What am I using and are they good?

J

jackiecorn

New member
I've built my own studio in a spare little room of my house in Hong Kong.
I want to ask a bit about sound insulations here.
Since I am a beginner I have no idea what the best sound insulataion materials I should use in my studio.At first I thought those foam pads with semi spheres sticking out are the best ones cuz I see almost every rental band rooms in my area have them.
However my mum went to China and asked for the best sound insulation material and ordered it for me. It came out to be some rather thin pads made of either fibreglass or mineral wool,I still cant identify them but they cost a lot more than those foam pads commonly used.
I glued them to the wall of my room and at first the room sounded weird when i talk in it,like I'm talking in an aquarium and has echoes. But after a month or so it sounds normal again like other rooms without them.
My primary goal of sound insulation is to block the sound from my studio from my neighbours as we live right next to each other. However the insulation effect was not as good as desired,we can still hear sounds from it from outside of the house.
I have an air conditioner attached to the wall with the other end facing outside the house and I think much sound is leaked through the air passage,how can I solve this?Should I stick foam pads on the front of the air conditioner so it blocks some sound but allow air passage too?
I also have a door that is made of thin wood and i think it also allows the sound to leak through it and travel to outside the house since our house's front door is very near our studio's door
Finally I would like to know what material am I currently using and are they better than foam pads at all at sound insulation?
They are thin,very light,kinda hairy and rather expensive.
Thanks for reading and I hope someone could help me out!
 
Hey...I'm doing the same thing...I'm in HK too....I have a square room 2x2x2 meters basically. Let me know how you go...I wonder if Tom Lee's has any treatment material...and how much it'd cost?
 
Hello Jackie,

You are confusing sound isolation with acoustic treatment.

They are two very different animals.

(1.) Isolation is the process of blocking or stopping the sound from transferring through the walls to/from adjacent spaces or outside.

Isolation is accomplished with a mass - air - mass wall/ceiling system

rule #1: Mass and airtight sealing is needed to block sound. For example; To 'sound-proof' a door you must: replace the door with a heavy solid core door and place additional mass on the door as necessary - and - install heavy duty door frame and threshold with air tight seals.

The ideal isolation wall is two 25 cm concrete walls separated with 1 meter sealed airspace. - But this would be ridiculous in practice. I hope you get my point though. ;)

If sound is leaking out of your walls, ceiling, or floor, you must either add mass, apply mass with a CLD like Green Glue, build an internal shell (room in a room), or move. :D

(2.) Acoustic treatment is done to control the acoustics of an enclosure.

Acoustic treatment like bass trapping, absorption panels, polys & diffusors all control the waves and rays of sound determined upon their design & placement. You would do well to read up on their applications at Ethan's site, the GIK site and my papers.

(advertizement) ;) If you need some personal help see my web sites. :D

Cheers,
John
 
oh my god,so I've been doing it all wrong the whole time? I spent a few thousand bucks(in HKD) on these pads and I'm not doing anything at all?
Is there anything that I can do now to make good use of my pads into sound isolation?
I have a very litttle room and I have no idea how to achieve isolation though
The air conditioner problem is still there too...
Thanks for the info anyway! Truely appreciate it.
 
You are very welcome.

Remember; the only stupid question is the one that is not asked. I am here to help. Keep us posted on your progress.

Cheers,
John
 
thank you very much
I wish you can answer the questions I asked in the above reply.
I really dont want to waste my acoustic pads...
 
Jackie,

I'm sure that your pads will be very very helpful in taming the room acoustics. Use them mainly in the corners and at reflection points. Don't be afraid to stack these up.

You can place some on the ceiling as a 'cloud' to eliminate reflections from the ceiling.

Cheers,
John
 
jackiecorn said:
thank you very much
I wish you can answer the questions I asked in the above reply.
I really dont want to waste my acoustic pads...
Click to expand...

The short answer is no...they will not help in terms of isolation, not even a little. As a matter of fact, they're probably making it a little worst by providing a layer that transmits mechanical vibrations in and out of the space.

