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View Full Version : Say you had a pair of 2245H's...



JeffW
11-02-2003, 07:35 PM
And you wanted to build a 4 way system for home use...

I'd like to build a couple of speakers similar to the 250, but with an 18" LF speaker. I'd like to replicate the shape and the tower design so they might fit in a similar floorspace....realizing they will of course be larger. I see the studio monitors, large rectangular shapes cabinets, and just wondered if I could build some "home speaker" looking enclosures that would perform similar to the boxy looking monitors.

What other drivers would you guys recommend? Any 4 way cross over networks available??

Is this even a worthwhile project, or would the design constraints compromise the performance to the point that a rectangular box would be a better alternative??

Just looking for some advice, if you guys tell me I'm full of it, I'll understand..Just seems like a project I might be interested in.

Thanks.

Oh, partly inspired by This Thread (http://www.audioheritage.org/vbulletin/showthread.php?s=&postid=8954#post8954)

Robh3606
11-02-2003, 07:58 PM
Well you could clone 4345's. Ian is building a pair up now and Bo has a pair. Both in home enviornments. Not sure about a pyramid design as the 2245 needs some space. Take a look at these threads. You certainly came to the right place:D


http://www.audioheritage.org/vbulletin/showthread.php?s=&threadid=952


http://www.audioheritage.org/vbulletin/showthread.php?s=&threadid=314

Or you can build sub cabinets for seperate placement and do a 3 way pyramid. But that way you would have to extend the LF in the pyramid. What drivers do you have beside the 2245's?? Passive crossover for the larger monitors the 4 ways are hard to come by. There are 3107's in the "Tent Sale" but they are for the 4350 and may or may not work depending on what drivers you put in the mix.

Rob:)

JeffW
11-02-2003, 08:58 PM
I had seen Ian and Bo's respective threads...searching for 2245H..

I don't have anything, the guy on Ebay had another pair of 2245's, I have spoken to him. I'd be starting from nothing, that's why I'd like components I can still buy, not necessarily new production, but something not extinct.


About the 4345's...

That's the complement of components I'm looking for. I don't know if I can get Giskard to make me as good a deal on the 2122H's :)

If I can get the volume for the 2245's, and a 10" like a 2122/23 right above, the top speakers might be a little high, Bo mentioned his were at just the right height.

And as for the crossovers and stuff...I'm not sure if I would be the best judge on what would work.

I see the crossover for the 250 is no longer available from JBL. How this stacks up against the 4345 crossover, or if that crossover is available, I'd need some advice there.

As far as cabinet construction, that's more along the line of something that doesn't bother me. Knowing what to put into the cabinet is what has me buggered. That and I would like an aesthetically pleasing design. If possible. If the 4345 shape is inherent to it's performance, I guess I'd better not monkey with it
:)

Just asking around..not something I'm gonna start tomorrow.

GordonW
11-02-2003, 10:12 PM
OK, I'll bite.

Woofer: 2245 (as mentioned)
Midbass: 2123J
(here's where I leave the canon... warning, non-JBL recommendation follows! :o )
Midrange: Audax PR170M0 (hey, it's Audax, it's a Harman company, a "cousin" to JBL, what's the problem with that?)
Tweeter: Unsure. 035TiA? 2404H?

I'd be inclined, to do crossovers at about 200-250 Hz, 800-1000 Hz, and 3000-5000 Hz, depending on tweeter.

What would this do? Combine probably the FASTEST drivers existing on the planet, for their respective frequency ranges. With a 250Ti-esque first-order network, just with enough tweaking to deal with the rising responses of the PR170 and 2123, this could be a DEADLY combo. As in, guaranteed to cause people to while away WAY too much time listening... :cool: I'd expect it to be sort of a "bridging of the gap" between the "smoothness" of the original L250/250Ti, and the "attack speed" of the big monitors such as the 4343/4350/etc. As in, having possibly, the best of both...

If you really had to do an all-JBL combo, I'd be looking a the 093Ti mid dome... that, with the 035, would be quite interesting too.

As far as crossover design: I'd be inclined, while using the 250Ti schematic as a model, to find someone with access to LEAP/LMS, SoundEasy or the like, and work out the crossovers, in-situ, with the drivers in box, for the SPECIFIC box you build. No way "prefab" crossovers for another driver combo, can exceed the precision of tuning the crossover JUST for the EXACT drivers used...

Regards,
Gordon.

JeffW
11-02-2003, 10:34 PM
Well, the 2123J is on tent sale right now....Ignorant question to follow..

Is the 16 ohm J model not a problem in the 8 ohm scheme of things..or with a "custom crossover" is the individual driver impedences not a factor??

Mr. Widget
11-02-2003, 11:33 PM
Originally posted by JeffW



About the 4345's...

That's the complement of components I'm looking for. I don't know if I can get Giskard to make me as good a deal on the 2122H's :)

If I can get the volume for the 2245's, and a 10" like a 2122/23 right above, the top speakers might be a little high, Bo mentioned his were at just the right height.

And as for the crossovers and stuff...I'm not sure if I would be the best judge on what would work.

