Subwoofer Phase with Receiver Crossover

[shelbydz28]

If I understand subwoofer phase correctly, it is an adjustment to overcome cancellation of frequency between the mains and the SW at the same frequency. I have a Denon 3808-CI. If I set the subwoofer crossover to 40Hz – it should not put out below this frequency for the mains and only below this frequency for the sub. In this case is adjusting phase still necessary?

Thanks,

Doug

[TheEAR]

YES

To have a proper setup first set your mains to full range,the sub freq. to a high 80Hz.The sub will cancel the mains in the bass if the PHASE is not matched. After you have set the phase,set your sub to your desired 40hz and mains to start at 40Hz. You are set....well level match them after,that is the easy part.

[Matnick]

Do you go back and set your mains to "small"? Should I set the phase to 0 degrees first to determined if out of phase? I can never understand how to adjust the phase. I never notice much difference.

[Mr. RF62]

I am faced with somewhat the same issue. I move around the room and bass is different, I play with the phase and at different frequencies, it gets louder which means it is being in phase. only in a perfect world would there be NO phase knob. I play with the phase alot, then reverse the polarity through my reciever to see if I should change it again, it can be quite frustrating but I think I'm getting it. Until I move the sub to another location, then start all over again.

[Guest srobak]

There will always be some cancellation *somewhere* in the room. It has to... even between your left and right speakers, as "identical" compression waves reach your ears at different times when you move around the room. You have to position your mains and sub to have the best possible effect in your general listening area - where you plan to spend the majority of your time. Of course you can defeat this a little more by placing more speakers all around the room, but that would also sound pretty messy.

[kelA]

Technically speaking, if you are setting your speakers to a "small" setting with a crossover of 80hz, is it necessary to set the phase for the sub? If setting the phase is to reduce cancellations between the sub and mains, is this a problem with the above scenario? Since your mains theoretically will not be playing the same time as the sub, is this correct? Seems to me it is more of a issue if you are running your mains as large with a sub setting of "mains+sub." I have the sub connected via the receiver by the LFE connection. Inquiring minds want to know.

[CECAA850]

Yes, it is necessary to set the phase on the sub. Try this, sit in your normal listening position. Play some test tones at different frequencies. Record the dB at each frequency (you do have a dB meter don't you??!!). Change the phase on your sub and measure again. You'll see how important it is.

[Mr. RF62]

I for the life on me don't know why I didn't think of doing that. Yes I own a dB meter and out of sight out of mind. Got it going last night and got it, it works awesome. Thanks for remindeing me that I have a dB meter CECAA850.

[CECAA850]

No problemo.