing options...
masterngc Posted July 5, 2005 Author Share Posted July 5, 2005 Thanks, i'll check it out! Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 6, 2005 Share Posted July 6, 2005 ---------------- On 7/5/2005 7:49:57 AM bsafirebird1969 wrote: Carefull taht you get what you want going to an 18" .. lotsa 15" drivers really offer better performance than a cheap 18 .. ---------------- Ditto that. For the price you just about always get better performance out of a 15. The reason that 15" drivers tend to outperform 18" is due to a few things. First, an 18" driver requires a much larger cabinet in order to achieve the same frequency response slope. We're talking on the order of 1.5 to 3 times larger than for a corresponding 15" system. Let's just average it out and call it twice as big. I don't know of any 18" driver that doesn't cost less than twice the corresponding 15" driver. So basically, you can purchase two 15" drivers for the price of one 18" and end up using the same size cabinet. What you end up gaining is more acoustic output and cone surface with dual 15's than you would with a single 18. That said, most 18" drivers out there that are available to the DIY world are geared strictly towards PA use...which means they drop fast below 30Hz, but do give you insane SPL. There's no need to exceed 120dB in the home let alone 130dB, so it's totally a worthwhile compromise to sacrfice SPL for lower extension. Ascendant has provided graphs for their drivers at different tunings, but to compare apples to apples I'm showing the sealed responsed (because they don't show a ported tuning for the Avalanche 15). So here we are seeing the response for the Avalanche 18 in a sealed enclosure versus the Avalanche 15: I'm personally not a fan of the Ascendant 15" drivers, but the two graphs show how closely the 15 and 18 drivers line up as far as slope is concerned. (Make sure you compare the same size cabinets...the smallest on the 18 graph versus the largest of the 15). I modelled all these drivers in WinISD and you can get about the same SPL and slope as the avalanche 18 with the AES AV15 and the Dayton Titanic 15 mkIII, but in a cabinet half the size. If you were going with an IB design, you could get four AES IB15's for the same price and get about 3dB more output with the same slope and with a smaller amplifier. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted July 6, 2005 Share Posted July 6, 2005 I don't know of any 18" driver that doesn't cost less than twice the corresponding 15" driver. So basically, you can purchase two 15" drivers for the price of one 18" and end up using the same size cabinet. That said, most 18" drivers out there that are available to the DIY world are geared strictly towards PA use...which means they drop fast below 30Hz, but do give you insane SPL. There's no need to exceed 120dB in the home let alone 130dB, so it's totally a worthwhile compromise to sacrfice SPL for lower extension. Ascendand must be the exception to the rule. The normal price for the 15 is 75% of the 18. The sale price of the 15 is 82% of the 18. The Avalanche 18's Fs is 16Hz, but yes, the majority of 18's are as you described. Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 6, 2005 Share Posted July 6, 2005 ---------------- On 7/6/2005 10:36:32 AM CECAA850 wrote: Ascendand must be the exception to the rule. The normal price for the 15 is 75% of the 18. The sale price of the 15 is 82% of the 18. The Avalanche 18's Fs is 16Hz, but yes, the majority of 18's are as you described. ---------------- I just wanted to mention that the avalanche 18 is by no means a shabby driver. A pair of them in an IB would shake the walls down. I would just never consider using them in a dual 18 bass bin unless you want a 20 cubic foot cabinet (which is the size of a closet). Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted July 6, 2005 Share Posted July 6, 2005 You don't need 15's or 18's for that matter, better results can be had by using multiple smaller drivers that can react quicker to dynamics and transients than there much larger counter parts. For example the Vifa P25WO 10" woofer has an FS (18Hz) just as low as that big sloppy/slow 18" woofer, when used in a 7th order bandpass enclosure the bass is solid and smooth into the teens. Use 4 of them in dual bandpass boxes with ample power and expect to be really, really surprised. Bigger is NOT always better! Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 6, 2005 Share Posted July 6, 2005 Is this the driver you're talking about? http://www.madisound.com/pdf/vifa/p25wo00-08.pdf It's the P25WO, but it shows an Fs of 24Hz and models pretty crappy in comparison...four of them show 103dB @ 20Hz (-4dB point) in both ported and bandpass designs. Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted July 6, 2005 Share Posted July 6, 2005 That's them but can you configure the modeling software for a 7th order bandpass/isobarik type enclosure since the drivers are mounted in a clamshell type arrangement. They don't have tremendous output but what they do have is very smooth warm deep bass and lots of it, and you don't need a closet sized enclosure either. Quote Link to comment Share on other sites More sharing options...
