[Electric_Haggis]


I think it's time to start a thread discussing & promoting the use of DIPOLE surround speakers in 5.1 and 7.1 systems.


I've used many different types of speakers as surrounds. But until recently, I always thought that regular front-firing speakers were better for the surrounds, as they were a closer match to the fronts.


Damn... was I wrong!


After trying out a few types of dipoles and bipoles, I wonder why everyone doesn't have dipoles in their system. I'm also amazed that more hi-fi shops don't sell or push them... or even KNOW about them, as is all too often the case here in Australia !


Quick Definitions....


BIPOLE :

A good bi-pole speaker will have two sets of drivers facing away from each other, firing sound out into the room. This sound will then cover a wider area, and bounce off the side and back walls, helping to create a bigger sound that allows more people in the room to "get surrounded".


DIPOLE :

The same as bi-pole , but the drivers on either side of the speaker will run out-of-phase with each other. THX recommend this. The advantage is that it's harder to tell exactly where the speaker is as it sounds more diffuse. It's also harder for you to get ear-bashed by one of the surround speakers if you're stuck sitting off to one side. So opens up the "sweet spot".


So here are some advantages...


1. A wider, bigger sound - much closer to the result you get from multiple surround speakers in a movie theatre.

2. A much wider listening sweet spot for everyone in the room.

3. They're easy to wall-mount.

4. They're often more compact than a regular bookshelf speaker, and a lot more wall-friendly.


Here's an interesting shoot-out between dipoles and front-firing speakers. There are six pages with pictures. This will link to the summary...
http://www.hometheatermag.com/bootcamp/25/index5.html


Here's some more blurb: "The Case for Dipole surrounds":
http://www.paradigm.com/en/pdf/dipolar_confusion.pdf


One issue dipoles can have compared to bipole or front-firing speakers, is reduced bass. This is because the bass drivers are running out-of-phase with each other. Be aware though, that several manufacturers make dipoles that avoid this problem....


PARADIGM really know how to make great surround speakers. Their ADP190 would have to be my favourite all-round surround speaker for the majority of people. Paradigm design all their surround speakers so that the deeper bass is kept in phase....
http://www.paradigm.com/en/paradigm/...ounds.paradigm


MONITOR AUDIO also make nice surround speakers. The less expensive models have only one bass driver, but they can be switched between dipole and bipole, like this one...
http://www.monitoraudiousa.com/produ...e=3&product=21


JBL make some THX-approved models...
http://www.jbl.com/home/products/cat...=US&Region=USA


INFINITY make a unique speaker called the ES250. I own a pair of these. They can be switched between dipole, bipole and dual-monopole, where they operate as two separate speaker channels in one wall-mounted unit. Handy for 7.1 where you can't mount rear-wall speakers....
http://www.infinitysystems.com/home/...USA&Country=US


JBL now make one just like the Infinity...
http://www.jbl.com/home/products/pro...at=SSS&ser=PER



ANY OTHER THOUGHTS OR SUGGESTIONS?

 

[Alimentall]

Ummm, I didn't know Australia was 15 years behind the rest of the world.


Time for a "The Packard is the best car ever" thread........

Quote:
1. A wider, bigger sound - much closer to the result you get from multiple surround speakers in a movie theatre.

No, not really, that's entirely different dispersion techniques. Only multiple monopoles will get you close.

Quote:
2. A much wider listening sweet spot for everyone in the room.

Not necessarily true. With dipoles, you get out of the sweetspot much more quickly.

Quote:
3. They're easy to wall-mount.

So are most monopoles.

Quote:
4. They're often more compact than a regular bookshelf speaker, and a lot more wall-friendly

Often, but that means they're putting drivers into a box that is too small for the drivers, assuming that you won't notice, and clearly, they must be correct as you didn't notice.

 

[Bing]

John,


you're just being difficult.

Quote:
3. They're easy to wall-mount.


So are most monopoles.

I don't recall bookshelves having holes built into the cabinet, as well as a template to show you exactly where to drill holes.

Quote:
Often, but that means they're putting drivers into a box that is too small for the drivers, assuming that you won't notice, and clearly, they must be correct as you didn't notice.

