Determining right way to drive a polarized speaker.

I did a little project out of Make: Electronics that uses a TEA2025B to create a small mono audio frequency amp. I have what appears to be a polarized speaker, one input is marked with a dot of red and I am taking that by convention that means the speaker is polarized and that is the positive input. The project and the datasheet for the TEA2025B don’t really say how to hook up the speaker. It works either way. The datasheet gives the outputs as OUT1 and OUT2 and never mentions which one goes to the positive input of the speaker. How do I determine this? Does it matter?


Project schematic.


Speakers arnt polarized. They work on AC. However most speakers do have some kind of mark on one of the terminals to allow multiple speakers of the same kind to be connected in phase when stereo sound is needed. The mark indicates which way the speaker cone moves for current thru the voice coil in a particular direction.

As audio is a AC voltage there is no real 'polarity' for a speaker. In fact if your just using one speaker with a mono amplifier it makes on difference how you wire the audio output pair to the speaker. The purpose of marking one of the speaker's terminals is for proper phasing of the speaker in stereo operations where you have two channels of audio going to two identical speakers. In that case it is desirable that the two speaker cones to move in the same direction for the same 'polarity' of a AC voltage, otherwise there can be a sound cancellation if the speaker cones move in opposite directions with the same audio signal applied to both.

One can actually determine the phasing of a otherwise unmarked speaker by applying a 1.5 volt battery to the terminals and note if the cone is forced out on in from neutral position. Typically one marks the terminal red where the positive terminal of the battery forces the cone outward.

That make sense?


Yes, that all makes sense. Thank you both.