Tom Holman's opinion on dipoles vs. direct-radiating surrounds

[Seb]

HornEd's not going to like this...

But here is the link anyways:

http://www.paradigm.com/Support/TechFAQ/DipolarConfusion.pdf

At least he refers to his use of LaScalas...

Enjoy!

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http://members.fortunecity.com/sebdavid - go laugh at my crappy website/equipment

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This message has been edited by Seb on 04-08-2002 at 11:31 PM

[T2K]

Thanks for the post Seb. Enjoyed reading in text what I have found to be true ACTUALLY USING a variety of different speakers in my HT set-up. Maybe if one went back and reread some of my earlier comments they would see the parrallel with the comments of the knowledgeable gentleman.

Keith

"Frankly, using six monopoles sound better with DVD's with an audio mix from 1998 on sound better than the wimpy "Pro Logic mix" of yesteryear... for which the 180° wedge-shaped KSP-S6's do a particularly good job."

HornED

"The point is that as the art of sound mixing for home theater improves... the monopole side/surround and rear effects can be sent discretely integrated sounds that provide ambient and/or "structured localization" for the rear speaker array."

HornED

"Of course, the ideal is 5 (or more) identical speakers since that is what the assumption is when the actual mixing for the DVD is done in the studio."

HornED

"I agree that putting another scatter-sound KSP-S6 on the back wall will confuse rather than provide the localization required for maximum advantage."

HornED

This message has been edited by talktoKeith on 04-09-2002 at 12:41 AM

[boa12]

yea right on. the reason there's so much dif of opinion, besides the dif tastes, is that some stuff sounds better w/ those & some better with that. even within the same program. f.e., movies that have a lot of side sweeping surround effects and a lot of music.

that's why the denon a, b surrounds which i think is ingenious if somebody wants to spend the dough on 2 sets of surrounds. that's better than my idea of the wdst/direct auto directional finder speaker. a speaker

that has the tweeter horns on swivels and automatically adjusts to direct or wdst by getting it's electronic cues from the material.

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My Home Systems Page

This message has been edited by boa12 on 04-09-2002 at 12:10 AM

[T2K]

Sorry boa,ED's idea is better.A monopole that plays a discreet pre-ambieated signal.

Keith

[HornEd]

Thanks, Seb, it is a very interesting link... and I agree with much of what he had to say... but I have made experiments which go beyond those in the article. I find his conclusion more valid than his shopworn examples. In the end, he alludes to the fact that any "problem" is overblown by the hype and that both mono-pole and di-pole approaches have both ambient and direct radiating characteristics.

One of the areas not covered in the article, except by barest mention that it solves the problem, is the M&K tri-pole (which presumably includes Klipsch WDST and the KSP-S6 wedged approach). In fact the author effectively makes a case against the use of the Klipsch approach since the core of his argument is that a "null" has to be directed toward the listener in order to get an even sound as reflected by the walls.

It is interesting that in his illustration he places the "classic" dipoles slightly behind the listeners head as I would place monopoles to get an increased ambient effect. You may also recall his comments about the benefits of a rear center speaker as being an example of why "Quadraphonic Sound" took a dive. And that is why I favor a 6.1 arrangement (7.1 for non-typical listening spaces) in the rear array.

Clearly, I have often recommended these M&K and Klipsch approaches for people who want to broaden the sweet spot in their HT environment and have used them in the awkward audio environment of motorhomes. However, I find the "classic" di-poles (as illustrated in the set-up disc Video Essentials) produce too much cover-up ambience with too little localization for maximizing HT pleasure. It is interesting to note that that set-up disk favors putting a floor standing speaker vertical above one's TV in order to fulfill the need for adequacy at the center position.

Perhaps I have been a bit overboard in my attempt to get Klipschers to try to set up their systems to what I see as the trend in move mixes for HT use. This issue is a bit like the one where horn fans prefer the clarity that makes good recordings wonderful and reveals the flaws of poor recordings. Well mixed audio in movies is wonderful... poorly mixed audio is not. Dipole speakers tend to even out the sound and cover the flaws... and also help to cover acoustic shortcomings in awkward listening environments.

Of course, the author has a huge investment with his participation in creating the THX approach... an approach that seems to be (IMHO) a bit contrived and losing industry support. His "scientific" methodology is also somewhat suspect in my experience.

