What's the deal with phase in subs? (1 Viewer)

[Doug Smith]

I recently got a hold of one of those tuning up your home theatre DVD's, and a sound meter. The part about putting your sub in the proper phase is confusing. Any easy way for my good old ears to notice when it is either in or out of phase?

 

[John Garcia]

Pretty simple. Assuming you have only 0 and 180, set it to both, and see which gives you better results and leave it that way. Sub phase is relative to the other speakers, and is not exactly an easy thing to hear. You would likely notice if there was a lot of cancellation going on compared to your other speakers, otherwise, it's not a big deal.

 

[Doug Smith]

Thanks - what is cancellation though? And there doesn't deem to be a big defference between 180 and normal.

 

[Cees Alons]

Dough,
Cancellation is when the bass pressure in your room is less than it should, because the big sub's baffle is moving inwards while at exactly the same time the other speakers that are reproducing the same bass (well more or less, of course) are moving outwards and vice-versa. So if your bass sounds weaker - that's probably what's happening!
To avoid a polarity mismatch, you can turn the polarity of the input voltage by an inside switch on your sub. Just listen in which position it sounds loudest.
And the difference isn't that big, because probably the other speakers aren't producing much of the bass frequencies after all! Which is good, of course .
Now, if you had 2 subs, the phase would become mighty important...
Cees