The speaker has a pos and neg connection, I just wired this up to the tip and ring of the stereo plug for left and right. Is this correct? Or should speaker negative go to the sleeve for ground??
Sleeve is allways connected to the negative terminal, the positive terminal is connected to the Tip, in a stereo setup, if it's the left channel, or if it's mono. For stereo, the Sleeve is positive for the right side.
If you connect only Tip and Sleeve to a single speaker in a stereo system, you'll get the sum of both channels (with distortion and diminished volume) and if you play the same signal 180° out of phase, they'll sum to exactly zero.