Seb, I appreciate your publishing this link to an "authority" who seems to show that poor speaker placement is a bad idea and that bouncing sound off of walls can be advantageous. And, Keith, I appreciate your posting my comments (even out of context) and your conclusion that much of the problem is in the failure of program content to be ideally mixed.

I am only sorry that my lack of ability to communicate my experience has caused misunderstandings in the past. The time and money that I spent experimenting with six Klipsch subwoofers in my HT came from reading T-T-K posts a long time ago. My recommendations in favor of KSP-S6 and WDST solutions also came as a result of reading T-T-K posts that led to actual experiments... not mere supposition.

The real issue is about monopole speakers and how best to set them up for a particular acoustic/psychoacoustics benefit in a given listening area. When you get right down to it... bipole, dipole, tripole, WDST... are all ways to gang monopole speakers aimed in different ways to enrich ambient sound... and diminish localization... but, IMHO, too much of a good thing can lessen the overall quality of one's sound experience.

"Adequate ambient sound" and "structured sound localization" are key elements in a quality HT experience. Fortunately, our brains have the ability to overcome much of most "audio" presentation shortcomings and still make a pretty good time of HT.

In summary, I found the article worth reading to better understand the bias and shortcomings of the person so responsible for THX. I find that his recommendation for three speakers up front and two "classic" dipoles with the nulls toward the center to be a "dated" approach that flies in the face of better K&M and Klipsch surround approaches. It also neglects to include the rear center speaker which the author claimed spelled the failure of Quadraphonic Sound.

Frankly, I much prefer the logic and applied science of PWK and Floyd Toole to that of the author, Tomlinson Holman. And, with a bit of serious thought, I think most Klipschers would as well.

But that is just my opinion... considered though it may be. -HornEd

PS: By "structured sound localization" I mean that a voice or a rifle shot can be made to appear to come from any particular spot in the 180° degree rear array by correctly mixing the sounds sent to two or (preferably) three monopole speakers correctly set-up in the rear array... just like good stereo imaging in the front array will make the individual instruments in an orchestra seem to come from the familiar places concert goers would expect.

By the same token, the reflected (ambient) sound of a great music hall is critical to maximal listening... and that, too, can be helped by the current trend setters in sound mixing. As the installed base of 6.1 (or above) ready home sound systems climbs high enough, the mix quality of recorded HT and multi-channel music will likely improve.

PPS: Seb, I admire your spirit of independent thinking and your zeal to find authorities on subjects of your interest. As a student, you have a duty to yourself to seek answers beyond the "knee jerk" reactions to less than critical thinking... even if it is authored by an "authority."

In many ways you remind me of my own university experience... and, fortunately, learning and critical thinking do not have to be left behind at graduation. I know that to many people I must sound like an old fossil... a curmudgeon so set in his ways that change, even by divine encounter, is quite unlikely. I submit to you that all of my opinions are open to review and change... and the construction of several different sound system configurations over the past few years is evidence of that fact.

Be careful, Seb... independent critical thinking can lead you down a path of becoming a maverick like me!

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Photo update soon! -HornEd

This message has been edited by HornEd on 04-09-2002 at 09:35 AM

[boa12]

what i've been tryin to say is that no matter how well the mixing is done in movie sountracks, certain fx are better done by wide dispersion speakers. f.e., the fly II when the fly is buzzing around the good dr's head - 360 degrees.

w/ most HT set-ups, the side surrounds are on the long wall. so i'm contending that wdst would do a better job than directs with these front-surround panning. iow, w/ directs you could much more easily have a hole in the sound.

ed, you said, "By the same token, the reflected (ambient) sound of a great music hall is critical to maximal

listening... and that, too, can be helped by the current trend setters in sound mixing. As the

installed base of 6.1 (or above) ready home sound systems climbs high enough, the mix quality of

recorded HT and multi-channel music will likely improve."

ed, are some mixers now using techniques to alleviate this "hole" problem w/ these panning sounds? delay, reverb & such? how are they doing it?

even if so, it would seem a wdst type speak would still produce the best results for these sounds by doing them mechanically in lieu of electronically. but if they can create imaging that replicates wdst then i'd be glad to here it, w/ all directs myself.

so the question is how are they now doing it, & how well & consistently are they doing it?

