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

From an acoustic perspective, any normal sized domestic room is small.

I suggest you watch the video. Darko clearly states that this is not about low frequencies. If folks watch the video, they will see why RT60 is relevant.

In most small domestic rooms it's not that big of a deal. Darko is not someone to go to for acoustic advice or really any advice IMO. If you're doing HT in a dedicated room it's a good idea because it can help get better sound field over more seats.  I've done some measurements using REW for interest only.

REW

RT60 is a measure of how long sound takes to decay by 60 dB in a space that has a diffuse soundfield, meaning a room large enough that reflections from the source reach the mic from all directions at the same level. Domestic rooms are usually too small to have anything approaching a diffuse field at low frequencies as their behaviour in that region is dominated by modal resonances. As a result RT60 is typically not meaningful in such rooms below a few hundred Hz. Use the RT60 Decay, waterfall, spectrogram and Decay plots to examine the decay of low frequencies in domestically-sized rooms.

@djones51  I'm interested to hear you say that about Darko. Your posts have always struck me as exceptionally well-informed, and I get a good impression from Darko, too. Can you tell me why you think he is generally untrustworthy or at least someone folks need not pay attention to? Thank you.

I don't think he's untrustworthy just in it for money which is fine but I take these  YouTube  guys that have a vested monetary interest with a grain of salt. the video you posted has some good advice and some lousy advice. For example when he says you can't get exceptional sound in a normal living space without room treatment from ANY speaker that's nonsense. Cardioid speakers can work very well in untreated rooms.  Wall to wall carpet with thick pad is good floor treatment. Speaker directivity and listening distance is equally important. Is a dedicated listening space optimized better? Well yes but very few people can have that. 

That’s quite the swipe you take at Darko, calling him out as being in it just for the money and denigrating his character, but then, you’ve done it here as well. At least you’re consistent.

As for floor treatment, he covered that, saying that from what he’s read, experienced firsthand, and from the experts he spoke to, floor treatment doesn’t do as much as thought. He also addressed speaker distance. Did you just get a case of the heebie-jeebies watching his video and miss some of it?

All the best,
Nonoise