Basically, you're saying multi-directional surrounds are "afterthoughts" to a manufacturer. Just recycle the drivers from the rest of the lineup, and stuff'em into a box that is easy to wall-mount. Then charge double because J6P sees a pair of tweeter/woofer and can rationalize the premium.

Quote:
1. A wider, bigger sound - much closer to the result you get from multiple surround speakers in a movie theatre.



No, not really, that's entirely different dispersion techniques. Only multiple monopoles will get you close.

"How" they achieve the effect is secondary to me. What matter is, di/bi create surr effects that do not call attention to themselves. I don't care how accurate monopoles may be in comparison, but if there are two clusters of pirates over my shoulders instead of a boatload, they don't go on my walls. Music is a different story entirely as there is no visuals for the brain to process.



You started a thread some time ago about 10 things a "real" HT should have. I agree with everyone of them except this.

 

[Alimentall]



Quote:
Originally Posted by Bing /forum/post/0


John,


you're just being difficult.

Oh, I'm being more than difficult!

Quote:
I don't recall bookshelves having holes built into the cabinet, as well as a template to show you exactly where to drill holes.

I do. Heck, many of our bookshelf speakers can be hung on a wall as fast as you can screw a screw.

Quote:
Basically, you're saying multi-directional surrounds are "afterthoughts" to a manufacturer. Just recycle the drivers from the rest of the lineup, and stuff'em into a box that is easy to wall-mount. Then charge double because J6P sees a pair of tweeter/woofer and can rationalize the premium.

That is correct. But it's also true.

Quote:
"How" they achieve the effect is secondary to me. What matter is, di/bi create surr effects that do not call attention to themselves. I don't care how accurate monopoles may be in comparison, but if there are two clusters of pirates over my shoulders instead of a boatload, they don't go on my walls. Music is a different story entirely as there is no visuals for the brain to process.

You should hear a correctly setup theater someday.

Quote:
You started a thread some time ago about 10 things a "real" HT should have. I agree with everyone of them except this.

All in good time. All in good time.

 

[CAVX]



Quote:
Originally Posted by Alimentall /forum/post/0


Ummm, I didn't know Australia was 15 years behind the rest of the world.

Actually we are not, but I have even made that statement from time to time...

Quote:
Time for a "The Packard is the best car ever" thread........

What is a Packard?

Quote:
No, not really, that's entirely different dispersion techniques. Only multiple monopoles will get you close.

He is referring to the fact the sound is very diffuse when using dipoles - like in a movie theatre. Tom Holman actually made that decision and it became a standard feature of the Home THX audio system. When dipoles are mounted on the side wall with the "null" aimed at the listening position, what you hear is mostly reflected sound energy. This is described as emulating the movie theatre surround arrays (which are made up of many direct radiators). The reason the surrounds sound the way they do in a cinema, is that the sound reaching your ears comes from many different locations and at different arrival times - the result is spaciousness...

Quote:
Not necessarily true. With dipoles, you get out of the sweetspot much more quickly.

I would have to disagree having used them for a number of years. FIY, I don't use them today, but rather BIPOLES set up the same way that dipoles would be positioned.

Quote:
So are most monopoles. Often, but that means they're putting drivers into a box that is too small for the drivers, assuming that you won't notice, and clearly, they must be correct as you didn't notice.

The size of the box really depends on the TS parameters of the drivers, but in a similar fashion to an isobaric sub-woofer (the gap between the drivers), a dipole (without a dividing wall) does not compress the air inside, so the drivers can operate in a much smaller volume...


Mark

 

[Lawguy]

I have used both dipoles and monopoles. I am now using dipoles and think that, on balance, they sound better to me. I mostly watch movies and TV. There are some kinds of scenes in which monopoles sound better to me, but on most material, dipoles do a better job. My answer would likely be different if I listend to a lot of multi-channel music (I don't).

 

[Paul Scarpelli]

I could have predicted where this thread would go.

I've chimed in on the dipole debate before, and here's my spiel again. If your room is smallish and/or acoustically dead and/or you have multiple seats, dipoles tend to work better, with an even but compromised listening window. If you have a larger and/or more live room with less seating, or seating away from the surround speakers, direct-radiating surrounds can be better. If you are a sad, lonely, pathetic little man who sits in his solitary, cushy theater chair, five identical direct-radiating speakers, equidistant from your ears, can provide an absolutely holographic movie experience, allowing you to momentarily forget that you are lonely and unliked, with no friends.