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My Home Systems Page

[HornEd]

Boa, let's take a recording with which you are familiar... Hell Freezes Over by the Eagles. I believe there is mention made of the session being recorded on 48 tracks. The sound engineers will combine segments, adjust volumes and shape the sounds contained in those 48 tracks to make five discrete tracks plus the bass info track.

By placing similar background content (to one volume or another)on two or more channels... ambient sound is projected into a room... whatever the speaker configuration may happen to be! A wide dispersion speaker mechanically sprays the ambient sound around the room... and that is good in many ways. But, when a sound comes through that is supposed to be localized... it too is sprayed around the room... which is not the effect intended by the sound engineer who mixed the music video.

Thus, a set of three monopole speakers correctly positioned and calibrated in the rear array can provide both ambient and/or discrete sound depending on how the sound has been mixed on the DVD. However, the wider the dispersion pattern of the speaker, the less accurate sounds meant to be "localized" will be.

Consider how well the sound can be integrated to reveal instrument location on a three speaker front array... why should a three speaker rear array be so difficult to be just as seamless.

You bring up the question of panning from back-to-front... certainly the timbre match of identical speakers adds to the realism of the sound pan from back to front and back again. It is very difficult to make a smallish side/surround match the timbre of a floor standing main... no matter how wide the dispersion may be.

The problem is that the speaker, preamp/amp and sound source industries have not come up with a sufficiently coordinated game plan. Hopefully, the future holds a better promise for the future. -HornED

[boa12]

ed, & on the fly II fly buzzing at 360 degrees?

this is a sound you don't want localized. what are the mixers doing to make these sounds sound better with directional speakers? or are they?

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My Home Systems Page

[Seb]

disclaimer: I only posted this link for informational purposes, as I had never seen it posted before, and I thought it was of interest, as the issue itself had been brought to attention several times. Discussion is always good, isn't it?

I myself do not agree with Mr. Tom Holman, as I have tried both approaches and like the direct-radiating one better, because it was able to reproduce enveloping sound fields almost as well as dipoles, and direct sounds (like gunshots) MUCH better. With a 6.1 approach, the point is moot, because as Tom Holman sas it himself 3 direct speakers in the back asre able to reproduce a diffuse sound field much better than two direct, and a little better than two dipole speakers.

Besides, he seems to unjustly discredit Corey Greenberg's opinion because 1) he didn't use THX-certified speakers (he seems to assume that all other speakers are unable to reproduce a flat freq response) and 2) he mistook bright direct-radiating speakers for detailed speakers (essentially he doesn't know how to listen and thus is opinion is worthless). This kind of argumentation alone made me really suspicious, but the fact that a lot of his case is built on early experimentation with little or no discrete 5.1 material, and the rest of his case built on 5.1 (which is IMO not nearly as good as 6.1, which will mostl likely end up a long-lasting standard), which is now kind of outdated, just drove me away. That, plus the fact that at the beginning he simply makes the assumption that everybody agrees dipoles are better for movies, which is far from the truth.

In summary, he may have contributed a lot, but he should update himself and his experiments to keep with the times and with the new discrete 6.1 surround formats that offer the best of both worlds when used with direct-radiating speakers (i.e. provide ambience and directional effects).

BTW, don't worry about me, I didn't wait for University to start thinking critically, and I won't stop at graduation (if that ever comes!) either.

P.S.: I digged out and old "Son et Image" magazine with a VERY interesting interview of Dr. Floyd Toole, and I will try eventually to translate it in Shakespeare's language so that you may all enjoy his insights. Damn final exams, never have enough time in a day!

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http://members.fortunecity.com/sebdavid - go laugh at my crappy website/equipment

http://www.dvdprofiler.com/mc.asp?alias=Sebdavid - go laugh at my puny little DVD collection

This message has been edited by Seb on 04-09-2002 at 01:37 PM

[boa12]

well said seb! for all the different tastes, set-ups & sounds out there, i conclude the best answer is there is no definite answer.

