Basement Studio Room

[kek181]

So I think I have finally done enough research and conceptual design to post and get some feedback on my assumptions and designs.

The Design and Space

I currently have about 1000 sq ft finished basement, and a section that is about 800 sq ft that is unfinished. I plan on knocking down a wall and using about 100 sqft of the finished basement, and then finishing another 100 sq ft. The room will end up being about 13.5 by 15, with a ceiling of about 7.5 ft. There is a section of about 2 ft and the width of the room that has the steel support beam and some HVAC that causing the ceiling to drop another 9inches. I plan on using the room at typical db level for a guitars (including bass) and drums (for now I have little ones that will join the fun in a few years). We have a single family home, and my main focus is isolation within the house.

Isolation Strategy

I am looking to get the best value for isolation, but not looking to break the bank....so with the construction and isolation I am budgeting 6-8k, which seems reasonable based on my research, and should get me to the solid level of isolation. Not the 100 percent Cadillac version, but should achieve what I am hoping for. Also please note in the budget, I will be doing most of the work, with some hiring of contractors on the HVAC ductwork and carpet. My main focus is trying to keep the sound in the basement, even if it expands a bit into the finished section.

Design Assumptions

Before getting through the detailed design, I would to have my initial design assumptions reviewed, challenged and input from the group:
-I'll be isolating the walls as best a possible within the design constraints and existing structures. 2 walls will be completely decoupled, 2 walls will have staggered studs, and the ceiling with have isolation clips (any input on effectiveness of clips would be appreciated, GG Whisper, RSIC (IB-1, IB2). Also interested on hearing opinions on insulation in the walls (rockwool versus regular)
-Floor is concrete with a carpet pad (0.5 in), and carpet
-Drywall will be double 5/8s, with GG in the middle, acoustic caulk to seal
-There will be 2 doors, I plan on getting solid core door from a big box store, and then soundproof the jam and do soundproofing around the door, and a sweep at the bottom. Would be open to hearing material and strategy for soundproof around and the bottom of the door.
-All outlet boxes and switches, using a backer box. I have seen a mix of opinion on material for the back boxes, would like to hear additional input.
-There will be 1 supply and 1 return register. Still working on sizing with the HVAC contractor. Both ducts will come in through the unfinished portion of the basement. I plan on building a silencer (founds some good design on the forum here) that will be between the inner and outer leafer and connect directly into the inner leaf. Yes this decoupled gap will be big, but I have that luxury with the unfinished side of the basement.

Would love to hear from the group, to help with getting into the detailed design!

-Keith

[Gregwor]

Hi Keith! Welcome to the forum. Sorry about the late reply, but with holidays, it's been tough.

I will point out that you didn't fill out your profile enough, so please review the forum rules and fill it out better. This is very important. Thank you!

The room will end up being about 13.5 by 15, with a ceiling of about 7.5 ft.

Okay so you are going to have ~200 ft2 room. The problem with your plan is that your longest dimension is exactly twice that of your height. Because of that, this room will not sound good. I would suggest changing the dimensions of your room to one that doesn't fail the tests on Bob Gold's Room Mode Calculator website.

I plan on using the room at typical db level for a guitars (including bass) and drums (for now I have little ones that will join the fun in a few years). We have a single family home, and my main focus is isolation within the house.

So this isn't a studio, more a jam space for your band?

There is a section of about 2 ft and the width of the room that has the steel support beam and some HVAC that causing the ceiling to drop another 9inches.

Sounds like a normal basement headache!

I am looking to get the best value for isolation, but not looking to break the bank....so with the construction and isolation I am budgeting 6-8k, which seems reasonable based on my research, and should get me to the solid level of isolation. Not the 100 percent Cadillac version, but should achieve what I am hoping for. Also please note in the budget, I will be doing most of the work, with some hiring of contractors on the HVAC ductwork and carpet.

We have no clue where you live so none of us can comment on whether that budget is too high or too low.

From this comment, I will tell you right now that carpet is a bad idea. It provides the exact opposite acoustic response that a good sounding room needs.

