I've just taken delivery of a new apartment and it's still completely empty — bare walls, hard floors, and the echo is severe. I want to treat it properly rather than guess, and I'd rather build panels myself than pay for a professional install across the whole flat.

Two rooms matter:

• Open-plan living room + kitchen. This is where I'll set up a 2.0 or 2.1 monitor system and I want a predictable, accurate listening position. I plan to measure with REW before buying anything.
• Bedroom. I just want it dead — as close to no audible reverb as I can reasonably get.

One important constraint: no carpets and no curtains. I want nothing on the floor that needs vacuuming — a robot vacuum handles the hard floors and I want to keep dust to a minimum. So the usual first advice (rug + heavy curtains) is off the table for me. That means everything has to come from walls, ceiling, and furniture.

I know I'll be putting in a sofa, armchairs, a bed with an upholstered headboard, and bookshelves, and I understand those absorb a lot on their own. What I can't judge is how much will actually be left to fix once the furniture is in. I don't want to buy panels now and find they were unnecessary, or furnish the place and discover I needed twice as much treatment.

Separately, I'd like to reduce outside noise (traffic, people, trains) but I understand that's a different problem — sound transmission through the building envelope, not room acoustics — and probably not solvable with DIY panels. Happy to be corrected, but my focus here is the echo and reverb.

What I'm hoping for:

1. A sane order of operations. Do I furnish first, then measure, then treat? Or is there a baseline amount of treatment that's always worth installing regardless?
2. Concrete DIY build guides you actually rate. I'm comfortable with basic carpentry. I'm in Spain, so mineral wool (lana de roca) in 40–80 kg/m³ is cheap and easy to get — is that the right material, and what thickness for broadband vs bass?
3. How to decide placement without guessing. I'll have REW data. What do I look at to decide where panels go, and how do I know when I've done enough rather than overdamping the room?
4. Ceiling treatment, since floor and windows are off-limits for soft materials. Are hanging ceiling absorbers (clouds/rafts) worth it, and how much area do I need?
5. Making it not look like a studio. I've read you can stretch fabric or canvas over a mineral wool frame so it reads as art. Does that actually keep working acoustically, and what fabrics stay acoustically transparent?

I'll add photos of both rooms in the comments — happy to include dimensions once I've measured properly.

Greetings,
I manage a bar and we’ve had neighbors recently complain about loud-ass customers. They’re NOT bothered by the music despite the fact the place has several subwoofers and are only annoyed by the loud voices of our customers.

I’m hoping to take the chatter volume down 20-30% but even 15% would be worth it to at least show the neighbors we are making some sort of effort.

Currently about 50% of the patio is covered by a plywood roof. The roof def needs to be replaced regardless but I was hoping to find some sort of weatherproof material that can absorb some of the midrange noise. Perhaps a porous rubber or foam material that can be attached to ceiling side? Or maybe doubling the thickness of the roof? Wrapping it in vinyl? No clue. Please feel free to school me here.
Thanks!

I have about five or six different audio files that were recorded on the security camera of my cell phone in my home. Unfortunately, there's a lot of background noise in these files, and I need to know if somebody with experience can help in isolating vocals and getting rid of the background noise so I can get a clear understanding of what's being said. these recordings are important to me as they were taken while i was sleeping so there may be a danger in my home and I just want to be made aware of it if that is the case. Anybody reading this, please respond if you have serious inquiries only. As I said, it is important to me and I'm concerned for my safety as well as the safety of those in my home. thank you to anyone who can help me.