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View Full Version : What Would Provide a Smoother Transition to The Woofer?



toddalin
11-23-2007, 01:03 PM
Would a 2445J on an HL93 provide a smoother low end response with an 800Hz crosover point when compared to an LE85/LE175 on and HL-92 (or even an HL-91)?

4313B
11-23-2007, 03:21 PM
Nope. Don't use the H91/2307 and H93/2311 below ~ 1.2 kHz.

Have matsj hook you up with some custom H9800 horns and wave goodbye to those exponentials unless you are going to use them in a 4344/4345 or 4355. Worst case, use some of those waveguides Robh3606 and Zilch have tried.

Robh3606
11-23-2007, 06:11 PM
Nope. Don't use the H91/2307 and H93/2311 below ~ 1.2 kHz.


Couldn't agree more. They sound much better crossed above 1K.


Worst case, use some of those waveguides Robh3606 and Zilch have tried.

Let's agree to disagree on this point. It would be nice if the consumer horns were readilly available but they are not. That doesn't leave you too many choices to try out the newer drivers. You have not tried any of the 1.5" PT waveguides that I am aware of. The PTH 1010 with 2435's were a direct drop in replacement for aguaplased 2425's/2344's I had used for at least a year. The PTH/2435 combination was simply better. I can't say if it was the 2435 or the waveguide but it was clear that the combination was a step in the right direction. Aguaplassed they are better still.

Rob:)

Zilch
11-23-2007, 06:40 PM
I agree the consumer horns are tops, but they're certainly difficult to acquire.

My current favorite readily obtainable combination is the 4" Aquaplas'd titanium-diaphragm 1.5" exit 2452H-SL on the "Compact" PT-F95HF (338650-001).

I still like the compact PT-F1010HF (338786-001) plenty, though, and for budget systems with 1" drivers, the $9.90 90° x 50° thread-on 338800-001 is a good introduction to Progressive Transition waveguides.... :thmbsup:

4313B
11-24-2007, 08:03 AM
It would be nice if the consumer horns were readilly available but they are not.
I agree the consumer horns are tops, but they're certainly difficult to acquire.Yeah, it sure seems that way.

Maybe you guys might want to help toddalin see the light because he sure hasn't listened to anything posted in the last several years. It's kind of weird.

toddalin
11-24-2007, 11:38 AM
Yeah, it sure seems that way.

Maybe you guys might want to help toddalin see the light because he sure hasn't listened to anything posted in the last several years. It's kind of weird.

Maybe you are missing the big picture here. :blink: I'm simply trying to make the best of what I have at hand most economically.

I have no problems with the exponential horns and obviously JBL had no problems with them for years using them in their best studio monitors. Most of the music that I listen to was probably mixed on 4333s, or equivelent, so this is what the engineer most likely heard during the mix.

I ALWAYS sit in the "sweet spot" so dispersion is just not an issue. Smoothness and a flat frequency response at that point in the room are!

I've listened to some of the other JBL horns as well as some other offerings, and sitting in the sweet spot, hear little difference in the horn itself, though the drivers can sound different.

So, with limited wood working skills, or tools, I have little desire to cut up my nice cabinets for what may be little or no sonic benefit.

Like I said, I try to use what's at hand. Today I'm picking up a pair of 2445Js that I will either use, or flip. As such, these are the choices.

4313B
11-24-2007, 12:16 PM
As such, these are the choices.Well shoot, that's a bummer... :(

Hopefully the 2445J's will do it for you.

Earl K
11-24-2007, 02:15 PM
Like I said, I try to use what's at hand. Today I'm picking up a pair of 2445Js that I will either use, or flip. As such, these are the choices.

One Idea :

- 2445s on 2311 throats , with a ( round ) exponential bell -extension added to the 2311 ( & located on the surface of the baffle board / in place of the 2308 lense ) should just get you there ( ie; loading to 800 hz ) . You may need a custom High Q hipass filter to bump up slightly saggy response in the bottom octave .

- You might have just enough depth under the existing grills for a functional extension .

- You'll need someone to turn ( on a lathe ) these bell extensions and likely someone else to figure out the necessary exponential curve ( ie; a useful "flair constant" to mate properly with the 2311 / H93 throat ) .

:)
*

Ian Mackenzie
11-24-2007, 02:20 PM
Would a 2445J on an HL93 provide a smoother low end response with an 800Hz crosover point when compared to an LE85/LE175 on and HL-92 (or even an HL-91)?


