So, here is the question I sent to Bill.

Bill, thank you for all the support you provide to us audiophiles on
Audio Asylum and other Internet Forums. Â I picked up some old
Frazier Dixielander folded horn speakers that came out of an old movie
theatre. Here is a picture of one. Â I planned to sell off the wooden
horns and compression drivers, and wanted to explore if the folded horn
boxes could be used in a car trunk for my kids ? Â The drivers in
there are look like either an 8 or a 10, paper cone, looks like an old Quam
speaker if you recall them ? Â I do not know what the low freq cut
off of this folded horn box is, and if it would be low enough for my
kids rap music use ? Â I have my doubts if the stock driver will take
Rap either ?  How does one calculate the low end cut off of a
folded horn box ? Â I know you make a bass tuba, and know what it takes to
make kids happy. Â Think I have a chance with the right driver of
making these work for my kids ? Â Â
>

Hey, maybe if I stuck a longer throw driver in it the kids could use it ?

Are you sure you remember the dixielander ?
It has a top mounted compression driver.
I will come back and post a picture of it

• http://www.audiokarma.org/forums/showthread.php?t=81393&highlight=dixielander

In a car, if a speaker will go down to 40 hz, it will sound ok with the gain from the car.

What do you think this box might go down to with the right driver ?

That's a Frazier, and while it has some relationship to a horn, and it's definitely a folded air column, it is also clear that the mouthsize is far too small to act as an effective horn as we know it. More like a short (but expanding?) labyrinthic (capacitive) column with diffraction slot or a wide(r) bandpass port.

It will go low; how low, who knows? My GUESS is that:
(1) due to the VERY SHORT pathway, but which still affords some expansion, it has a wider bandpass than a simple reflex port, and it will (due to capacitance), decrease the upper frequency bandpass.
(2) it is also apparently front-loaded, and it will display somewhat higher efficiency due to the air column increasing acoustic impedance.
(3) the "slot" exit effect is another acoustic filter subject also to difractive dispersion characteristics.

So it should do lows, sort of a precursor to slot-loaded subwoofers. Now as to the driver employed, probably NOT a modern subwoofer type. My guess is effective down to approx. 50 Hz, probably with some good punchiness.

I've never heard one, I'm just guessing. Take all of this with a grain of salt!

DM

I used the 8" MCM woofer, purchased for about $35. Don't be discouraged by the small driver as this horn will easily keep up with a decent 12" or 15" speaker that are using a lot more power. I am using less than 100 watts at any given time, most of the time less than ten watts.

BTW way, I like to listen to a lot or rap, metal, sometimes some Josh Groban (for the wife). It easily keeps up with any music. The bass is very precise and tight at any sound level.

This is the speaker I used

http://www.mcminone.com/product.asp?product_id=55-2421&catalog_name=MCMProducts

These are three different reviews,each differing in use and design.

http://billfitzmaurice.com/phpBB2/viewtopic.php?t=1539

http://billfitzmaurice.com/phpBB2/viewtopic.php?t=4201

http://billfitzmaurice.com/phpBB2/viewtopic.php?t=3682