Curtains for Sound Absorption?

prime minister

Site Owner
Staff member
I've seen heavy curtains on many an audio store, and as the space in my living room could easily look ok with some heavy curtains behind the speakers, I'm wondering how well this idea would work. Anyone ever tried it?
 
It can help but it is room and system dependent. I have had requests to do a seminar on room treatments because of my rooms at shows and the consistency of good sound I produce (I have had a bad show or two - it happens). I never intend to do one because even similar rooms can be different enough to produce completely different sound.

You could start by using varying thickness of sheets/blankets in the areas and see what happens.
 

billfort

Administrator
Staff member
I've used them in the past and they can be very effective - but they won't fix bass problems, and there effectiveness in other frequency ranges varies with several factors.

Some of the things that affect their frequency absorption; the weight, material, 'draped' amount (bunching), how far they are from the wall and what wall material is behind them. They can be very nice for adding a level of flexibility and tuning to the room too, where you can open them to varying degrees changing the draping and exposing whatever is behind them.

In a listening room I built in the country home I built years ago (in a previous life), I first got the bass dealt with by getting the room size right, building in some bass traps and 'staining' the block walls - sealing block with paint hurts the bass absorption. I then used heavy curtains to get higher frequency absorption where I wanted it to get the reverb time reasonable. You could then open or close up some of the curtains to expose the more reflective walls behind them, which had the effect of making the room 'sound' a little larger or smaller. I got so addicted to this tune-ability, that I did something similar in my existing room by using acoustic panels with absorption characteristics similar to those heavy curtains - I move/add/remove them to change from a small smokey bar (my favourite) to a larger space for 'bigger' music. You have heard the small smokey bar and Massey Hall version of this here Erik. :)

This is well covered right down to all the ugly math in F. Alton Everest's Acoustic Techniques for Home & Studio and The Master Handbook of Acoustics. These are books you really must get IMO - all you've heard in my current room sprung from those pages and my well worn copies are still right here in the bookshelf.
 
Along these lines I have two listening rooms that have openings into other rooms that can not be closed off by a door. They are on the side. At times I really wish I could as others in the house are doing other things elsewhere like maybe watching TV. There is a fair amount of nice decorative trim work around each so adding anything along the lines of doors isn't going to happen so I've always though some tastefully done curtains on rods would possibly work. A combination of isolation and addressing reflection points (although they are mostly open)...
Anyone got a good source for curtain/drape materials that would be suited to this application.
 
My old house was built in 1967 with hard plaster walls and an L shaped living room dining room where my large speakers lived.

We moved into the house and there were floor to ceiling pleated curtains. They were lined and heavy. One day my wife said, Take those curtains down and the rods too. I hear and obey. And installed Levelors. After that the room was much brighter and more reverberant. It took me a while to get used to it. I regretted removing the curtains.
From a sound system point of view. They were sunbleached and too old.
 
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My first business (after I got tired of being fired from job after job) was a high end drapery installation service. We did a ton of empty new homes. I was a nascent audiophile at the time and couldn't help but notice the effect. Yeah, the heavier the better.
 
There is a YouTube channel called Acoustic Fields. Although they are an acoustic design company their info is excellent and they discuss all aspects of acoustic design and results. I think they did an episode on drapes...

Having designed a couple of imperfect studios for myself, I learned that the foundation of design is architecture. You can make a room better but not "right" without a correct room to start with. In design books there are golden ratios of w/h/length required. There are no easy fixes for an "incorrect" room shell and they increase in cost significantly if the room is not right. When I built my first studio I was lucky enough to get some help from Frank Comantale (sp?) who designed the original Hit Factory. One thing he told me was that a good room uses diffusion and splayed walls before absorption..he said a rule of thumb was a one inch per foot slant horizontally to the walls.

I think all audiophiles would benefit from a copy of F.Alton Everest's Acoustic Techniques for Home and Studio. It's easy to understand and is a great primer.

The drapes might help or not...my instincts say the heavier the fabric and deeper the folds the better...definitely check out that channel...it's really very informative. Good luck in your endeavors!
 
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@Drugolf I remember as a kid going to the 42nd Street library in Manhattan just to look at books like this as there was no internet or Amazon. That's where I found the Alton Everest book when it was really hard to find resources. By extension, one would be led to believe we have better sounding rooms today. Probably, the ceiling height of a room is, for many, the biggest problem but larger rooms require more $ and more treatment with the prospect of better sound...it's a real balancing act.
 
There is a YouTube channel called Acoustic Fields. Although they are an acoustic design company their info is excellent and they discuss all aspects of acoustic design and results. I think they did an episode on drapes...

Having designed a couple of imperfect studios for myself, I learned that the foundation of design is architecture. You can make a room better but not "right" without a correct room to start with. In design books there are golden ratios of w/h/length required. There are no easy fixes for an "incorrect" room shell and they increase in cost significantly if the room is not right. When I built my first studio I was lucky enough to get some help from Frank Comantale (sp?) who designed the original Hit Factory. One thing he told me was that a good room uses diffusion and splayed walls before absorption..he said a rule of thumb was a one inch per foot slant horizontally to the walls.

I think all audiophiles would benefit from a copy of F.Alton Everest's Acoustic Techniques for Home and Studio. It's easy to understand and is a great primer.

The drapes might help or not...my instincts say the heavier the fabric and deeper the folds the better...definitely check out that channel...it's really very informative. Good luck in your endeavors!
Agreed, on the value of Acoustic Fields' youtube channel, long time subscriber. And very much agreed on the value of nonparallel surfaces.

As one adds damping to a room, it does take more power to energize it. That means having to run your system harder to attain the same perception of loudness, and there can be some trouble there. You have to try to keep those two things separate. DR naturally diminishes as you push things (and usually in a nonlinear fashion with respect to F) - that does not mean that "excess" damping is sucking the life out. It means you need a larger DR envelope. ;););)
 
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