Acoustic Lens = Karlson etc ? - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 21st June 2015, 04:24 AM   #1
Zero D is offline Zero D  United Kingdom
diyAudio Member
 
Join Date: Aug 2009
Lightbulb Acoustic Lens = Karlson etc ?

Att. freddi et al

Hi, i thought you might find this interesting. I see some similarities between the two.

Quote:
High frequency power dispersion and amplitude response

1. "The power response should be as flat and smooth as possible relative to the free field frequency response
2. "Strong floor and ceiling reflections should be avoided
3. "Strong reflection off the wall directly behind the loudspeaker should be avoided"[8]

The device that is used to accomplish this is called an “Acoustic Lens.” It is a scalable reflecting device that fits over a conventional treble dome tweeter or mid-range driver, which is facing upwards. It was invented by Manny LaCarrubba of Sausalito Audio Works, and is licensed to Bang & Olufsen

Moulton Laboratories :: A new loudspeaker design

The Acoustic Lens

The effect of the lens is to distribute energy emitted from the driver (which is facing upward) across 180 horizontally and approximately 30 vertically (angled approximately 15 upwards). Other properties of the lens permit the lower crossover point of the driver to be lowered in frequency, extending the effective range of the driver and permitting the relative directivity of the two drivers at the crossover frequency to be evenly matched.

Moulton Laboratories :: A new loudspeaker design
Wonder how they got a patent, "if" it's not actually totally new ?
  Reply With Quote
Old 21st June 2015, 04:52 PM   #2
freddi is offline freddi  United States
diyAudio Member
 
freddi's Avatar
 
Join Date: Aug 2005
looked at those for years and Paterick Bateman's YouTube videos - another useful lens would be the old slot tweeter type such as the discontinued Selenium ST320 - it was quite even in the horizontal plane http://www.selenium.com.br/sitenovo/...os/ST320_p.pdf
  Reply With Quote
Old 21st June 2015, 10:45 PM   #3
Zero D is offline Zero D  United Kingdom
diyAudio Member
 
Join Date: Aug 2009
@ freddi

That's a slot tweeter, which seems like a different concept ? Fane used to make them, & a bullit version too. I installed a number of them over the years into various systems. The slot was about 110dB & the bullit about 112dB @ 1W. The slot was a bit smoother sounding, but both were good, if xovered correctly & not over driven ! None ever burnt out. Pity they don't make them anymore.
  Reply With Quote
Old 21st June 2015, 11:36 PM   #4
xrk971 is online now xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Sausalito Audio Works (SAW) acoustic lens is very different than Karlson aperture. It's for high frequency and acts as both a reflector optic like an off axis parabola and a diffraction lens at same time. K aperture really does provide some amazing wide dispersion. My measurements of polars of a driver behind a K aperture such as in the XKi or the Kazba are truly amazing. However, the K aperture will introduce dips and coloration. However it is not offensive.

XKi - X's ab initio Karlson 6th Order Bandpass

Rockin' the KaZba Dipole (K aperture Z-baffle Dipole)

Last edited by xrk971; 21st June 2015 at 11:39 PM.
  Reply With Quote
Old 24th June 2015, 11:42 AM   #5
Zero D is offline Zero D  United Kingdom
diyAudio Member
 
Join Date: Aug 2009
@ xrk971

Hi & thanx for posting. I realise the SAW designs are HF & reflectors etc. I just thought that the shape of the openings were similar, & if enlarged & placed over a bigger driver, it would more or less equate to a K type design, in that respect anyway.
  Reply With Quote
Old 24th June 2015, 07:50 PM   #6
freddi is offline freddi  United States
diyAudio Member
 
freddi's Avatar
 
Join Date: Aug 2005
I've love to try that lens but can't make the shallow 1/4 ellipse cavity in a good way. That cavity's depth is about 1/2 of the diaphragm's diameter - Patrick Bateman's rough mockups sound very good. Here's an old related patent
(reminds me of a urinal )

https://docs.google.com/viewer?url=p.../US2643727.pdf
  Reply With Quote
Old 24th June 2015, 09:52 PM   #7
Zero D is offline Zero D  United Kingdom
diyAudio Member
 
Join Date: Aug 2009
@ freddi

1950 ! Another very old invention that got rediscovered etc
  Reply With Quote
Old 25th June 2015, 02:45 AM   #8
freddi is offline freddi  United States
diyAudio Member
 
freddi's Avatar
 
Join Date: Aug 2005
the basic idea goes back further - but 1927 is recognizable in function
https://www.google.com/patents/US1786279
Click the image to open in full size.

Last edited by freddi; 25th June 2015 at 02:49 AM.
  Reply With Quote
Old 26th June 2015, 06:13 AM   #9
Zero D is offline Zero D  United Kingdom
diyAudio Member
 
Join Date: Aug 2009
@ freddi

Amazing ! That was also reinvented in later years too
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Enhanced L91 Acoustic Lens for JBL / Selenium / PRV WG14-25 (1"), WG14-50 (2") Horn. TomHinton Swap Meet 1 5th January 2015 07:24 PM
Acoustic Lens whgeiger Multi-Way 3 12th December 2011 11:13 AM
Karlson HF waveguide tweeter lens freddi Multi-Way 0 22nd August 2007 01:12 PM
Helper tweeter lens via ~Karlson idea "THE KUP" freddi Full Range 0 25th November 2006 06:54 PM
DIY acoustic lens jmikes Multi-Way 1 13th January 2005 11:12 PM


New To Site? Need Help?

All times are GMT. The time now is 04:56 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2