Beginner improvements for room acoustics; very helpful Darko video on reverb and RT60

@djones51 Thanks for expanding on your comments. 

My experience with both absorption and diffusion massively changed the sound of my room. I'm presently in a space with a 6.5 foot ceiling, and putting absorption on the ceiling was a game changer in terms of dealing with very harsh highs. I do have an unusually low ceiling, but I think it's true that unless one has ceilings over 9 or 10 feet (with the average, mid-field listening distance), ceiling bounce is a thing that really induces first-reflection problems. If that's right, then Darko's final piece of advice -- to at least do something about one's ceiling -- seems uncontestable.

I know that all of this advice is dependent on the many specific factors involved. For my own part, I measured with REW's impulse graphs among others, and even used the "string method" to narrow down where the first and distal reflections were coming from. Then, I treated those areas. The result is a much wider, deeper, and articulate soundstage. People who come over to listen are usually amazed at what they hear, given the visual cues of the space.

Ceiling is the one thing you can’t do in a living room.

If possible always ceiling first.

It’s obvious. It’s usually the shortest boundary (floor to ceiling) and can be the most offensive …

When building studios it’s the very first thing addressed …oven when vaulted 

it’s called “lifting the ceiling” 

There is no " one size fits all". My biggest problem with peddlers like Darko is convincing people he has the answers when he simply repeats the same old tropes. Absorb, diffuse or reflect first point? Depends. Ceiling or floor bounce good or bad? Depends. All rooms are different, all listeners are different, types of speakers matter, listening distance matters, hearing ability matters, preference matters, most of all the recording matters. Read Floyd Toole, here's an article better yet read his book. 

Ceiling is the one thing you can’t do in a living room.

Doesn't your living room have a ceiling? ;-)