[crwilli]

Originally Posted by Charles

The internal wiring of the XVX and the Thor is such that if you go red to positive and black to ground with the Audioquest speaker cables, the system will be in phase. It cannot be otherwise. Therefore, the phase should be set to 0 degrees for maximum coupling of the Thor with the XVX. I believe this is regardless of where the sub is positioned relative to the main speakers.

Let's take a pair of main speakers and intentionally wire them out of phase. They sound awful. The bass is diminished and the voice sounds disembodied. Anyone who has heard this immediately recognizes the speakers are out of phase. With my Maxx3 installation they let an inexperienced technician connect the speaker cables. I was quite nervous, it being my first Wilson. I heard the sound and was shocked until I realized the Maxx3 were out of phase. With this corrected the speakers sounded great.

I don't believe moving the Maxx3's forward or backward would have corrected the awful sound by correcting the switched wires. I don't believe this type of problem can be corrected by positioning.

Similarly, I believe no matter where you position your subs, if they are wired correctly, they will be electrically in phase. If you are using a sub and main from different manufacturers, due to different internal wiring, even if you obey the red to positive and black to negative rule, your sub could still be electrically out of phase with your mains.

So first and foremost, you must be certain your sub(s) begins electrically in phase with the mains. Placement of the sub(s) in relation to the mains or to each other cannot cause them to go out of phase. That is my opinion.

I believe it beneficial to have the subs in the same plane with the mains, if possible but we are talking about low bass and using positioning to smooth out the bass, so having the sub(s) in the same plane with the mains is not necessary, if you achieve better base with say a corner placement behind the mains.

Using the phase control on the crossover affects the electrical phase and a 180 degree setting is like red to negative and black to positive. Regardless of where you ultimately place your sub(s), altering the electrical phase will alter the bass of your system. This is another way of saying that electrical phase is independent of the positioning of the sub(s) in relation to the mains. This is my opinion.

I previously would have thought that sub(s) out of phase with the mains would only be deleterious in a manner similar to wiring the mains out of phase. No one would ever want their mains to be 90 degrees out of phase with each other, for example.

That's what is so counter-intuitive about Greg Weaver's tip. I thought that the phase control was their to correct for the fact that most of the time sub(s) are behind the mains. I no longer believe this to be the case.

So be sure your sub(s) and mains are wired in phase to begin with. Then position your sub(s) for smoothest/best bass. If still dissatisfied discover the frequency that the 180 degree out of phase most affects and then go from there to see if changing the phase might have a beneficial effect.

It did for me which surprised me greatly. It smoothed out my bass without affecting the quality in the least. In fact it improved the quality.

Best

Charles

I think you misunderstood my comments. I fully agree all your speakers should be wired in phase with each via +/-.

The point I was making is that your sub as well as the JL Audio Fathom I use both have a phase adjustment on them. It is not the same thing as wiring them +/-.

The process JL Audio suggests only TEMPORARILY wires them out of phase because it is easier to find a null or low point than it is a maximum. By finding the null, you will have put the wave fronts in alignment from the sub and your main speaker when you reverse (correct) the wiring on your main speaker.