All rooms are different, and no generalization can be made about surround speakers without considering the room.


Now back to the bickering. I am enjoying it.

 

[Rijax]

AH! The voice of reason, as usual.

 

[Eddie Horton]

Paul, that's one of the funniest things I've read on here in a while. There's nothing like a dry sense of humor with good delivery slapping you upside the head.

 

[Electric_Haggis]

Nicely put, Mr Scarpelli !!


Over the years, I've used a bunch of different surround speaker types in a bunch of different configurations in a bunch of different rooms....bookshelf speakers, even towers, angled in, out, up, down, etc, in 5.1, 6.1 and 7.1 configurations.


Mostly, I made the mistake of not seriously considering dipoles (or even bipoles) based on theory over practice. Finally HEARING good dipoles - properly placed and calibrated - has changed all that. If they're dipoles that have the bass running in-phase like the models I mentioned above (or Triad!), then better still.


Of course, it's always going to be room-dependent (same goes for any speaker).

But the bottom line is this... MOST people, in MOST rooms, whether 5.1, 6.1 or 7.1 setups, tend to get better results with diffuse-radiating dipole speakers - especially for the side-surrounds. Every time I go to someone's house and am not sitting in the absolute sweet spot, I'm reminded of this. And every time I've persuaded someone to change over to dipoles, they've been very happy they did...

 

[CAVX]

Electric_Haggis,


Are you running a 7.1 system at present and are you using dipoles as back surrounds as well as side surrounds?


Mark

 

[Paul Scarpelli]



Quote:
Originally Posted by CAVX /forum/post/0



Are you running a 7.1 system at present and are you using dipoles as back surrounds as well as side surrounds?

That brings up a good point. While I sometimes favor dipoles for the sides, I rarely like them in the back. A diffuse soundfield is not desireable when the speaker is firing into a deflector of pink cartiledge...the back of your ear.

 

[Paul Scarpelli]

Useless information department...


Originally, dipole surrounds were developed to open up a large surround field, but mostly to mask or compensate for the gross flaws of early consumer surround, which was analog. Dolby Stereo was passive with no steering logic, and separation was 3 dB from front to back. It was derived by subracting one front channel from the other and shoving that info into the rear channels. Dialog could still be heard in the back. Pro Logic was a crude matrix which actively steered sounds and derived a center channel. It was bandwidth limited like an AM radio, throwing out the baby with the bath water. If there was little high frequency content, the sounds were less likely to be localized in the rears. Also, the attack and release times of the control voltages was slowed tremendously to try to smooth out artifacts. I never liked Pro Logic, although in the early days of it (1986) it masked lots of it's own flaws and flaws in crappy movie soundtracks. I thought it was pretty good until I heard Jim Fosgate's propriotary surround technologies of the late '80s, which had fast response times, full-range rear channels, and stereo rears. As Jim continued to improve his surround technologies through Citation 6-Axis, the antiquated Pro Logic looked older and more outdated. At this point, Dolby adopted Jim's latest surround version as Pro Logic II. (Now Jim and Norma are rich, and I am here.)


Pro Logic II steers signals with few enough artifacts that you can use direct-radiating surrounds. DD and DTS, which use discrete multichannel, not two channels processed into five or seven, work very well with direct-radiating speakers, but in the appropriate situation.

 

[otk]



Quote:
Originally Posted by Paul Scarpelli /forum/post/0


If you are a sad, lonely, pathetic little man who sits in his solitary, cushy theater chair, five identical direct-radiating speakers, equidistant from your ears, can provide an absolutely holographic movie experience, allowing you to momentarily forget that you are lonely and unliked, with no friends.

 

[caesar1]



Quote:
Originally Posted by Electric_Haggis /forum/post/0


I think it's time to start a thread discussing & promoting the use of DIPOLE surround speakers in 5.1 and 7.1 systems.





ANY OTHER THOUGHTS OR SUGGESTIONS?

After years of direct side surrounds, I'm still getting used to my Paradigm ADP dipole/bipole side surrounds (ADP 590s); which I've had now for 3 months.