I see the crossover for the 250 is no longer available from JBL. How this stacks up against the 4345 crossover, or if that crossover is available, I'd need some advice there.

As far as cabinet construction, that's more along the line of something that doesn't bother me. Knowing what to put into the cabinet is what has me buggered. That and I would like an aesthetically pleasing design. If possible. If the 4345 shape is inherent to it's performance, I guess I'd better not monkey with it
:)

Just asking around..not something I'm gonna start tomorrow.

First ask yourself if you like the horn sound of the 43XX series or if you like the more neutral but slightly less dynamic direct radiator sound of the 250Ti. This is huge as they are completely different animals.

I like things about both types of systems. If you are drawn to the 250Ti because of it's shape, that is no problem, you can certainly change the shape of the 4345 and not affect it's sound, but I would strongly suggest you go with a single 2235H instead of the 2245H as the pyramid becomes quite large and to my eye unappealing when you scale it up to the necessary 10 cu ft volume. (8 cu ft for the woofer, 0.5 cu ft for the mid and 1.5 cu ft of wall thickness, bracing etc.) With a single 2235H you will be able to keep the original 250Ti basic proportions and scale. The driver height is fairly critical and if the 4345 is the sound you are after then you will need to place the drivers at the same basic heights of the 4345. I would recommend that you place the 2405 above the 2421 and angle it downward slightly assuming your primary listening position is seated. If you go with the 2235H you will be building the 4344 instead of the 4345. You can get the crossover schematic from the JBL Pro web site. The 4344 has a bit less bass extension and a slightly lower maximum SPL but unless you are into massive bass or crazy SPLs I would bet you would be happy.


If your goal is to build an amazing speaker system that is not necessarily the 4345 or 250Ti than the issue of what drivers to go with depends on your goal. The Audax mid that GordonW has suggested is very good and only about $58 ea. from Martin Sound. It is very dynamic for a direct radiator and has a very neutral sound if handled properly. The problem is that you need to have a specific design goal before you go to the drawing board. That goal will direct you down a path that will lead to a selection of drivers. If you are trying to recreate the 4345 but want a different cabinet shape, then half your battle is won. You only have to decide where you want the boxes to grow. They will definitely have to be pretty deep, but they will have to grow in the other dimensions as well. If your goal is less specific, you need to make some more decisions. Budget, size, band width, maximum SPL, sensitivity, dispersion, voicing,... these are all items that will determine your final design.

Mr. Widget
11-02-2003, 11:35 PM
Originally posted by JeffW
Well, the 2123J is on tent sale right now....Ignorant question to follow..

Is the 16 ohm J model not a problem in the 8 ohm scheme of things..or with a "custom crossover" is the individual driver impedences not a factor??
The "J" version will require a modified crossover. It is not an insurmountable obstacle.

JeffW
11-02-2003, 11:56 PM
Thanks all...

I'm not dead set on anything... Im not really set on the 250 shape except that it's more of a tower instead of a box. Not that boxes are bad... I wasn't so much referring to the horn mid of the 43XX as opposed to a 4 way something, I like the cone driver sound of the 250 just fine,,,

The pyramid would have to be pretty squashed at 10 cu ft. and not get above your ears setting, to be sure. If you put the smaller drivers along the straight side and gave the LF some volume up the hypotenuse, even a row of ports like the 4345, might squish it a little.

I'm really just looking for some distinctive "furniture" (gasp!) style speakers..and wanted the 18" LF punch...a lot to ask out of a speaker.. Kinda a 350Ti, but I don't have to have Ti tweeters..the 2404H looks pretty good and isn't super expensive.

mikebake
11-03-2003, 04:40 PM
The 2245's are great, but you can get pretty much the same thing from 2235's and save the space. Sell the 2245's and buy the 2235's.
Use the 2123 instead of the Audax, just for purity!!!!

MBB

TimG
11-03-2003, 05:10 PM
You can buy all the drivers from JBL for the LSR32, now named 6332, and the crossover network, and build yourself some 250ti-esce cabinets, with 2245Hs on the bottom, and have the best of the new and old JBL all wrapped up in one. The LSR32 is the model that Drew Daniels currently recommends in place of his older "Ancient Audiophile" system. I read that he is currently updating his horn design, so this could change.

There were previous posts on the prices for the LSR32 drivers: http://www.audioheritage.org/vbulletin/showthread.php?s=&threadid=822

Current JBL prices posted by Giskard
15" 2235H $366.00
8" 218F p/n 124-58002-01 $181.68
12" 252G $233.46
5" C500G p/n 331366-001 $150.02
1" 053Ti p/n 123-10003-00X $122.00

The 218F is the 8" 2ohm woofer from the LSR28P. This could be used above the 2245H, but then you are on your own for a crossover. The bottom three drivers are from the LSR32. The LSR32 crossover price is around $105. If you don't have crossover design software and a measurement system, you could go with these drivers and crossover and then use a plate suwoofer amplifier with a built in crossover. You can get a variety of flexible plate amps with between 250 and 350 watts (some with features like remote controls and adjustable phase and bass boost for around $125-155 each). If you want to spend more money on separate amps and crossover for the 2245s, you could go with a prosound Rane AC22 or something custom like a Marchand. If you want to get really fancy you could get a Behringer DCX2496 and have the ability to use parametric equilizers in the bass reqion. I feel an active crossover is a better, and more flexible solution, than a passive network at the crossover frequency you would use for the 2245H in a system like this, which would likely be between 50 and 100Hz. You can get the plate amps from Madisound, Partsexpress, Adireaudio, or Acoustic-visions, to name a few.

