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

How to design a dipole surround speaker
How to design a dipole surround speaker
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 27th October 2013, 09:43 AM   #1
Baldin is offline Baldin  Denmark
diyAudio Member
 
Baldin's Avatar
 
Join Date: Jan 2005
Location: Copenhagen
Default How to design a dipole surround speaker

I'm the happy owner of a complete JBL HT1 speaker set. I use the HT1F as rear in a 7.1 setup, and the HT1D as sides. I use my own center and front speakers, and I have built the subs into other boxes.

The interest here is the dipole HT1D speakers. They are placed on the sides directly out from the listening position.
It imploys a vented design and goes to 110 Hz according to JBL.
Though I think they work well, there is always a thought of upgrading

Have searched the net for diy constructions of a dipole surround speaker, without much luck.

Not really sure about the requirements either. How low frequency is it going to see? ..... of course cant find any good information on THX requirements ...... seem the proffesional speakers for cinema use go down to btw. 40 and 60 Hz .....

As a dipole, if nothing special is done, then it will fall rapidly at something like F = 0.17*c/D, where c = 343 m/s and D is the distance btw the opposite speaker units (in meters) (according to Linkwitzlab.

As mine go down to 110 and uses a port something must done in the crossover ot handle this .... not sure how.

Some uses an extra single bass .... guess below the dipole frequency mentioned abowe ..... some (e.g. Jamo) uses also long cabinets to increase D and thereby lower ths frequency.

Any of you have any experience with such designs?
Does anyone have some links / articles / other information on the subject ..... or schematic on crossover design etc.

Could be really fun to build something which really works, and which sounds better than my old speakers without costing a fortune .... anyone game??

Regards Baldin
Attached Images
File Type: jpg HT1D wall.jpg (5.2 KB, 443 views)
File Type: jpg jbl-ht1d.jpg (4.7 KB, 440 views)
  Reply With Quote
Old 27th October 2013, 10:22 AM   #2
sreten is offline sreten  United Kingdom
R.I.P.
 
Join Date: Nov 2003
Location: Brighton UK
Hi,

You won't find decent dipole designs because the design
process reveals how seriously flawed they really are.

Quote:
Zaph
Any chance of designing bipole and/or dipole surrounds?
No chance of that, and I recommend a ZA5.2 monopole for surrounds. The reason is that typical bipole and dipole surround speakers are seriously flawed designs, and the issues can be very audible in most installations. With dipole, generally 2 woofers and 2 tweeters are mounted in an angled cabinet and wired out of phase. If you sit exactly on axis, it's a full null in response and all you get is a reverberant sound field comprised of the systems's flawed power response. Interesting and sometimes freaky spacious sounding, but not at all realistic. Going off axis, even slightly, will result in a seriously combfiltered frequency response. Bipole surrounds have similar issues except that they will only sound normal on axis. Off axis, comb filtering shows up fast, particularly if the design has two tweeters. A final bit of information is that most mixing and mastering studios use monopole surrounds because studio designers are also well aware of the problems of bipole and dipole designs. The commercial hifi market is loaded with bipole and dipole surrounds because people keep buying them.
rgds, sreten.
  Reply With Quote
Old 27th October 2013, 10:44 AM   #3
Baldin is offline Baldin  Denmark
diyAudio Member
 
Baldin's Avatar
 
Join Date: Jan 2005
Location: Copenhagen
I think it's about compromises .....
A monopole speaker as surround in a small room will I think, always be "detectable" and "pointy" .... In a large cinema this is not a problem as you achieve far field ...

To say it's simply no good I think is just a bit too fast .....
Still required by THX .... and you can of course always just say that they dont know what they are doing ..... which would also be a bit too fast I thing ....

What dipoles do you have experience with?

I think in my room, no matter how I would place the surround speakers, they would always be too close and to dominant ....

So how could we design a dipole with better power responce??

best regards Baldin
  Reply With Quote
Old 27th October 2013, 06:34 PM   #4
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä, Finland
I have never understood why anyone wants to make "dipole" or bipole surround speakers! The Dolby Surround or THX or any concept use only monopole speakers. Mixing studios use monopoles. Multichannel preamplifiers have a setup scheme where speaker distances (delays) and levels are set.

Surround sound - Wikipedia, the free encyclopedia
Surround Sound Mixing
http://www2.grammy.com/PDFs/Recordin...rs/5_1_Rec.pdf

This is from the Grammy paper
Only direct radiator speakers should be used for music surround sound mixing.
Because of their dependence upon reflective surfaces and the phase anomalies
inherent in their design, dipole speakers will produce inaccurate results when
placed in an acoustically tuned professional mixing environment. However, it
may be helpful to check a surround mix on a consumer system equipped with
dipole speakers, provided the system is physically located in a room that
simulates a typical home theater listening environment. (See section 2.3)
Attached Images
File Type: png 5.1 mixing speaker locations.png (154.2 KB, 412 views)
__________________
Radikal aktivist AINOgradient speaker project

Last edited by Juhazi; 27th October 2013 at 06:46 PM.
  Reply With Quote
Old 27th October 2013, 07:00 PM   #5
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä, Finland
By the way a quite poplar solution for surround speakers is to use omnipole speakers! The problem is always treble - how to get wide dispersion without cancellations/lobing. Some kind of diffusor is used by Mirage, Duevel and Visaton Fontana

Mirage : Omnisat Series : OS³-Sat
Duevel high-end loudspeakers
FONTANA
Pluto introduction

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.
Click the image to open in full size.
__________________
Radikal aktivist AINOgradient speaker project
  Reply With Quote
Old 28th October 2013, 04:36 PM   #6
Baldin is offline Baldin  Denmark
diyAudio Member
 
Baldin's Avatar
 
Join Date: Jan 2005
Location: Copenhagen
Hi Juhazi and sreten

My goal was definitely not to try to convince anyone that dipoles are better or the only way to go. If I had a larger room (or only one seat), I’m sure I would be better off with direct radiating speakers. Actually I’ll try in the near future to shift from my side speakers to the HT1F speakers I have in the back (used for 6.1 and 7.1), to see whether they sound better.
I also like the idea of using omnipolar speakers or maybe something like the lenses B&O is using.