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My Home Systems Page

[HornEd]

Boa, the best implementation of a fly buzzing around one's head in the sweet spot would be accomplished by direct radiating monopole speakers. The concept is to perceive the location of the fly buzzing around one's head... and not just a general diffuse buzzing bouncing off the front and rear walls of the room... which is what classic dipole speakers that Tom Holman supports. See how his illustration uses speakers that fire front and back but not in the direction of the sweet spot.

One of the best examples of sound mixing I have observed is the one that was developed to aid combat pilots in identifying the direction of an approaching enemy... and it was achieved on two-channel headphones! I consulted briefly with the start-up company that brought this technology to the computer gaming industry. It was uncanny to "hear" a helicopter buzzing around my head when I knew that the only speakers in the room were a single pair of two-channel mains.

Seb correctly, IMHO, observed flaws in Tom Holman's presentation and, it seems, that Seb and I have come to similar conclusions from our separate experiences. Seb posted the link as a point of information to stimulate discussion... and not as a point of difference with me. I have a great respect for his scholarly approach to problem solving and his ability to think critically. I don't always agree with him any more than I would expect that he would always agree with me. Neither of us seem to fear admitting when we have made an error.

It is papers like this one of Tom Holman that suggest solutions that do not hold up in point of modern audio technology as Seb clearly demonstrated. -HornED

[boa12]

ed, yes this is just a debate. but this is going in circles like the fly. dipoles aren't wdst. sorry that's I was refering to wdst.

wdst speaks generally do a better job imho for frontside to backside panning effects than a direct speaker stuck in a wide hole because they also maintain the direct element.

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My Home Systems Page

[avman]

which brings me back in..hi y'all! the ksps-6's ARE pointing toward my sweet spot, at least the front array of the speaker is,while the back array fire into the plastic covered/painted fiberglass-backed panels that make up my ceiling and in this case, rear wall,and the bricks of the side rear walls.they are positioned about 2 1/2 ft.above my head in a seated position,and about 4 ft.behind me,about 2 1/2 ft.forward of the rear wall. on 'eagles,h.f.o. in dts, 7 bridges road sounds great, w/all 5 voices be localized. in movies where sound pans l to r,and/or front to back, i'm not detecting any 'holes',ESPECIALLY on 6.1 encoded material,i.e.:t2 metal box edition,opening scene toward the end of the 'battleground'footage, a terminator turns toward the camera and fires, it sounds like i have a center rear!

so, it seems as though the trend for my ht setup to have come together 'easily' w/many thanks to all on this bb,friends in 'the biz',and devine intervention-really,my ksps-6's are working well for me.

i would like to try some other configurations, and have the electronics to add an actual center rear,but the concept of a klf-20/30 main center is of more interest at this time i'm not doing any of that, i'm trying to find more time to listen to my system!

last note: i absolutely see what hornEd means about sound mixing w/3 direct rears being able to give both kinds of sound,direct and ambient,by changing the level-per-channel 'mix',think about the l to r panning across the front, and how that sounds, especially w/identical speakers. avman.

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1-pair klf 30's

c-7 center

ksps-6 surrounds

RSW-15

sony strda-777ES receiver upgraded to v.2.02 including virtual matrix 6.1

sony playstation 2

sony dvpnc 650-v 5-disc dvd/cd/SACD changer

dishnetwork model 6000 HD sat rcvr w/digital off-air tuner

sony kv36xbr450 high-definition 4:3 tv

sharp xv-z1u lcd projector w/84" 4:3 sharp screen

Bello'international Italian-made a/v furniture

panamax max dbs+5 surge protector/power conditioner

monster cable and nxg interconnects/12 gua.speaker wire

KLIPSCH-So Good It Hz!

This message has been edited by avman on 04-09-2002 at 03:53 PM

[T2K]

After reading this thread the idea of something buzzing around comes to my mind too,boa. And to quote PWK that something is "BULLSHIT!".

I would like to hear from the posters here as to what non-direct radiating speakers/other components/set-up they used upon which they base their scholarly opinions.I'll go first: Klipsch KSP-S6's(see sig),Klipsch KT-DS THX certified dipole surrounds.

I'll not go thru Mr.Holman's article and try to 'splain his meaning to you Seb because it appears you either do not or can not understand his meaning.For example(without re-reading the article)he may have discredited Greenburg's dismal findings because THX certified speakers would,as you know,have met THX criteria........

