Check out the new Infinite Baffle driver-out displaces all other drivers currently made:
Stereo Integrity | 24" IB subwoofer
video of it in action:
Stereo Integrity 24" subwoofer - YouTube
They are working on a sealed/ported version now.
Stereo Integrity | 24" IB subwoofer
video of it in action:
Stereo Integrity 24" subwoofer - YouTube
They are working on a sealed/ported version now.
Not even close. If you believe the manufacturer's claims the Jackhammer (with 24 inch square cone - 3116 sq cm) does 35 mm linear one way excursion. That's WAY more than this thing - almost 1/3 more for those who don't care to do the math. And the Jackhammer will take 4000 wrms (again, according the manufacturer's claims), well over 3x the SI 24 rated limit. The Jackhammer is a lot more $$$ but that's not the point, the point here is that the new SI driver isn't breaking any records and isn't really that special, no matter what spectacular (but incorrect) marketing claims Stereo Integrity wants to make on their website.
http://www.mtx.com/_mtx+mobile+jackhammer+24+dual+2+937+4000w+rms+superwoofer_no-ts9924+22_22/b
And like the Jackhammer, just because you can doesn't mean you should. All the SI drivers have very small voice coils and very small power ratings. This 24 inch driver has only a 3 inch voice coil. This is bad news in terms of probable power compression and possible thermal failure. And 5.3 mh inductance is kind of high. In fact it's so high I'm surprised they even mentioned it, most manufacturers would prefer to hide info like that.
Anyway, the 18 inch SI HT was a decent bargain at the preorder price (it's only an average value at it's current price) even though it suffers from a lot of the same problems I just mentioned, this new one is not quite as impressive.
If I was looking for a high excursion IB driver I'd much prefer the RE XXX. It's got about 85 percent of the SI 24's displacement potential and it's only a bit more expensive but it's a MUCH better driver. (Actually the XXX has free shipping in the US and the SI 24 doesn't so it's probably the same price overall for US customers.)
RE Audio XXX18D2 (XXX18-D2) 18" Dual 2 ohm Car Subwoofer
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You're comparing apples to oranges, the SI IB 24 is specifically designed for a home theater application, the Jackhammer is designed for automotive use. The SI IB 24 is currently the biggest displacement IB driver for a HT application.
No I'm not. This is the claim directly from the SI website.
That's also the claim in the first sentence of this thread. Both of these claims are wrong.
Furthermore the Jackhammer would work just fine IB. It might need a bit of eq but there's no reason it couldn't be used in that configuration.
Yes, the overhung version has higher inductance, as you pointed out. The split coil version has less. (5.53 mh.) Still high but very comparable to the SI 24.
Data-Bass
I'm not looking for a driver of this type but if I were I'd choose the XXX over the SI.
They probably did. Would still applaud the effort they put into it, it's not a huge company, they probably spent a lot of time on this. Too bad the focus is purely on xmax and power handling.
The 18 HT seems like value for money though, have not crunched the numbers yet, but you could probably reach 13-14hz f0 with one of Bjorno's designs.
SI 18 HT
Or in a sealed type for QTC = 0.700 in a 200.0 L enclosure, F3=32Hz, F10=20Hz with only 660 W@4 Ohms.
Yes, it does infrasound in a easy way. Sim is in a standard (large) ported enclosure (with 4x~4"ports).
Or in a sealed type for QTC = 0.700 in a 200.0 L enclosure, F3=32Hz, F10=20Hz with only 660 W@4 Ohms.
Attachments
What has the Wattage to do with -10dB or -3dB point?Yes, it does infrasound in a easy way. Sim is in a standard (large) ported enclosure (with 4x~4"ports).
Or in a sealed type for QTC = 0.700 in a 200.0 L enclosure, F3=32Hz, F10=20Hz with only 660 W@4 Ohms.
Yes, it does infrasound in a easy way. Sim is in a standard (large) ported enclosure (with 4x~4"ports).
Or in a sealed type for QTC = 0.700 in a 200.0 L enclosure, F3=32Hz, F10=20Hz with only 660 W@4 Ohms.
I simulated it in a reflex bin and achieved –3 dB @ 18 Hz, managed 1000 watts, while residing below 10 mm xmax @ 18 Hz.
Will have a look at it when I have time on my side, maybe friday evening if I'm lucky. Key points are usually: lowest realistic goal frequency is 2/3 to 3/4 driver FS, between 1/4 to 3/4 SD, 2-3xSD. VAS gives indication of volume, but not accurate, variations of 100-200% VAS equals volume of box excluding material (pending on f0 goal). Aim for flat response but expect around maybe 79-81dB/2.83v at f0 with this driver pending on design choice and how low f0 is.
In my book the -3db point is not anything you should look at. Many port based enclosures will often start having breathing problems there because of various phase and impedance loading issues (most enclosures emulating closed box response curves usually excepted), not to mention velocity and possibly difficult room interaction pending on location of port.And I think a good practice is to have a HP at ~66% of f0 to slowly roll off undesired side effects. Unless you have allready taken usage patterns and the rest of the system into account.
Feel free to argue these points. I make mistakes.
In my book the -3db point is not anything you should look at. Many port based enclosures will often start having breathing problems there because of various phase and impedance loading issues (most enclosures emulating closed box response curves usually excepted), not to mention velocity and possibly difficult room interaction pending on location of port.And I think a good practice is to have a HP at ~66% of f0 to slowly roll off undesired side effects. Unless you have allready taken usage patterns and the rest of the system into account.
Feel free to argue these points. I make mistakes.
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That only applies to small boxes. I make large boxes designed for Sound Reinforcement applications since that is the field I’m in. The -3 dB point is standard and used by all reputable manufactures in Professional Audio for decades.
Very good. Most professionals would also use HP filters at just below -3dB, to dampen these effects, it is just good practice, leaving more power and headroom for frequencies above -3dB. So I still see this as valid, your input is appreciated.
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What has the Wattage to do with -10dB or -3dB point?
The connection is made only by you.
I said less wattage for the sealed version for max excursion (Xmax) obviously.
Any more questions you don't understand?
You will automatically have more headroom above the -3 dB point if you design the box to have a flat response above the -3 dB point. Not sit a -3 dB and hover there a few octaves before collapsing down to -10 dB. That is the benefit of using a big box with a driver such a Stereo Integrity 24" IB.
Professionals use HPF for numerous reasons however, there is no rule saying you must use a HPF.
Personally it defeats the purpose using the HPF of a Loudspeaker Management Processor which, offers the lowest settings of 20 Hz, when your bin above -3 dB @ 20 Hz.
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