Bipole/Dipole, + TQWT? - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range

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 10th June 2005, 02:27 AM   #1
diyAudio Member
 
Join Date: Feb 2003
Location: Québec
Default Bipole/Dipole, + TQWT?

Just saw this design http://www.t-linespeakers.org/FALL/bd-pipes.html

What are they? Bi-poles? Di-poles? what is the difference between these designs?

Then on the same page, there is a pipe built around FE 103, two drivers per box, one in front, one at the back. Why??

http://members.shaw.ca/t-linespeaker...pes-FE103A.jpg

Are there specific advantages to that use?
__________________
Sylvain, Québec
  Reply With Quote
Old 10th June 2005, 02:30 AM   #2
diyAudio Member
 
Join Date: Feb 2003
Location: Québec
Default Bipole/Dipole

One more question:

Are the drivers electrically in phase? reverse phase?

And are they plugged in serie? parallel?

Sorry for so many questions, but that's the way to learn, right?
__________________
Sylvain, Québec
  Reply With Quote
Old 10th June 2005, 06:49 AM   #3
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
Very true, and no question is daft! Both of these speakers are basically the same classic Bert Doppenberg design. Strictly, they're neither bi, nor dipolar, though they're much closer to being bipoles.

The best way of describing a DIpole speaker is to think of an open baffle type design. The driver[s] mounted to the baffle radiate energy both forward and backward into free space.

A BIpole speaker technically requires two drivers, facing directly away (or directly toward, though I've never seen that!) from each other on opposite sides of a normal cabinet -it doesn't matter what type -sealed, BR, TL etc. So, the BD pipes you've noticed are obviously closer to a bipole, though strictly speaking I wouldn't describe them as such. Probably pedantic of me.

What's the rear driver for in this design, and bipoles in general? It has a similar effect to a dipole open-baffle design (now there's a surprise!). A normal speaker radiates energy in a conical, or better, a globular fashion forward of the driver. Bi and dipolar types radiate energy rather differently. I can best describe the pattern like this: think of two snooker balls connected together. This has quite a few advantages, not least of which being that it eliminates baffle-step problems, and, energises room modes far less than conventional speaker types -the exact reverse of what many people suppose.

How to wire a bipole speaker? In parallel, and in phase. If the rear driver is mounted directly behind the front (as, stricktly speaking, it should be), you can also apparantly get some real advantages by having a mechanical connection between the drivers -a length of dowel-rod for example, so they work in push-push configuration against each other. Cuts down on cabinet stresses.

Here are some larger bipole designs, also from Dave's page:
http://www.t-linespeakers.org/FALL/bipolar/index.html
I'm in the process of modifying the dimensions of designs number1 to and 3 to use the Fostex FE167E and FE127E respectively.

For more information on dipoles, and speaker radiation behaviour in general, I cannot reccommend reading the articles here highly enough:
http://www.linkwitzlab.com/
Look in the Concepts section at the articles there.

Hope this helps
Best
Scott

Oh, by the way, these BD pipes are supposed to be quite good with the FE103E -even TNT-Audio built and reviewed a pair:
http://www.tnt-audio.com/casse/tqwp_e.html
I take all reviews with a ton of salt, but it's always nice to have another oppinion!
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 10th June 2005, 11:54 AM   #4
diyAudio Member
 
Join Date: Feb 2003
Location: Québec
Quote:
Originally posted by Scottmoose
Very true, and no question is daft! Hope this helps
Best
Scott

Hi Scott,

You are throwing some light here, for sure. Thanks for that.

I swear that I'll read all the theory links you have sent. Now, if I could understand a little bit more about the calculations and drivers specs behing TQWT designs.. Well, it will come.

Can't wait to enjoy the Zigmas first. And yes, I find those BD pipes quite appealing.. but summer is here, and it will have to wait 'til fall. First things first..

And I'm leaving for Ogunquit (holidays) in July!
__________________
Sylvain, Québec
  Reply With Quote
Old 10th June 2005, 03:06 PM   #5
SCD is offline SCD  Canada
diyAudio Member
 
Join Date: Nov 2003
Location: 1/2 way up Vancouver Island
If you are interested in Taper Quarter Wave designs have look at the wonderful work done by Martin King. Bob Brines also has some very good stuff to look at as well. You will also find a lot of discussion here on this forum.

I have built a few TQWPipes and heard the speakers that Dave made and they sound very good.
Welcome to a new world, It is quite nice.
__________________
SCD
  Reply With Quote
Old 10th June 2005, 07:25 PM   #6
chrisb is offline chrisb  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
Quote:
Originally posted by SCD
If you are interested in Taper Quarter Wave designs have look at the wonderful work done by Martin King. Bob Brines also has some very good stuff to look at as well. You will also find a lot of discussion here on this forum.

I have built a few TQWPipes and heard the speakers that Dave made* and they sound very good.
Welcome to a new world, It is quite nice.

