JBL Everest DD55000 horns

[aertex]

I became aware of the enthusiastic primarily Melbourne and Geelong group who were discovering the potential of the JBL Everest DD55000 3 way speaker with horn loaded mid and tweeter. This speaker was being cloned in various ways from close to original to highly modified. The common thread was however always the retention of the unqiue asymetrical mid range horn. This horn has unique audio quality which was found to be very very special, especially when hooked up to a high quality mid compression driver. The more I found out the more I wanted a part of it. So I started hunting for what I needed. Some bits I had already which were mainly an assortment of suitable drivers. The cabinets I planned on making but ended up "finding" some copies of the originals. Thanks again LPG, Red and Matt. I needed the help from all of you fine gents 

 

The horn was the tricky part as they dont make them any more and there are only a relatively small number of them out there in the world. After much hunting  got a pair which are the original profile, at least 1 is an original JBL DD55000 horn...maybe both???...but thats another story and is irrelevant here

 

So, after getting the original pair I decided not to use them but rather to make my own in fibreglass (as are the originals), with 2 improvements. Let me explain.

 

1. The stock horn has a 1" throat for the original JBL driver it ran. So, if you wanted to run an improved 1.5" or 2" driver (like the B&C DCM50 or TAD 4003, Vitavox S2 or RCA field coil MI-1428  etc) you would have to fit a clumsy 1.5" or 2" to 1" "restrictor" adaptor to the end of the original horn which made no sense to me, which too extended the length of the horn unneccessarily. Also from what I saw the driver end with round to slot transition was a dismall rough as guts affair which generally needed fixing first anyway

2. Some of the original horns were made in 2 "sides", a front side which forms the horn face you see from front, and a back side which is a 2nd skin which is cast seperately and joined to the front. This creates a hollow section in between the 2 in places which is an audio/resonance "not so good". Why did they do that??? I believe to make the horn look better from the back. I cant think of any other good reason. So, to fix this the hollow resonant section must be drilled into and filled with something of resonant benefit. Some use garnet. There are other alternative too

 

So, with these shortcomings taken on board I decided to cast my own improved versions which I have done. The horn is essenatially 2 sections, the main big horn bit with a rectangular flange cast into it and a smaller horn bit with a matching rectangular flange one end and a round flange the other end to which the driver is bolted. The pics should explain better. The small horn is the tricky bit and requires a very complex 3 piece mould. This piece takes about 5 times longer to make than the big horn. The combined, bolted together horn sections are the same profile and dimensions as the original

 

The pics give some idea. Keep in mind the pics here are the bits right out of the moulds and the 2 sections need cleaning up, "facing" and flange matching, round to rectangular tranistion smoothing, hole drilling, painting etc. Still a bit more to do to make them look schmick back and front-as they will become. The horn here has a 2" diameter throat on the driver end

 

I can in fact make any configuration of the horn (or any other horn for that matter) I like and choose to make the design I did. It would be somewhat easier to make a same as original style, 1 piece horn simply with a 1.5" or 2" or other diameter throat to suit any driver you liked. I might still do that some time. I have got quite into this project and plan on maiking a few more versions. I have a second pair waiting to be finished and another pair not far behind that

Edited December 18, 2018 by aertex
added info

[skies2clear]

Very nice work there Aertex, and your comments about the horn throat make sense. A rough transition is not a good idea and neither is extending the horn length which will effect the HF performance somewhat. 

[aertex]

yes, every design has compromises I guess and its interesting when you assess and dissect the JBL design of this horn. Not being a horn guru myself but considering what I have, it might be fair to say JBL got the main design spot on and then there are just a few other considerations they made their own decisions on at the time

Edited December 18, 2018 by aertex
grammar

[Full Range]

How I love a good horn speaker project 

For mid range driver try Great Plains brand 

 

I use this model 

 

 

[aertex]

yes Paul GPA would be a decent option for a horn like this from around 500Hz-ish and up. There are of course many very decent driver options depending on budget and flavour preferences

[Full Range]

4 minutes ago, aertex said:

yes Paul GPA would be a decent option for a horn like this from around 500Hz-ish and up. There are of course many very decent driver options depending on budget and flavour preferences

 

For more flexibility I tend to go for compression drivers with greater band width 

Also the lower Htz the better for integrating a sub 

[skies2clear]

Have you compared other drivers with this GPA unit?

I’ve no experience with them and curious how they sound.

[Full Range]

2 hours ago, skies2clear said:

Have you compared other drivers with this GPA unit?

I’ve no experience with them and curious how they sound.

 

I have heard many compression drivers but it’s hard to compare due to other factors like horn material , size , and shape 

 

Bat I can say this about the drivers in my system 

Not many come close to the overall presentation 

Could be something to do with the Pascalite Diaphragm as Altec Lansing used 

 

Edited December 19, 2018 by Full Range

[skies2clear]

Thankyou, of course I should know better than asking a simplified question like that as many factors come into play.

I am reading through the thread about your speakers and setup to understand better. Great reading so far!

[Full Range]

1 hour ago, skies2clear said:

Thankyou, of course I should know better than asking a simplified question like that as many factors come into play.

I am reading through the thread about your speakers and setup to understand better. Great reading so far!

 

Best advice I can give is 

Think wholistic 

Little steps one at a time until you achieve your goal 

[Wozza_Lee]

These look fantastic. Great work, I can't be stuffed with fibreglass any more it's just a messy smelly pain in the a**.

These look good enough to sell, maybe a fellow diy'er who has been wanting to try horns but who can't be bothered with the fibreglass work might be interested in some commission work *cough

[aertex]

Wozza mate, you gotta get that cough sorted out mate . I am gettin ya too though 

[aertex]

just letting you all know I will not be on SNA again till Jan 8th due to festive season holiday starting right now, so all the best for the festive season. I will return

Alan

[skies2clear]

All the best Alan and all.

[aertex]

I'm back from holidays as all good things must end way too soon as we know. Best wishes for this new year to all on SNA. Lets work towards a happy, peaceful, sucessful year ahead

 

cheers

Alan

[Brian Skov]

Hallo Alan

how can i get some jbl 2346 clone from you ?

best regards Brian (Danmark)

[aertex]

hi Brian

welcome to SNA. I have sent you a personal message (pm)

cheers

Alan

[.fprm]

Would be super interested in a 2346 clone too. Greetings from Germany