I have heard from multiple sources that the book 'Getting Better Sound' by Jim Smith is the holy grail of speaker & equipment setup.

So as I read through his book there are multiple items that do make some sense but other parts that fly in the face of what was told to be right.

On tip #20 through #23 he touts that all your speakers especially the front 3 must be the exact same as that is the only way to make them all sound the same.

His take is that any change to the shape and components in one speaker to another would change the characteristics of how sound radiates from that speaker and so what you hear will be different than what was intended on the recording. (OK maybe)

On his tip #26, he tells that you should just say no to horizontal centre channel speakers. So even having the exact same speaker but putting it on it's side, the sound dispersement will change, so it's more directed along the horizontal axis and more wide in the vertical.. where as a vertical speaker orientation like you would have with your left and right will be the opposite.

He then goes on to say if you abosolutely need to have a horizontal speaker then you need one with the tweeter directly over top of the mid range.

The VP160 would fit that bill.

But I am wondering if he is talking in generalization of misinformation and making broad assumption that all speakers are made the same.

So for instance, will the tonal quality and sound dispersement of a VP180 be vastly different than that given off by a M80 speaker? Or have Axiom taken those issues into the design to make the off axis dispersement on the horizontal speaker match that of the vertical main counterpart?

To put Jim Smith's optinions into perspective, his tip #24 is not to have any centre channel speaker at all as he feels it is not needed and a better set of left and right speakers can generate a wide and detailed enough sound stage with out it.

I have not tried out every speaker combination to prove or discredit his posting. But I also know that people like Alan Loft don't just pull the company line because a dedicated center channel is cool. He goes with what actually works and is proven

One word.
MARKETING

Not "vastly" different. I know that Ian designs around this concept, and IMO is very successful. But you can't get EXACTLY the same dispersion out of an enclosure of such dramatically different proportions.

A phantom center channel only "works" if you don't care about people outside the sweet spot.

That's the good thing about the LFRs, it sounds like the surrounds are on in direct mode.

Matt, I'd be in general agreement with most of those views as you describe them. On the separate center speaker point there are two advantages: the volume of the center channel can be increased independently of the mains to compensate for the low dialog level mixed into some movies; the center channel image stays anchored to the middle of the screen for off-axis listening, while the "phantom" center image shifts to the outside to stay in front of him as the listener moves to the outside(but not farther out than the speaker on that side).

This phenomena is definitely known by Axiom as in their blog about speaker placement of bookshelf speakers there is a section talking about putting the bookshelf speaker on it's side



But what they don't go into in the video is if that knowledge was used in the design of the centre channel speakers and they are constructed in such a way to overcome that phenomenon.

If I am paying over $1000 for a centre speaker to match my M80, I would like it to sound right, and not off-axis different.

Hello Matt,

A couple of points need special emphasis here. As JohnK has pointed out, advice about not using a center channel to anchor dialog at the screen is really limiting: you can't adjust the dialogue volume levels for lots of movies that are mixed with too-low dialog levels, or to compensate for hearing losses with age. All men over 50 suffer such losses to a greater or lesser degree, and the losses increase with age for most men.

Also, no two identical speakers will sound exactly alike using an ultra-critical test signal such as pink noise, because of the speakers' locational differences and boundary effects within the room. Try it if you want to confirm this: use pink noise and switch from the left speaker to the right speaker of an identical pair. You may be surprised at the tonal coloration that room effects cause in two identical speakers. The result is that using a third M80 as a center channel will not result in all three speakers sounding precisely the same when you do comparisons with pink noise (the latter has equal energy per octave across the audible spectrum).

However, such small differences in tonality that are audible with pink noise are not significant with program material -- dialog or music. Our brain and hearing system accommodate small differences in coloration, and blend the three front speakers into a cohesive front soundstage.

I did double-blind listening tests to the prototype Axiom VP180 and an M80 floorstanding tower. The VP180 is extremely similar to the M80, but not identical, however, it's a wonderful center channel that blends very smoothly with the M80 floorstanders.

I suspect that Mr. Smith may have not done careful listening tests using pink noise to three identical front speakers, otherwise he wouldn't make such statements. The slight differences in coloration from room effects and design configuration of the center speaker are simply not significant when playing back dialog or music.

You'll find the VP180 center speaker will be quite transparent and a beautiful match to the M80 towers.

Lastly, I do not work for Axiom anymore. I'm retired, and any contributions I make to the forums are purely to add what I've learned from decades of professional experience and because Axiom does indeed make highly neutral very good speakers at remarkably low prices.

Regards,
Alan Lofft

Alan - Excellent response, as always.

Warmest congratulations on your retirement!

The fact is, what he is saying in his assessment is nothing new. The actual THX parameters that they touted for years said the same thing. Also, for many years, the gurus at "Widescreen Review" emphasized this idea back in the day especially during the introduction of 5.1 DD and DTS soundtracks in the early nineties and carried the idea even further. I believe Andrew would probably remember the large flagship Mirage bipolar speakers that Widescreen Review had set up in their review listening room, these speakers were positioned in ALL the channels, not just L/C/R.

Of course, much of this is impractical, including many of Smith's ideas because of space and that is why horizontal centres were developed. Certainly they are a compromise but once you integrate a large full range centre channel in to your set-up(VP160, 180)they negate a lot of the issues he seems to be concerned about. As we all know, even if they are exactly the same model, just moving speakers in to different positions will change their tonality, the acoustics of the room will ultimately be the arbiter of that.

