Axiom Home Page Forums General Discussion Home Theater Axioms vs. NHT for Home Theater - any thoughts?

Chess:

The NHT M5 has a 3.5 inch mid-range as well as a 1" tweeter and two 5 inch woofers. You must be confusing it with some other speaker. I have in-house an M5 (actually 5 of them) and a CSW MC500. The CSW has a 4" midrange on the same plastic baffle as a 1 inch tweeter. The baffle is rotatable. If you play it horizontally you put the tweeter above the midrange. If you put it verically, you roatate it 90 degrees, so that the tweeter is above the mid-range. i doubt CSW would have gone to his length and expense if they didn't feel it helped the sound. Again, I would love to see anechoic measurments of the VP150 at 0, 15, 30 and 45. I would bet loonies to Krispy Kremes that there is a mid-range suckout as you move off axis. Now Ian will say it's not audible. I heard it (not just with pink noise). As I moved off axis I heard a change in timbre of the voice. I attributed this to the offaxis suckout inherent in the design. I do not hear the same change in timbre with the CSW500 or the NHT M5. Have you ever lived with a center that is a 3-way design with a centrally located mid-range and tweeter? I have lived with many. I wanted to love he VP150 but it didn't work for me. It did not sound as accurate (to me) as any of a number of centers I have had in my house.

Quoting Alan is great but there are a number of writers who argue that a properly designed includes a mid-range driver to minimize suckouts. In fact, the only place where I have heard it argued that this is not important is ...here. If it makes you happy, more power to you.

Tony,
I don't doubt you believe what you have heard but a large part of my point is that what you heard seems to keep changing. Never in your previous posts did you say that you also heard this effect with music, and now all of a sudden you say you did.
Previously you had reported a 2dB SPL difference (which somehow moved up to 5) which is barely distinguishable to the human ear, and now you are saying that the timbre also changes off axis.
Can you understand how all your scattered reportings are casting doubt on your reflections about the VP150 as an ineffective center channel?
What is really going on here and what exactly have you done in the past to solidify your personal results? Did you measure the VP150 with pink noise first, detect some difference, then listen to music and say "oh ya, what's up with that?". Did you then test out the other center channels in the same way or were these center channel tests done first?
Why would Axiom sell a speaker model (that has been tested off axis both with sound measurements and as well human sound tests) that is so incredibly flawed?
They certainly do not come off as the type of company that sells by marketing and not research. In fact, if i remember correctly, the VP150 started off as a WTWTW config and the sound tests concluded that the TWWWT config was preferred by blind listening tests and by the gist of it, sound measurements as well.
Do you think Axiom has not done off axis measurements with the VP150? Why do you think they would sell this model as an improvement in soundstage dispersion over the VP100 which is a standard 3 driver config (like so many other apparently more? successful center channel companies' designs)?
Why do you think placing a tweeter above a woofer will remove this 'suckout' effect?
How do you figure placing the tweeter in the middle of a woofer config will remove this effect? Why can you not measure an off axis response with the M2 placed on its side? My M60s on their side certainly have it.

I was over at a friend's place and recently measured the off-axis response from his Tannoy center channel (a single driver). It was not a 3 driver config but the Tannoy design is unique in its sound dispersion. Nonetheless, the dB dropped rather quickly (-5dB) after moving to the far left of his couch (7 feet) and beyond, probably about 110 degree off axis. My VP150 did not. I had to move to about 130 degrees off axis and an extra 4 feet left of my couch (7 feet long so total of 11 feet) at 8 foot distance to measure another 2dB drop beyond the one already measured by all of us (total of only 4dB lost at 11 feet left of centre of VP150!!).
I would say that is a pretty impressive sound stage, far more than the single driver config. This was measured only with pink noise though as i would have had to unhook all my other speakers to isolate the center channel with music playback. With all front channels driven, there is NO loss in SPL like what is measured with pink noise isolated to one channel and this IS something that is incorporated into the idea of setting up one's HT surround system properly. EVEN if a speaker had some issue such as comb filtering, again something Alan also concurred with, the effect is minimized with the speaker setup as a whole.

I am certainly not saying you should have loved the VP150 but i'm doubtful about the dramatic sound difference (during music or movie playback) you report and the reasonings that are being presented to support it.
The only reason to think a difference exists for you and no one else comes down to the room and the dispersion of the VP150 specifically. Perhaps you have one truly unique room.

Nor have I said in the post you are quoting that I heard it with music. Please reread.

I'd love to see those anechoic measurements at 0 15 30 and 45, though.

Re why Axiom would develop a flawed center: for marketing reasons. It's tough to develop a 3-way center and have it fit under or above a TV. 2-way centers were developed for marketing and not best sonic performance reasons. If you go out a little more (outside of this forum) and read some of the center channel tests done by SGHT among others you'll actually see what I'm talking about. Two way designs with HUGE suckouts off axis.

Re the suckout, it has to do with wavelengths and driver interference. I posted the question about pink noise and driver interference on the Lexicon forum (describing my measurement results) and here are some of their comments:

"I just checked that website.... the driver layout of that speaker is going to cause all sorts of interference problems in the area the tweeters operate in. Wether or not it also does this in the woofers will depend on where they cross over. Since this is a two way speaker I'm sure the woofers are be driven very far into the region where they are comb filtering between them. They would need to be crossed over probably around 300-400hz or lower to avoid most problems. They are instead probably being run into the 2-3kHz range."

and

"The NHT Evolution series are really smartly designed, and takes into consideration these dispersion issues. I'm not surprised that you liked them. I was very shocked to see the configuration of the Axoim center channel. I don't even know what the designer was thinking. It's possible that the dispersion of the tweeters are very narrow so they don't interact very much, but this would then imply other serious problems elsewhere. The designer may have access to NRC's facilities, but a tool is only as good as its user, and for something as complicated as speaker design, many tools often lay out booby traps for their users."

