Evolution of a new driver: XJ18

Kevin Haskins · « **on:** 6 Oct 2007, 10:38 pm »

I've dropped a couple hints about our new 18" driver under development. Rather than fighting a bunch of little fires I figured I'd just start a thread.

The XJ-18 is going to be the big brother to the Shiva-X & Tempest-X. The design goal was for another home audio driver to be used in a wide variety of applications, ported & sealed, IBs (which is essentially just a very large sealed box) & dipole applications. Basically, like the Shiva-X & Tempest-X its an all purpose large-box driver with dual 8 ohm VCs.

Most people wanting 18"s want them for one reason... output. The idea of a small box and an 18" driver is sort of an oxymoron. The XJ18 will be optimized for BIG output that goes DEEP. Why not a small box that goes deep? Because.... its not possible. The laws of physics are tough to change, so we let God have his way, and designed the XJ18 for large box/deep bass applications.

The XJ18 uses a different motor structure than the Shiva-X & Tempest-X. We couldn't get the BL necessary out of a their motor structure so we pulled out the stops, and designed one that could supply us with as much BL needed. Its an XBL2 motor of course.... with the full fledged, don't spare a detail, attention to design that the Shiva-X & Tempest-X share. We didn't pinch pennies.... this is a beast with an approx. weight of 55lbs and is extremely linear over its range of throw.

Here are some early design screenshots.

Please don't ask for T/S parameters, & deliver dates. We are too early in the process to give you a good answer. I don't even know where the price is going to land but I would expect somewhere between $300 & $400 as a reasonable guess. I'll post more information as we move through the design process and I'll give final price and delivery schedule when we have the information.

Larry McConville · « **Reply #1 on:** 9 Oct 2007, 07:48 pm »

Good Afternoon Kevin,

I'm curious to hear additional information concerning these guys; I'm looking to assemble a 4 X 18" IB as this years winter project.

Larry

Kevin Haskins · « **Reply #2 on:** 9 Oct 2007, 08:01 pm »

I'd just warn you.... development cycles are very unpredictable. Don't plan around vaporware, even mine.

We might get lucky and get them on time because the dev. cycle with my build-house is much shorter than it used to be. We designed the Shiva-X & Tempest-X in April and it took 6 months to get it right, even though they had built the motor before.

I'm hoping to get a sample built and approved before the end of this month and have an order going for them in November. There is a 45 day build-time and another 3-4 weeks from then until they are in stock. If everything goes as planned (big if), thats late Jan early Feb 08. You also have to consider the holidays and CES is in January so everything takes time.

Four Tempest-X make a great IB setup though.

Larry McConville · « **Reply #3 on:** 10 Oct 2007, 04:26 pm »

Thanks for the prompt reply Kevin; I realize the process presents hard to predict timelines.
I suppose I'm mainly interested in any information you may share regarding the drivers specs and composition. I'm fine with waiting until Q1 of 2008; I have many other projects to keep me occupied. Additionally, I find myself strangely attracted to the 18" driver; perhaps I'm compensating here...LOL

Regards,

Larry

Kevin Haskins · « **Reply #4 on:** 10 Oct 2007, 05:20 pm »

Well... 18"s make a lot of sense for IB. The size isn't as much of an issue and the large swept area is a real bonus.

The motor is designed and we have design data on the rest also. The motor's performance is easy to predict. Its based roughly on the old Tumult motor so its 32-33mm x-max .

The cone/suspension is going to look a lot like the Tempest-X & Shiva-X, black, nothing radical and designed to work without drawing attention to themselves. The basket is a cast aluminum unit. The motor is black... we like black.

I know I said I wouldn't talk about T/S parameters but I may as well spill the beans. These are PROJECTED parameters. In real life the values will change because we try to design around standard soft parts. Production tolerances and some part changes may wiggle these one way or another but the final version will work in large sealed & ported boxes and it will work great in IB applications also.

Re: 3.06
Fs: 18.6 Hz
Qms: 11.39
Qes: .431
Qts: .415
Sd: 1080 cm^2
Mms: 486.53 g
BL: 20.15
Le: 4.0mH
Cms: 0.15 mm/N

I'm really going out on a limb on pricing because we don't have a final quote. I'm going to say between $350-$400 per driver. I may be eating crow because these are massive motors and not a cheap driver to build.

Larry McConville · « **Reply #5 on:** 10 Oct 2007, 05:46 pm »

Kevin,

Sounds like a promising driver; I'll stayed tuned to this station as I look forward to this guy's development.
My application will be four 18s in an IB install supporting a front stage consisting of 3 x OB-7.

Regards,

Larry

Larry McConville · « **Reply #6 on:** 25 Oct 2007, 05:19 pm »

Hi Kevin,

Any additional information you may share?
Sorry to be a pest.

Regards,

Larry

Kevin Haskins · « **Reply #7 on:** 25 Oct 2007, 05:32 pm »

Quote from: Larry McConville on 25 Oct 2007, 05:19 pm

Hi Kevin,

Any additional information you may share?
Sorry to be a pest.

Regards,

Larry

Nope.... nothing new. Well.... nothing new to report at least. We are on track and the first sample is being built. I should have some preliminary measurements within the next couple weeks.

AK · « **Reply #8 on:** 26 Oct 2007, 09:32 pm »

any plans for 21in or 24in driver?

these would be really unique. it's hard to find drivers of this size.