sfogg Posted July 6, 2005 Share Posted July 6, 2005 " better results can be had by using multiple smaller drivers that can react quicker to dynamics and transients than there much larger counter parts. " Transients by their very definition are higher frequency waves. If you want to run a subwoofer up to the tweeter range that is important to consider but for long wavelengths that is a misnomer. Draw a 20hz wave and a 200hz wave to scale on paper. Notice how much longer it takes for the 20hz wave to complete one cycle compared to the 200hz wave. You can't define a 20hz wave that is 'quicker' then what you just drew... if you try you are drawing higher frequency waves. Typically what is really meant by 'fast' bass is non-resonant which is a function of both the sub itself and the room. The idea of a larger woofer accelerating slower then a smaller driver is not set in stone. F=MA. A smaller driver with a weak 'motor' could easily be slower then a larger driver with a much stronger motor. Shawn Quote Link to comment Share on other sites More sharing options...
sfogg Posted July 6, 2005 Share Posted July 6, 2005 " I would just never consider using them in a dual 18 bass bin unless you want a 20 cubic foot cabinet (which is the size of a closet)." Compound load then and the enclosure would be 5 cubic feet. Not the best use of money though considering you don't gain the output benefits of the second driver, it is just used to decrease the needed enclosure volume. Shawn Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 6, 2005 Share Posted July 6, 2005 ---------------- On 7/6/2005 11:49:20 AM sfogg wrote: " I would just never consider using them in a dual 18 bass bin unless you want a 20 cubic foot cabinet (which is the size of a closet)." Compound load then and the enclosure would be 5 cubic feet. Not the best use of money though considering you don't gain the output benefits of the second driver, it is just used to decrease the needed enclosure volume. ---------------- on top of that you're left trying to fit a ~20Hz tuning inside that "small" cabinet which gets difficult if you want to keep port noise down. Mike Hurd and I talk about all sorts of different possible combinations and we always come to the conclusion that it's a huge system of compromises and you just gotta choose what best fits your situation. I would start by determining the subwoofer type and how large the cabinet will be (even with IB designs you need to take into account the room behind the woofer, which is basically just a really huge sealed cabinet). From there it's just a matter of matching a woofer to your situation and then you can be creative in implementing the design (like curved ports, or fancy ports, alternative driver mounting options, etc etc). Quote Link to comment Share on other sites More sharing options...
sfogg Posted July 6, 2005 Share Posted July 6, 2005 "on top of that you're left trying to fit a ~20Hz tuning inside that "small" cabinet which gets difficult if you want to keep port noise down." Use a passive radiator, no port noise and you can fit much more 'vent' into the box that way. But I was really assuming you meant a sealed sub since all your earlier plots were sealed enclosures. Shawn Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 6, 2005 Share Posted July 6, 2005 with the passive you've just raised your cost a good $300. But passive designs are actually my favorite, even moreso after talking with deon the sub designer at klipsch. Though I think a lot of people forget that you have to subtract the port volume from the enclosure...something you don't have to do with a PR. Quote Link to comment Share on other sites More sharing options...
Cleve Posted July 6, 2005 Share Posted July 6, 2005 If you could go with either an 18 or 15, bigger is better, at least judging by those Ascendant graphs. Go with 18. The 18 appears to dig 4-5 hz deeper, and has 3 db more output at 20 hz than the 15. If I was choosing, that's all I'd need to see. For home theater, the deeper the bass, the better. Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 6, 2005 Share Posted July 6, 2005 ---------------- On 7/6/2005 12:33:29 PM Cleve wrote: If you could go with either an 18 or 15, bigger is better, at least judging by those Ascendant graphs. Go with 18. The 18 appears to dig 4-5 hz deeper, and has 3 db more output at 20 hz than the 15. If I was choosing, that's all I'd need to see. For home theater, the deeper the bass, the better. ---------------- well that's cuz the ascendent 15" drivers aren't that good (but what do you expect for $300). Here are some graphs showing the max SPL of all sorts of drivers in 10 cubic feet cabinets each tuned to give as flat a response as possible. Notice that the Adire Audio Tumult 15" (white line) goes much much lower (and it has plenty of cone excursion to spare), but also notice that the Tumult 15" (yellow line) in a sealed cabinet is the second worst in the bunch. It's also interesting to note that the Tumult 18" and Avalanche 18" perform nearly identical. The Titanic MkIII looks kinda puny in comparison. All the vented enclosures are within in a 2dB window @ 20Hz, but the sealed cabinets are in a 7dB window with the 15's performing worse. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted July 6, 2005 Share Posted July 6, 2005 ---------------- Bigger is NOT always better! ---------------- I'll bet you've never used that line before . Quote Link to comment Share on other sites More sharing options...
masterngc Posted July 6, 2005 Author Share Posted July 6, 2005 I was thinking of making a cabinet similar to this: http://www.electrovoice.com/Electrovoice3/products.nsf/pages/MTL-1X Best Damn Sub EV Ever Made Id need to change the dimensions of the cabinet to move the tuning frequency of the cabinet down from 38HZ into the low 20's... It's just one of my crazy ideas, like putting a pro audio single 18" into the back of a sportscar... Quote Link to comment Share on other sites More sharing options...
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