Dink said:
you won't blow a speaker by connecting it up backwards
Who said you would ? Wiring up the wrong way round will just make it sound bad.
LECTURE COMMING UP.......
The polarity of a speaker has to be correct for it to work and produce the correct sound pressure wave.
Simple test. Take an old speaker, some wire and a 1.5 volt battery. (this is why I said an old speaker)
Connect the wires to the speaker and touch the battery terminals briefly and watch which way the cone goes. Now reverse the connections on the battery and you will see it goes the other way.
Now, if everything is as it should be, when you did this test the positive on the battery connected to the positive on the speaker, should have driven the cone out towards the front of the speaker.
THIS IS CORRECT. if this were a speaker driven by your amp or head unit, it would be correctly "in phase"
The reason this is important is, the cone going forward produces the sounds pressure wave which ends up in your ears as music.
If the speaker was going the wrong way it would , if you like, be sucking instead of blowing, You would still hear it but it would be "out of phase" and not sounding as good.
Still with me ?:sleepy:
Now the worse case scenario. If you have one speaker "in phase" and the other "out of phase" you get a cancelling effect. That really sounds awful.
I have seen a test done at an Alpine installers course I attended, where the had 2 x 10inch Subs in a sealed box, they drove them with a 50hz signal via a 200w amp and they were LOUD. They then swapped the terminals on ONE speaker, re-applied the same signal......almost total silence. Everybodys jaw dropped.
As music is not a continuous single tone, you dont get an absolute cancellation to achieve that sort of silence, but work out how much you could be missing if you get it wrong. This is most noticeable at the low frequencies that produce the bass everybody loves.
Lecture over.........Lunch time......be back at 1pm sharp or I will you will get detention.
