Midbass J horn

[tade]

I want to build a mid bass J horn to cover the kick drum area from eighty to maybe 500 hz. i will cross over to midrange probably around 150-200hz. That way I can put my two subs in optimal places in the room for below that, and whatever can handle the midrange and treble above.

I want it to be full size for its bandwidth.

I want to fudge compression drivers out of a pair Hi Vi B4N four inch aluminum cone woofers:

http://www.partsexpress.com/pe/pshow...TOKEN=17170838

That cone almost looks like a compression driver itself. Efficiency is absent but i figure with horn loading it will improve. I also like the idea of a four inch driver producing bass if it can, it should be quick. How should I figure out what size to make the throat and the front and rear chambers.

Many thanks and advice is welcome.

[Magnetar]

After horn loading that little 4" inefficient driver and building a full size horn you'll be lucky to end up with the sound of a good 10" direct radiator. IMO way too much work for the end performance - plus it will be quite large

[tade]

you know, i bet you are right. I should save the effort and save up for some PA tens.

[dwk123]

I like the basic idea, but Magnetar is right - the HiVi's are pretty much useless for this application. No efficiency, and no motor strength. I looked at using 4 of the B3N's in a Unity prototype, and even 4 of them horn loaded only get into the low 90's, and bandwidth was disappointing (according to sims, never built it).

[tade]

what is good about compression driver midbass horns? The super high efficiency?

[tade]

this is what sparked my interest:
http://www.audiofederation.com/blog-images/IMG_9227.jpg

http://audiofederation.com/blog-images/IMG_9234.jpg

[rick57]

Somewhere there is a site with a clever project by a Swedish guy called matheus (sp??), to accomodate that horns really only behave like ideal horns when the WL inside the horn is several times shorter than the horn length, and allow this where floorpsace is limited, by a 90 degree midbass J horn (using IIRC a 15" JBL driver) - with a good "how I did it section"

It sounded like a very good way to get sufficient length for good performance down to about 80 Hz, "using height rather than length".

Does anyone have the link?

thanks

[ears4hire58]

Originally posted by tade
what is good about compression driver midbass horns? The super high efficiency?

Yes, the super high efficiency and the uniform dispersion, but not the fidelity. I installed some in large auditoria (but now avoid the use of fiber-glass MB horns due to ringing)

[rick57]

Steve Schell who posts at the High Efficiency Speaker Asylum is developing new compression drivers midbass horns.

http://db.audioasylum.com/cgi/m.mpl?...ad&r=&session=

and others here

http://db.audioasylum.com/cgi/m.mpl?...ad&r=&session=

Steveis I think are for domestic use rather than auditoria. I don't know if fiber-glass, more likely I think with wood.


Cheers

[rick57]

There's also this thread referring to two bass horn with 15" drivers:
Steve's bass J horn (no links, but Steve can email sketches); and
Mathias *U bass horn (link gone, but drawings there)

http://www.audioasylum.com/scripts/t.pl?f=hug&m=117170