Speaker wiring

[GAZZA3354]

Hiya, i have a 89 318i fitted with a standard radio, the front right footwell speaker has two wires going to it one black and the other black/red, can anyone tell me what one of these two wires is plus or minus please as i am replacing the speakers
Thanks

[kam-325i]

The colour of the wires dont match up to OEM colours.

you might have to trace back to the head unit to get the phasing right.

[Brianmoooore]

Doesn't matter in the slightest, as long as all are the same.

[GAZZA3354]

Thanks forgot to say that one is a small spade connector and the other ia large

[Brianmoooore]

There's no DC component in a speaker signal, so there's no plus and minus. The drive signal is ideally pure AC, with an equal and opposite amount of positive and negative - any DC component just moves the speaker cone away from its rest position, limiting the dynamic range of the speaker at best, and permanently damaging it at worst.
All that matters is that you connect all the speakers the same way around.

[GAZZA3354]

Thanks, much appreciated

[miniblob]

You may also find that most car speakers have the larger terminal marked +ve and the smaller terminal marked -ve!!!