Beyond the Ariel - Page 856 - 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 28th March 2013, 03:46 PM   #8551
nuconz is online now nuconz  United States
diyAudio Member
 
Join Date: Jan 2006
Location: central north florida
i'm also wondering if there is a possible relationship between baffle size and f3 in system repsonse.

anyway, at some point in the future i hope to have a speaker system that 'blends' into the home without actually having a cave. people boast that systems integrated into the walls sound vastly superior to free standing ones and you don't have to dust around them!

oh yes, and you don't have to worry about 'how wide is enough'?

Last edited by nuconz; 28th March 2013 at 03:47 PM. Reason: omission
  Reply With Quote
Old 28th March 2013, 03:55 PM   #8552
diyAudio Member
 
Kindhornman's Avatar
 
Join Date: Aug 2012
Location: Los Angeles, California
nuconz,
Yes a speaker in the front wall makes things much easier to understand and takes away many factors of room reflection. It is as close to an infinite baffle as you can do. If it is open in the back then that is one way to do it. but if it is a closed box in the wall you will have to determine the correct enclosure size and if a bass reflex design the proper port size. And wives love it when the speakers disappear from the room so to speak.
  Reply With Quote
Old 28th March 2013, 05:30 PM   #8553
nuconz is online now nuconz  United States
diyAudio Member
 
Join Date: Jan 2006
Location: central north florida
Quote:
Originally Posted by Kindhornman View Post
nuconz,
Yes a speaker in the front wall makes things much easier to understand and takes away many factors of room reflection. It is as close to an infinite baffle as you can do. If it is open in the back then that is one way to do it. but if it is a closed box in the wall you will have to determine the correct enclosure size and if a bass reflex design the proper port size. And wives love it when the speakers disappear from the room so to speak.
hope to have it open into the utility/laundry area. with some hardware cloth around the back to keep 4 legs from playing with the drivers and some good padding about, should be about right. maybe a couple of the dayton ib woofers will do good.
  Reply With Quote
Old 28th March 2013, 05:41 PM   #8554
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
The horn I will be trying first is wooden Iwata 290. It has a width of about 25". The original plan was to have the baffle flat for about 16-17" and then have it follow the contour of the Iwata. This would give me a wide baffle as well as large, smooth round over. The back will be slightly swept back. Haven't decided whether to make it straight or curved side.
__________________
...Shape the sound , Man!
  Reply With Quote
Old 28th March 2013, 05:45 PM   #8555
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Quote:
Originally Posted by buzzforb View Post
The horn I will be trying first is wooden Iwata 290. It has a width of about 25". The original plan was to have the baffle flat for about 16-17" and then have it follow the contour of the Iwata. This would give me a wide baffle as well as large, smooth round over. The back will be slightly swept back. Haven't decided whether to make it straight or curved side.
Similar to this.

Wardsweb DIY 3-way horns
__________________
...Shape the sound , Man!
  Reply With Quote
Old 28th March 2013, 06:11 PM   #8556
diyAudio Member
 
Kindhornman's Avatar
 
Join Date: Aug 2012
Location: Los Angeles, California
Buzz,
That will work well for the horn but what about the direct radiator. It is much better than a square corner that is for sure and would help with the cone speaker also. That was a major consideration when I built the speakers in my avatar. Each horn has a radius around it and blends into curved sides ending with a curved back. This was something I did before B&W came out with their enclosure with the extended rear flares on their snail enclosure. Funny how people laughed when they first saw the design and then loved it when B&W took the concept and built their enclosure after me.........The bottom section is a down firing bass speaker that went with the top horns and limited the diffraction problem and any floor bounce from the driver.
  Reply With Quote
Old 28th March 2013, 06:15 PM   #8557
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
The direct radiator is what I was describing. It will be if I cut convex shape for entire baffle, then took out a slice that is flat and 17" wide. What reservations do you have? The horn will maintain its shape .
__________________
...Shape the sound , Man!

Last edited by buzzforb; 28th March 2013 at 06:17 PM.
  Reply With Quote
Old 28th March 2013, 06:21 PM   #8558
diyAudio Member
 
Kindhornman's Avatar
 
Join Date: Aug 2012
Location: Los Angeles, California
Buzz,
I thought that you were direction your attention only to the horn mounting. I think what you are proposing is fine. Could you just leave the majority of the curvature to the face and make a minimal recess to blend the edges of the frame into the curvature? It would perhaps take some hand carving but you could have a nice contour around the frame.
  Reply With Quote
Old 28th March 2013, 06:42 PM   #8559
diyAudio Member
 
Join Date: Apr 2005
Location: Sitting behind the 'puter screen, in Illinois, USA, planet earth
Hi Kindhornman
So far as the baffle dimensions, if your source is too small to have it’s own directivity (simple radiation is a good thing generally), then you can treat a flat baffle just like a horn (a baffle less than 180 degrees).

This is possible because the way sound propagates from a source and behaves over a boundary is the same in a horn or flat baffle, only the words are changed to obscure the innocent as they used to sort of say..

Just as a horn has a point (dimension vs frequency) where the impedance transformation ceases (when the horn > K=1 or about 1WL in circumference) and at a much larger dimension where the directivity is controlled.

From that it is interesting to note that at 20KHz, ALL of the impedance transformation has taken place within the compression driver well before reaching the 1” exit into the horn and a 1” exit “large enough” to already confine the radiation to about 60-80 degrees within a horn..

For a flat baffle or simple horn, Don Keele’s thumb rule for pattern loss frequency still holds true.

The pattern loss F goes down with increasing size and increasing angle, for example, a 20 inch wide 90 degree horn has a pattern loss F about an octave higher than a 20 inch wide flat baffle and a 20 inch wide 45 degree horn has a pattern loss F about an octave higher than the 90 degree horn.

The same pattern control point moving back into the horn is why so many curved wall horns have narrowing directivity with increasing frequency.
Anyway, the thumb rule appears first in Don’s paper here;

http://www.xlrtechs.com/dbkeele.com/...xp%20Horns.pdf

Best,
Tom
__________________
Bring back mst3k and futurama
  Reply With Quote
Old 28th March 2013, 07:08 PM   #8560
diyAudio Member
 
Kindhornman's Avatar
 
Join Date: Aug 2012
Location: Los Angeles, California
Tom,I was really trying to just throw out hypothetical's so others would have to think about the problems. I wasn't thinking much about horns, just direct radiators on a flat front baffle. Yes we can look at the baffle as a 180 degree horn, but if the baffle isn't much wider than the direct radiator it isn't really adding much in the way of directivity.

I haven't looked at one of Keele's books in a long time. I found in the past some of what were in earlier books were just repeats of incorrect information that many would site. Don't ask for a specific instance I don't remember any more.
  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



New To Site? Need Help?

All times are GMT. The time now is 10:56 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