18"-driver basshorn

[Jakob]

I've searched the net but all I came up with was some PA-horns. Can You use one of those for home-hifi with good result? They seem to have a rather high tuning (>50Hz)?

Any tip?

Regards and wishes for a nice weekend!

[TimG]

http://diy.cowanaudio.com/hornsub.html

Works with a variety of 18" drivers, although some may work better than others. You want a stiff strong cone because of the compression ratio in the horn throat. This subwoofer also models well with the Parts Express Dayton 18" pro woofer.
http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=295-085

Here is another Eminence made woofer that should work well. This one may have a stiffer cone, but it is a closeout so act fast.
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=299-444&CFID=750318&CFTOKEN=80950110

[Hoerninger]

http://diy.cowanaudio.com/hornsub.html

Works with a variety of 18" drivers, although some may work better than others. You want a stiff strong cone because of the compression ratio in the horn throat .... It looks great. The simulation is mentioned here:
http://audioheritage.org/vbulletin/showthread.php?t=12810
Check dimensions and weight. ;)

I'he made good experience with the basshorn mentioned here:
http://audioheritage.org/vbulletin/showpost.php?p=121158&postcount=3
There is sound pressure without limit, "although" it uses a 15 inch driver It goes far below 50 Hz and is very linear.

I used a 18Sound driver (sorry ... ) with an 3 inch voice coil. A 18 inch speaker should have a 4 inch voice coil due to cone stiffness.
____________
Peter

[Hoerninger]

Not 18" but there is made a real measurment in comparison to Hornresp:
http://hem.passagen.se/sajberrapid/50hz.html

Each 15" horn can theoretically be shortened to an 18" horn, but it must be checked for irregularities before (Hornresp). This implies a new design in any case.

As long the room is not very big it works more like a compression chamber and there would be another frequency responce (barely predictable).

For real deep bass a horn is extraordinary big. :blink:
____________
Peter

[Jakob]

Thank You for your input. The "cowanaudio"-horn looks awesome!

I dusted of my old K25-horns with Beyma (sorry;)) 12"-drivers last week and the difference in sound compared to my JBL 2243-subs is astonishing. Ok, the low end is more pronounced in the subs and maybe they are more linear, but the horns are so tight and sound very dynamic and crisp. But would an 18"-driver horn be as tight?

regards: JR

[Wardsweb]

I ran two of these bass horns in my system for years. They are similiar design to the cowanhorns. I used 18" McCauley 6174 ultra subs. Due to the design of a horn the drivers don't have to move much at all to move a lot of air. So the 6174's didn't have to use much of it's 2" excursion capability. This translates to a very quick response that could keep up with my Martin Logan CLS electrostats. The bass was tight and filled the room with house shaking (literally) intensity. The picture shows the large size (4'x4'x22"). That is an Altec A7 sitting on top.

http://wardsweb.org/misc/B1side.jpg

[TimG]

If the JBL 2243 has T/S parameters similar to the 2242H it should work fine in the Cowan design. Bruce Edgar uses the JBL 2241H in his subwoofer horns and they won't go as low as the Cowan design. I wrote to him to see if he could send me some response measurements from people who have already built this horn but I haven't heard back from him yet.

[Hoerninger]

... , but the horns are so tight and sound very dynamic and crisp.
That is why I like so much bass horns.


But would an 18"-driver horn be as tight?
The cone has to be stiff. It's easier with a smaller one, and a bigger voice coil. Especially when there is used a compression chamber, most often adviced, pressure is high, so stiffness is required. (But I can't say anything special about an 18" driver.)