Heck, I'm tired of butting my head on this subject.Common sense,logic,and experience should bring questions to mind in regards to this ?debate?.The WDST speakers that Klipsch offers(RS-7)address the issues brought forward here.

A monopole radiates monopoly?.The WDST's radiate in a diffuse pattern with some localization.

EDIT> Misspeell.I hate mespells!

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KSP-300 FL/R

KSP-C6 CENTER

SW8II C/SUB

KSP-S6 SURR

KSP300 SB

SW12II

SONY KP53XBR35 RP

DENON 3801

DENON DVD3300 DVD-A

SONY MDP455 LDP

ACURUS 125X5

ACURUS 100X3

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KG5.5 FL/R

KLF-C7 C

KT-DS SURR

SW12II

This message has been edited by talktoKeith on 04-09-2002 at 04:07 PM

[Seb]

I have tried both real dipole surrounds from a couple companies, most notably Energy.

I have tried Klipsch's WDST approach (which imo is better but not as good as direct-radiating) with the Synergy line.

I have tried direct-radiating approaches in my own environment, of course, but also with a Klipsch system with SB-1 in back and SF-2 in front.

The best results are in a 6.1 config with all direct-radiating, again IMO.

And I know he was discrediting Mr. Greenberg's opinion because of his non-use of a THX certified system, my point is precisely that you do not NEED to have a THX-approved system in order to have flat freq response and good tonal qualities, among other things. I regard THX as an aid to newbies who want to make sure their equipment is of a minimum quality standard, but not as the be-all end-all of home or theater audio. The fact that Mr. Greenberg wasn't using a THX-certified system in no way justifies putting his opinion and results aside. That is just snobbish, I-know-the-truth-and-you-don't, I'm-Mr.THX-man rethoric. I am sure Mr. Greenberg didn't use a Bose system in his research, as I am sure he is knowlegeable enough to distinguish between a bright and a detailed speaker. So there.

Plus, THX is basically prostituting itself with their THX Select standard you find on some JVC and other mass-produced electronics. Ridiculous, THX is starting to lose all meaning now.

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http://members.fortunecity.com/sebdavid - go laugh at my crappy website/equipment

http://www.dvdprofiler.com/mc.asp?alias=Sebdavid - go laugh at my puny little DVD collection

This message has been edited by Seb on 04-09-2002 at 06:29 PM

[maxg]

This divergence in the "proper" structure of a surround sound system is going to run and run.

It is interesting to note that Sony recommend 5 identical monopolar speakers for SACD surround. They state specifically that bipole rears (as specified by the THX standard) are not suitable for SACD surround sound music.

This would imply to me at least, that SACD surround is created for monopolar rears and that therefore is pre-designed to create the ambience and diffuse sound craved here.

In other words which is better probably comes down to how each individual multi-channel recording has been created.

As someone who has no centre channel I am happy to rely on soundstaging for both front and rear channels to fill in the gaps. What might surprise people is that I would rather expand my system by adding 2 intermediate bipolar speakers (side speakers) to fill in the gap between front and rear rather than a centre channel at either end.

In summary therefore I would say that the ideal surround sound system would have direct radiating speakers front and rear and bipolar's in the middle - which would come out as 8.1 allowing for front and rear centre channels.

I would expect that the above setup would be ideal for both multichannel music and for the movie experience - in other words diffusion where you need it and direct targetting when required all in one system.

Of course I am also something of a maverick in MC. I use 2 stereo amps rather than a receiver and the built in decoder on my player to achieve surround sound. I also run my sub off the mains rather than the dedicated LFE channel so it is probably safe to ignore this.

Just my $0.02

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My System: http://aca.gr/pop_maxg.htm

[Steve Crowley]

I have read the following posts and can truly feel what in the hell are you concerned about? If it sounds good to you then live with it. As a regular member of the Houston Symphony I do not know of having members of the orchestra sitting in different corners of the hall playing their instruments. The only exception to this is Tannhauser when the brass is at the back of the hall and only have I heard this one time while at Sam Houston State back in '74. It was conducted back when Dr. Fisher Tull was director of music. As having very old equipment and in two channel I have begun to assemble some HT equipment by reading the posts of all the great people who have given great responses. Movies do sound better now that I have put together some equipment, but I still prefer good ol' 2 channel. One thing I have noticed about Klipsch speakers is that they do produce effortless dynamics associated with classical music. And one thing to remember is that no two music halls will reproduce the the same timbre. The Berlin Philharmonic hall has adjustable reflectors for the size of the orchestra in order to maximize the sound from the stage for coverage to the audience. I want to thank all of you for great info on getting into Home Theater.

