How do you know when speakers are 'in phase' ?

[restocat]

I bought a set of old panasonic home stereo speakers, and the wires coming out the back are solid brown. How do I know when I have the pair correctly wired (positive/negative)?

This question also can relate to boomboxes. I have one box that 'doesnt sound quite right' and I suspect one of the speakers may have the wires switched, but how can I tell for sure?

Thanks

 

[sony_apm_fan]

Hi Restocat,

Common problem with a simple fix!

Caution - the test below if used incorrectly can cause speaker damage.

Old tried and true method is to take a 1.5v battery, mark one speaker wire as positive and connect it to the positive battery terminal.
The speaker woofer cone should move outwards, repeat same with other speaker and confirm outward movement.
If the cone moves inwards, then reverse the polarity connected to the battery and mark accordingly.

Don't pass DC voltage through the speaker for more than an instant test, as it will heat the voice coil and may cause damage.
Also, don't try this test on tweeters, and don't use any higher voltage than 1.5v.
Use this test cautiously!

You could also remove a driver from the cabinet and trace it from the terminal to the rear connections.

When playing a mono signal, the image should be centered.

Generally speaking, out of phase speakers have poor (cancelled) bass along with a confusing stereo image.

There are also test CD's available which are much more elegant than the above method!

 

[Superduper]

I bet if you look at the wires carefully, you'll see minute differences. One might have a small molded stripe (same color so look carefully) or one might have a square ridged corner.

 

[sony_apm_fan]

I bet if you look at the wires carefully, you'll see minute differences. One might have a small molded stripe (same color so look carefully) or one might have a square ridged corner.

 

[redbenjoe]

if you set your balance control to dead on balls center --
and the bass output from both speakers seems to disappear -
then one set of speakers wires is mixed up-]
and you are out of phase.

 

[restocat]

Thanks everyone!

Interesting battery trick.

Yes, there are faint dashes on one of the brown wires.

 

[2steppa]

Out of phase speakers = :annoyed:

The times I've tried to tell people they've connected the speakers up incorrectly and they look at me like I'm from a different planet.

'What do you mean, it sounds fine' No it does NOT sound fine.... grrrrrr :annoyed:

 

[MasterBlaster84]

Out of phase speakers = :annoyed:

The times I've tried to tell people they've connected the speakers up incorrectly and they look at me like I'm from a different planet.

'What do you mean, it sounds fine' No it does NOT sound fine.... grrrrrr :annoyed:

Yep I've had that same experience a number of times and always from someone who has no clue about HiFi, Stereo or anything bigger than a pocket radio.

 

[petergriffin]

from my "Bose" speaker manual, they actually tell you to face the speakers toward each other, about 12" apart. And listen to the bass. And if one seems less "bassy", then it is out of phase

 

[Marty Machine]

Without having to get inside your box with batteries etc, why not use a good solid thumping drumbeat track, crank it up, pan the balance to left or right to test each speaker is pushing OUTward.....

Additionally, lay your box on it's back, rest a sheet of papaer over the speaker grill, and it SHOULD elevate up in the air with each drumbeat.....if it stays still or sucks in, you got phase issues....

I used to use New Order "Blue Monday" and/or Grandmaster Flash "The Edge" as my pahse-tracks

MM.