SCOTT: sorry for tooting my own horn, but while the inspiration (and drivers) came from Dave, the material and sweat was by yours truly.

Sylver300B: Bert's design was orginally for a kit to be marketed with a custom labelled ( ACR) version of the Fostex FE103E. Apparently that supply line dried up, and he decided to pull the design from his site.

I've built at least 6 or so pairs of these, best results with the vintage Fosters ( as dubbed FE103A by Dave); with phase plugs on front drivers & the tweeter is optional.

IINM, this design could be classified as a folded TQWP, and the exact dimensions may not be optimal for some of the newer FR drivers (i.e the VERY interesting CSS WR or FR125) The WR125 is available in 16ohm version intended for MTM designs, and would be very interesing to try in this enclosure.

FWIW, one or two of the early pairs of these were built in MDF, all others in 13ply baltic birch with superior results to our ears.

If using just 8ohm FR drivers, there's no reason you couldn't wire them in series for 16ohm load that some tubed amps might prefer. Until I recently had and accident with utility knife trying to "improve" on Dave's dust cap circumcision for phase plugs, I was running a pair of bipole MLTL FE127E in series. While some weight in the lower octaves is sacrificed, the bass is cleaner and more articulate on my little EL84RH parafeed amps
  Reply With Quote
Old 10th June 2005, 08:17 PM   #7
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
And why not toot ones' own horn (perhaps I should re-phrase that... :-) ?

I should have mentioned series wiring shouldn't I? Agreed wholeheartedly -very useful in some cases. Do you have any design info / dimensions for the bipole MLTLs with the FE127E you could share by the way? Perhaps we could swap notes once my ML TQWTs are completed. Did you couple the drivers together at all, or were they just firing in opposite directions?
Best
Scott
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 10th June 2005, 09:21 PM   #8
diyAudio Member
 
Join Date: Feb 2003
Location: Québec
Quote:
Originally posted by chrisb
I've built at least 6 or so pairs of these, best results with the vintage Fosters ( as dubbed FE103A by Dave); with phase plugs on front drivers & the tweeter is optional.

FWIW, one or two of the early pairs of these were built in MDF, all others in 13ply baltic birch with superior results to our ears.

While some weight in the lower octaves is sacrificed, the bass is cleaner and more articulate on my little EL84RH parafeed amps
Hi Chris,

The pair of drivers I am using right now, are Fosters. Too bad I don't have 2 pairs. I am building Zigmahornets. As well, I intend to experiment by making them "bipoles" after I have had some experience with them in original form..

About MDF. I always have felt that MDF had its particular sound signature, and I don't like it. And as well, baltic birch is not much more expensive, and so much easier to work with, to cut etc.. Perfect for the novice like me.

About "weight" I'm over 200 oops. . about amps, I have a some nice ss amps at hand, but always prefer the musicality of my SE-300B (I built it after Fi Primer's plan) and I am about building an SE-45 parafeed, but that's another story. Too many projects, too little time. I read it somewhere..

As for the BD pipes, I would apreciate if you could share your plans. The ones for the Foster drivers interests me a great deal, and I can't wait to chase and recycle a few more of these drivers.

Thanks for sharing all of this, same applies to folks here.
__________________
Sylvain, Québec
  Reply With Quote
Old 10th June 2005, 09:22 PM   #9
chrisb is offline chrisb  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
Default CSS FR125 BP

As designed by Tim Foreman, and sketched by dld; after hearing the new FR125 at Al Wooley's last week, I'll be making these without tweeters. And just for fun, 2 identical pairs in MDF and 13 ply Baltic Birch.




http://www.diyaudio.com/forums/showt...317#post641317
  Reply With Quote
Old 10th June 2005, 09:25 PM   #10
chrisb is offline chrisb  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
Quote:
Originally posted by Sylver300B


Hi Chris,


As for the BD pipes, I would apreciate if you could share your plans. The ones for the Foster drivers interests me a great deal, and I can't wait to chase and recycle a few more of these drivers.

Thanks for sharing all of this, same applies to folks here.


Sylvain:

I think that Dave may have the complete cut plans archived from Bert's site; all that I have is a hard copy of drawings, and my Autosketch CAD drawings.
  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
TB w4-1052SA bipole/dipole kscharf Multi-Way 0 9th April 2007 04:12 PM
Bipole; TQWT vs. BR Jeb-D. Full Range 1 10th April 2006 06:37 PM
Bipole into Dipole? Howard Multi-Way 1 30th January 2005 05:31 PM
which is better for rears in H/T dipole -bipole busterno1 Multi-Way 0 16th January 2004 11:33 AM
Dipole/Bipole Designs? Marcus Multi-Way 3 24th October 2002 03:15 AM


New To Site? Need Help?

All times are GMT. The time now is 01:07 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