Axiom Home Page Forums General Discussion Home Theater VP150 as left, right, and center?

James, I'm curious as to what you are using for speakers right now. With a screen that big you need big sound

If you raised the screen as much as possible, how much height would you have under the screen?

When using the rated frequency responce of the VP 150 (Freq Resp +/-3db (Hz): 85 - 22 kHz) there is a 6 db "window" within the +/-3db. The graph of the VP 150 is taken in an anechoic chamber. When typical room gain is taken into consideration the VP 150 should have no problem meeting the stated specs.

May be, still kind of strange.

I mean, cover the part of the graph above 500 Hz and look at the low frequency part (that's what we are interested in). An immediate reaction would be: well, looks like the sensitivity is about 90-91 and there is an about 12db/octave roll-off with fc=100Hz.

The +/- 3dB describes some wobble in the mid- and high frequencies but I don't understand why it should change the corner frequency in the low part.

Anyway, even if it is 85 kHz, crossing at 80 would leave a dip in the overall speaker+sub responce. One should cross at at least 120 Hz.

Sorry if it comes up as some dopey arguing, it's not. I really want to understand all this stuff better.

Regards,
Gena

James,

That is cool !

It makes me want to do some shopping. I think I will move my 65" TV into the bed room.

It seems like this sight is full of audio biased people who don't care about the video. I got my TV first(fell in love with HD) and the audio was an afterthought.

But now I really think the audio, especially surround sound, is half the movie experience.

You won't go wrong with 3 VP150's but if it was me I would move the image higher( you can have the center under teh screen), make it a little smaller, or somehow accomodate M60s or M80s.

In reply to:

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I mean, cover the part of the graph above 500 Hz and look at the low frequency part (that's what we are interested in). An immediate reaction would be: well, looks like the sensitivity is about 90-91 and there is an about 12db/octave roll-off with fc=100Hz.

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I'm not quite sure I understand your concern with the roll off under the 85 Hz rating. Why would a steep roll off in the first two octaves be of concern when the 150 is typically crossed over @ 80Hz?

Hello James,

You seem to have my future problem except my pull-down screen is about 84 inches wide in a 143" wide room. My unfinished floor to ceiling height is 82 inches and once the flooring and ceiling go into place I will likely lose about 2 inches. While the room width gives me almost 30" on either side of the screen for "ideal" height placement of the speakers, the center channel will not be in-line at the same "ideal height" (my definition of ideal height is when the tweeters are about at ear level at the seated position).

I believe that in order to get a proper sound-stage, I have to keep all speakers in line. I am considering building a bulkhead over the screen that will house three in-wall speakers. The bulkhead will be built at a slight angle to aim the speakers directly at the listening area. This will also yield the benefit of better soundstage for a second row of seats.

Incidentally, are you using an anamorphic lens for you projector?

Rick,

Theoretically, it is recommend to set the cross-over at the frequency 1.5 to 2 times higher than the corner frequency. Example: for m60 fc=37-40Hz and it is recommended to cross it over at 60 or even 80 Hz. Indeed, when I set it at 40Hz I do hear the excess of 'boom'. My setting is 70z. Following this recommendation for VP150 it would result at at least 120Hz.

I have read that the crossover is recommended to go 10 Hz above the -3db point. So even going by this the VP 150 would be crossed over @ 95 Hz. Seeing that no receiver or subs crossover is a brick wall filter I would expect that even if it where to be set to an 80Hz crossover there would be no hole within the 80 Hz frequency. We also should take into account the other front speakers, even the M22s have an in room response down to 60 Hz. With that taken into consideration I don't see there being a problem.

jamesdmc,

How about 6 M3s. Two each L/C/R run in parallel for each channel. One above and one below the screen for each channel. I find that my M3s have a nice frequency range. Two M3s run in parallel have the same output as one VP150.

Add a EP600 horizontal and you're covered!