Hybrid90

Can someone please help me understand what the "phase" button on an amp is for? I just finished my system and on my amp.. there's a button that switches from 0-180 and on top of it it says phase.

What exactly does that do? I tried switching it back and forth but don't hear a noticeable difference in sound.. please explain.. thanks!

Paul350Z

iTrader: (1)

The phase button switches the output polls on the subwoofer flipping the woofer's phase. Depending on the listening and speaker locations you can or can not hear the difference.

VO...

iTrader: (25)

Paul, I've always questioned the functionality of this button. I know what a phase change physically does to the woofer, but does it really serve a purpose? I've reversed polarities on a sub, and IMO it sounds horrible. The only reason I'd see to reverse polarities is if:
1. You're using some type of push-pull configuration
2. You messed up the polarities when wiring up the sub and are just too lazy to rewire everything, so you flip the switch instead

Please clarify what other beneficial uses this option offers.

StreetOC192

iTrader: (7)

It reverses the + and the - on the sub. Like said above, depending on where the sub is located it can cause cancellation in the sound where the sub and mids overlap frequencies. What the phase button does is make it so where the sub would normally push, it will instead pull, and vice-versa. This way, instead of cancelling the overlapping frequencies, it will reinforce them.

Hybrid90

The amp I'm using with the button on it I'm using for my surround speakers not my sub. So what exactly does this button do? You can switch from 0-180.. what do those numbers mean?

VO...

iTrader: (25)

Personally I've never heard a "good sounding sub" when it's pulling.

I'm trying to conceive an application where it could be benificial.

VO...

iTrader: (25)

You're probably better off just knowing that one way the sub pushes outward when it hits, but sucks inward when it hits if the button is switch to the other position. It's alittle complicated going into theory.

Hybrid90

So basically this is mainly used for subs? My amp is connected to my surrounds.. so should I set it at "0" setting then?

StreetOC192

iTrader: (7)

It's hard for me to explain without drawing a diagram....let me try this - pretend the lines below are sound waves:

This will cause cancellation of the sound, the sound waves are opposite each other, while the sound from the mid is up, the sound from the sub is down:
Mid _--_--_--_

Sub -_--_--_--


Reversing the phase to "180" will make the sub react the exact opposite of what it does at "0", like this, which will not cancel the sound waves:
Mid _--_--_--_

Sub _--_--_--_


99% of the time you will leave this setting at "0", it's that 1% that it comes in handy and you are glad the feature is there.

StreetOC192

iTrader: (7)

Yes, leave it at "0" and forget that setting even exisits....Phase is not as much a problem at higher frequencies, although it does exist. With the rear speakers, you typically have them turned down since they are only for fill anyway, so it's no big deal.

StreetOC192

iTrader: (7)

Gotta love images.google.com!!!!!!

VO...

iTrader: (25)

Excellent

What are some audiable indications that sound waves are being cancelled?

StreetOC192

iTrader: (7)

You will hear dullness in the sound. I always try changing phase to see which sounds fuller on any system I install. The fuller sound will be the most in-phase setting. I rarely have ever needed to leave the setting at 180.

Of course all of the above phase talk pertains to the subwoofer phase setting. There also exists the phase problem between right and left channels if you reverse your speaker wiring during install. This will throw off the imaging. You can usually tell this problem by sitting in the middle of the two channels and move your head slightly from right to left. If the sound shift is VERY noticable then you reversed the + and - on your right and left channels.

VO...

iTrader: (25)

I've experienced this before. It's quite noticeable.

Hybrid90

Hey GREAT explaination on the soundwave phase and also.. nice diagrams! Come to think of the above quote.. I did noticed my sound went dull one day when I switched to 180, I know it's still at that setitng cuz the wife keeps complaining how much her R&B crap music sounds suckier.. well either way.. her music will always sound suckier to me hehe

StreetOC192

iTrader: (7)

hehehehe, i tried to explain to the best of my ability. If I left something out, I'm sorry. BTW, you asked what those numbers (0...180) actually mean - it is the degree of phase. Think of a circle....0 being your starting point and 180 degrees around is the opposite side of the circle, so at 0 degrees your phase will be "+ -" and at 180 degrees your phase will be "- +"

Hybrid90

Ahh I see.. too bad you're not in Cali or else I'll treat ya out to a big fat juicy steak! Ok ok I was just kidding.. I'm broke from this damn system hehe Once again.. mucho grande grassy-***