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Author Topic: DB Keele JBL 18" W bin  (Read 19898 times)

Stu McDoniel

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DB Keele JBL 18" W bin
« on: July 15, 2012, 10:25:38 am »

I scored four of these cabs yesterday (freebies) and Im curious what the typical HPF was used on these?  I dont want to blow up the loudspeakers in them, and want to get the HPF right.
Thanks guys.
« Last Edit: July 15, 2012, 10:47:46 am by Stu McDoniel »
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Ivan Beaver

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Re: DB Keele JBL 18" W bin
« Reply #1 on: July 15, 2012, 12:54:00 pm »

I scored four of these cabs yesterday (freebies) and Im curious what the typical HPF was used on these?  I dont want to blow up the loudspeakers in them, and want to get the HPF right.
Thanks guys.
What drivers are in them?

They were designed for the JBL K151 bass guitar speaker.

Many people make the mistake of putting a "better" driver in them-and the result is a lowered performance.

Just because a driver may have a better bass response-in a ported cabinet-does not mean it will work well in a horn cabinet-like the Keele W cabinet.

I am sure there are other drivers that would work well in the cabinet.

I would start with a highpass around 40-45Hz (and that is just a guess).  Those cabinets were not designed to go real low-but rather to have a high sensitivity-based on the short horn used in them.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
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Tom Young

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Re: DB Keele JBL 18" W bin
« Reply #2 on: July 15, 2012, 02:25:59 pm »

I scored four of these cabs yesterday (freebies) and Im curious what the typical HPF was used on these?  I dont want to blow up the loudspeakers in them, and want to get the HPF right.
Thanks guys.

I used to make dozens of these for sound companies, bands and installations. It was a pretty darned good bass horn.

The K151 was discontinued only a year or two after these plans were made availbale. So very few that I ever sold, used or saw were equipped with the K151. Other JBL 18's (2240, I think ?) worked quite well in this horn but (as Ivan has pointed out) others did not.

Another point is that for every "real" Keele bass horn you came across back then (and would come across now) there was another which has been modified (or just plain built wrong) by folks who knew nothing about what they were doing.

Another point is that when these were introduced few of us were aware of the benefit of using a HPF on a bass horn or subwoofer. We certainly knew of the importance of the LPF, but not the HPF. And very few crossovers around back then had a HPF for this purpose. As a reference:  all crossovers were analog and it was just around this time that the first 24dB-per-octave Linkwitz-Reilly filters were being introduced. Prior to this there were very few crossover fliters steeper than 18dB-per-octave.

This link will take you to Don Keele's original document and it looks to me (freq response chart on page 7 plus in text) like a steep HPF between 50-60Hz would be a safer bet.

Edit: Hmmmmm.... conflicting info. Elsewhere in this doc Keele claims it is useable down into the 30-35Hz range. Based on my memory of how low these went and the freq response chart in this doc, I'd not go that low.

Woops. I cannot copy & paste it.

Google: JBL Keele 18" folded horn

and go to the  "audioheritage" site that comes up near the top.
« Last Edit: July 15, 2012, 03:31:08 pm by Tom Young »
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Stu McDoniel

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Re: DB Keele JBL 18" W bin
« Reply #3 on: July 15, 2012, 09:25:13 pm »

What drivers are in them?

They were designed for the JBL K151 bass guitar speaker.

Many people make the mistake of putting a "better" driver in them-and the result is a lowered performance.

Just because a driver may have a better bass response-in a ported cabinet-does not mean it will work well in a horn cabinet-like the Keele W cabinet.

I am sure there are other drivers that would work well in the cabinet.

I would start with a highpass around 40-45Hz (and that is just a guess).  Those cabinets were not designed to go real low-but rather to have a high sensitivity-based on the short horn used in them.
Im not sure yet Ivan on what bass drivers to load in them.  I still see SONIC makes these cabs and loads them with Emminence drivers.  I do realize some of the drawbacks on
these cabs but I also remember in clusters they could knock you down.   I have to get the TSP's right and get some drivers for them.   I have new front loaded EAW designs but I am
excited to play with these things.  I spent the past two days stripping, priming and painting.
I still have old vintage Altec horns, JBL horns, and drivers and vintage Altec mid bass cabs.
I have some EAW mid high 600 series cabs I could Xover at 250hz to these cabs.
I will try higher HPF for them and see what happens.  I love this old stuff :)
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Stu McDoniel

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Re: DB Keele JBL 18" W bin
« Reply #4 on: July 15, 2012, 09:32:09 pm »

I used to make dozens of these for sound companies, bands and installations. It was a pretty darned good bass horn.

The K151 was discontinued only a year or two after these plans were made availbale. So very few that I ever sold, used or saw were equipped with the K151. Other JBL 18's (2240, I think ?) worked quite well in this horn but (as Ivan has pointed out) others did not.

Another point is that for every "real" Keele bass horn you came across back then (and would come across now) there was another which has been modified (or just plain built wrong) by folks who knew nothing about what they were doing.

Another point is that when these were introduced few of us were aware of the benefit of using a HPF on a bass horn or subwoofer. We certainly knew of the importance of the LPF, but not the HPF. And very few crossovers around back then had a HPF for this purpose. As a reference:  all crossovers were analog and it was just around this time that the first 24dB-per-octave Linkwitz-Reilly filters were being introduced. Prior to this there were very few crossover fliters steeper than 18dB-per-octave.

This link will take you to Don Keele's original document and it looks to me (freq response chart on page 7 plus in text) like a steep HPF between 50-60Hz would be a safer bet.

Edit: Hmmmmm.... conflicting info. Elsewhere in this doc Keele claims it is useable down into the 30-35Hz range. Based on my memory of how low these went and the freq response chart in this doc, I'd not go that low.

Woops. I cannot copy & paste it.

Google: JBL Keele 18" folded horn

and go to the  "audioheritage" site that comes up near the top.
I think what I saw was in clusters of 4 or more they claimed 3db down at 40hz?
I will try the 50hz-60hz range on a HPF. 

Edit: According to Sonics page on the copy of this cab clusters of 8 or more
give high spl @ 40hz
« Last Edit: July 15, 2012, 09:54:39 pm by Stu McDoniel »
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duane massey

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Re: DB Keele JBL 18" W bin
« Reply #5 on: July 17, 2012, 10:25:24 pm »

You might consider this driver:
http://www.eminence.com/speakers/speaker-detail/?model=Impero_18C

They are available in 8ohm. I've used them in a couple of front-loaded horns in place of the Omega-series, and was quite pleased, even with the $$ difference.
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Duane Massey
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Chris Dobson

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Re: DB Keele JBL 18" W bin
« Reply #6 on: August 07, 2012, 12:25:27 am »

Stu, I too have several of these old W-bins that we use quite a bit. Most or ours are loaded with EV180b's and I have another quad (Electrotec) loaded with McCauley 6174's.  We run old Crest 8001's bridged and a nice steep filter at 50hz and have never had a problem. 
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Riley Casey

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Re: DB Keele JBL 18" W bin
« Reply #7 on: August 11, 2012, 09:56:58 pm »

In the interest of nostalgia I've attached the first couple of pages of the original Don Keele documentation in which he does assert response down to 40 hz.  As I remember it you could get a solid response down to 40 hz ( low E on a bass guitar was a more reliable signal source than my surplus store HP tube sig gen ) if you stacked up eight boxes into one array.  Since we only had eight it wasn't a common daily set up but they were great for kick drum when powered with PSA2s.

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Re: DB Keele JBL 18" W bin
« Reply #7 on: August 11, 2012, 09:56:58 pm »


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