Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Baffle Diffraction
Baffle Diffraction
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 8th January 2018, 07:20 PM   #21
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä, Finland
Cones and domes have very different off-axis radiation pattern from planars! And soft vs rigid cones have different patterns. In real world, it is very hard to find a driver that behaves like a simulation model or has flat response.

Klippel Online Training

Click the image to open in full size.

I made a quick and dirty test with a cone in open baffle off-axis vs. The Edge. Besides the ripples in unequalized response, directivity change off-axis looks pretty much the same!
Attached Images
File Type: jpg edge vs measurement 0 30 60¤.jpg (304.3 KB, 345 views)
__________________
AINOgradient speaker project
  Reply With Quote
Old 8th January 2018, 07:51 PM   #22
Oneminde is offline Oneminde
diyAudio Member
 
Join Date: Jun 2014
Quote:
Originally Posted by scottjoplin View Post
Not really, special delayed crossfeeds can fix that.
Care to go under the surface just a bit on that ?
  Reply With Quote
Old 8th January 2018, 08:02 PM   #23
kimmosto is offline kimmosto  Finland
diyAudio Member
 
Join Date: Oct 2005
Location: Kuopio
Quote:
Originally Posted by Juhazi View Post
I made a quick and dirty test with a cone in open baffle off-axis vs. The Edge. Besides the ripples in unequalized response, directivity change off-axis looks pretty much the same!
What is the point of this? Some kind of response to my message?
  Reply With Quote
Old 8th January 2018, 08:03 PM   #24
gedlee is offline gedlee  United States
diyAudio Member
 
gedlee's Avatar
 
Join Date: Dec 2004
Location: Novi, Michigan
Quote:
Originally Posted by AllenB View Post
By rounding the baffle you give the waves something to (partially) follow so the diffraction happens gradually.. but by using absorbing material on the baffle you are doing almost the same thing through different means.
You should keep in mind that absorption material is almost ineffective for sound traversing at a grazing incidence. Hence, for all practical purposes the felt, or whatever, doesn't do a heck of a lot. Corner radii are much more effective.
__________________
Earl Geddes Gedlee Website
  Reply With Quote
Old 8th January 2018, 08:09 PM   #25
scottjoplin is offline scottjoplin  Wales
diyAudio Member
 
scottjoplin's Avatar
 
Join Date: Dec 2015
Location: Penrhyndeudraeth
Quote:
Originally Posted by Oneminde View Post
Care to go under the surface just a bit on that ?
Something to chew on Head-related transfer function - Wikipedia
__________________
Woofer Assisted Wideband is the New Testament renounce the anachronistic acronym FAST
  Reply With Quote
Old 8th January 2018, 08:56 PM   #26
Oneminde is offline Oneminde
diyAudio Member
 
Join Date: Jun 2014
Quote:
Originally Posted by AllenB View Post
You keep mentioning what you want the baffle not to do, but what do you want it to do for you? Are you going to let it make a mess and fix it with absorption? Do you want imaging or spaciousness or both?
That one is simple - I think . I want the baffle to be acoustically transparent, no interference or conflicting waves of cancellation.

Imaging is solved by:

1. Driver placement or distance to one another, for the tweeter and midrange, the closer they are the better but since each tweeter model behaves differently, the optimum distance must be experimented with. The larger the woofer is the less imaging you can control, so woofer size dictates if the position is important or not.
2. The other part is the height of the tweeter and midrange. Traditionally the tweeter height is placed with a person sitting down as the frame of reference, so and average position of 980-1100 mm is often used, but this also depend on if its just MT or MTM configuration.
3. Baffle size and shape as we've talked about.
4. Crossover: Time alignment & Baffle Step Compensation (BSC).
5. Distance between the loudspeakers, toe in/out and tilt is often neglected as a very important part of imaging or spaciousness - Room related.
6. Room Acoustics.
7. Last but not least, a DSP can address some of the issues a loudspeaker has.

Did that answer your questions ?
  Reply With Quote
Old 8th January 2018, 09:20 PM   #27
AllenB is online now AllenB  Australia
diyAudio Member
 
Join Date: Oct 2008
The reason it has been suggested that headphones can image is the relative lack of non-direct energy. You speak of the size of the sources, or the collective of sources. As diffraction also becomes a source, and one that has uniquely identifiable properties such as time delay and angle to the listener it can be an issue that affects imaging. I don't necessarily agree about the driver size. Some of your other points refer to room reflections which should similarly be taken into account.

Why will you choose to begin with a flat baffle?
  Reply With Quote
Old 8th January 2018, 09:29 PM   #28
Oneminde is offline Oneminde
diyAudio Member
 
Join Date: Jun 2014
Quote:
Originally Posted by AllenB View Post
Why will you choose to begin with a flat baffle?
I have enough engineering skills to work with other geometrical shapes, but they dictate a completely different construction method and hence will cost more and require other tools, jigs etc. A straight answer to how can't be given since that totally depend on shape(s) and choice of materials which there are plenty to choose from, aka casting, milling, lamination or a combination of them all.

One might say that me exploring the ideas of damping and diffusion of an apparent flat surface is an effort to bypass more complex shapes.

PS: Time consumed during development should not be correlated to fixed production methods as they are very different in all cases.
  Reply With Quote
Old 8th January 2018, 09:42 PM   #29
planet10 is offline planet10  Canada
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Baffle Diffraction
Quote:
Originally Posted by Juhazi View Post
WE have at least two published diy-copies of it
Not a copy, but inspired by, and borrowing the name “ellipsa” from the smaller one.

Click the image to open in full size.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 8th January 2018, 09:44 PM   #30
scottjoplin is offline scottjoplin  Wales
diyAudio Member
 
scottjoplin's Avatar
 
Join Date: Dec 2015
Location: Penrhyndeudraeth
The tempting thing to do with a wide shallow speaker cabinet is to place it right against the front wall
__________________
Woofer Assisted Wideband is the New Testament renounce the anachronistic acronym FAST
  Reply With Quote

Reply


Baffle DiffractionHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Baffle edge diffraction vs baffle step skogs Multi-Way 47 21st August 2016 05:15 PM
Best material for baffle to help diffraction? Stewart Holmes Multi-Way 35 15th February 2014 02:40 PM
Edge diffraction: large, rounded baffle, or narrow square baffle fortyquid Multi-Way 23 12th February 2013 02:23 AM
Qs about baffle diffraction elambert Multi-Way 1 30th November 2005 09:09 PM


New To Site? Need Help?

All times are GMT. The time now is 10:05 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki