Acoustic lenses

[kelticwizard]

Actually, I remember reading in an old audio book from the sixties that acoustic lenses were used in the study of optics. This would be before 1950, I believe.

So the two are interconnected, although quite a few years back.

Also, the lenses they used back then, as I recall from the text, were series of dots, not plates.

 

[roddyama]

Also, the lenses they used back then, as I recall from the text, were series of dots, not plates.

Circular lenses like this JBL. Different format, same principle.

Rodd Yamashita

 

[kelticwizard]

Roddy:

Yes, that looks just like the drawing from the old book. However, the dot density kept changing at different distances from the driver-I could not tell from the picture if the JBL unit did that.

 

[fdegrove]

BLIND OR DEAF??

Hi,

Having seen the size of your lenses...I can see clearly now...

Thx for the piccie Rod.

 

[roddyama]

Re: BLIND OR DEAF??

Hi Frank,

Having seen the size of your lenses...I can see clearly now...

Thx for the piccie Rod.

The pic in the previous post is from eBay. Below is a pic of my speakers.

TMC,

You can see my implementation of the L91 lens. The 2312 horn is tightly wrapped with heavy rubber. I still have the JBL level pot in until I get it where I like it. Then I'll replace the pot with Caddocks (not an issue for your application).

Rodd Yamashita

 

[fdegrove]

IMPRESSIVE STUFF!

Hi,

Wow,that stuff is BIG!

The ones I had from JBL were for a tweeter (4502?).

Rodd,

If my brother in law would walk into your living rooom he would go straight to the lenses and ask you why you put those heaters so high up.

Cheers,

 

[tmc]

hi ya'll,
Nice looking horns you got roddyama,
and thanx for the clarification on the optics/acoustic issue
Kelticwizard....my dad was involved with microwave tech. way back when ( civil service ) and i have some of his old ref material for that and numerous other projects he was involved with, anywho some of the repeater rigs used GIGANTIC horns of intresting shapes....the optics reference came from one of his old ref. manuals , now, if only i were as smart as he was!
I also remember a series of science books that had all sorts of lenses set up for a pictorial representation of the effects a lense will have on various freqs using strobes and fog and captured on film....the bad thing is those books are packed up somewhere and the task of going through all the books my dad had ids a daunting one........one of these days i'll dig it up and post them .