[brj]

First, let me say that this circle was a great idea, Rob!  And now, on to our regularly scheduled question...

My living room has 5 floor to ceiling windows that span an entire wall.  Each window is separated by maybe 8 inches or so.  Just out of curiosity, what type of acoustic control (or nightmare) could I expect from:

a) 2 inch slatted blinds in each window adjusted to whatever angle would be most acoustically beneficial.  (Aimed 45 degrees down into the carpet would be my guess.)  The blinds are already installed, but usually left completely closed.  They hang from the top of the window "box" itself and thus don't protrude past the inner drywall.

b) option (a) plus drapes/curtains in front of each window.  I don't have any yet, and thus I have the chance to select whatever material would be most effective (with some concessions to price and "decor", of course)

I originally intended to place the speakers on the wall opposite the windows and was contemplating what treatments I could get away with on that same wall - treatments that wouldn't look too drastic in what is the primary living space of the house.  It only just occurred to me that I might get some natural benefit simply by reversing the room and using blinds/drapes as the rear wall.  (For reference, the room has low pile wall-to-wall carpeting over a concrete slab, but is a bit lively based on a simple "clap test".)

Any thoughts would be appreciated!

[Ethan Winer]

BRJ,

> what type of acoustic control (or nightmare) could I expect from <

Blinds and curtains are not really useful as acoustic treatment. You might get a bit of deflection - but not true diffusion - from leaving angled slats halfway open. But curtains and other such thin materials offer no appreciable absorption. And certainly not below a few KHz which is where most rooms need absorption the most.

--Ethan

[Carlman]

I have a similar situation/room.

I was thinking of making drapes from soft or possibly suede leather and lined.  It'll be a while, though so I don't know what the effect will be.  I might get the properties of it measured so I can see what exactly I'll be absorbing.

I can hear a difference with the blinds vs. no blinds in my room.  However, which way they're turned makes no difference to me.  I had thought about putting some kind of material on each slat to control echoes but I could never figure out what would work for me.

-C

[tybee]

I have been using wood blinds made of basswood, and find they offer great acoustic value if kept closed.  If the blinds  are open partially, they shift the soundstage.  When they are closed the soundstage and imaging return to what I expect.

[brj]

I assumed that I wouldn't get much in the way of bass control, but I hoped that some measurable benefit could be obtained with this approach, especially since I can select the drape material for the purpose  Between a heavy material and the "draping" effect, I'm guessing it would at least deaden the room a bit.

I keep considering my options, but I'd really like to be able to treat the room in a less intrusive manner.

Thanks for the feedback, everyone!

[Tonto Yoder]

I'm unsure if these are anything special or if they're just normal drapes--

http://yahoosoundproofing.com/accur.html

They claim a "vinyl thermafoam" backing, but it's not clear how that's different from a normal lined drape???

[Zitoun]

Do you think these curtains will help with diffusion, they re supposedly made to reduce noise, I guess using the tone of wrinkles they have, see below

[JLM]

BRJ,

> what type of acoustic control (or nightmare) could I expect from <

Blinds and curtains are not really useful as acoustic treatment. You might get a bit of deflection - but not true diffusion - from leaving angled slats halfway open. But curtains and other such thin materials offer no appreciable absorption. And certainly not below a few KHz which is where most rooms need absorption the most.

--Ethan

+1

Look up acoustical curtains (heavy, ugly, and barely effective as treatments). 

[Letitroll98]

No, they won't do a thing for diffusion, they'll absorb a tiny amount of higher frequencies.  Rugs with padding and heavily upholstered furniture do a better job of broader band absorbtion.  Heavy curtains, foamed back like these, don't hurt a thing and I've found they can reduce a bit of the glare, sound wise, from window reflections, but nothing like dedicated absorbers, either commercial or homemade.

[richidoo]

Those curtains are intended to reduce sound coming in from a noisy street through your windows. They only affect higher frequency noise, like tire noise.

Diffusion must have a hard surface to reflect sound hitting it. Even amplitude diffusion which works by selectively absorbing some sound still has >50% hard surface.

[Zitoun]

Thanks a lot,

I got some high density velvet, that will be a start, I might double the with another layer later if needed but that's a start and better than the sliding glass door.

Step1 done.

[Early B.]

Thanks a lot,

I got some high density velvet, that will be a start, I might double the with another layer later if needed but that's a start and better than the sliding glass door.

Step1 done.

It's good that you didn't accept anyone's advice and decided to find out on your own. The more you get into audio, the more you realize that conventional rules often don't apply. Let us know if the velvet curtains improve the sound.

[Tyson]

I agree, having heavy drapes over the glass is way better than leaving them bare.  Glass in particular wreaks havoc on imaging and soundstage, even more so than a flat drywall or concrete wall. 

[Zitoun]

It's good that you didn't accept anyone's advice and decided to find out on your own. The more you get into audio, the more you realize that conventional rules often don't apply. Let us know if the velvet curtains improve the sound.

I am actually carefully reading and listening, but I am also aware that we don't have the same constraints, and adding panels on windows won't be necessarily a nice use of my living room. It's just about compromises. I'll certainly do the panels and diffusers later for the sides ceiling and rear, but I am trying to adress the most important and easiest challenges first.

But thanks I do appreciate your observation, and I will let you know.

[Zitoun]

I agree, having heavy drapes over the glass is way better than leaving them bare.  Glass in particular wreaks havoc on imaging and soundstage, even more so than a flat drywall or concrete wall.

Right, just the vibrations on the glass limit the volume of the sound that can fill the room, this is kind of the worst place to put speakers... and the only place I have .

BTW I do have on the left side of the room a 4 meter recess in the kitchen, I am thinking that I can put heavy drapes there as well to be able to get some symmetry in the room, knowing that on the other side I have a chimney with briques.
Do you think it worth a try ?

[Tyson]

With that kind of asymmetry I would strongly recommend trying open baffle speakers.  I dealt for years with exactly that type of acoustic problem and I could never, ever get a box speaker to sound balanced, no matter what I did.  Once I tried open baffle, it solved the entire problem instantly. 

[Zitoun]

How would you rate nx-otica to solve that issue ?

[Early B.]

With that kind of asymmetry I would strongly recommend trying open baffle speakers.  I dealt for years with exactly that type of acoustic problem and I could never, ever get a box speaker to sound balanced, no matter what I did.  Once I tried open baffle, it solved the entire problem instantly.

My friend had a very troublesome basement. He tried lots of acoustic treatment which helped some, but once he went with OB servo bass subs, ALL of his problems vanished and he threw the treatment in the trash. Of course, the naysayers and audio academicians will be quick to quote acoustic theories and post articles to debunk it.

[Tyson]

How would you rate nx-otica to solve that issue ?

Probably the best OB speaker in the world right now.  So yeah, good solution!

[jtcf]

I have two large windows in my room.Bamboo blinds make excellent diffusors.Thick heavy curtains in a second layer over top will help enormously with echo and glare.Controlling bass requires a different solution.Three tried and true methods are #1 multiple subs #2 DSP room correction #3 bass traps.