Western Electric 1928 - WE 555 Dissect, Design, DIY?? - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 4th June 2012, 02:07 PM   #11
diyAudio Member
 
speaker dave's Avatar
 
Join Date: Nov 2009
Location: The Mountain, Framingham
Quote:
Originally Posted by bear View Post

Afaik, almost all the compression drivers operate below their fundamental resonance frequency when loaded with a horn. I find that a bit confusing, but iirc this is correct...

_-_-bear
Yes, I believe you are correct on this. The resonance is revealed in the impedance curve and can be more in the middle of the band.

We are fairly conditioned by our understanding of direct radiators, while horns are different. With a horn the air load is flat (for an ideal horn) rather than rising as it does with a small piston, and constant velocity gives flat radiated power.

Getting wider range out of a horn system still requires more than just a larger horn. Higher excursion with low distortion is still required from the compression driver.

David
  Reply With Quote
Old 4th June 2012, 07:04 PM   #12
Bill F. is offline Bill F.  United States
diyAudio Member
 
Bill F.'s Avatar
 
Join Date: Nov 2001
Location: SW MI
Quote:
Originally Posted by bear View Post
Ron, I suspect the stiffness and the mass of the surround is an important design criterion?
Playing with my Hornresp model of a WE555 on a 15ft. expo flare, I noticed something interesting about the diaphragm suspension compliance. Once when I mistakenly had the compliance set two orders of magnitude too high (too soft), I found that it made hardly any difference at all in the system response.

The air load entirely swamps the effect of the diaphragm compliance up to a certain break point.
  Reply With Quote
Old 4th June 2012, 07:13 PM   #13
diyAudio Member
 
myhrrhleine's Avatar
 
Join Date: Jan 2006
Location: Avalon Island
So, could we start with an off the shelf driver and go for maximum excursion?
Maybe maximum SPL @ 500 HZ?
__________________
Just because you can't hear it doesn't mean no one can.
  Reply With Quote
Old 4th June 2012, 07:18 PM   #14
Hentai is offline Hentai  Romania
diyAudio Member
 
Join Date: Nov 2006
Because it operates below resonance, suspension has a more critical role in compression driver than direct radiators i believe.
If we look at the equivalent electrical circuit we can see that below resonance the driver is controlled by its suspension system. In my mind the best solution is to use mylar. It's also pretty easy to source Ti diaphragms with mylar surround.
Because the diaphragm is very hard to make at DIY level, i think design work should start from here. From available dia to work down to motor structure which can be made accordingly to the WE555.
Designing a phase plug for an available dia will take most of the time. I have found Axidriver to be a very useful tool. Example of a diaphragm/phase plug assembly below:
Click the image to open in full size.

Parameters that need consideration once a diaphragm diameter is considered, are dome height and compression chamber height.
Although PP structure has evolved ( to better or worse results :P) i find Henricksen's paper a good start:
Henricksen_1978_Tangerine_PP.pdf
  Reply With Quote
Old 5th June 2012, 12:17 AM   #15
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
the 555 does not use the "modern" slit type phase plug...
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 5th June 2012, 05:56 AM   #16
Hentai is offline Hentai  Romania
diyAudio Member
 
Join Date: Nov 2006
yes, of course, my pic was just an example for the software. The WE555 type of phase plug (which is still common today i believe) can also be modeled easily adjusted to the shape of today's diaphragms.

Click the image to open in full size.
  Reply With Quote
Old 14th June 2012, 11:55 PM   #17
Banned
 
Join Date: Apr 2012
Wow Bear , this thread is really active.
  Reply With Quote
Old 16th June 2012, 01:15 AM   #18
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
it's my fault/job?
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 16th June 2012, 12:13 PM   #19
Banned
 
Join Date: Apr 2012
You catch on quick.

I really wanted to see this thread go somewhere, it is very interesting.
  Reply With Quote
Old 16th June 2012, 03:01 PM   #20
DavidL is offline DavidL  United States
Banned
 
Join Date: Jul 2010
How can what has already been beat to death go any further? Is anyone going to actually build a 555 type driver or is this just a mental exercise? After the previous 1000+ post thread I think everyone got what needed to be said ..........said.
  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
Western Electric 1928 - How far have we come in the last 100 years? JZatopa Multi-Way 1050 15th May 2013 07:34 PM
Western Electric Transistors simon7000 Swap Meet 2 14th May 2012 10:59 PM
Western Electric 374A john Tubes / Valves 4 21st December 2005 03:17 PM
Western Electric 300B serengetiplains Tubes / Valves 4 16th December 2004 06:16 PM
Western Electric PassFan Tubes / Valves 0 26th April 2003 01:09 PM


New To Site? Need Help?

All times are GMT. The time now is 09:07 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2