The TCL Alto 7+ sounds really good using Bluetooth. The sound shakes my house. On the other hand, there is almost no sound coming out of it until I reach volume level 70 or above like other users have said. Turning it up to volume 100 is still not loud. I went through troubleshooting with TCL support and everything is hooked up correctly. I tried using both THE HDMI ARC and optical cable on my 75" TCL's, and it made no difference. I also have a 55" TCL TV and I hooked it up, and it sounded the way I would expect a sound bar to sound. The bigger TV is brand new, so I would expect the soundbar to integrate better with it.
*** Update *** After reading other reviews, I was able to get the contact information for TCL Support. Apparently, the issue was not with the soundbar, but with my TV. TCL Support was able to resolve the issue. I'm changing my review for the soundbar overall to 5 stars, because it sounds fantastic on my 55" TCL TV.