Soundproofing my studio | Hacker News Reader

Soundproofing my studio

jeffgeerling.com

77 pointsmikece19 comments

> But it's a lot easier to treat the inside of a space once you've already built a good structure that prevents outside sounds from getting in.

I’ll argue that by isolating your room from the outside that you’ll actually have a tougher time balancing the acoustic response of the room.

Yes sound may no longer be getting in, but it won’t escape the room either, so you’ll have to put more effort into absorbing the energy that would normally leave the room. The low -end in particular is going to be problematic and require a good strategy for handing it.

Source: I project manage for a company that designs high-end recording studios for musicians.

I would like to make a 120 square foot (internal dimensions) max 10 feet high roof to foundation listening room in the back yard. Very mild climate so heating/cooling is not necessary. Wall thickness is not an issue.

Do you think that is possible while still getting good base response and have minimal sound escape?

What is your intended purpose for the room? Listening to records for pleasure? Critical listening for mixing and editing audio? Something else?

My first rule of thumb is don't make the ceiling 8' high. 12' high is ideal, but 10' high works too. When people sit in a chair their heads are located 4' from the floor, which means that with an 8' ceiling their ears are located halfway between the floor and the ceiling. This is the primary vertical room mode and will cause your low-end to cancel itself at 70Hz right off the bat.

A solid concrete slab in the floor is ideal so that your floor doesn't resonate.

120 sq ft is relatively small and not ideal, but if that's what you have then so be it. What you DON'T want is for your room dimensions to be square. The more rectangular that you can make your room without the length and width being integer multiples the better. Don't make the room 11'x11'. Make it 9'x 14', or something in that neighborhood. This will distribute your room modes more evenly, whereas a square room will have the same modes along the length dimension and the width dimension. This will give you a massive cut and boost at in your low-end.

If your speakers won't be soffit-mounted then place them as close to the wall as possible. Some people may advise you to place them 3' off of the wall because of a phenomena called Speaker Boundary Interference Response. Ignore this and place your speakers against the wall and save yourself some trouble.

Lastly, you don't want your listening position to fall on a position that is 1/2 or 1/4 of the length of the room from the front to back wall. Those are where your largest room modes (and therefore largest bass cancellations) are going to occur. Ideally your listening position should fall at the point 38% of the room length between the front wall or rear wall.

Unfortunately it's hard to advise you further on the room treatment and isolation without discussing the project holistically. Your room dimensions, speaker choice, level of isolation, room treatment, listening position, and furniture all interact with one another and I need more information.

I would definitely start to monitor CO2 levels once the studio is finished, it’s one of the issues I had to tackle when converting a sea container to a garden office (https://www.msgtrail.com/articles/20200902-1005-sea-containe...)

I'll be installing a few AirGradient units in the space once all is said and done; need to make sure the HVAC runs enough to keep fresh air cycling in all the spaces.

I wish this were taken into account more often. Where I live there's been a major push for insulating older buildings where possible, and moving from single-glaze to double-glaze windows and well-closing entry doors has converted these places to an almost air-tight box with close to no air replacement. These are compounded by the usual lack of any mechanical air extraction.

I live in one such apartment, and even though it's reasonably big, if I sleep alone with the windows closed but all the doors open, CO2 will reach around 1000 PPM according to my Airgradient.

The home theater enthusiasts have figured this out, going back many years. For maximum soundproofing, you essentially build a floating room within a room. Walls and ceiling are double layers of drywall with Green Glue sandwiched in between. Rockwool insulation filling in between the studs and joists.

https://www.soundproofingcompany.com/soundproofing_101/build...

Jeff - did you look into constructing the front & rear walls so they wouldn't be parallel to each other? This reduces standing waves. Radio studios do a similar thing where a window into the production booth will be dual-pane glass, but with one of the panes slanted so that sound waves bounce at an angle and don't impact the other pane as strongly.

Of course, by now you're probably already past that point in construction and are choosing paint colors...

Yes, we discussed this with the architect and builder (both of whom build radio studios with some frequency), and they said it could help a little, but would not be a large issue for spoken word-only, and is more of a concern when you have more sound sources, and less control over mic locations and the interior treatment.

It would've been nice, but would've added a little cost to the project (not much, but not worth it if I could allocate it to resilient channel or neoprene, instead).

I think the key to blocking sound (especially low frequencies) is to make the wall really heavy. MLV (mass loaded vinyl) is designed for this purpose.

If you yell into a roll of MLV, it echoes like a concrete pipe, so you still need the rockwool to absorb reflected energy.

As someone else commented, a lot of times extra layers of drywall are added to add mass to a wall (this is a fairly effective solution). But there are complications to 'thickening' the wall like this (at least, if you want it to look professional in the end!).

There's a great document from the US HUD on the topic: https://www.hud.gov/sites/documents/DOC_16419.PDF

Heavy mass walls will keep all but the lowest noises from entering the room from outside, but it will also prevent the energy from your speakers or instruments from leaving the room, causing the room to ring at various modal frequencies.

You can absorb high-end and most mid-range frequencies using broadband absorbers on the wall and ceiling, but they're ineffective at capturing low-end. Treating the low end requires a different strategy.

The most effective solution for absorbing low-end in the room will be limp-mass membrane absorbers that are tuned to the lowest room modes. They'll be up to 18" thick, but they are by far the most efficient way to keep the low-end from ringing inside of your room.

I would pay good money to have just my bed soundproofed so I can enjoy a quiet night's rest. Those capsule hotel 'rooms' seem like they could do the job, I'm not sure where to get one.

Room within a room would be nice to have, sort of like those fancy canopy beds, just with thick walls instead of curtains.

Sleep mask with speakers is my solution: https://www.amazon.com/MUSICOZY-Headphones-Bluetooth-Wireles...

It is very relaxing to sleep in a quiet studio. That said, the level and complexity of the build-out necessary to convert your canopy bed would effectively make it a room within a room. It'd be like climbing into a closet with a bed in it.

How about some custom-molded earplugs while you sleep? That is by far the most cost effective way to go.

I remember watching a video of Adele recording a song (“When we were young”) at the Church Studios in London in a room that’s obviously part of a church without noticeable anechoic protection, and thinking “How on earth do you keep London noise out”.

Maybe it was pre-recorded? It's pretty remarkable what we can do with that now.

The thing about church is the 2ft of stone the walls are made of.

They spent a metric f-ton, is the answer.

https://gearspace.com/board/photo-diaries-of-recording-studi...

Reply on news.ycombinator.com