Acoustical Lens use questions

[m8o]

Hi all,

I have a couple of questions regarding Acoustical Lenses that I'm hoping someone can help me with. (please pardon, I'm a newbie in regards to this particular aspect of the pro JBL offering)

I have a question regarding the Lenses covered in this document:
http://www.jblpro.com/pub/obsolete/Acoustic_Lens_Family1.pdf

1) Do the Horns known as the "Potato Mashers" work on their own as is with just the stepped-concave screen visible within them, or are they supposed to also be used/coupled along with the folded or slant plate acoustical lenses in that document above?

2) Does the plate lens, model 2310, "do it thing" of providing diffusion with only specific JBL horns they are made to work with (as in the 2309), implying they have a specific type of horn expansion, or will it work with a wide range of horns? ...and my most important question, which I'm hoping is not a "no no" to ask here, but will it work with the Klipsch K400/K401 horn used in the La Scala speakers if I put tje 2310 in front of them?
(this speaker: http://www.klipsch.com/products/details/la-scala-ii.aspx )

A very common thing done with the bigger K-horn is to mate it to an Altec mid horn, and use a JBL 2404 tweeter. The La Scalas don't get a lot of mods though. Aso I've inexplicably always wanted a speaker with the plate lenses for decades since 1st seeing it, I am thinking about mod'ing my mid horn with one. No kloo of the science. I'm hoping someone here can help.

I may change the mid horn too from the venerable but problematic K401 used in my speaker if using the Lens really requires it (K401 has a very narrow throat to increase pressure, but that increases distortion I understand). That would however mean I raise the x-over frequency about an octave, as the La Scala x-over to the bass horn is 400 right now; the bass horn can do 800, but that's out of its comfort zone.

Thanx for your thoughts,
Steve

edit: corrected K70x to K40x

[Thom]

I'm no expert, but I can tell you that the potato masher is self contained.

I've read theory on the slant plate and wave plate, and it seams like they should have effect with any horn. At least to some extent. But, if someone more expert counters that, smart money might be on them.

[Robh3606]

Hello m8o

Take a look at this as it will help explain a bit about how they work

http://www.lansingheritage.org/html/jbl/reference/technical/lens.htm

Thom right the Masher is a stand alone as the grid is the lense. The only issue I see about using the lenses with another horn are the actual horn dimensions. They seem to be about 2X the horn mouth width but you should double check that in the spec. sheets. If the K horn is the same or similar size it should work. If it is too wide I don't think it will work properly. Another thing to consider is you need some baffle area to load the horn/lense combo. If I remember the K midrange horn there is very limited baffle area available so you may have to do some mods.

I use the smaller serpentine lense on my 4344's. Like the way it looks!!

Rob:)

[m8o]

Thank you. Great reading.

I discovered this wonderful section too, where I now visually see the same as described above regarding the Potato Smasher (ok, they're out then for my need) http://www.lansingheritage.org/html/jbl/specs/jbl-specs.htm

Yes, the La Scala's mid-horn is probably too wide then as it's just a tad narrower then the lens. But I'm still going to give it a shot and take some measurements.

[Maron Horonzakz]

In taking measurments...You will need to make polor plots to see how even the dispersion angle is.