I have speakers, similar to the ones here. I am able to connect them to the raspberry pi 3 using the 3.5 mm input. There is one main speaker, that can works independently, and there is an additional speaker that can work together with the main one. Whenever I connect only the main one, the sound is barely audible. When I connect both, I notice that it is only the helper speaker making the sound. I tested the same thing out by connecting the main speaker with a cord to my iPad, and it worked fine.
Is this a speaker issue or a raspberry pi? Is there any way I can try to fix this?