Gearslutz

Gearslutz (https://www.gearslutz.com/board/)
-   Studio Building / Acoustics (https://www.gearslutz.com/board/studio-building-acoustics/)
-   -   Realistic/Real World STC of Sound Isolation Clips? (https://www.gearslutz.com/board/studio-building-acoustics/1313969-realistic-real-world-stc-sound-isolation-clips.html)

MsmithGS 7th June 2020 09:58 PM

Realistic/Real World STC of Sound Isolation Clips?
 
Hey folks,

TL;DR:
My kick drum in my unfinished basement reads at 74.7 db when on the first floor and 54.9db on the second floor. If I soundproofed my basement with insulation, isolation clips and 2 layers of drywall and greenglue for both the walls and ceilings and solid core doors with air gap treatment, will it realistically bring those levels down low enough that it won't disturb people in the rest of the house at both 1PM and 1AM?

Details:
I'm building a jam and recording studio in my currently semi-unfinished basement, which includes drums, mic'ed vocals, and amped guitars and mostly plays heavy/thrash metal. The space consists of one 1' x 2' window, 1 exterior door, and 2 interior doors which both lead to another side of an already finished basement. I have a family of 5, and I'm the only guy, so you understand the concerns.

Currently, if I play the kick drum heavy and I use a sound meter (just an app on the phone) in the 1st floor living room right above it, I reach a max 74.7 db. If I go to the second floor bedrooms, which luckily is not directly above the basement, I reach a maximum of 54.9 db. So, I feel like I'm starting at a reasonable point, agree?

The perimeter 2x4 walls are already up (house came that way), so I plan to use insulation (insulation is already present in the walls but not the ceiling) with isolation clips and 2 layers of 5/8" drywall and green glue in between. Similar for the ceiling. Also plan to replace the doors with solid ones and getting those door soundproof kits to remove the air gaps around them.

My question is with my first floor at 74.7 db and second floor 54.9 db, is it realistic to think I can get it to a level that I can play while someone is watching the tv in the living room and not be annoyed, or while the kids are going to bed or at 1 AM with the family asleep and no one will wake up?

Greenglue states their isolation clips have an stc rating of 61 with 2 layers of drywall, which if true I think would bring it to a quiet enough level? But are those real world numbers? Do most people actually achieve that? Or should I expect more like an stc of 30? Also, since a second layer of drywall only adds an extra 5 STC, given my current specs is it worth it to add or should I just go single layer, which has an advertised stc rating of 56?

Thanks in advance

MsmithGS 11th June 2020 12:52 AM

Hmmm....Maybe I added too much info :) Ok shorter way of asking the question, how many db can I realistically expect by adding isolation clips and 2 layers of drywall to walls and ceilings in a basement?

Kyle P. Gushue 11th June 2020 01:43 AM

Quote:

Originally Posted by MsmithGS (Post 14793043)
Hmmm....Maybe I added too much info :) Ok shorter way of asking the question, how many db can I realistically expect by adding isolation clips and 2 layers of drywall to walls and ceilings in a basement?

You have to check the test data sheet for the particular model clip your interested in. Remember isolation is frequency based. A wall that blocks 50db at 1khz will be lower at 100hz and higher at 10khz. So when you look at the data sheet don't look at STC, look at how many Db in attenuation at each frequency band. For live music the stuff under 150hz is critical to block, but also difficult.

If your looking to play metal at 1am, and not bother people, you need clips that can handle many sheets of drywall, or do a room in room construction method.

A metal band is easily going to hit 110db, drums by themselves can exceed that.

MsmithGS 11th June 2020 04:12 AM

Interesting. Thank you for that explanation. According to: https://www.tmsoundproofing.com/prod...R_TechData.pdf it seems like 1 layer of drywall with clips will drop it 23 db-35 db when below 150hz, while 2 layers will drop it 28 db-40 db.

Granted, they didn't have the green glue compound in there, but I'm not sure this would work as well as hoped. I'm kinda thinking I should start with 1 layer of drywall as the cost and effort of the second layer may not be worth the 5db difference and it may not be good enough regardless. Or maybe I should go a different route altogether like no clips and just the greenglue compound between 2 layers of drywall. That seems to have a similar rating.

Hmmmm...Lots to think about.

Thanks for help!!!

Kyle P. Gushue 11th June 2020 04:28 AM

Quote:

Originally Posted by MsmithGS (Post 14793284)
Interesting. Thank you for that explanation. According to: https://www.tmsoundproofing.com/prod...R_TechData.pdf it seems like 1 layer of drywall with clips will drop it 23 db-35 db when below 150hz, while 2 layers will drop it 28 db-40 db.