Mr. Widget
11-03-2003, 06:58 PM
TimG,

I think your suggestion to build a hybrid new/old system around LSR parts is very interesting, perhaps not very cost effective, but if one could get the components at a lower price, you could end up with a very nice system indeed!

I disagree with your choices of electronics completely however. The plate amps sound like $#it, and the Rane AC 22/23 does not sound very good in a high resolution application like this and the Behringer has that digital hash. I have not personally used the Marchland, though Scott seems to like them. I would recommend the Bryston or a custom line level passive. These have been discussed earlier on other threads. The LSR systems are worthy of top quality electronics and so are the 2245 s even when used as a sub.

Just my thoughts on the subject.

Widget

scott fitlin
11-03-2003, 07:14 PM
Marchand will build to suit your needs! Its cost effective, and very flexible, and they sound good, not as good as the Bryston 10B,s but it wont set you back 3G,s either! Unless you go for the Marchand tube crossover. Havent heard this one though. Phil Marchand says his tube crossover has amazing clarity! Well, for what it costs, it should!

Rane I do not like, no way, no how.

I am a big fan of second and third order butterworth filters, anything higher just sounds too unnatural for my ears.

If your in it for the best possible, the Bryston 10B,s are really good. If you get the normal ones, you can select anywhere from 6db to 18db per octave roll offs! This comes in handy, you might like your woofers with a 12db slope, and 18db going into your horn! They are also incredibly well built, well designed all discrete cicuitry, and have a 20yr warranty! But, as all good things are, they are pricey. These get my stamp of approval all the time.

Then of course, theres always the vintage market. Old Crown MX-4,s and VFX-2A,s, or Urei 525,s make excellent sounding crossovers and will not break the bank!

:flamed:

TimG
11-03-2003, 10:02 PM
Here is another amplifier and another crossover I forgot to mention. Adireaudio offers several models of Hypex plate amplifiers, and they are not your typical Taiwanese built amps. I believe that they are assembled in Germany. http://www.adireaudio.com/diy_audio/amplifiers/hs500.htm
The amps range in power output from 200 watts to 1500 watts per channel. They have built in crossovers and parametric equilizers, which is a great feature to have for a subwoofer. These amplifiers also use toriodal transformers. These plate amps use 4th order high and low pass, which is definitely not ideal for a midwoofer to subwoofer crossover. You would probably end up with close to a 6th order high pass and 4th to 5th order low pass slopes with some sort of hump or notch where they meet. If you are crossing to a subwoofer you will probably use a sealed midwoofer, which will have a characteristic sealed box 2nd over rolloff, so you would want 2nd order electrical to achieve a 4th order target. On the low pass you will probably need either a 3rd or 4th order electrical slope to meet a 4th order acoustical target. It is also nice to be able to have adjustable phase or time delay at the crossover point.

If you want to go with separate amps and crossover, which will be the best sonic solution, if you can afford it, you could have Marchand build you something like this http://www.bamberglab.com/aaf.htm
An assymetric active crossover like this would work perfectly to mate a sealed woofer to a ported or sealed subwoofer. Most plate amplifiers don't allow this level of adjustability of the slopes, unless you have engineering experience and can modify the circuitry yourself. The Marchand crossover at the BESL link sells for $600, but you could probably get a Marchand kit and put one together for less than that if you are comfortable doing some soldering. The kits at marchandelec.com sell for around $300-400. You could probably find a used one for less. I agree with Scott that Bryston crossovers and amps would be an excellent solution if you can afford them. With a 20 year warranty I would be confident buying them used. I'm really happy with the stack of used Adcom amps that I have collected, but I would trade them for Brystons if somebody wanted to make a trade.

If you don't get the 2245Hs, Giskard posted a while back that he had some 2242H's for sale, but he didn't list a price.

JeffW
11-03-2003, 11:36 PM
Thanks for all the input, guys!! My head is spinning from information overload right now. It'll take me a couple of days to try and research some of these options..

4313B
11-06-2003, 07:43 PM
I had a pair of 2245H's...

GordonW
11-06-2003, 11:41 PM
Originally posted by Giskard
I had a pair of 2245H's...

... but now you have 2242HPL's, so everythings better.

Right???? :D :D :D :D

Regards,
Gordon.

4313B
11-07-2003, 05:43 AM
Well, I do love the way one can just flog the hell out of the 2242H/HPL that's for sure :p
The 2245H is one exceptionally nice driver though! :)
I don't see how you can go wrong owning either.