I still sometimes miss the more direct side sounds I was used to (particularly in DVDs I'm familiar with) -- but it is more all enveloping. Its weird when I cant' tell that's its coming directly from the side -- I actually have to physically put my ear near the side surround to tell that the sound is coming from that speaker.


Because basically it now sounds like its coming from all over the left side -- not just the left side middle.

 

[otk]



Quote:
Originally Posted by Paul Scarpelli /forum/post/0


Useless information department...


Originally, dipole surrounds were developed to open up a large surround field, but mostly to mask or compensate for the gross flaws of early consumer surround, which was analog. Dolby Stereo was passive with no steering logic, and separation was 3 dB from front to back. It was derived by subracting one front channel from the other and shoving that info into the rear channels. Dialog could still be heard in the back. Pro Logic was a crude matrix which actively steered sounds and derived a center channel. It was bandwidth limited like an AM radio, throwing out the baby with the bath water. If there was little high frequency content, the sounds were less likely to be localized in the rears. Also, the attack and release times of the control voltages was slowed tremendously to try to smooth out artifacts. I never liked Pro Logic, although in the early days of it (1986) it masked lots of it's own flaws and flaws in crappy movie soundtracks. I thought it was pretty good until I heard Jim Fosgate's propriotary surround technologies of the late '80s, which had fast response times, full-range rear channels, and stereo rears. As Jim continued to improve his surround technologies through Citation 6-Axis, the antiquated Pro Logic looked older and more outdated. At this point, Dolby adopted Jim's latest surround version as Pro Logic II. (Now Jim and Norma are rich, and I am here.)


Pro Logic II steers signals with few enough artifacts that you can use direct-radiating surrounds. DD and DTS, which use discrete multichannel, not two channels processed into five or seven, work very well with direct-radiating speakers, but in the appropriate situation.

yup and THX was a "band-aid" for that horrible pro-logic format


but i do love the old THX trailers used on AC3 laserdiscs

 

[Electric_Haggis]



Quote:
Originally Posted by CAVX /forum/post/0


Electric_Haggis,


Are you running a 7.1 system at present and are you using dipoles as back surrounds as well as side surrounds?


Mark

Actually...no!


Currently, I'm using a pair of Infinity ES-250's on my side walls on either side of the usual listening positions. (Or very slightly behind, for those sitting closer to the screen.)

I've previously tried them in both Dipole and Bipole mode for 5.1, but I settled on using them in Dual-Monopole mode in 7.1.

Here's a picture of the ES-250's again...
http://www.infinitysystems.com/home/...OPE&Country=AU

The front-most drivers are outputting side-surrounds, and the back-most drivers are outputting rear-surrounds. So of course I've got 2 sets of wires (and amps) running into each speaker, and I use ProLogic IIx to convert all 5.1 Dolby soundtracks to 7.1.

This has the advantage of offering better steering and spaciousness than the alternatives... at least in my room.


I have in the past used various types of speakers at the back of the room in 6.1 and 7.1 modes. But my problem is that we're just sitting too damn far forward from the back wall, and IIx processing steers too much surround into the rears. So I could never get the balance right - even with properly mixed EX or ES films. In my current room, this particular arrangement works just PERFECTLY.


Having said all that - it isn't ideal. If I had a different room (or a bigger projection screen) and we were sitting closer to the back wall, I'd much rather go for 4 speakers. Definitely dipoles on the side walls, and probably dipoles (or perhaps bipoles) for the back wall.



Again, here's a link to the dipole/bipole/monopole shootout I mentioned earlier...
http://www.hometheatermag.com/bootcamp/25/index5.html

 

[6SpeedTA95]

I much prefer the sound of decent bookshelfs as the surrounds than a dedicated "surround" speaker. I think the bookshelfs sound far better in all the applications I've heard them in.

 

[Electric_Haggis]



Quote:
Originally Posted by 6SpeedTA95 /forum/post/0


I much prefer the sound of decent bookshelfs as the surrounds than a dedicated "surround" speaker. I think the bookshelfs sound far better in all the applications I've heard them in.

Really? In what way?

 

[CAVX]

Interesting...


Mark