Kevin Haskins · « **Reply #9 on:** 26 Oct 2007, 10:29 pm »

No plans.... Non-standard drivers are a curiosity, but they are not very practical.

Larry McConville · « **Reply #10 on:** 12 Nov 2007, 05:42 pm »

Quote from: Kevin Haskins on 25 Oct 2007, 05:32 pm

Quote from: Larry McConville on 25 Oct 2007, 05:19 pm
Hi Kevin,

Any additional information you may share?
Sorry to be a pest.

Regards,

Larry

Nope.... nothing new. Well.... nothing new to report at least. We are on track and the first sample is being built. I should have some preliminary measurements within the next couple weeks.

Hi Kevin,

Were you able to get the sample unit assembled yet?

I'm simply curious to see/hear how this guy is coming together; any pics you can share.

Regards,

Larry

Kevin Haskins · « **Reply #11 on:** 13 Nov 2007, 01:05 am »

No news yet.

Larry McConville · « **Reply #12 on:** 4 Dec 2007, 09:54 pm »

Whew; that was close!
This thread was almost pushed to the second page; my what a tragedy!

Larry

Larry McConville · « **Reply #13 on:** 4 Dec 2007, 10:06 pm »

Kevin,

I'm curious to hear your opinion for how the following systems would compare (based upon your design goals for the XJ18):

F1200TS Amplifier + x8 Tempest-X $XXXX = 34L, or
F1200TS Amplifier + x4 XJ18 $XXXX = ?L.

I promise not to hold you to any musing you may share; I believe a quad pack of XJ18's may be a little more $ than an eight pack of Tempest-X's. How do the two packages compare for swept volume? Ideally, my install will be IB; if this doesn't work then I'll work my way down the ladder moving to LLT next.

Your December specials, amps + drivers, has me at odds with my debit card.

Larry

Kevin Haskins · « **Reply #14 on:** 4 Dec 2007, 10:33 pm »

In an IB the Tempest-X is going to be a better deal in terms of cost/amount of displacement.

The XJ-18 will have a more advanced motor but if your looking just at displacement (4.3L vs 7.1L) and cost ($175 vs. $350), then the equation will probably work out in the Tempest-X favor.

vinculum · « **Reply #15 on:** 24 Dec 2007, 05:01 am »

Hi Kevin.

I seen you post some preliminary recommendations on box/port sizes for ported XJ18s. Do you have any rough estimates on sealed box sizes?

Thanx!
Dr V

Kevin Haskins · « **Reply #16 on:** 24 Dec 2007, 05:40 am »

Quote from: vinculum on 24 Dec 2007, 05:01 am

Hi Kevin.

I seen you post some preliminary recommendations on box/port sizes for ported XJ18s. Do you have any rough estimates on sealed box sizes?

Thanx!
Dr V

With the current parameters it looks pretty good in a relatively small sealed box. Relative for 18" drivers.... the larger the better extension you get but with a little EQ you could run it in 3.5 cubic feet. I'd aim for >5-6 cubic feet for the most musical alignment.

I wouldn't build anything until I get final production parameters though.

vinculum · « **Reply #17 on:** 24 Dec 2007, 10:07 am »

Sounds like a 24" cube might work out really well. I'll just sit tight before any dust flies and shop for amps.

I did leave you an email about the Face amp special from the website. Hope to hear back before the sale is over!

Dr V

Larry McConville · « **Reply #18 on:** 27 Dec 2007, 06:22 am »

Hey Dr. V,

As we exchanged PM's on AVS; my model 1200 arrived in great condition, and these guys are monsters!!!

I'm really looking forward to the 18's; ideally, I'd like to try four in an IB install, I'm having concerns regarding a lossy room.
Fortunately, I have a few weeks to think through the options; the 1200 should be able to accommodate most any configuration.

You do have me thinking per the 24" (sealed) cubes though...

Larry

Quote from: vinculum on 24 Dec 2007, 10:07 am

Sounds like a 24" cube might work out really well. I'll just sit tight before any dust flies and shop for amps.

I did leave you an email about the Face amp special from the website. Hope to hear back before the sale is over!

Dr V

vinculum · « **Reply #19 on:** 27 Dec 2007, 10:25 am »

Hi Larry..

I didnt realise you were the same Larry! Dolp!

Amp sounds nice. Just don't depend on those rated power output levels. It appears they rate the power output with 200vac input and 100% efficiency. YOu can only get 1800 watts rms out of the 15amp plug on the back. It was also pointed out to me the damping factor isnt spectacular for a class H amp, but this shouldnt be much of an issue. I still may get a pair when Kevin gets back to me.

I considered an IB as well, but my only location is off to one side (rancher with split basement) I dont want to be stiffled on my crossover selection and im aiming for a balanced sound. Then i had to consider noise contamination from the backwave coming through the inwall rack, ceiling,ect. I think quad 24" cubes (7cft externally, 5 or so internally) will offer the abiltity to move the boxes around, be simple in construction, offer just as much air displacment as IB, albeit a little more power needed (got power?!) seeing those 4 drivers facing the listening position will also have a nice menacing look as well. I am also looking at other drivers just in case. I hope the Maelstrom 18's have atleast 90db sensitivity and a low Mms, but i know i cant have everything. Keep me posted on your project...

Dr V