Axiom Home Page Forums General Discussion Technical Questions Dipole VS. Bipole? ?

I've got a pair of Polk Audio RTFX surround speakers that feature dipole/bipole modes...is there usually a general rule of thumb when using different modes (dipole/bipole) when we are using Dolby Prologic or Dolby Digital encoded movie material?

Thanks and any questions, about my room, please feel free to ask me...
-MitchM2006-

I have a pair of Cambridge Soundworks surround speakers that feature a bipole/dipole switch. I keep mine on bipole because I think it sounds better that way. I've tried both and I think the dipole mode makes the sound too diffuse.

It really comes down to what you think sounds best. That's the rule of thumb.

OK, I give up. What is the difference between a dipole and bipole?

I went through both di/bi pole speakers in the polk line (the ones you mentioned and the LSi series). Comparing them to the Axiom surrounds is night and day. It is completly amazing the difference, like oranges and apples. As good as the Polks were the sound and information heard by way of the Axiom is a big difference. Although you will read reviewers state the Axioms are wide, and airy and diffused I was shocked how direct they can also be. It's amazing how they can produce both kinds of amient and direct sounds when called to do so. Wind, rain, echoes are all spread out evenely - but when they need to show off a jet zooming from the front to the rear left (or right) they do so perfectly. One of my favorite test discs is THE EXORCIST (THE VIERSION YOU NEVER SAW) when the mother brings home the priest for the first time to see her daughter. When they walk into the house you should hear wrasping breathing in the rear (or side, depending on if you have a 5.1 or 6/7.1 set up) the sound then switches to the front right channel as the characters move onto the top the steps in the hall. Next, when the room shakes during the exorcism you should hear bits of plaster fall in each of the two side/rear speakers - that's different crumbling sounds. Later when the young priest goes into the room alone to check on the girl he sees the image of his dead mother sitting on the bed - you should clearly hear different moans, laughter, and sighs in the side/rears. These are not big explodisions but subtle effeect that should stand out in a well balanced system with good speakers. Hearing these same scenes with various sets of speakers I can honestly state it has played out the best on the Axiom surrounds.
There's also a scene in the same film, at the end after the priest fall down the steps you will hear a crowd all aound you - differnet voices it's incredible.
I have the QS8s (four) I'm sure the smaller versions work just as well.

BTW, Mitch, the whole di/bi pole thing was originally developed by Lucus for his THX bogus way of doing home theather. Dolby never had anything to do with it. It was Lucus' way of dispersing sound at home in a way a mulit-speaker set-up at the movie theater. With the advent of 6.1 and 7.1 systems, it's not really needed since there so many speakers anyway. Besides, then THX was first done there 5.1 or Dolby Digital was alreday in in theatres not THX approved. With the Axioms you won't have to worry with di or bi is needed for a rear or side application since one is for a more direct sound and the other a more dispersed. I think the problem with Lucus ans with his THX system is it is what HE WANTS us to hear, not the film's producer/director. If a film is mixed with direct firing side and rear sound then it sould be heard that way. If it's meant to be a more dispersed sound effect, then the mixers with mix it that way. With 5.1, 6.1 and 7.1 avaialble for set-up at home the need for a speaker that does more than is required by the producer/director, mixer is now a thing of the past. The technology is such it has out dated what was thought needed to recreate the movie theater experience. The Axioms do what other brands have tried and failed. They may all work good enough - but when comared, the difference is simply clear

I wasn't sure either so I found this. LINK

Thanks! I sometimes wonder how much of the theoretical stuff we can actually hear because of our actual hearing, actual speaker performance, room configuration, and sitting location.

Some of these notions may look good on paper, but I don't know that I could "hear" the difference.

I strongly suspect the same is true for many others even though they would claim the opposite.

I just want to correct some misinformation. Dipole/bipole had absolutely nothing to do with THX. Dipole was developed to help disperse sound before Pro logic systems, we're talking as far back as 1974, before Pro Logic and even longer before DD or THX. Also the QS8's and 4's, the whole reason I bought them is because I've heard M&K's tri-poles and since the concept was similar I knew Axiom had a winner.