Granted, they didn't have the green glue compound in there, but I'm not sure this would work as well as hoped. I'm kinda thinking I should start with 1 layer of drywall as the cost and effort of the second layer may not be worth the 5db difference and it may not be good enough regardless. Or maybe I should go a different route altogether like no clips and just the greenglue compound between 2 layers of drywall. That seems to have a similar rating.

Hmmmm...Lots to think about.

Thanks for help!!!

Look at the difference at 80hz. It goes from around 20db to around 30db attenuation just by going from a single layer to double. That's significant.

You definitely would be wasting money doing extra drywall and GG without decoupling with clips or seperate framing.

MsmithGS 11th June 2020 04:16 PM

I see. So even 80hz is important.

I wish QuietRock wasn't so expensive. I can't find the db attenuation by frequency, but their stc rating is competitive with this approach, and it certainly seems simpler/easier and less likely to make critical mistakes with. Although maybe without the clips it would be a waste like you said was the case for gg.

My main concern is that I invest all the money and it doesn't solve the issue. Maybe I should try to hire a consultant to let me know if the plan would work. Trick is finding one. Might have to give Rod Gervais a call and see if he travels to MA. Maybe it could even save me money like, maybe they would say doing only the ceilings this way would give me 90% of the benefits since this is a basement anyway, or some tips like that.

Ok, well thanks for the help!

QuietSleepNow 11th June 2020 06:28 PM

Quote:

Originally Posted by MsmithGS (Post 14793284)
Interesting. Thank you for that explanation. According to: https://www.tmsoundproofing.com/prod...R_TechData.pdf it seems like 1 layer of drywall with clips will drop it 23 db-35 db when below 150hz, while 2 layers will drop it 28 db-40 db.

Granted, they didn't have the green glue compound in there, but I'm not sure this would work as well as hoped. I'm kinda thinking I should start with 1 layer of drywall as the cost and effort of the second layer may not be worth the 5db difference and it may not be good enough regardless. Or maybe I should go a different route altogether like no clips and just the greenglue compound between 2 layers of drywall. That seems to have a similar rating.

Hmmmm...Lots to think about.

Thanks for help!!!

I highly doubt that 2 layers of drywall is going to affect drums or a metal band much at all. Your neighbors will be complaining. You'll need at least 2 sheets of 5/8 drywall with green glue on BOTH sides of a 2x6 or 2x8 framing with some sort of insulation in between, and the floor of this room within a room completely decoupled from the floor.

QuietSleepNow 11th June 2020 06:31 PM

Quote:

Originally Posted by MsmithGS (Post 14794153)
I see. So even 80hz is important.

I wish QuietRock wasn't so expensive. I can't find the db attenuation by frequency, but their stc rating is competitive with this approach, and it certainly seems simpler/easier and less likely to make critical mistakes with. Although maybe without the clips it would be a waste like you said was the case for gg.

My main concern is that I invest all the money and it doesn't solve the issue. Maybe I should try to hire a consultant to let me know if the plan would work. Trick is finding one. Might have to give Rod Gervais a call and see if he travels to MA. Maybe it could even save me money like, maybe they would say doing only the ceilings this way would give me 90% of the benefits since this is a basement anyway, or some tips like that.

Ok, well thanks for the help!

It will not necessarily be a waste without the clips if you have green glue and enough drywall (mass). Tests showed that the clips are not needed if you add enough mass, though they might be able to help considering you have drums. If you are not on a slab, you need to decouple the floor.

You can find local reps. Just google it, and some acoustical companies can point you to sound consultants in your area.

Kyle P. Gushue 11th June 2020 11:31 PM

Quote:

Originally Posted by MsmithGS (Post 14794153)
I see. So even 80hz is important.

I wish QuietRock wasn't so expensive. I can't find the db attenuation by frequency, but their stc rating is competitive with this approach, and it certainly seems simpler/easier and less likely to make critical mistakes with. Although maybe without the clips it would be a waste like you said was the case for gg.

My main concern is that I invest all the money and it doesn't solve the issue. Maybe I should try to hire a consultant to let me know if the plan would work. Trick is finding one. Might have to give Rod Gervais a call and see if he travels to MA. Maybe it could even save me money like, maybe they would say doing only the ceilings this way would give me 90% of the benefits since this is a basement anyway, or some tips like that.

Ok, well thanks for the help!

Yeah, 80hz is very close to a low E string on a guitar in standard tuning.

Bang for the buck 5/8 drywall is what to use. Quietrock works, but is relatively expensive cost vs performance. Even with quite rock you'd want to use clips, or independent framing. Decoupling is the a critical part of isolation construction.

What it really comes down to is how quiet it needs to be outside the jam room.

I can say Rod was very helpful to me on a couple of projects.

I am in southern MA, but have retired.

Green glue isn't a waste by default, its just important to know where it is most effective.

Its smart of you to plan properly and asess, even if in the end you decide its beyond budget, better to know ahead of time.