My first suggestion would be to listen to a song that was not mixed in stereo, which you would find in very old songs from the mid 1950s or earlier before stereo equipment was widely manufactured. Nowadays every song is mixed in stereo and so the response on either channel is not the same. Ever notice how you hear drums and vocals mainly through your right speakers and things like guitars and organs through the left? That's because they were mixed differently. Another way you could do this with your music is open a song into Audacity and convert it to a mono track (see images) and play it see if they react the same. Then you should play with the individual volume controls to see if you can balance it. There is a chance that your speakers have a balance knob which you could use to make the response equal on both sides for all audio that goes through it.
Just a note, the RMS power of this speaker set is apx. 4.24 watts. So you shouldn't try to make these speakers too loud. An average home speaker system is about 600 watts RMS.
