DIY acoustic panels?

The physics of the propagation of sound is immensely complicated, and when the assortment of materials that make up the walls, floors and ceiling (plus any windows, doors and furniture) are added to the equation, it's very difficult to predict what will happen to sound waves once they've left their source. What's more, every room is different, and it's not just the dimensions that will dictate how the room will sound... Imagine two rooms of the same shape and size. One has two‑metre-thick concrete walls, and the other a single‑layer plasterboard stud-wall. Even with those brief, albeit extreme descriptions, you probably know already that the two rooms will sound very different.

It’s not necessarily a compliment to say about a young woman she makes her own clothes.

It’s not necessarily a compliment to say about a young woman she makes her own clothes.

Geoffy “Toiletbreath” The Fuse Troll has spoken. 

Sleepstalker, the man who eats his own poop, strikes again. 😋

FWIW, I tried the DIY approach to making absorption panels and then I  tried GIK's products. Considering the time expended and cost of purchasing quality materials to make DIY panels of equal quality to GIK's, I can't imagine why anyone would bother unless you just enjoy experimenting to occupy your time. Their products have an outstanding price/benefit ratio. They will also give you guidance on the best products for your project. 

You asked if the expanse of television glass affects your audio quality. Yes, big time. Getting rid of the tv between my speakers was one of the best things I ever did. Unfortunately, many of us have to compromise and combine AV and audio in one location. In my past experience, acoustic panels in front of the tv help some but don't entirely ameliorate the bad effects of the tv.