Reading the question as you have asked the only advantage is power handing, not smoother. The problem is the way the particular horn design loads the driver down low and the dispersion at the crossover point and integration at the crossover point.

Ideally the horn dispersion should be a match for the woofer (horizonally).

Ideally the acoustic centres should be in the same plane.

There are some good papers by JBL on the subject. Frankly I find the 4333 horn transition horrible and the papers cover the theory. You only have to compare to the 2344A. The 2307 above 1.2khz seems to get a pass.

The PT progressive wave guides do all this better on paper although they are not intended for consumer applications.

I agree the consumer horns are a better option for domestic use. Some of the guys in Europe are working on some diy consumer horns.

The older horns are fun to play with but none of this stuff is plug and play.

If you aim is a smoother transition you need access you a measuring kit and software. You can grab the best horn and plug it in but unless the crossover and horn eq is optimised it could be worse than your current set up.

toddalin
11-24-2007, 02:32 PM
Reading the question as you have asked the only advantage is power handing, not smoother. The problem is the way the particular horn design loads the driver down low and the dispersion at the crossover point and integration at the crossover point.



Thanks..., and thanks for addressing the question on point.

4313B
11-24-2007, 03:49 PM
ThanksYes, that was a really nice post Ian.

Robh3606
11-24-2007, 03:50 PM
Hello Toddalin

You have a horn brace if you decide to try the 2445?? That is one heavy driver.

Rob:)

toddalin
11-24-2007, 05:07 PM
Hello Toddalin

You have a horn brace if you decide to try the 2445?? That is one heavy driver.

Rob:)

Tell me about it! I carried two to the car today at once. :jawdrop:

Ian Mackenzie
11-24-2007, 07:45 PM
Yeah they are quite weighty.

Wear steel capped boots.

We need more pics ....please.

Ian

Zilch
11-24-2007, 09:53 PM
With regard to the original question, I fall back on Don McRitchie's analysis of the S8 sytem -- there's not much in the way of loading going on with that truncated horn, and the 375 is behaving more as a direct radiator at the low end.

If that sucks with 2445s, then put them on horns designed to work with them in the 800 Hz range, which likely means 2380 series flat-front biradials:

http://www.jblpro.com/pages/components/2380ser.htm#2380A

I use the "Keeper" crossovers to run 2450s (with -SL diaphragms) on 2380As here. Tweeters are 2407 on $10 PT waveguides....

Zilch
11-25-2007, 01:19 AM
The PT progressive wave guides do all this better on paper although they are not intended for consumer applications.Neither are 2344(A)s, nor just about every other component routinely used by LHF members in their DIY systems.... :p

hjames
11-25-2007, 08:07 AM
Neither are 2344(A)s, nor just about every other component routinely used by LHF members in their DIY systems.... :p

We are NOT "consumers" ...







We are Audio buffs ... collectors ... FANS! :applaud:

4313B
11-25-2007, 08:39 AM
We are NOT "consumers" ... Which is exactly why JBL doesn't sell the "good stuff" in the States anymore. There is no market for any of it here.

In any case, the H9800 data is available to everyone and I'm sure the H4338 will be soon as well so everyone can DIY their own.


The PT progressive wave guides do all this better on paper although they are not intended for consumer applications.

Neither are 2344(A)s, nor just about every other component routinely used by LHF members in their DIY systems.... :p...

Anyway, it's kind of weird that JBL doesn't just use the waveguides in the Consumer systems. They are a ton cheaper and JBL could just leave the systems at the same price points and make alot more money. Maybe that's next. :)

Robh3606
11-25-2007, 09:59 AM
Anyway, it's kind of weird that JBL doesn't just use the waveguides in the Consumer systems

Well one issue for sure is cosmetics another is stiffness. They don't look very nice and for sure the sonoglass is a much better material which probably get's us into cost as well. They look optimized for SR and the difraction slots don't appear as narrow so above 15K I don't think they are too worried.

Take a look at the difference between a 2344 slot and the PTH1010. Funny thing is it sounds good off axis, maybe it's the wide open throat. You can see the phase plug from anywhere you are supposed to have coverage.

Rob:)

pos
11-25-2007, 01:25 PM
In any case, the H9800 data is available to everyonewhere is it?
I've been looking for that information since I have seen Matsj's and John W's H9800 DIY threads, but it looks like it is in the private project may forum.

4313B
11-25-2007, 03:01 PM
Well one issue for sure is...;)