Axiom Home Page Forums General Discussion Technical Questions Interference between speakers?

A few months ago i bought new Axiom M80 speakers for the front side of my HT.
The Energy 22 Ref. speakers i was using before were sent to the back for surround duty.
I put them about 1 foot behind me and next to the side walls, facing each other.

Wow, did i have bad sound!
It seems there was interference between the Front Left and Rear Left speakers in such a way that it seemed to produce a kind of flutter echo at some mid frequencies.
This interference seemed concentrated in my auditory canal and was loud and very unpleasant.

At first, i changed the front speakers' toe-in with no effect.

After thinking about the problem for a while, i changed the angle of the back speakers to face the back wall so i would not get direct sound from them, but mainly reflected sound from that back wall.

Result: very good sound.


I would love to have an explanation for the reason i got this interference from those speakers - mainly on the left side, and also is there any way to solve this problem and still keeping the back speakers looking at each other instead of being pointed towards the back wall.
The left side of the room has more sound absorbing material than the right side.

I used for a long time RS Minimus 7W speakers for surround, and never had that problem.

Was the delay setting incorrect on the receiver, resulting in a time-delay issue between the front and rear sources?

or possibly you have your speakers out of phase, wired incorrectly.

I say if it sounds good that way, keep it that way.

i was so sure speaker phasing had been done right that i did not check again with an Ohm meter.

i reversed the wires going to the left rear speaker and now all's nice;
rear speakers facing each other and no screechy noises in my ear.

thanks a lot Sir Quack for your tip.

i double checked the time delay, and it's ok, Mark.

:-D

Wow! I got one right with out JohnK, lol..

do you mean you did not have WAF this time?

;-)
LOL

JB, it's great that Randy was able to point out something that wasn't at all obvious on first impression and that you're okay now.

I've sometimes suggested that when direct radiators are used as side surrounds that they be placed directly alongside, but pointing to the back wall, as you tried. Even with the polarity now correct, it may be worthwhile to try that again in order to get the less direct, more reflected sound that's generally better for surround effects.

I've tried it before, but i think it's better with them facing each other; the imaging from the back spkrs is better.
thanks.

i'd like to add that the Surround Sound decoder i have precedes Pro Logic, and it's very difficult to set up; Yamaha is of no help and even Dolby Labs did not send me a satisfactory answer when i asked them how it should be done.
it is barely a notch above the "Hafler Surround" i used many years ago, and there are cheap parts in that decoder.
that makes me very eager to get a nice new pre/pro.