Two channel system

Grommes 2 channel(20wpc) circa 1956

Grommes Monaural FM (really need stereo)

Heresy '78

Thorens TD124 B&O cartridge

HT

Onkyo 797

Same Heresy and TT

KV-2 Center

KV1.2 surrounds

SW8 sub

Sony DVD (I did not know pictures could be this clear)

[HornEd]

MaxG, what you say does make good sense for the present. Actually, for most listening environments, a single wide dispersion speaker for 6.1 or two monopoles toed-out for 7.1 will work in the same way to fill any ambiance gap in the rear array.

These days, most rear center channel information is a product of building a matrix from the rear channels of 5.1 source. So a wide dispersion speaker between the left and right side/surrounds seems entirely in order.

Of Course, when you have source material with discrete sound available, like dts 6.1 Gladiator, you can always square up the monopoles to hear what the sound engineers intended.

You are right on the SACD calling for identical speakers. Mixing for identical speakers make the mixer's job easier... there is no need to try to match all the most prevalent sound system set-ups. Also, it is difficult to achieve a sound to match the mains with auxiliary speakers that have considerably fewer cubic inches and are not ported.

I have just finished reading the new book on PWK... and it covers Mr. Paul's preference for "three-channel stereo" which he derives from the Left and Right Mains. MaxG, you should pick up a copy, the drawings, schematics, old Klipsch ads and photos should make for good conversation at the Athens Audiophile Club. -HornED

[avman]

what i've found with the positioning of my ksps-6's (about 4ft.behind my head,3 1/2 ft.up//23 ft.deep by 12ft. wide room size)is the forward-facing array(horn AND woofer unlike the rs-"x" series whose woofer faces the side)is that that array points toward my 'sweet spot' and the rear wall (plastic-covered,painted fiberglass tiles)may not be too reflective?+the s-6's are about 2ft. in front of the rear wall,so they don't 'hit' the middle of the back wall. they do a GREAT job of simulating a center speaker on 6.1 encoded material, as well as sounding good w/ sacd multi-ch. music and other surround sound formats dd,dd-ex,dts,dts-es. the sim ctr rear is well placed between the l and r surround, but i get great separation on material like 'seven bridges road',where too diffuse a surround would sound really bad.

hornEd-buddy-are you suggesting a wdst or wide dispersion center rear?? i would think a direct radiator would be more appropriate in that position so as not to muddy up the l,r rear surround.why would a wide dispersion speaker go there? did i misunderstand?

ps:the biggest problem i have w/sacd ISN'T my speakers, it's not being able to use my sub on 2-ch sacd discs, and LOW output on multi-ch sacd.

man, am i glad i've got klf-30's(can i get a a-men?)when i'm using 2-ch sacd, that's as pure as you can get-dsd decoding to straight-thru-to-amp signal, w/a pair of 30's waitin' to let 'er rip!,but i'd like to get the rsw-15 involved.

avman

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1-pair klf 30's

c-7 center

ksps-6 surrounds

RSW-15

sony strda-777ES receiver upgraded to v.2.02 including virtual matrix 6.1

sony playstation 2

sony dvpnc 650-v 5-disc dvd/cd/SACD changer

dishnetwork model 6000 HD sat rcvr w/digital off-air tuner

sony kv36xbr450 high-definition 4:3 tv

sharp xv-z1u lcd projector w/84" 4:3 sharp screen

Bello'international Italian-made a/v furniture

panamax max dbs+5 surge protector/power conditioner

monster cable and nxg interconnects/12 gua.speaker wire

KLIPSCH-So Good It Hz!

[boa12]

i think ed is not digressing from the direct rad(s) as rear surround logic, but instead suggesting they be placed on lazy susan(s). that's another idea along the lines of my swivel-horn auto direct/reflecting electronic que surround speakers.

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My Home Systems Page