Why do you want to use an 18" driver? It's upper frequency limit will be significantly reduced because of increased cone mass.
A modern 15" driver will deliver more than enough sound pressure:

When I was testing the above mentioned horn there came along some pupils - girls - asking what is this about. I said horn speakers - listen. I was just fiddling with a syntheziser and made some tremendous tones around 25-35 Hz. (There was no rattle or recognisable distortion at an unbeleavable level powered by ca. 90 W.) The girls first didn't know what will happen and placed themselfs right in front of the horn.
Screaming "Iiiih!" they run away. :uhmmmm:
____________
Peter

[Thom]

I couldn't give you any titles or authors and you can only do it if you have land and building skills and they were never built around lansing drivers for some reason , frequently university. Also I never saw plans that used an 18 but if you were going to do this that would be a minor inconveience. There were many plans published, maybe Roger Russel would have a copy, of monster horns in the late 40's and early 50's. I mean horns that maybe you could put a spare bed or at least an air mattress in if you had unexpected guests. I remember as a kid, stereo came along while I was a kid. Seeing such things in books and magazines. Most likely this is nothing like what you are looking for, Still if you've got a spare basement and it's under your listening room??? For you real technical types, if you've got a bunch of reasons they never worked, well I never heard one and I'm way to far outside my field of expertise to argue about it,still when I hear base horns I always wonder.

[Jakob]

wardsweb: Is it the driver You see to the right, or is it a frontloaded design as the cowan? Did You build them yourself? Any buildingplans? How high in frequency did you use them?

hoerninger: I'm open to all driversizes. I began thinking of 18" because I have the 2243's and with a Qts of only 0.19, they should be perfect for horn mounting, don't You think?

[spkrman57]

Sounds good for a horn-loaded system!

Ron

[whizzer]

In bass horns, full efficiency is achieved when the throat is equal in area to the diaphragm used to drive it (and when the horn's length is actually equal to one full wavelength of the desired cutoff frequency although the F3 figures usually provided are for 1/2 or 1/4 wave horns--but those, loud as they may be, are not full efficiency horns); in practical terms, this often means that little if anything is to be gained by using a larger diameter driver, for in order to keep size somewhere within shouting distance of reason, part of the driver is "masked off" on order to obtain a "reasonable" throat size. This has several disadvantages, however. First, compression effects are increased, placing greater physical stress on the cone, increasing the risk of mechanical failure as well as non-linear response; second, spurious velocity-induced noise and turbulence are introduced, particularly in the area of sharp bends or "folds" in the horn. Since the cutoff frequency is determined by the length of the horn and the ability to generate coherent low-frequency wavefronts is a function of the mouth size, which is itself determined by the flare rate of the horn, thus by the desired cutoff frequency, output capability and musicality are both enhanced by using a smaller rather than a larger driver and a "full-sized" throat. This is to say, output capability is determined more by the horn itself than by the size of its driver. Horns that are too short generate lower frequencies directly, increasing the the risk of diaphragm failure by reason of the physical impedance presented by the airmass in the mouth of the horn. Some of the more advanced, deepest reaching, and loudest playing bass horns now extant use 10 or 12-inch drivers; the Lab series come readily to mind.

[Hoerninger]

hoerninger: I'm open to all driversizes. I began thinking of 18" because I have the 2243's and with a Qts of only 0.19, they should be perfect for horn mounting, don't You think?

I think so. ;)

Here is a very conservativ simulation for a JBL 2243H.
The TSP I've found in this forum.
There is no vague assumption of the influence of the walls.

The horn is assumed to be in the corner of a big room (angle 0,5 x pi).
The speaker works on a compression chamber (3:1).
Mouth area 6500 cm2
rear chamber 60 liter
Horn length 240 cm
netto volume 596 liter (brutto round about 720 l)
efficiency 110 db /w /m
f low (-10 dB) 31 Hz

If I would own these speakers, I would give them a try. :bouncy:
(I like horns. :blah: )
JBL can very good with horns. (But not everybody can achieve them, there are good reasons for bass reflex designs, there is a hype around other speakers and may be lack of knowledge.)
____________
Peter

PS: I have remembered this link, W-horn with 18" driver JBL 2240H, designed by D.B.Keele (yes, the well known) for JBL:



http://zmatek.jinak.cz/diy/wbin/w.doc