Hi.
I have a 2007 electraglide Classic. this bike came with only to speakers . last year I installed a 4ch amp I have upgraded the speakers to larger J and M.
My question is can I hook up 2 more speakers to the amp? or is the original harmon radio only good for 2 speakers?
I would like to install speakers in the lower fairings I added the fairings.The bike is a classic NOT Ultra. Thanks.

 

What you need to find out from the spec of the amplifier is the impedance or resistance of the output. If for example it is 8 ohms then the speaker(s) you connect also need to be 8 ohms. That is 2 x 4 in series or 2 x 16 in parallel or any other mixture that adds up to 8.

If the speakers you have now match the output of the amp adding another will affect its output power.

You might want to Google resistors in series and parallel to get a better idea. There will probably be the same available for speakers to amplifiers.

 

Same radio in your bike or ultra, just different software installed, different add-ons.

Start here:
https://www.hdforums.com/forum/touri...-speakers.html
.