What is best I think highly depend on the room. Mine is small, narrow (long) and well dampened, and direct radiating sound is quite easy to locate. It’s all about striking the right compromise.

Anyway, what I would like to hear is whether anyone have some experience building or constructing dipole surround speakers, or whether anyone have some material on some either diy or commercial? ……

Thanks in advance
Baldin
  Reply With Quote
Old 28th October 2013, 07:46 PM   #7
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä, Finland
Ok I understand your problems! Bipoles and dipoles are used to make a real mess of the sound coming from surround speakers. This mess of reflections is much stronger (in energy) than direct sound from these surround speakers - this is the trick. But then we loose the localization info (cues) "packed" in surround channels.

This will get really difficult because dipoles are really sensitive to positioning (the nulling at 90¤, but it is never perfect!) In real life their output at large angles is very different from on-axis. And respectively also power response is very much dependent on positioning, becaus most of "power" is reflections. You must do many many tests in your spesific room! It is easy to use our monopoles and just turn and push them around. Try also different heights! Remeber to play with delay settings too, also use non-ideal delays

This comes from my thinking ad rationalizing. I have two multichannels systems, for ten years and in three different rooms. All speakers are monopoles (Well dipoles as main LR in the other now). I am not happy at all about surrounds either but it is mainly because the rooms don't allow proper positioning. I have accepted that.

I believe that a "by book" home theaters are really rare!

Surround Sound Speaker Set Up THX.com

Home Theater Surround Sound Speaker Placement and Setup Guide

Home Theater Speaker Layout - An Essential Guide | Audioholics
__________________
Radikal aktivist AINOgradient speaker project

Last edited by Juhazi; 28th October 2013 at 07:54 PM.
  Reply With Quote
Old 28th October 2013, 08:29 PM   #8
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä, Finland
Oh - I just noticed that THX surrounds are supposed to be "dipole" unlike Dolby Surround and Dolby 5.1 or 7.1!

I have never before even looked at THX web page!

Now I understand why they are marketed! We know that THX and DD5.1 mixes are different, it must be because of the different type of surround SL SR speakers. THX says monopoles for rear speakers though.

Surround Speakers | Klipsch

Notice that Klipsh Palladium (top of the line) is breaking the rule with midbasses that are monopole! Other models look more like di - or bipoles but specifications don't tell how drivers are wired. There is a HUGE difference between those actually, in the way they work and sound.
Click the image to open in full size.Click the image to open in full size.
__________________
Radikal aktivist AINOgradient speaker project

Last edited by Juhazi; 28th October 2013 at 08:39 PM.
  Reply With Quote
Old 29th October 2013, 04:38 AM   #9
Okv is offline Okv  Norway
diyAudio Member
 
Join Date: Jul 2009
Location: Aalesund, Norway
I recently designed a surround loudspeaker system configurable for wide - bipole - dipole configuration.

By using drivers with proper radiation pattern, proper placement and angling of the drivers, and proper crossover, it is possible to get reasonable performance in all those configurations.

However, it is not possible to avoid the inherent characteristics of the dipole design - the sound will be extremely dependent of listeners location, because on-axis there will always be a null, and there will be lobing. It sounds quite bad.

The bipole configuration is really only the normal wide with extended horisontal dispersion - 180 degrees full coverage. The sound is much better than the dipole config, and may be usable in some set-ups.

After measurements and testing I have never run them in dipole or bipole configuration. The normal wide sounds better with much better perceived location of sounds, and the speakers still disappears on reasonably good source material.
  Reply With Quote
Old 29th October 2013, 05:08 PM   #10
Baldin is offline Baldin  Denmark
diyAudio Member
 
Baldin's Avatar
 
Join Date: Jan 2005
Location: Copenhagen
Quote:
Originally Posted by Juhazi View Post
Oh - I just noticed that THX surrounds are supposed to be "dipole" unlike Dolby Surround and Dolby 5.1 or 7.1!
THX is a certification of equipment and installations to ensure that the sound will be as closely to what the film maker wanted to achieve. Dolby or DTS is the encoding system. ..... though both Dolby and DTS also have their own guide to setup .... yes confusing

Yes there is many ways to go. The Klipsh Palladium is not THX certified, but their KS-525-THX is.


Okv: do you have some pictures of your speakers? And would you share a bit more on the construction and how they measure?

Best regards Baldin
  Reply With Quote

Reply


How to design a dipole surround speakerHide 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
How to get started with speaker measurements for Dipole design? (and I have a Mac) santiu Multi-Way 4 12th January 2008 03:56 AM
Should I use baffle step compensation for a DIY surround speaker x-over design? marchel Multi-Way 10 21st November 2007 07:49 PM
Theoretical Design - Current Feed Active Dipole Speaker ThorstenL Multi-Way 34 2nd November 2006 08:01 PM
dipole surround XO design -Visaton John Allen Multi-Way 1 6th August 2004 08:07 PM
Dipole Surround Speaker Design standingwave26 Multi-Way 9 2nd June 2004 04:05 AM


New To Site? Need Help?

All times are GMT. The time now is 01:08 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki