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Considering a DIY JBL speaker build

RS Steve

RS Steve

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I have some JBL 2235H 15" woofers that I am considering using to build a JBL Array type speaker. I would build the cabinet for the woofer, and add a JBL horn on top. Anyone have any suggestions as far as the horn to use and the size of the cabinet for the best balance?
 
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Very good advise- also look into some of the original JBL design, the plans are everywhere, the original L200's get it done nicely!
DC
 
I would want it to be a two way, and use something like this horn in the picture. I would need help doing a crossover, maybe an econowave?
 

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I have everything I need to build a pair of 4430's, but I found a nice pair already. I would love to do something custom, but it needs to be over the top sounding so picking the right horn is a must.
 
RS Steve said:
I have everything I need to build a pair of 4430's, but I found a nice pair already. I would love to do something custom, but it needs to be over the top sounding so picking the right horn is a must.
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Maybe try Edgar "saladbowl" tractrix horns if you can find them. There are also round plastic tractrix horns available, made in Poland by Autotech, that sound pretty good. They also make style LeCleach horns, those sound good too; a couple of pals in Chicago use Autotech tractrix and LeCleach horns. I see they also make a crazy Iwata horn. These horns look really good, sound great (IMO) and are SO much cooler than the run of the mill constant directivity horns so common now.

http://www.diysoundgroup.com/horns/autotech-horns.html



An Autotech LeCleach horn, very sharp.

Do you know Paul Butterfield? He's a central Floridian who knows a great deal about horns.
 
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Tom Brennan said:
Maybe try Edgar "saladbowl" tractrix horns if you can find them. There are also round plastic tractrix horns available, made in Poland by Autotech, that sound pretty good. They also make style LeCleach horns, those sound good too; a couple of pals in Chicago use Autotech tractrix and LeCleach horns. I see they also make a crazy Iwata horn. These horns look really good, sound great (IMO) and are SO much cooler than the run of the mill constant directivity horns so common now.

http://www.diysoundgroup.com/horns/autotech-horns.html

Do you know Paul Butterfield? He's a central Floridian who knows a great deal about horns.
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Thanks Tom, great ideas to think about. :thmbsp:
I'm not familiar with Paul B.
I was considering building a wooden horn, my friend has a nice lathe. :thmbsp:
 
RS Steve said:
I was considering building a wooden horn, my friend has a nice lathe. :thmbsp:
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Don Bunce, a pal and famed Hoosier horn fanatic, built a few round tractrix horns on lathes. There are several online articles on doing so, also on building round tractrix horns by stacking thin open wood sections, each section having a slightly different sized opening to match the flare.

http://www.volvotreter.de/roundhorns.htm

Paul B. had a treasure trove of TAD compression drivers he bought dirt cheap from Disney in Orlando when they installed a new PA throughout the park. He cleaned them up (many were used outdoors) and sold them cheap. Cool guy, I met him a dozen years ago at the Lima Ohio audio fest. Now that I'm in Florida I should look him up.
 
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The nice thing about what I plan on doing, is that the woofer will be in its own cabinet, and I can always switch out horns on top, and adjust the external crossover with ease. I just need to get the dimensions correct on the woofer cabinet, and port sizes.
 
I just need to get the dimensions correct on the woofer cabinet, and port sizes.
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Ideally, that would be determined empirically based on what you choose for a horn and how low it can play well.

The first horn you pictured looks like a JBL 2385, that's large format(2 inch throat), do you have large format drivers to work with?
 
Steve, I have the auto tech, oris 150, and Martinelli wood horns you need to take care of the two way setup. Shoot me a pm if you want to talk about the various ways you might want to go. Oh yea, also have some custom fiberglass and three or four RCA metal horns, and the Jbl 2350 horns.
 
bowtie427ss said:
Ideally, that would be determined empirically based on what you choose for a horn and how low it can play well.

The first horn you pictured looks like a JBL 2385, that's large format(2 inch throat), do you have large format drivers to work with?
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I have the 2425H's but I'm not sure if they will get high enough or be the best bet. I don't want to use the cheeks for this build and I'm not sure how they would work with a different horn lense.
 
RS Steve said:
I have the 2425H's but I'm not sure if they will get high enough or be the best bet. I don't want to use the cheeks for this build and I'm not sure how they would work with a different horn lense.
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JBL's data shows 110 db sensitivity and a pretty smooth response from 500 to way past 10khz on a 2350.

That kind of sensitivity gives you room to work some EQ into the network to perceivably extend the top quite a bit.
 
bowtie427ss said:
JBL's data shows 110 db sensitivity and a pretty smooth response from 500 to way past 10khz on a 2350.

That kind of sensitivity gives you room to work some EQ into the network to perceivably extend the top quite a bit.
Click to expand...

The picture below is what I'm interested in, the 2350 would look great done in candy apple or bright red. :D
 

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The 2425 was used in the 4430 so if you find the highs of that speaker satisfactory it will probably work for you when, as Bowtie says, it's properly EQed. This EQ comes at the cost of sensitivity.

Now some horns,such as the round tractrix, kind'a self EQ because their coverage becomes narrower as response goes higher (and is rolling off), this has the effect of a higher level of high frequency response <on axis> and the need for less EQ, if any. Thus higher system sensitivity. You give up constant coverage but in a hi-fi situation, as opposed to pro sound, the need for constant coverage is not a given and many audiophiles are very keen on the sound of "collapsing" horns. Something to ponder.

This article explains the design of the 4430.

http://www.audioheritage.org/html/profiles/jbl/4430-35.htm
 
Very cool!

That setup makes the 2350's look HUGE.

I'll be watching this project with interest.

I have a downsized similar project in mind for a pair of little brother to the 2350 horns.

These were made by JBL for another company, they're essentially a scaled down version of 2350, probably only good down to 1200hz or so. I've only collected dust wiht them so far.

horna_zpsd4b52a69.jpg
 
Tom Brennan said:
The 2425 was used in the 4430 so if you find the highs of that speaker satisfactory it will probably work for you when, as Bowtie says, it's properly EQed. This EQ comes at the cost of sensitivity.

Now some horns,such as the round tractrix, kind'a self EQ because their coverage becomes narrower as response goes higher (and is rolling off), this has the effect of a higher level of high frequency response <on axis> and the need for less EQ, if any. Thus higher system sensitivity. You give up constant coverage but in a hi-fi situation, as opposed to pro sound, the need for constant coverage is not a given and many audiophiles are very keen on the sound of "collapsing" horns. Something to ponder.

This article explains the design of the 4430.

http://www.audioheritage.org/html/profiles/jbl/4430-35.htm
Click to expand...

Great, so I will look to use my 2425's, and try to match them with a horn that will bring out the best in them.
If there are any crossover experts that can help design the best one for this please chime in. If I use an econowave one, will it do the best job?
 
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