Tire Kickin' a design... how'd you think THIS would sound?

[GordonW]

OK... I've been hinting around at this for a while. I've recently decided, to ditch my C70 Alpha III project, to instead build a modified 250Ti design...

I've decided to "go for broke", in some ways... to change the few things, I always thought were not quite to my liking in the 250Ti design...

Here's what I've come up with, as far as a driver complement is concerned:

Highs: 035TIa (naturally)

Midrange: slightly "customized" 104H-2 (treated paper cone rather than the poly cone 104H- I always liked the transient response of the treated paper cone better, as I thought it hit a good balance between the "rowdy" LE5-X variants and the "overly polite" 104H)

Midbass: 2118H. Closest thing to a 108H available. I also just plain LIKE the way 2118Hs sound... a BUNCH.

Bass: "Customized" 2235H, with a custom made "PR460"... ie, a passive radiator, made from an 18" basket, loaded with an aftermarket 2245 cone and soft spider, with a weight-adjustment bolt/nut arrangement. This PR would be mounted on the rear of the 250Ti cabinet, instead of a port...

I decided to try the 2235, due to much more ready availability WRT the LE14H-1 (those 15" frames are everywhere)... I'm thinking of using a slightly longer voice coil (possibly a 2245 coil, 1" winding length instead of 3/4"), to increase the X-max, raise the Q a bit, and raise the Mms just a bit. According to my calculations, this should wind up giving me within 1/2 dB of the same sensitivity to a LE14H-1, and a solid 29-30 Hz or so f3 point, before considering room gain. And the nice thing about the PR, is that I will be able to tune the bass rolloff, to the room...

Crossover, would be as close to a stock 250Ti, as I can do, accomodating the new drivers. I would assume I can retain the stock topology, but tune various sections to optimize them for the new drivers, using LEAP/LMS...

So far, I've got a pair of 2118 frames, a pair of LE5-10 frames (which I will custom recone as "104H-2-type" drivers), and a pair of 2225 frames and aftermarket 2235 cones to go into them. I still need 035TIa tweeters and some baskets of some sort, to build the passive radiators into. I'm hoping I can find a couple of Peavey Lowrider or Black Widow 18" frames... they should make quite good PR chassis, as dimensionally, they're very close to JBL 18" frames.

So, any comments? Yes, I know I could go with more "modern" drivers such as the 1500AL or other exotic new stuff, but I thought I would try to build them with "in the day" components... stuff that COULD have been assembled, back in the day the 250Ti was built. An alternate universe version, as it might have been...

Of course, I now need to manufacture some time, in order to get to work on these. Gee, who hasn't heard THAT story before?

Regards,
Gordon.

[Mr. Widget]

I am with you on the midrange and tweeter.

If you love the 2118H that is a very good reason to go with that for the mids/mid bass. I have no working knowledge of it so I'll take your word for it.

The low end has me stumped. I would use a 1500AL, but that is just me. I was just listening to Don's and they kick ass and are articulate as hell... I can't imagine a fatter than stock 2235H with passive could ever approach the punch and tactile detail of the 1500AL.

How about the bottom of a 4345? A 2245H and 2122? Actually the 1500AL, 2245H, or 2235 are all more sensitive than your upper range so you would likely have to bi-amp the system if you use any of these options.

Widget

[Ian Mackenzie]

Why bother screwing around?

Just max out Visa card on a pair of LSR 6332 or LRS 6328 monitors and a 1500 sub and be done with it.

Ian

[jblnut]

I'm not quite on board with the upper end....


If you're "going for broke" then you want a better tweeter than the 035. I'd search out a 044TI or the 046Ti from the XPL. And speaking of the XPL, why not ditch the whole 5" 104 deal and use the 093TI mid (or the car variant that shows up on ebay frequently) ?

You've got some excellent ideas on the lower end, but I don't think you're quite reaching as far as you could on the high end. I've had plenty of time to compare 035/044/044ti/046ti and 104h/104h-3/le5-11/093ti in my house. If you want the best, you want a 044ti and that amazing mid from the XPL in your JBL showcase.

You also want to talk Giskard into sharing his new charge-coupled 250ti xover secret recipe....



jblnut
PS - I still need to talk to you about that custom center channel project one of these days....

[Robh3606]

"Why bother screwing around?

Just max out Visa card on a pair of LSR 6332 or LRS 6328 monitors and a 1500 sub and be done with it.

Ian"

Geez man what a party pooper!!!

Actually I would like to give that combo a listen.


I like the 2118 myself and 104H-1,2 also. Curious to see how it works out if you build them.

Rob

[Ian Mackenzie]

Sorry,

Having heard John Nebel's LSR's I figure I am a spoiled JBL brat
If you can't make it, buy it!


Ian

"Why bother screwing around?

Just max out Visa card on a pair of LSR 6332 or LRS 6328 monitors and a 1500 sub and be done with it.

Ian"

Geez man what a party pooper!!!

Actually I would like to give that combo a listen.


I like the 2118 myself and 104H-1,2 also. Curious to see how it works out if you build them.

Rob

[4313B]

Why bother screwing around?

Just max out Visa card on a pair of LSR 6332 or LRS 6328 monitors and a 1500 sub and be done with it.

Ian

Free tip - LSR6328's and LSR6312SP's - I won't elaborate.

I'm not quite on board with the upper end....

Me neither.

BTW jblnut - G.T. liked your charge coupled 250Ti filter pictures.

[Earl K]

- Opinion on 250ti Rework ; Retracted

[moparfan]

Seems to make a lot more sense than the 6332 and subwoofer. I would think that they could also make the crossovers behave ideally, or moreso, than the passive crossovers in the 6332.