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18" subwoofer
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imported_Baloo
Golden Member
That long excursion is gonna introduce a lot of distortion. If accuracy, of fidelity, is important, go with a much lower excursion, the lower the better.
Looks can be deceiving. That is probably one of the best choices for getting ridiculously loud at ridiculously low frequencies.
And if you want to talk about "pro sound calibre" , I have a pair of 18" Mach5Audio MJ18's in 3.25cf sealed each, that withstood 1200 watts RMS a piece from a Yorkville AP4.4 amp, at clipping, for over an hour, on music.
They only have 3" coils and are only rated for 600 watts RMS.
Assuming the TC Sounds driver wouldn't go into overexcursion, I wouldn't worry about plugging it directly into a wall outlet just for kicks. I have a TC Sounds based driver, and they're TANKS.
Rubycon
Madame President
Anything that can perform day after day without losing its character sound. LOUD and CLEAR with sufficient headroom to make people run if needed. :evil:
A 120VAC outlet has 60Hz at 1875W available assuming the impedance is low enough at 60Hz to draw that. And if it is, the voice coil will heat excessively increasing the impedance - a victim of power compression. If the driver is relatively unloaded and the excursion is high enough to pump sufficient air throughout the gap the coil could stay decently cool. Either way it's a fun experiment. 🙂 Most "hyper" drivers have progressive suspensions with extremely tight restraints to prevent them from getting out of control - a shorting ring affords that extra protection in case there's no low cut and a dj drops the needle from way up. :Q
There is no replacement for displacement. I guarantee you she knows that much being a gear head. :Q JL is not pro stuff. Heck look at the manufacture's warranty. If it's used for reinforcement (PA etc.) warranty VOID. Why do you think that is? As a performer/engineer I can tell you we push equipment to the MAX. Good stuff stays clean until people cry uncle. 🙂 A boxie that roars 160 dB in a hatchback is barely going to be heard at the back of our 1000 seat theatre.
Sure but why stop at 12"?
Getting back to the OP -
You know you can take care of pesky vermin with a strong tank (1" thick steel will work), a neon sign transformer, spark plugs and acetylene tank. Get the right mixture and it will go BOOM with the report of an 8" howitzer spewing several yards of bright orange flame out the end. That rat will sail like St Judy's Comet with a trail of something. (the pressure isn't high enough to turn rat poop into diamonds but you will get something.)
IHateMyJob2004
Lifer
BTW: excursion implies peak to peak .... the peak to peak jsut confuses people that kno what excursion is.
Rubycon
Madame President
The other aspect of pro sound - and probably the most important is field availability. Drivers - even the finest - do go bad, blow out (accidents always happen hehe) and nothing is more aggravating than not being able to remedy this in short order. The show must go on...
Most pro woofers can be field stripped and parts replaced and up an running in minutes. Ditto for compression drivers for mid and hi sections. Of course in theater most of the MF and HF sections are flying high in the air making access difficult in short order. A quick fix is the Poly Switch from Raychem. This is a self resetting fuse. I don't like their affect on the sound as they falsely intervene on lots of passages due to impedance shift however if a higher value Poly Switch is used which will intervene only with a serious continuous condition and a light bulb is used the rest of the time - a sonically acceptable protection circuit is established that keeps the mids and tweets singing faithfully. The incandescent bulb works quite well because its filament has an extremely low resistance when cold - as it heats up the resistance increases so the extra power heats the filament instead of the voice coils. It works well and lots of PA cabinets have them - as a matter of fact they use the popular 1156 tail lamp bulb so if it blows out from n00b jocks it can be field replaced easily. 🙂
BTW the purpose of reflex loading is to increase pressure on the cone at the tuning frequency and reduce excursion - the air inside the vent is essentially the radiator. Lots of excursion is good for sealed systems that beg for EQ to get down lower and it affords higher outputs on IB systems that run unloaded which can be disastrous to some suspension designs.
I'm sure with a sufficient amp and one of these jackhammer style woofs mounted in the floor, you could splat the rat on your ceiling if you get him on the dust cap and play a cannon shot at 0 dB into that thing.
If you are looking for a target SPL use this formula:
SPL = 112 + 10 log ( 4 * pi^3 * Ro / c * (num * Vd)^2 * f^4)
Vd = (.83 diam)^2 * pi / 4 * Xmax
solve for Xmax:
Xmax = srqt ( 10^((SPL - 112)/10) / (pi^5 * Ro / 4 / c * num^2 * (.83 * diam * f)^4) )
Most pro woofers can be field stripped and parts replaced and up an running in minutes. Ditto for compression drivers for mid and hi sections. Of course in theater most of the MF and HF sections are flying high in the air making access difficult in short order. A quick fix is the Poly Switch from Raychem. This is a self resetting fuse. I don't like their affect on the sound as they falsely intervene on lots of passages due to impedance shift however if a higher value Poly Switch is used which will intervene only with a serious continuous condition and a light bulb is used the rest of the time - a sonically acceptable protection circuit is established that keeps the mids and tweets singing faithfully. The incandescent bulb works quite well because its filament has an extremely low resistance when cold - as it heats up the resistance increases so the extra power heats the filament instead of the voice coils. It works well and lots of PA cabinets have them - as a matter of fact they use the popular 1156 tail lamp bulb so if it blows out from n00b jocks it can be field replaced easily. 🙂
BTW the purpose of reflex loading is to increase pressure on the cone at the tuning frequency and reduce excursion - the air inside the vent is essentially the radiator. Lots of excursion is good for sealed systems that beg for EQ to get down lower and it affords higher outputs on IB systems that run unloaded which can be disastrous to some suspension designs.
I'm sure with a sufficient amp and one of these jackhammer style woofs mounted in the floor, you could splat the rat on your ceiling if you get him on the dust cap and play a cannon shot at 0 dB into that thing.
If you are looking for a target SPL use this formula:
SPL = 112 + 10 log ( 4 * pi^3 * Ro / c * (num * Vd)^2 * f^4)
Vd = (.83 diam)^2 * pi / 4 * Xmax
solve for Xmax:
Xmax = srqt ( 10^((SPL - 112)/10) / (pi^5 * Ro / 4 / c * num^2 * (.83 * diam * f)^4) )
Its not car audio. JL happens to also make one of the best HT/music sealed subwoofers as well. Subjectively its better than the Velodyne DD-18, objectively it is better as well. (Also better than my ACI Maestro XL). If you are limited to "normal" subwoofer sizes, these three are where its at. If you have unlimited desire for bass with no compromise, then that opens up doors.
Pro sound will have higher power handling because they are meant to deliver in vast spaces. But for sound quality, pro sound will not be better on a general scale (the typical stuff you can get for pro sound). The huge exception to what i just said is anything take comes out of Danley labs for sure. The DTS-20 or BDEAPs for example are very applicable for Home theater applications and even musical bass. For DIY, there are plenty of nice subs, TC Sounds, Avalanche (if you can find the 18), ...
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