Axiom Home Page Forums General Discussion Technical Questions Sub phase

I am in the process of setting up my Epic 80 and I just wanted to understand the meaning of phase 0 or 180 in sub woofer? The manual says experiment on which one sounds better but I would prefer to understand what I am experimenting on.

I was also somewhat confused with the one coax wire pre-out from my receiver. The other speaker pre-outs have L and R while there is only one sub preout. It was right beside another pre-out labeled center. On the other hand the EP350 has two coax in (L/R). I almost assumed that I should have used the center out for L and the Sub out for R. I decided against it and used a y connector - one from the receiver then split into two for the sub. The question is would it have been devastating if I continued with using the center preout for L and the sub preout for R in the sub?

Ed, phase can be a fairly long story, but with the 180 setting the sub cone is pulled in at the instant that it would be pushed out at the 0 setting. The idea is to find which setting has the sub cone and main speaker cones pushing and pulling in relation to each other so that at your listening position the bass produced by the combination is loudest. If you have a test-tone CD check the level at about 80hz if this is the crossover point which your receiver sets for the sub and other speakers(set the sub crossover itself to the max setting to get it as far out of the way as possible). Otherwise listen to some bass-heavy material to check. The majority of time the 0 setting will be picked. Don't worry too much about this since phase relationships change with frequency and it's impossible not to have partial cancellations at various frequencies. Incidentally, the best position for the sub is nearly always right in the corner, which gives the loudest and smoothest bass because of being so close to both the floor and both walls. If the bass is too "boomy", the idea is to turn down the sub level, not to move the sub.

As to the sub output on your receiver, it's mono and it's only necessary to connect it to either one of the two inputs on the sub(they're joined inside the sub). Using a y-connector to both inputs is ok and supplies more voltage to the sub, but this isn't a significant advantage and isn't necessary. The center pre-out is for the center channel speaker if you would be using a separate amp to drive it; it has nothing to do with the sub.

John,

Thank you very much. I will just leave it at 0 and my Y connector in. When I find another use for the Y connector, then I will just use one coax cable. I am still waiting for my Sound and Vision DVD for final calibration. But even without it I am already enjoying the clear sounds on the movies and beautiful music from my CD's.