Axiom Home Page Forums General Discussion Home Theater Question about VP150 v2 and Surround speakers.

okay so i'm looking at getting an Axiom 5.1 system with M22 and Vp150 v2 and showed it to a friend who knows more about auido then i do and he came back with this obversation.

"The Vp150V2 perplexes me. Two tweeters separated that
far apart will interfere with each other. I wonder
how they deal with that. Plus the tweeter to furthest
woofer spacing is large. As a rule of thumb tweeter to
woofer center to center spacing should be less than
the wavelength at the crossover frequency. I assume
they have simulated and measured the response at
various angles, and it sounds good, but it perplexes
me how they overcome the physics."

so how does the VP150 deal with this?

Also i have an oddly shapped room, with sorounds that will be behind and above the listener about 3 to 4 feet. How would the QS4 v2 be vs. the M3 v2. (about 90% of the use would be movies/games/TV not music)

Thanks
Steve

That's a good question. I can't really answer it, but I'm sure someone will be along soon who can.

I just wanted to say welcome.

thanks really like the look and style of the speakers, and they get great reviews, just a speaker newb so doing all the homework i canbefor i drop $1500+ on them.

The best way to get this answer is to call Axiom. Ask for Alan if he is in. He may chime in on this one when he catches up with the boards.

As he is talking about rule of thumb it is not a physics law and it does work as the graphs show on its web page. I also am not able to explain the dynamics behind it. If the VP150 design is holding you back on a purchase, we could use the lay out of the room, at least just the size to possibly let you know if you even need the VP150, the VP100 works very well. . I have a one(VP100) with M22's and 3QS8's sound is great all around, very even.

Not sure why this question keeps coming up about the VP150 design over the years. The VP150 was changed at one point from a WTWTW design to the current TWWWT layout based on years of testing by Axiom engineers. The result is better imaging, the tweeters do not interfere with each other.

Below is a response from Ian back in 2002 in regards to another persons perplexity on how they could possibly create such a design that should be a failure.

"There seems to be quite a bit of confusion over how identical parts interact with each other (the two tweeters) in a room environment. The comment about comb filtering is a red herring. This effect can be measured in anechoic environments but it is not an audible reality in the room. If it were we would have all dumped stereo a long time ago and would be listening to mono again. The off-axis lobing effect of the tweeter and woofer is a reality in the down-axis measurement of all speakers that use a tweeter above the woofer, and does create an interesting dilemma with center-channel design because this phenomena now exists in the right and left off axis in a WTW layout. As to how big an issue this is in the real world is best determined by double blind listening tests. It is audible, especially when seated far off axis from the TV, but always surprised me as to the how slight the effect in the room is when compared to the measurements. A testament to the importance of the family of measurements as opposed to the single axis you are directly seated in. The VP150 driver layout does eliminate this issue altogether by effectively not having this particular axis no matter your seating position. The result is excellent, and it has been proved out in our double-blind listening tests. In fact it was so impressive we actually changed the VP150’s driver array to this layout mid-stream from a WTWTW layout. "

There are others that know more about audio than your friend, I am just not one of them.

that helps. my room size is 18x19x7.5. i plan on using m22 fronts and QS4 rears, just not sure if i should get the v150 or v100. viewing angle will be slightly off axis.

I'd lean towards the VP150 myself... if you're doing a lot of movies and that's where all your dialog comes from, makes sense to ensure you've got the best speaker for the job there (maybe the VP100 would be adequate as well? Never heard one).

It's funny, a lot of discussion goes to mains and subs, but dialog is the meat and potatoes when it comes to movies, mains just take directional dialog and ambience in movies, and they're chosen painstakingly while a centre is just slapped in (or not used at all in the case of "Phantom Centres"). Always found that odd, most people say they use their systems for 75%+ movies, and yet give the centre no love.

And I tested an M22 as a centre channel, and found the inverse of what Hutzal did, that off-axis, the VP150 performed better than an M22 vertically. Seating for 6 in a 90 degree semi circle in my HT, and the VP sounded better off-axis to me.

Bren R.

The VP100 is also an excellent speaker. It lacks bass pretty bad, but that's what a sub is for. It is very clean in the rest of its range. I haven't yet found a movie where I don't know what someone said because of the speaker. The main reason to go for the VP150 would be if you have a really big room and sit far back or like to listen loud. I haven't heard a VP150, so I can't compare the two directly.