That's the thing...there are two ratings involved here: the STC rating, which measures the soundproofing in a space between 125Hz and 4Khz. The STC rating tells you NOTHING about what happens above or below that bandwidth. Then there's the NRC rating, which tells you something about the frequency response inside an enclosed space. The tricky thing is that the higher one is, the lower the other typically is.

Sorry man...if the goal was sound proofing, you threw away a bunch of money. :( The only way to do what you're wanting to do is to add mass-airspace-mass. There is absolutely no other way...no shortcuts of any kind.

Frank
 
oh well... :(
Just wanna ask,does acoustic foam pads do any good? I see them both as sound absorbers but wiki says that acoustic foam is somewhat related to soundproofing.
At the moment I dont think I will invest much more on soundproofing my room,the furthest I could get is to fix my door by placing a thick blanket to cover the whole door,would you suggest this and should I place the blanket inside the room or outside the room?
 
jackiecorn said:
oh well... :(
Just wanna ask,does acoustic foam pads do any good? I see them both as sound absorbers but wiki says that acoustic foam is somewhat related to soundproofing.
Click to expand...

As is the case with many things, Wiki is wrong.

jackiecorn said:
At the moment I dont think I will invest much more on soundproofing my room,the furthest I could get is to fix my door by placing a thick blanket to cover the whole door,would you suggest this and should I place the blanket inside the room or outside the room?
Click to expand...

The blanket won't do any good at all, which makes sense considering that the acoustic treatment won't either. Neither one has even remotely enough mass to be effective. Sorry.

Frank
 
Weasel9992 said:
The blanket won't do any good at all, which makes sense considering that the acoustic treatment won't either. Neither one has even remotely enough mass to be effective. Sorry.
Click to expand...

Speaking of mass,instead of blankets if I use those extra heavy cloth used to block most drama stages inside from the outside,will it be better?
Cuz from looking at my school hall's setup,those heavy cloths block EVERY sound from the inside to the outside,even if we are screaming inside no one could hear a thing outside.

Or should I just change my door to a more rigid one?

Thanks
 
Weasel9992 said:
No, it won't. Your school experience notwithstanding, the physics don't add up.

Frank
Click to expand...

So what exactly is the principle behind the sound isolation on stages after the cloth is closed? I know for sure that without anything covering the stage even walking on the wooden deck is loud as hell.
 
jackiecorn said:
So what exactly is the principle behind the sound isolation on stages after the cloth is closed? I know for sure that without anything covering the stage even walking on the wooden deck is loud as hell.
Click to expand...

Well, of course there is some high frequency dampening, but aside from that it's purely your ears trying to line up with what your eyes are seeing. Pure placebo effect.

Frank
 
Jackie,

There are lots of Voo-Doo / snake oil salesmen out there. Do you have a link to the 'sound proofing' curtain? I'd like to add it to my VooDoo list.

Mass - Air - Mass

Only way.
You are in good hands with Frank. :D

Cheers,
John
 
It is so terrible to hear that almost all beginners in audio producing or such are cheated by commercial lies. Whenever an average person think of sound isolation and such the first things that comes to mind is foam pads and odd shaped wall,rarely do we know the difference between soundproofing and acoustic treatment,even shops comfuse us by claiming their products in between the two.
There isn't a specific site I was referring to,just google soundproof curtain and
you will see lots of sites selling similar products.
 
jackiecorn said:
It is so terrible to hear that almost all beginners in audio producing or such are cheated by commercial lies. Whenever an average person think of sound isolation and such the first things that comes to mind is foam pads and odd shaped wall,rarely do we know the difference between soundproofing and acoustic treatment,even shops comfuse us by claiming their products in between the two.
Click to expand...

I couldn't agree with you more, and that's why John and I post here and elsewhere. Believe it or not, it's not for the purposes of generating sales. We get very, very little sales traffic from doing this. It's mostly in the interest of dispelling all the silliness out there...and there's plenty of it, trust me. Don't even get us started on the audiophile stuff...:eek:

Frank
 
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