Seeking Advice on Acoustic Door Curtain

[JakeK]

Hi,

I have a detached garage which I've done some work on soundproofing the walls, ceiling and door. I want to achieve a few more db on the door and I think the most convenient thing that won't cost too much would be a curtain. Does anyone have experience of this? What would you recommend?

The best option I've found here in the UK is this https://www.vocalboothtogo.co.uk/p/...50g-m2-40mm-grommets-blackout-thermal-curtain

 

[Pareto Pragmatic]

What would you recommend?

As heavy as possible and wide enough to have a lot of pleats. 4x the width of the door should give you a lot of pleats. Ideally you would have all pleats and no single layer areas when installed.

The ones in the link look pretty good, btw.

 

[JakeK]

As heavy as possible and wide enough to have a lot of pleats. 4x the width of the door should give you a lot of pleats. Ideally you would have all pleats and no single layer areas when installed.

The ones in the link look pretty good, btw.

Thanks! 4x the width does sound like a lot but maybe it makes sense! How wide a curtain to order for the door is something I have to work out but I do have to consider how much room I have for the curtain to bunch up at the side of the door.

 

[tmuikku]

Hi, soundproofing and acoustic treatment are two different things. Sound proofing in short is to make airtight and decoupled structures so that sound (pressure variation) doesn't transmit.

Curtain doesn't do either so it's acoustic treatment, which could reduce reflections some and make sound level a bit less, on high frequencies.

Put proper sealing on the door to cut air leakages, and then dampen it somehow, like constrained lauer damping. I bet this is much more effective than curtain. However, soundproofing is as good as weakest link, so for example having isolation on bass would need quite dramatic measures, air tight sealing is not enough as the bass transmits easily through the structures, floor and walls and ceiling, everything.

ps. above is based on observations and bits and bobs here and there. I'm no acoustician or soundproof pro but a hobbyist, so perhaps get few more comments.

edit. I see you got this advice on another thread already.

Acoustic sealing a door. Seeking recommendations and a little science with db meter.

I've lined my detached garage with insulation, OSB and plasterboard (drywall) to soundproof it and now I need to add seals to the door. The thin metal door did very little to stop sound and I've filled it with insulation, added two layers of solid wood and finally stuck on some thin acoustic...

www.audiosciencereview.com

 

[Audio Science Pal]

I want to achieve a few more dB on the door

Add some rubber or mass loaded vinyl sheeting to the door face. Hopefully you have a solid core door to begin with.

 

[JakeK]

edit. I see you got this advice on another thread already.

Acoustic sealing a door. Seeking recommendations and a little science with db meter.

I've lined my detached garage with insulation, OSB and plasterboard (drywall) to soundproof it and now I need to add seals to the door. The thin metal door did very little to stop sound and I've filled it with insulation, added two layers of solid wood and finally stuck on some thin acoustic...

www.audiosciencereview.com

Yes I already did some work on the door itself and I don't think I can do much more without risking breaking the hinges. I'm hoping a curtain can just absorb a few more db. I plan to measure afterwards to see how effective it is.

 

[tmuikku]

Did you patch all air leaks? Sealing of the door gaps is critical. Also plastic moisture barrier on the walls and ceiling properly implemented and sealed with tape should help. The room needs to be air tight basically. This of course requires HVAC system to keep moisture and air quality in check, and requires appropriate mufflers and stuff to prevent noise leak out through the HVAC system, which of course cannot be air tight.

I suspect the curtain won't help much at all, except for acoustics inside the garage. I bet what you hear outside is not high frequencies but the lows, and curtains just don't work on lows. In the other thread it seems you already got >20dB of reduction, which I bet higher frequencies got even more attenuation already, but you could try estimate this with some RTA, even with your phone, compare relative frequency response door open and then closed. So, to reduce SPL outside you'd need to work more attenuation on frequencies that you measure outside, and they are most likely lows, and require quite dramatic actions to soundproof, structural decoupling. Basically floating room inside room to be most effective.

 

[Pareto Pragmatic]

Thanks! 4x the width does sound like a lot but maybe it makes sense! How wide a curtain to order for the door is something I have to work out but I do have to consider how much room I have for the curtain to bunch up at the side of the door.

2x gives you gentle wave pleats when closed.

Given the thickness of the curtain, you might not need so much fabric. But 4x will give you all pleats or close to it, and so a lot thicker material between space and door.

 

[JakeK]

Did you patch all air leaks? Sealing of the door gaps is critical. Also plastic moisture barrier on the walls and ceiling properly implemented and sealed with tape should help. The room needs to be air tight basically. This of course requires HVAC system to keep moisture and air quality in check, and requires appropriate mufflers and stuff to prevent noise leak out through the HVAC system, which of course cannot be air tight.

I suspect the curtain won't help much at all, except for acoustics inside the garage. I bet what you hear outside is not high frequencies but the lows, and curtains just don't work on lows. In the other thread it seems you already got >20dB of reduction, which I bet higher frequencies got even more attenuation already, but you could try estimate this with some RTA, even with your phone, compare relative frequency response door open and then closed. So, to reduce SPL outside you'd need to work more attenuation on frequencies that you measure outside, and they are most likely lows, and require quite dramatic actions to soundproof, structural decoupling. Basically floating room inside room to be most effective.

My feeling is that it's more high frequency that's a problem at the moment and there is nothing more I can do for bass without rebuilding the whole thing. I've added a lot of weight to the building which was already concrete all round and it's a heavy little door now with all the solid wood, insulation and rubber I added. Almost breaking the hinges I fear! I can't hear the bass sounds outside at all with my current speakers and there is little difference with pink noise or white noise.