Now maybe Ian is on to something, but it certainly is not a driver layout that is supported by generally accepted loudspeaker design theory.

You seem to think I have an agenda. What do you think it is? I certainly think you have an agenda: to justify your purchase and defend it against any criticism. More power to you. I am happy you like the VP150. Again, I wish I could have. I ordered the VP150 because I was thinking about moving to an Axiom system. As I stated way back when: I like to change every year or so. Variety is the spice of life, I feel. (Not in women, I've been happily married for 25 years). And I was very, very impressed with the M2i. If I could have loved the VP150, I'd be grooving to a complete Axiom setup this very instant. Unfortunately, the anomalies I heard (and measured) made it a non-starter for me. Again, if this is such a great driver layout, how come no other manufacturer has picked up on it? I think it has to do with loudspeaker design theory. What do you think?

As I've frequently pointed out, I think that the way to go is to simply put a bookshelf speaker vertically just above or just below the screen(e.g.the M2)and forget it. Again I don't know to what extent the TMMMT configuration changes the situation, but since the reference Tony makes to the SGHT tests on MTMs hasn't been illustrated, note my reply in this thread on page 2 in which I linked to an SGHT review in which measurements at various frequencies and angles demonstrated a problem with the MTM there. Tom Norton also comments there on turning the thing vertically if it had been possible and the desireability of using their smaller speaker vertically instead.

Thank you, JohnK. I would do the links, but for the life of me, can't figure out how. They don't seem to work and I went to the help section. I've got to figure them out!

Tony, click on FAQ and then on "Can I use html..." to see the form for url links or hyperlinks. Then just fool around on the preview area until you get it right.

Thanks again, John.

http://www.axiomaudio.com

By golly, I've got it!

Thanks, again.

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...many manufacturers such as NHT...etc include proper mid-ranges above or below the tweeters in their high end center channel. They do it, so you won't get these measurement anomalies that you get with the WTW or TWWWT arrangements...

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It's interesting that B&W uses essentially the same WTW arrangement of the VP100 in center channels up to the LCR600 S3, which is considerably more expensive than the VP150. Their specs say dispersion can vary by 2db within the LCR600 reference axis, which is about what I measured on my VP150. Just an interesting comparison; most people would consider B&Ws to be decent speakers.

Ok tony, one more round.

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Nor have I said in the post you are quoting that I heard it with music.

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Then if you did not hear it with music, why conclude the VP150 is faulty?
The pink noise test is not completely relevant due to its nature. Music is relevant.

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If you go out a little more (outside of this forum) and read some of the center channel tests done by SGHT among others you'll actually see what I'm talking about.

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If you get all your info from magazines then you really are misunderstanding alot. Magazines are not scientifically reviewed publications and their results for tests do not hold water. I read alot more outside this single forum. Do not assume i'm stuck only here at Axiom. That would be a very erroneous conclusion.

Regarding posts from other forums:

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I just checked that website.... the driver layout of that speaker is going to cause all sorts of interference problems in the area the tweeters operate in.

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This conclusion is based on what data? Visual assessment of the drivers?
That is truly a biased opinion if i've ever heard one.
The rest of his post from what you clipped out, does not answer anything.

As for the second posted reply:

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The designer may have access to NRC's facilities, but a tool is only as good as its user, and for something as complicated as speaker design, many tools often lay out booby traps for their users."

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I will be sure to let everyone know after the Axiom tour if all i see is a bunch of monkeys in a room with typewriters.
I will also be sure to test Ian and his skills with a measuring ruler. After 20 years of working with sound electronics with one of the most revered acoustic scientists in the field (Dr. Floyd Toole) at a very expensive government lab, yes, this guy must be right. Ian doesn't know a damn thing.
How incredibly insulting to Axiom and their engineers.

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Now maybe Ian is on to something, but it certainly is not a driver layout that is supported by generally accepted loudspeaker design theory.

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Generally accepted?
You've got to be kidding me. This poll came from where exactly?

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I certainly think you have an agenda: to justify your purchase and defend it against any criticism.

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Insulting my integrity or the integrity of anyone who made a decision to buy Axiom speakers based on their always open policy for providing useful and scientifically credible information about their products will not change the fact that you also own Axioms. Perhaps you had better return your M2s since according to the poster from the Lexicon forum, they apparently equate to nothing more than a cardboard box with some metal parts constructed by a boob.

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Unfortunately, the anomalies I heard (and measured)

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Once again, as you stated at the beginning, only heard with PINK NOISE!!!.
I refuse to try and explain that concept again.

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if this is such a great driver layout, how come no other manufacturer has picked up on it?

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The Honda Civic is probably the world's best car for gas mileage near 70mpg. How come every car maker does not make an equivalent? How come only Honda and Toyota are producing hybrids? They are also a new and great idea. If so, why haven't the other companies hopped onboard?
This argument is incredibly feeble as proof of anything. Please quit using it.

Incidentally Tony, there are alot of questions from my last post that you have not answered. Holes in the story must be filled.