My main focus is trying to keep the sound in the basement, even if it expands a bit into the finished section.

Unless you build the "Cadillac version", there's no way your drums are going to be isolated enough to not be heard in your house. At least the bottom registers will be heard/felt. That includes low tom, bass drum and snare fundamentals. In order to isolate those low frequencies, you need a lot of mass and de-coupling which means an entire room in a room MSM construction.

-I'll be isolating the walls as best a possible within the design constraints and existing structures. 2 walls will be completely decoupled, 2 walls will have staggered studs, and the ceiling with have isolation clips (any input on effectiveness of clips would be appreciated, GG Whisper, RSIC (IB-1, IB2).

Your total isolation is only as good as your weakest link. So, your weakest link will be your staggered stud walls and your ceiling. All clips are going to do a pretty horrible job at isolating the bothersome frequencies (bass). So, know going into your build that you shouldn't expect good isolation in those lower octaves. Also, be sure to do the wall construction yourself to ensure you don't flank anything with those clips. Chances are, if you hire someone to do it, they will be careless and think that a few shorting out here or there won't hurt.

Also interested on hearing opinions on insulation in the walls (rockwool versus regular)

Your cheapest route will be using fiberglass insulation. Just make sure it is 20-25 kg/m^3. Where I live, R24 batts which are 5.5" thick made by either Owens Corning (pink) or Johns Manville (white) are as dense as they make. Talking to their nerd departments, they said their goal is to make them as light as possible which is the opposite of what we want in the acoustics world.

-Floor is concrete with a carpet pad (0.5 in), and carpet

No carpet. Use a hard flooring.

-Drywall will be double 5/8s, with GG in the middle, acoustic caulk to seal

Why are you choosing 2 layers of 5/8" drywall? Did you do measurements with an SPL meter in your space to determine how much isolation you need? Then did you do the calculations to figure out if two layers of 5/8" drywall will be sufficient?

-There will be 2 doors, I plan on getting solid core door from a big box store,

1 door at one end of the room and 1 at another end? Or two back to back?

and then soundproof the jam and do soundproofing around the door

Sound proof the jam means???
Sound proof around the door means???

and a sweep at the bottom. Would be open to hearing material and strategy for soundproof around and the bottom of the door.

Sweeps don't seal well enough. You need an automatic door bottom and a seal for the bottom of the door to press up against.

-All outlet boxes and switches, using a backer box. I have seen a mix of opinion on material for the back boxes, would like to hear additional input.

Why don't you save yourself the headache and just surface mount everything? You can hide most/all of it behind acoustic treatment.

-There will be 1 supply and 1 return register. Still working on sizing with the HVAC contractor.

This is contradictory

Both ducts will come in through the unfinished portion of the basement.

Tapped off of the existing air handler unit or a new designated unit? This is a ducted system or ductless?

I plan on building a silencer (founds some good design on the forum here) that will be between the inner and outer leafer and connect directly into the inner leaf.

So your silencer boxes will be between your de-coupled leaves? Your outer silencer cannot be touching your inner wall. And your inner silencer cannot be touching your outer wall. They are only connected through a flexible piece of duct. Whether that is neoprene or some rubber, a fabric of sorts, or even just flex duct. Heck, in a perfect build, they aren't even touching their respective wall. They would be sitting on frames that are anchored to the concrete floor. That's it.

Yes this decoupled gap will be big, but I have that luxury with the unfinished side of the basement.

Cool, but don't think that the big gap there is going to improve your isolation. Remember, your total isolation value is determined by your weakest link.

Would love to hear from the group, to help with getting into the detailed design!

You probably read most of my replies as me being a jerk. I hope you re-read them as replies that make you consider your design more and cause you to go digging around the forum using the heck out of the search feature. That's all. We are a self help forum here. We will gladly answer specific questions. But the world of acoustics is too large to give simple answers to broad topics.

I hope you come back with some great answers and maybe even a new plan (remember, your room dimensions suck right now!)

Have a great new years and I look forward to your reply!

Greg