The hope is that the curtain will improve the acoustics inside as well as reducing outside by a few dB.

I also have a work bench, shelves and a cupboard one end which will absorb and diffuse some sound and maybe work as a bass trap?

 

[JakeK]

2x gives you gentle wave pleats when closed.

Given the thickness of the curtain, you might not need so much fabric. But 4x will give you all pleats or close to it, and so a lot thicker material between space and door.

Thanks for the advice. 3x might be a good amount without having too much to store to the side.

 

[hat28]

You said the best option you have found in the UK is... and then give the weblink to the supplier.

Although they have a .co.uk website address, note they are not based in the UK at all.

 

[JakeK]

You said the best option you have found in the UK is... and then give the weblink to the supplier.

Although they have a .co.uk website address, note they are not based in the UK at all.

Yes I can see that is true when I look around their website. Hopefully they are still OK to seal with as they still seem like the best acoustic curtains that sell into the UK.

 

[hat28]

Yes, the site looks like it is genuinely informative and the curtains look plausibly effective. Let us all know how you get on.

 

[JakeK]

I have ordered a 'VB2GO deNoise (double-layer) 2600' curtain from vocalbooth to go at 1400 wide for an 800 wide door on their recommendation as the widest to go for on that size door. It should be here next week and I plan to put it up and do some tests next weekend.

 

[JakeK]

The curtain arrived and the first impression is just how stiff and heavy it is. Far heavier than I imagined having thought it would be more fluffy inside. This is a good thing though as this means it should block or absorb a noticeable amount of sound! I got it hung up which was not that easy for the size of it because of the weight.

It looks pretty good as well. You can get a 'pro' version which is lined with a fabric colour of your choice but I didn't feel like I needed that. In hindsight the thinner version would have done the job and I could have got the lighter but 'pro' version for plenty enough sound blocking and better looks.

Pulled to the side it makes a thick bundle and in no way fits inside the standard good size holdbacks I bought for the purpose. I don't mind that though!

 

[hat28]

The curtain arrived and the first impression is just how stiff and heavy it is. Far heavier than I imagined having thought it would be more fluffy inside. This is a good thing though as this means it should block or absorb a noticeable amount of sound! I got it hung up which was not that easy for the size of it because of the weight.

View attachment 400344

It looks pretty good as well. You can get a 'pro' version which is lined with a fabric colour of your choice but I didn't feel like I needed that. In hindsight the thinner version would have done the job and I could have got the lighter but 'pro' version for plenty enough sound blocking and better looks.

View attachment 400345

Pulled to the side it makes a thick bundle and in no way fits inside the standard good size holdbacks I bought for the purpose. I don't mind that though!

It blends well with your wall. Did it work db wise? That is, do you have measurements with the curtain open and closed?

 

[JakeK]

I set up the bluetooth speaker to play white noise and did some tests. I didn't turn it up to maximum for the first two measurements out of consideration for the neighbours.



Approx 70db with the door and curtain open. Then I closed the curtain and played the noise again at the same level.



Approx 54 db showing an amazing 16db reduction. That's nearly as much as the reinforced door (before I added the seals) and way more than I was hoping for. That's an effective curtain!



I turned up the noise to max, approx 100db inside and measured with the door closed and the curtain open.



Approx 63db. The door is blocking/absorbing about 25db without the curtain. I closed the curtain and the door and played the noise at max level again for the final measurement of the door and curtain combined.



I measured 53db. The curtain is adding at least 10db to the door which is much more than I was hoping. 53db is actually about the ambient level outside so it could be doing more than that. I'm very happy with this and I recommend them highly.

 

[tmuikku]

Hi! nice, the curtain is way thicker I envisioned.

Has it any effect on low frequency noise? Your meter seems to read dBA which rolls of lows, also white noise is peculiar having highs very loud to ear, while pink noise is "balanced" sounding. This means you see effect on highs reducing, which is to be expected. I'm afraid it does nothing for lows, which usually leak the loudest, but you beed dBC measurement to meter lows. Anyway, if there is no low frequency noises inside perhaps it doesn't matter. Just somethign I wanted to make everyone reading aware of.

Example, my friend has suburban house and rehearsal studio in the garage. All that leaks out is kick drum so much so that it hears inside to neighbouring houses, who were annoyed enough and called police once, and he had to switch real drums to electronic in order to keep the place in use and peace with the neighbour.

 

[Pareto Pragmatic]

Very thick, looks like it worked well!

Yeah, 4x the width would have been WAY too much for that thing.

 

[JakeK]

Has it any effect on low frequency noise? Your meter seems to read dBA which rolls of lows, also white noise is peculiar having highs very loud to ear, while pink noise is "balanced" sounding. This means you see effect on highs reducing, which is to be expected. I'm afraid it does nothing for lows, which usually leak the loudest, but you beed dBC measurement to meter lows.

I guess that's all my meter can do as it's quite a basic cheap one I bought just for this test. The speaker is only small so while it does have some dsp and does sound like it has a good bass extension for it's size and type the bass will be quite rolled off as well. This roll off on the dba also makes sense as to why pink noise measures basically the same as white noise. I could look at a dbc meter but I'm not for spending much on a db meter I'll only use once.

The next part of my project is to choose and buy some bigger speakers and more powerful amplification so after that I can test by ear how much bass is escaping but I won't want to push a new system anywhere near as high as 100db with noise in case it can do some damage. I don't mind with the bluetooth speaker as that's already old.