La Scala Horn

[D-MAN]

Gil, I originally posted that.

It is from here (under SITEMAP/SUPPORT/BASS HORN DESIGN):

http://www.bd-design.nl/

The author references Plach and D.B Keele, two well-known sources.

Also, see my latest post on this very subject in the following thread:

http://forums.klipsch.com/forums/5/633004/ShowThread.aspx

Other sites of interest concerning some acoustics and horn theory:

http://www.kettering.edu/~drussell/GMI-Acoustics/Filters.html

http://world.std.com/~griesngr/

http://www.lenardaudio.com/education/07_horns.html

Dana

[ajsons]

couldn't you do this by removing the dog house access panel and make a base per your diagram. Alloing the lascala to operate normally from the front of the driver, and having the rear of the driver project to the floor.

The horn will not function "normally" from the front 'coz now you don't have a compression chamber.

My understanding is that the compression chamber in a horn loaded woofer is actually the area in front of the woofer. see attached diagram and look at area vf indentifed as a compression chamber. While I was in europe from 86 to 89, I did a lot of work recovering and re-directing sound waves from the "enclosed" area of speaker cabinets. In this particular senerio, a base bin with an open side, fitted with a horizontal baffle 3/4's the lengths of the base bin, angled as the horrizontal baffle used in the electrovoice aristrocrat, would recover some of the waves while not canceling out the waves from the front. The idea of turning a lascala around and directing the waves into a corner or floor, would result in loss of some of the waves in the mid-bass area.

I'm completely aware of THAT compression chamber. Most people don't know that the REAR chamber is also called a compression chamber (see attached), and as far as the La Scala, Klipschorns, etc. etc., it must be completely airtight for reasons stated in the attached pages.

What you are describing may work for an Aristocrat, which was specifically designed with that in mind. I doubt that it will work for a La Scala, as it will be a serious LEAK. I will expect a drop in efficiency and loss of the bass frequencies.

Spill and recovery is not for me.

[ajsons]

These pages are from A. Cohen's "Hi-fi Loudspeakers and Enclosures"

[ajsons]

Third page.

[Guest " "]

couldn't you do this by removing the dog house access panel and make a base per your diagram. Alloing the lascala to operate normally from the front of the driver, and having the rear of the driver project to the floor.

The horn will not function "normally" from the front 'coz now you don't have a compression chamber.

My understanding is that the compression chamber in a horn loaded woofer is actually the area in front of the woofer. see attached diagram and look at area vf indentifed as a compression chamber. While I was in europe from 86 to 89, I did a lot of work recovering and re-directing sound waves from the "enclosed" area of speaker cabinets. In this particular senerio, a base bin with an open side, fitted with a horizontal baffle 3/4's the lengths of the base bin, angled as the horrizontal baffle used in the electrovoice aristrocrat, would recover some of the waves while not canceling out the waves from the front. The idea of turning a lascala around and directing the waves into a corner or floor, would result in loss of some of the waves in the mid-bass area.

I'm completely aware of THAT compression chamber. Most people don't know that the REAR chamber is also called a compression chamber (see attached), and as far as the La Scala, Klipschorns, etc. etc., it must be completely airtight for reasons stated in the attached pages.

What you are describing may work for an Aristocrat, which was specifically designed with that in mind. I doubt that it will work for a La Scala, as it will be a serious LEAK. I will expect a drop in efficiency and loss of the bass frequencies.

Spill and recovery is not for me.

If that were true, the ported base bins for the lascala's would be a failure. Measurements by folks who tried it report sepcific db increases at the expected tuned frequency.

The volume in the dog house of the lascala is a by product of the targeted foot print and not a design restraint. There have been countless variations of the w-bin implementation years before the lascala came into the picture. Some have ports, some have vents, some are not even totally enclosed.

[ajsons]

You said the magic word....tuned.

[WMcD]

Thanks for the info.

Gil

[Bill Cain]

Any thoughts on the distance from the adjacent walls to the front of the cabinets(shoved into the corner at 45) outer edges(horn mouth)one would desire to continue the mouth/flare in a somewhat close to ideal manner? Once this is determined, I will construct the reflector to the needed size to come close to the front(back)of the cabinet.

Oh, one more thought. I assume we would also want to seal off the top of the bass horn with a wedge running from the front bottom edge of the top section into the corner, like the Khorn right? So, the reflector/splitter would be the height from the floor to the top of the bass bin and the sealing wedge would go from the front of the La Scala and rest on top of the reflector/splitter in the corner. Otherwise we will have waves escaping out the top vertically. Am I making sense?

The flair rate of the effective horn, created by the walls, floor, cabinet and top wedge is a constant determined by the position of the cabinet in the corner. (The "top wedge" is a mirror image of the floor.)

The tricky part will be the corner reflector.

The reflector might well extend deeply into the La Scala bass bin in order to reduce the flair rate before the transition to the "wall horn." Imagine a hinged "wing," attached to each side of the back of the compression chamber corner. That wing could reduce the flare rate until you reach the reflective surface that re-directs the sound, almost 180 degrees, to exit the horn.

I envision working backwards, from the wall horn, into the "back" of the La Scala bass bin, so that the flair transition is smooth and relatively constant.