It's not at about what Lucas wants us to hear instead of the director, that's just silly to even say. Almost all studio equipment either meets or exceeds THX standards, things just fall into place down the chain from there. I'm not a THX fanboy but to call something bogus without any data is, well, bogus in itself. I have heard fully approved THX systems such as M&K including cables and rack equipment, all THX certified and they sound great. I have also heard non-THX systems that sound just as good. What you have to keep in mind is THX is a Standard and for the newbie to this hobbie, it can help. I don't agree with the cost factor that Lucas reams the manufacturers for but THX has it's place. The great thing about THX and Dolby is their on the same boat and without them we'd still be listening to quadraphonic sound systems for movies. So please, before slamming a technology that has brought us this far do a bit of research.

Sorry to sound so abrupt but I just hate misinformation.

Sorry, but I disagree. THX has nothing to do with DOLBY. Dolby labs was founded and created the sound system we all know today. It first started as a noise reduction system, a compression that added to the fidelity in a movie soundtrack by way of compression the mix to reduce the noise level in quieter moments of the mix. That was in the early 70s and applied to the film LISTAMANIA and later in the 70’s with films like THE MANITOU – where it was know as DOLBY SYSTEM. Until then any film recorded in stereo was either 4-track (which is compatible to the Dolby Surround method) or 6-track, which was only presented with 70mm prints.
THX was established in the early 80’s (about 1983) not a development in sound by rather as a “Watch Dog” system initiated by Lucas for theaters to have a more updated and standardized sound system. Pre-1970s theatre sound systems were mostly mono in nature due to the lack of stereo produced films. With the growth of film produced in stereo after the popularity of STAR WARS and CLOSE ENCOUNTERS in 1977 Lucas jumped on that bandwagon for theatrical use. Home video was still in the budding stages with Beta-Hi first then VHS stereo following suit. DOLBY did not have anything to do with a Bi/Di pole design. At the time Altec Lansing and JBL, and to a smaller level Cerwin Vega were the most prodigious theatrical speaker manufactures. (In fact it was Cerwin Vega who help develop SENSERROUND for Universal Studios.
The first di/bi pole designs came into the market in the late mid-to late 80’s just prior to the introduction of AC-3 for Laser Discs, a home version of the theatrical DOLBY DIGITAL. – Which for the first time allowed discrete multi levels of full range sound on 35mm film. Previously there was only 6-track (and that wasn’t completely full range aside from the front three channels) only on 70mm. It was the size of the film that allowed room the multiple tracks.
In those early days of THX for home video they only over saw the visual portion for video (Laser Disc) releases. After a fiasco mess up with the release of STARGATE it was exposed that THX DIDN’T even touch the sound portion. Although they managed to make people think they did. This was coved in the Hollywood Reporter and made waves since STARGATE was one of the first 3 AC-3 Laser Disc release for the new sound format which also touted the THX seal of quality. (I know because I was the reviewer who exposed it and was interviewed by the Hollywood Reporter).
After that due to the expensive rates studios paid for this “watch dog” assurance of quality THX encompassed both sound and visual into their practices.

1) I never stated Dolby and THX were the same, I said they were in the same boat. It's a figure of speech meaning they have the same agenda, sound processing. Yes Dolby started as a noise reduction system for "sound".

2) Your dates and times are all wrong, anyone who wants to know the history can look at reputable sources.

3) Aain I never said Dolby had anything to do with dipole/bipole.I said they were developed to help dispese sound before Pro Logic, hence quad. Yet once again, I guess my dipoles from '76 were a figment of my imagination, they came out prior to '74.

4) You were the reporter who exposed the "so called" star wars fiasco? No wonder so many people are confused about audio/video.

It's obvious to any who read this and take the time to research, how incorrect your post was. I'm not going to get in a pissing match with someone whom is so misinformed. You can't even get your facts straight to quote my post. You say I said Dolby and THX were the same and I said Dolby invented dipole, lmao. I'm done with this, if it makes you feel good to steer people down the wrong path and they are willing to buy into it, fine.