Unless we are dealing in virtual reality, if one has an HT room set-up and you have a movie night where several people are over to watch a movie, apologies to Jim Smith, but, it just not possible to have everyone sitting in the "sweet spot" at the same time. Full fledged professional movie theatres can't even do that.

My unscientific experimenting with 3 different horizontal WTW or MTM CC speakers (including the VP100) revealed virtually no detrimental audible artifacts until beyond 30 Degrees off axis. Even then the high end drop off was minimal & not a factor in our HT room. I suspect that this would be true in most real world situations. Some of this stuff is a bit overblown IMO.

The reason that I went to the bigger VP160 (with M22s L & R) was because I've been reading all over the net that the movie soundtrack mixes now direct much more content to the CC other than just dialogue. Bigger CC Speakers such as the VP160/180 are much more capable of handling this extended content.

The main problem with large CC Speakers is finding an appropriate place to put them. Many stands just can't handle them....

TAM

Yes. The LP180 that I ordered is quite a monster. The only problem that I have is I have not gotten the movie room built, so it is a little but more problematic to test everything as where they all are right now doesn't even have a TV.

The QS8 speakers really do need to be wall mounted and the wife will not let me make some holes in the walls to mount them in her front freashly decorated sitting room.

But I am willing to say that if the rest of the speaker I ordered sound even 1/2 as good as the M80s, then I am golden.

Matt , you can also take comfort in the fact that we have room correction built into modern receivers which goes a long way to correcting the gross deficits in most rooms. Since you are building a dedicated room , I suspect the room correction will take care of all minor irregularities you may encounter. I have not read the book you mentioned but I did notice it was from 2008 and a lot has changed since then, including peoples willingness to properly prepare their rooms.

The major points inside the book are all about how to go about properly voicing a set of speakers and what to do to acoustically correct a room.

But to put it into a photographers lingo. If you shoot RAW, you can correct many problems in Post Production. But then again, is it not far better off to shoot the photograph correctly (right exposure, light, aperture, shutter speed) when your took the photograph in the first place.

Yes, with room correction technology you can change the sound your speakers emit to compensate for the way that your room effect the sound. or the other option is to correct the room so that it minimizes the negative effects on the sound. But the speakers are what they are. A badly designed speaker will never sound as good as a well designed speaker. I can't ever hope to get my old Celestian DL6 speakers to sound as good as my new M80s. They are simply designed differently and so they product a different sound.

The idea in the book focuses on how to make your system sound like what a sound engineer heard when the mix was made and recorded to your medium of choice. Ideally you would have the same setup as (s)he did during the mix and you will experience the same sound. We all know this is not possible.

So the question goes, does a movie theatre have directional front left and right speakers? Do they have just a single speaker, or a bank of speakers? Does their center channel have it's off axis sound rotate 90 degrees to match the on axis sound coming from the left and right channel? If they don't then how can you expect your HT to sound like the local movie complex down the street?

I guess the most important side to it is asking, how much impact does it really make? Are we talking about a large night and day difference or the proverbial how many angles fit though the eye of a needle. I don't know the answer to that.

In trying to achieve the perfect sound, am I running into that point of diminishing return where yes you can upgrade your sound by 5% but you must invest 100% more money to do so. But I can get you 7% better sound for a 1000% cost to do so.

Thanks TT, for the compliments and best wishes.
I'm still an audio and music enthusiast, of course, and I get more time to indulge in both.

-- Alan

Matt:

Unless things have recently changed in movie theater design, If you were to remove the screen at a movie theater, essentially what you would see is three(LCR) vertical, usually horn driven speakers, plus a long tubular subwoofer. Speakers along the side and rear are direct driven. There are several only because of the size of the space and the number of seats. Once again, with reference to the THX parameters for HT design, they recommended dipole or bipole speakers for the surround and rear since those speakers simulate the multiple speaker layout in a movie theater, however, obviously you don't need all those speakers because the space is, of course, much smaller. Axiom has carried that bipole/dipole design to the next level by having speakers in the QS4s/8s putting out sound in all directions, that is why they are so forgiving to set-up.

Be careful not to do too much over analysis about this since in a home environment with Axiom's offerings you have the tools to easily duplicate the sound if not improve on the actual movie theater experience and I am sure others will confirm what I say.

20 years of playing around with this stuff gives me some insight along with spending a ton of money along the way to find all this out.

I think Matt is enjoying the analysis portion. I think many of us do. It's all part of the fun in the hobby.

Bill

Even having the identical presenter but placing it on it's part, the audio dispersement will modify, so it's more instructed along the horizontally axis and more extensive in the straight.

Currently I am using just L/R and I find that I have to turn up the volumn quite a bit more to get good dialogue in the sound stage.
Then when some action takes place it is too loud.

I find with a centre channel I do not need the volumn up as most of the dialogue is coming from one speaker in the middle and more direct. The when the action takes place the L/R speakers handle the level more acturatly

I love how the towers literally disappear. I've walked up to them numerous times (before and after placing the screen) to see which units were actually outputting sound. Even when you're right up close to them you still need to lean in to separate the sound from the other towers.

It was really interesting when I had all 5 across the room and only 2 connected. It would've been a lucky guess to choose the correct towers.

I totally agree with you. Sometimes I loose focus on the movie because I am marveling at the sound coming at me.