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JBLGUY
07-15-2005, 08:13 PM
All right all you madmen out here in JBL heaven. :nutz:

Have anyone here ever attached a 2 inch exit driver to a 1 inch style horn using an adapter to make it downsize to a smaller horn ? What does this sound like ? To me it seems that it may actually be pretty sweet. but sometimes I dream weird things so I'm asking the boys who would probably know. I heard Widget refer to this the other day, but he was mysterious about his thoughts and didn't elaborate.:idea:
I was thinking of putting my 2441 on to my 2344 cheeks to see what it would sound like. Unfortunatley I don't have those 1 inch to 2 inch adapter and I don't think scotch tape will work.
So have you guys tried this and what did you think ?

Robh3606
07-15-2005, 08:43 PM
I would not go the other way from 2" to 1". You are asking for problems. The drivers are designed to load into a suitable horn and the impedance it presents. Going through the adaptor the wrong way is going to mess that up as well as give you reflections back down the throat into the 2441. You could always give it a try but intuitively it doesn't sound like a good idea.

Rob:)

JBLGUY
07-15-2005, 08:49 PM
Where's the " Widget "

Ian Mackenzie
07-15-2005, 09:03 PM
If you look in the JBL Lansing Heritage Library the earlier JBL Pro Catalogue makes reference to using the adapter in reverse.

Ian

JBLGUY
07-15-2005, 09:20 PM
Lets face it boys. some of this stuff is pure " Voodoo " as the Widget say's. Sometimes you need to just try it when it comes to speaker design. I'm not really the measurement type. I have found sometimes that the stuff that " measures " really good..... sounds really bad. I believe when I hear not when I read specs usually in relation to speakers anyway.

Some of the highest end I have heard has actually sounded pretty low end when actually played and compared to so called " it will never work stuff "

This can be a surprising hobby at times.

Mr. Widget
07-15-2005, 09:50 PM
As Ian hinted at... the catalogs say that it "can be used in reverse with some high frequency loss above 8KHz."

I have a pair of 2327s ...never tried them around backwards... I hated them the correct way though. I found them very megaphone sounding. I guess they would sound different backwards.

Widget

Robh3606
07-15-2005, 09:59 PM
If you look at the catalog Ian is refering to it say in reverse with some loss above 8k. If you intend to use it with the 2344 are you going to use the 4430/35 network compensation????

http://www.lansingheritage.org/images/jbl/catalogs/1971-pro/page11.jpg

I hear what you are saying about trying it but there are actual limitations when certain things are done that simply will compromise performance and increase distortion. In a 3 way in may not matter as a 2 way there is only one way to find out.

Rob:)

JBLGUY
07-15-2005, 10:08 PM
Actually I didn't have a system planned for this little idea....just was wondering if anybody had thoughts on this hare brained sceme.

After hearing about the loss of highs... i would use some tweets then if it was worth putting this weird convertion to some use.

I thought maybe it might make for a very snappy midrange or something my mind seems to think may work.

Come on Widget put it together and sell it on Ebay as some Mega Super headphones to a teenager who can't get loud enough. He would need to purchase an opional neck brace to support the 60lb's of drivers.

louped garouv
07-17-2005, 03:56 PM
.... put it together and sell it on Ebay as some Mega Super headphones to a teenager who can't get loud enough. He would need to purchase an opional neck brace to support the 60lb's of drivers.

:rotfl: :rotfl: :rotfl: :rotfl:
you crazy...... the headphones would obviously need to be mounted to the neck brace.......

Ian Mackenzie
07-21-2005, 07:24 AM
All right all you madmen out here in JBL heaven. :nutz:

Have anyone here ever attached a 2 inch exit driver to a 1 inch style horn using an adapter to make it downsize to a smaller horn ? What does this sound like ? To me it seems that it may actually be pretty sweet. but sometimes I dream weird things so I'm asking the boys who would probably know. I heard Widget refer to this the other day, but he was mysterious about his thoughts and didn't elaborate.:idea:
I was thinking of putting my 2441 on to my 2344 cheeks to see what it would sound like. Unfortunatley I don't have those 1 inch to 2 inch adapter and I don't think scotch tape will work.
So have you guys tried this and what did you think ?

Thinking about it some more I think its a really dumb idea.

It would make more sense I you bought some JBL one inch drivers for the 2344 and did the job properly, or alteratively looked around for a good two inch hron, we have at least two excellent threads on diy 2397's.

Cyclotronguy
07-21-2005, 10:23 AM
Hey Ian,


Remember my ugly big theater horns? I turned those into three ways and at one point had adapters with TAD 4001's mounted up on Altec 511's. At domestic volumes, it seemed to work quite well up to 10kHz.... which worked out quite well considering they were crossed over to Audax PR-120's at 8kHz. Point in fact it allowed for a rather simple filter on the TAD 4001. Sounded quite a bit better than when you heard them..... for what that's worth.

Cheers,
Cyclotronguy

Mr. Widget
07-21-2005, 10:30 AM
Wow...just think what those 4001s would have sounded like on a proper 2" horn that isn't a good cow bell substitute?:duck:

The Evil Widget;) as opposed to the sometimes benevolent one..

louped garouv
07-21-2005, 10:41 AM
Wow...just think what those 4001s would have sounded like on a proper 2" horn that isn't a good cow bell substitute?:duck:

The Evil Widget;) as opposed to the sometimes benevolent one..

Widget, how do you feel about the altec cowbells after dampening....
either with the sand/latex paint method or with something like cascade dampening spray?

I agree that there is quite the ring on those horns without treatment.....

Mr. Widget
07-21-2005, 10:47 AM
Oh, why do you have to make it difficult.:applaud:

OK, a well dampened cow bell can make a decent horn... They certainly are readily available and relatively cheap. :bouncy:


Widget

edgewound
07-21-2005, 10:50 AM
Yeah...from my experience the bare altec horns light up at around 1KHz...they sound alot more tolerable when dampened.


Edgewound

Tom Brennan
07-21-2005, 11:50 AM
I recall an article about using drivers on horns with smaller entrances than the driver exit in the old EV PA Bible. They said it was a bad idea and showed a response chart with a very rough response compared to the same driver on a proper horn.

Steve Schell
07-21-2005, 10:43 PM
In Dr. Harry F. Olson's book Elements of Acoustical Engineering, a restriction in a pipe is modeled as being analogous to a series inductor in an electrical circuit. An accompanying graph shows a steeply declining high frequency response.

The effects of using a 1" to 2" adapter in reverse might be quite severe, as the cross section would reduce from 3.14 square inches to .79 square inches, a 75 percent reduction. My guess is that this might alter the driver loading in a frequency dependent way in addition to the h.f. rolloff. Not good.

Putting a glorious large format driver on an undersized high frequency horn doesn't seem like a good idea to me anyway, aside from the reverse throat issues. I discovered about 13 years ago that midrange compression drivers sound best on really large horns, much bigger than are normally used in commercial products except for stadium and theatre sound applications. I went through a succession of Altec and RCA 500Hz. and 300Hz. multicellulars until I discovered the fine listening properties of conical (straight sided) horns. These can require some EQ for flat response, but sound the least horn-like and offer a thrilling listening experience.

I am now using some homebrew rectangular conicals, about 32" long with a mouth of 24" by 32". You should try throwing together a pair of these from cheap plywood and give them a listen!

JBLGUY
07-24-2005, 12:25 AM
Steve

Show some pics of your horns