Check Yourself! Testing a Speaker's Ins and Outs

When you install new speakers in your car, one of the most important things to ensuring your new speakers actually sounds good is to make sure they're in phase. MECP defines phase as "The timing of a sound wave that is measured in degrees from 0 to 360". Speakers have both a positive and negative connection, and the signal that is sent to all the speakers in a car needs to be consistent. If one speaker is connected "positive/negative" and the other is hooked up "negative/positive" the speakers will be out of phase with each other. When one speaker is pushing in, the other will push out and vice versa. This 180° difference will cause the speakers to cancel out frequencies and sound very flat and hollow, like they're playing in a long empty hallway and will have very little, if any bass.

So what do you do if you've installed your system and as soon as you fire it up, you notice the "empty hallway" symptom? Follow the jump to find out!

in the forums!

SoundDomain member jory was curious and posted up this thread in SoundDomain Speaker Support.

If you want to solve the problem, you have a few choices: 

1. You can tear back into your door panels, remove your speaker, and check your wiring. This is the most time consuming and tedious.
   
2. If you can clearly see your speaker cones though the speaker grille, or can remove the grille, and your speakers are connected to a external amplifier, you can actually use a AA battery with speaker wire connected to either end to test polarity. Connect the negative wire of your speaker to the negative battery terminal and touch the positive wire to the positive terminal of the AA battery. You'll hear a *pop* noise and if you look at the speaker cone, it's either pushing out or in. Test all speakers and make sure all four speakers are moving the same direction when connecting the battery. If one ore more moves the opposite direction, you have a phase problem.
3. Rather than go to all this trouble, you could simply pick up the Phase-It speaker polarity tester.

The Phase-It Polarity tester is a safe and easy to use tool that could save a lot of time and frustration. The kit includes a test tone CD and the handheld phase tester. After inserting the CD in the CD player, a series clicks and pops will play through the speakers. Simply place the Phase-It in front of your speaker and the device will give you a green LED for positive or a red LED for negative. Test each speaker, and you'll easily and quickly find out which speaker is out of phase. True, this little guy will set you back about $100 when you can do something similar with a $2 battery, some wire and your eyes, but the Phase-It could save you time and frustration in the long run, especially if you're a professional installer.