Axiom Home Page Forums General Discussion Technical Questions 7.1 channel speaker plcmnt in a fairly large area?

I had heard null-ness (I'm prone to making up words as I go, so bear with me gang) can be made less null by playing around with the polarity switch on one of the two subs.

Have I missunderstood this? Let me know!

Thanks

WOO-HOO! I've been promoted from NEWBIE to REGULAR!

...so can I post links and photos yet or do I have to keep begging?

You can post photos and links anytime you wish. Go wild.

>>I had heard null-ness (I'm prone to making up words as I go, so bear with me gang) can be made less null by playing around with the polarity switch on one of the two subs.

Yes and no. The phase switch helps in two specific cases :

1. You have two subs and the signals from them are cancelling out in a part of the room where you like to sit. Flipping the phase means the signals will add at that point rather than cancel, although remember that this is very frequency specific.

2. You are running your mains in "large" so they are producing bass alongside your subwoofer, with the same cancellation issues as in (1). Here you are flipping phase relative to the mains, but the effect (and frequency dependence) is the same.

With a single sub running your mains in "small" the phase switch can affect how smooth your response is in the crossover region between mains and sub but that's it.

Thanks Obiwan Bridgeman!

It looks like I'll have some experimenting with my sub placement.

Heck, perhaps I'll sell off the Cerwin Vega sub (although I've heard the 350 is "moderate" (not strong) and stick with a pure Axiom system (I know my wife would love for me to give up another object and put the cash toward my toys)!

Here is (I hope) a photo of my old basement. Some of it may be distorted due to the wide angle lens that I had used. You'll get an idea of how close everything was.

http://www.spencesplace.com/images/Temp/P1010060.JPG

and a photo of the new Home Theater, looking from the back wall, to where the entertainment system will be located.
http://www.spencesplace.com/images/Temp/P8070127.JPG

CRAP! How is it that I can make a living, supporting end users and repairing PCs and I can't get a freak'n photo posted!

Here you go.

>>CRAP! How is it that I can make a living, supporting end users and repairing PCs and I can't get a freak'n photo posted!

ROTFLMAO !! Welcome to the club

Regarding speaker placement, Rives has some interesting reading :

http://www.rivesaudio.com/files/spkr_plcmt.pdf

Here is a follow-up to my earlier question. Thank you all for your responses. Given the advice and the links to suggested speaker placement, I have been able to come up with (thanks to my intermediate level of experience with Photoshop) the following, as proposed speaker locations;

Photo at: http://www.spencesplace.com/images/Temp/HT1.jpg

Note:
The view in the linked photo, is taken from where the area where my home theater screen will be located.

Due to limited photographic source material (photos of the QS8's), I was unable to show the orientation of the right and left surround speaker.

Main front speakers (M22ti) will be separated by about 15', about 14' away from the listening/viewing area.

A VP150 center channel speaker will set on top of my 65" Mitsubishi HDTV.

Right and left surround speakers will mount to the underside of the main support beam, about 14' from the home theater screen and will be separated by 16' to 17'. They will aim directly at each other (toward the listening/viewing area), but will be aimed downward slightly, in order to open up the drivers on top of the QS8s.

These will be mounted on the back wall at the same height as the right and left surrounds Rear surround speakers (mounted to the beam), approximately 27' from the home theater screen (about 13' behind the listening area). They will be separated by 6' to 7'.

The EP350 subwoofer will sit (depending on sound quality) in the corner of the room, 8' - 9' to the left of the home theater screen.

A supplemental 15" Cerwin Vega down-firing subwoofer will sit (again depending on sound quality) will be in the opposing corner (left side of photo at the rear of the room).

6" R19 insulation will be installed in all studded walls and between ceiling joists. 1/2" sheetrock will be on all walls, and acoustical suspended tiles (with high noise reduction rating) will make up the ceiling.

Question: The primary seating area will be located to the right of the post, and can be moved to be either slightly forward, backaward or centered on the support post (containing dimmer controls for the house lights). The post will be trimmed out in either sheetrock and painted to match, or oak panel (stained to match the room's trim).

Will the location of the post, in relation to the surround speaker pose any acoustical problem?

If the post poses a problem, I have the ability to move the right and left Surrounds speakers up to 5' to the rear of the post. Should I consider this?

Thanks again,

Spence

The photo assistance squad strikes again!