DCAudioDIY.com

DC Area Audio DIYer's Community
It is currently August 20th, 2018, 10:13 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 22 posts ]  Go to page Previous  1, 2, 3
Author Message
PostPosted: December 16th, 2017, 11:47 am 
Offline
User avatar

Joined: April 20th, 2014, 5:21 pm
Posts: 233
Here are copy diffusers fror the Eurodyn from the same Korean guy.

https://www.ebay.com/itm/Acoustic-Lens- ... Sw0hlZL~lL

They look like a less aggressive version of JBL Acoustic Lens but these predate JBL by decades.

A similar diffuser was used on the Siemens 10" full range cone, a general purpose speaker like the Altec 755A, made from the 1950s-70s. The end result looked a lot like the 1950s General Electric 12" with the "grills," if you ever saw those.

The Eurodyn module was typically bolted into a large flat baffle, like 8' high, 4' wide for theater installations, a pre-Roscoe OB setup.

German theater gear was great equipment that never made it to the US. Most of it is in Japan and Korea now.


Top
 Profile  
 
PostPosted: December 16th, 2017, 12:51 pm 
Offline

Joined: July 17th, 2016, 6:24 am
Posts: 419
German shop is closed today. Shall try calling again on Monday.

Found Bruce Edgar's interview with Positive Feedback.

Quote:
When you talk through the exponential horn, people can hear the coloration to your voice, which is a certain resonant quality that wasn't there before. You talk through a Tractrix horn and you don't hear it. It's completely open.

The explanation goes back to the difference between spherical and plane waves. When the plane waves travel down to the end of the mouth of the exponential horn, suddenly there's a bulge where they exit into space, and that bulge is essentially a discontinuity. So, you have reflections at the mouth, which travel back to the throat and set up a quarter-wavelength resonance condition. With the Tractrix horn, since the waves are spherical going through the horn, they exit the mouth with very few reflections. When I first started building Tractrix horns, I heard this immediately. They didn't have the same horn colorations I'd heard before.


https://positive-feedback.com/Issue4/edgarinterview.htm

Expo is good for low frequencies and Tractrix for mids and highs.

_________________
Shashi


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 22 posts ]  Go to page Previous  1, 2, 3

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 9 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group