John Sayers' Recording Studio Design Forum Archive

I'm just in the beginning stages of planning my studio, so I'll make a bigger post later about the entire studio plan, etc. But my first hurdle before I move forward is quieting the noise coming in from the sliding glass door which separates the studio from the backyard. It is a very new (<3yrs) and decent quality sliding glass door, it just lets in a lot of sound from the nearby roads, planes, etc. I'd say 90% of the noise is 400hz and higher.

If at all possible, I'd like to find an option that doesn't involve construction. We've just moved into the house and besides the cost being a little high for us to do construction right now, I actually love the room the way it is and would like to be able to access that sliding door when I'm not recording (for natural light in the room, fresh air, etc).

I had seen posts about curtains designed specifically for absorption, such as Hofa's product here: https://hofa-akustik.de/en/modules/curtain/, which claims to absorb 80% of the sound energy at some frequencies. Does anyone have experience with something like this? Any good?

I'm open to other options but I'd really love to find a solution that doesn't involve replacing the entire door or other construction.

Hi there "dbtothadb". and Welcome!

First, tell us more about that door:

1) Is it a proper acoustic sliding door, or just a typical "Home Depot" style sliding door?
2) Is it double-glazed, or single-glazed?
3) What thickness is the glass?
4) What is the acoustic rating of that door? (either STC or TL will do)
5) How much sound is it actually blocking, in decibels? (You'll need to measure that with a decent hand-held sound level meter)
6) How are the edges sealed?

My first point of attack would be the edge seals. Typical cheap sliders don't have seals around the edges, which means that they don't isolate at a, basically. Totally hermetic sealing is critical for isolation. Good seals = good isolation, poor seals/no seals = 0 isolation. If air can get through, so can sound. So I'd suggest you check all around the door, carefully, to make sure that you have several good quality full-perimeter seals (top, both sides AND ALSO the threshold).

which claims to absorb 80% of the sound energy at some frequencies.

Anything that claims to absorb a percentage of sound is going to be useless. Because percentage is a useless measure for sound in any case! Percentages are liner, but sound is not. Sound is logarithmic, not linear. The way our ears work is logarithmic, not linear. All sound isolation should be specified ONLY in decibels, or as a distant second-best option, in STC ratings. But nobody who makes a serious acoustic device would rate its performance in "percentage", since that is meaningless. Stopping 80% of a 120dBC sound is way, way different than stopping 80% of a 90 dBC sound. There's simply no logic in rating an acoustic product in percentage. That would be like rating your car's gas mileage in terms of how hot the engine gets in degrees Fahrenheit... .

So you can forget the product you linked to, since clearly the manufacturer either has no clue about sound isolation, or does have a clue but uses misleading terms anyway... (draw your own conclusions as to why he would do that... ). (I didn't even bother clicking on the link, so I have no idea who that is, but just from what you say about it being rated in "percentage", the product is not worth considering.)

In addition, you cannot stop sound getting in by absorbing it... That wont work at all. Here's why: Can you stop the water flowing out of your kitchen tap by holding a sponge over the end of it? In effect, that's what you are trying to do. You can only stop sound by putting a massive, sealed barrier in its path.

I'm open to other options but I'd really love to find a solution that doesn't involve replacing the entire door or other construction.

First check the seals. If those are good quality, full perimeter, and working properly, then we-ll move on to other possible causes, base on the info you provide about the door. Even better would be a link to the door manufacture's web site, or at least the make and model of the door.


- Stuart -

I don't know the model of the door, since it's not labeled anywhere. I doubt that it's from home depot, though. It is of good quality, but obviously not made for soundproofing. It is double glazed, and it actually has minimal sealing, as it appears to have very tight tolerances around the edges. Thusly, I doubt that I can do anything about the seals. The only place I could add one would be where the door shuts, but the sound appears to be coming from other places besides that end of the door.

So that brings up the next question. What brand of sliding glass door should I be looking for?

Here's a couple that are supposed to be good:

http://www.soundproofwindows.com/record ... dio-doors/

http://www.soundproofstudios.com/record ... dio-doors/

http://arcacoustics.com/interior-archit ... -doors.php

http://specadsystems.com/benefits-acous ... lass-door/


- Stuart -

Thanks, I've been looking at some of these products, both windows and doors...

I realize it may be impossible to answer without knowing specific details, but is there a way that I can find out how much of the exterior noise at my place is being transmitted through the walls and ceiling vs the windows? It obviously wouldn't make sense to buy and install soundproof windows and doors if a significant portion of the sound is coming right through the walls. In my case, it is mostly traffic noise from a highway .3mi away. But there is also a constant low rumble between ~50Hz-200Hz that seems to be coming from somewhere else (perhaps HVAC at nearby mall? accumulated bass frequencies from the hiway? not sure.) Anyways, is there any methodology or ghostbuster I can call to figure out what (if any) sound is being transmitted through the walls?

It's not really in my budget as a home studio guy to hire an acoustician. Though I would not rule out the possibility of hiring legit studio designer down the road. Assuming I have a micro-budget to do anything at all for the next couple of years, how should I proceed?

I realize it may be impossible to answer without knowing specific details, but is there a way that I can find out how much of the exterior noise at my place is being transmitted through the walls and ceiling vs the windows?

Not really, no. You could measure up close to the window, and up close to the ceiling, then compare that to a measurement out towards the middle of the room, but you can't get too close to the surface in each case, as that would introduce incumbencies due to possible reflections, comb filtering, and bass build-up.

So you can't measure it accurately, but you can calculate it, provided that you know all the details of how the walls, ceiling, doors, windows, etc. are built.

It obviously wouldn't make sense to buy and install soundproof windows and doors if a significant portion of the sound is coming right through the walls.

Right. Studio isolation is only ever as good as the weakest link, which is why you need to build your studio such that all parts of it isolate to to the same level.

But there is also a constant low rumble between ~50Hz-200Hz that seems to be coming from somewhere else

If you can't identify where that is coming from, chance are that it is structure-borne and therefor comes from everywhere! That implies that your inner-leaf walls are not decoupled from the rest of the building.

- Stuart -