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horn driver support


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i'm building 4 cabs. i have the carcasses made already and the baffles cut out. i designed them in bassbox pro. crude testing with minimal dsp (for the horn) and no smaart yet reveals they will sound great.

 

drivers are jbl 2226h

horns are ev dh1a (8 ohm) on an ev hp940.

 

yes i realize they are 90 degree horns. crude testing in my driveway shows they sound decent sitting next to each other in a typical arrangement.

 

it took me a long time to decide to build these.. i would have preffered to find another set of HDH4 tops. but i cannot.

 

so far i can lift these cabs. i cannot lift HDH4's

 

the cabs need bracing. the 2226 overpowers the 3/4" plywood walls. i am not surprised. the baffle needs braced as well. i crammed a lot of stuff in that baffle.

 

my question is how do i support the dh1a? its reall heavy and i dont want it unsupported. one big bump in the trailer and i foresee cracked horns

 

i could make a bracket for the holes in the base of the horn but i dont like that. driver is still unsupported. my current idea is to make a thin metal tab that bolts to the driver on one or two of the mounting hole where it attaches to the horn and bolt that metal tab to a wood brace.

 

or i could remove the rubber ring around the driver and directly support the driver?

 

ideas?

 

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I repaired my Yorkville EF500p volume knob a few years ago. A "helper" moved one and broke it. The horn was supported via a board. with a hole in it the same size as the throat where the horn driver/magnet threaded in. It may work with a bolt on as well. I wouldn't mess with the drivers screws.

Hope this picture can give you an idea.

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Look at the empty box. See how you cut the hole for the 15' driver? You do the same for the compression driver on a piece of plywood

about 8 inches wide and the width of the cab inside where the compression driver sits in the cab. Get the idea? The compression driver

slides in the hole you cut and supports the driver/horn. You have to make some blocks off wood to butt the compression driver support piece of plywood that mount on the inside of the cab. I recommend an xover of 800hz for your setup. This is what Altec used on their large format compression drivers to a 15" loudspeaker. I have used the same for many years when I used that great old stuff.

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The hole you cut is exactly the size of the compression driver diameter or a hair bigger so the driver slides into the hole and is supported. I kinda drew where the blocks go on either side and glue/screws to support. NEVER support the horn. Always support the compression driver. If you support the horn throat you could snap the driver right off. Attached is a make shift diagram I did on paint. [ATTACH=CONFIG]n32023015[/ATTACH]

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yes that is basically what i have come up with. the hole is around 8.9" or so and i am not sure how to take the rubber ring into account. i could support via the rubber ring, or i could take it off but it doesnt come off without wrecking it. there is some give in the rubber and maybe thats fine.

 

that brace would be a good sidewall brace too. i just received the handles from parts express an hour ago, i hope they fit my router templates from my last build. not sure. i can make new ones.

 

i've been playing with these speakers and they are pretty amazing. i did a show last night with the hdh4's and i think the dh1a might be a lot better top end. no idea on the 2226 vs the hdh4, different beast

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hey your right. i get way better results when i shorten the ports to 3 inches. freq response flattens out almost flat, vent velocity goes way down, cone displacement goes WAY down below 120hz, input power goes up a lot between 50hz and 100hz. i just lose a little response below 50hz which i dont care about at all. group delay and impedance gets high below 50z (not concerned) but both of those get lower above 50hz

 

its easy to shorten the ports!

 

i wonder why jbl said to use those ports? the computer model agreed but does like them best at 3". i tried 6,5,4,3,2 inches. 2" breaks up a lot of stuff.

 

i can post plots if you want. i wonder if 3" is best, or if i should be looking at 4".

 

thanks for suggesting this

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With the Dayton Audio DATS V2 you can measure and plot your wide band impedance of your box and get an exact measurement of box tuning. You can guess close ( or be way off...) or put on sign waves and look for least amount of speaker movement at box tuning but this makes it easier.

 

https://www.parts-express.com/dayton...ystem--390-806

 

With the effort your making to have these boxes you might as well know for sure.

 

Doug

 

Edited by Dookietwo
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Andy you were right. i shortened the ports to 4" and fired one up today with the bracing and backing. i used a mild amount of thick jeans type backing, i will add more but not much.

 

with the shorter ports the driver moves and pounds. air comes out the ports now. i only did it to ne so far and it sound a lot better. i raised the crossover point to 800 from 500 with the backing and the 2226 sings. i love it.

 

those big braces really work. i used my hands to learn where to place them, now i feel the horn area vibrating too so i may brace that.

 

i have air leaking out of the horn where it meets the cab. a lot. i need some type of gasket there.

 

i basically sat there stunned listening to this one speaker for an hour. i have not transfer functioned it yet.

 

[ATTACH=JSON]{"data-align":"none","data-size":"full","data-tempid":"temp_129753_1515373928206_320"}[/ATTACH]

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Edited by Coaster
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its roughly 5 cubic feet. its more than the driver wants

 

i did finish these and have been running them a lot. they get really loud but dont hurt ears. they carry several hundred feet before freq response dies off. they outrun my peavey double 18's like mad. subs cant keep up.

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