Next drill two holes in your walls bottom plate which is accessible from the unfinished basement ceiling. One hole goes below the wall plate and the other goes below the in wall speaker.

Hdmi Wall Plate Vs Straight To Tv Device Wiring Closet
How to run hdmi in wall. Pro tip fish the wires from the top down first wiggle them in the wall and use a flashlight to check the bottom hole for the cable as you fish it down. Start by feeding the cable down the top hole until you can see it in the bottom hole. Push the fish stick up through the tube and out of the top low voltage box. But thats not the tube in question in the picture. The walls studs prevent horizontal runs. Getting an hdmi cable run through that is going to be tough.
Carefully push the top low voltage box into the wall cavity just enough that you can easily access the tube from the bottom hole. How to hide tv cables in the wall low voltage hdmi cat5 speaker wires duration. Otherwise it will be difficult or impossible to run the cables. Take your drywall hand saw and cut the rectangular holes out. Its a steel ring reinforced tube so it wont completely crush. Just wiggle the saw in no need to go any deeper than the drywall say about 12 inch.
It does expandcontract a bit. In the example shown here you cut two holes in the wall one for a wall plate and another for an in wall speaker. This only works in a vertical direction. Extend the fish stick so that it protrudes out of both the top and bottom holes and you can tape it to the wall temporarily. When installing or remodeling a home theater or av system all you have to do is run a length of hdmi cable through your wall or ceiling and plug each end into the hdmi ports on the back of the wall plates. The jackets on hdmi cables are fairly plump and the cords themselves not the most pliable things.
I also marked the best spot for the power outlet. With these reference points it was easy to locate the best spot to place the media box so the hdmi cable would run directly into the desired input port on the back of the tv from the wall. Make sure these holes are directly in line with each other in the same stud bay. That looks like a 34 smurf tube.