I have a hard time hearing people in front of me when I'm in a crowded room and people or music is behind me.
Have you tried closed captioning?
I tried the portable bluetooth speaker, JBL Charge, and it's a world of difference.
Not all portable speakers are created equal. I have 3 different brands and they all sound different.
Are you using a stereo plug/cable for the speaker?
Some are just mono plugs.
I also spend some time adjusting the speakers in the tv settings to make it right
good luck
I said
GOOD LUCK! :)