[BrandonB]

I am starting to think thru my room treatment.  I have some curtains that are made of a velvet material.  I would say they are medium thickness.  I have a large window on the side of the room and two sets of double doors on the other side.  The curtains cover the double doors and the large window.  Oh and the large window has pretty thick blinds that you can adjust the angle on them.  I was thinking about running the curtains all along the side of the room with the window but I am not sure how effective they would be as room treatment.  Also the large window is part of the first reflection of one of my Otica's.

[JLM]

You can never tell acoustic performance by visual appearances.  Curtains/blinds are minimally effective.  One of the best materials for absorption is Owens Corning 703 high density fiberglass as used by GIK (see their circle here).  Thicker the better, shoot for 4 inches. 

For diffusion you can't beat painted quadratic 3D blocks of wood but they're heavy and only effective down to 1100 Hz for 7.5 inch deep panels. 

Warning:  vendors tend to over sell their products.  Start with a small set, focus on first reflection points.  The room shouldn't be small or squarish, it is the 2nd most important component of the system (after speakers).  My room was 8ft x 13ft x 21ft (Fibonacci ratios) and without treatments performed well. 

[MrDonald145]

Hi, I am new to this forum and a lay audiophile. I believe in room treatment and sue to exaggerated prices for panels I built my own. I used 2’x4’ roxul panels then built shadow boxes and covered them with a material called farmhouse in white with gold specks. I made 8 of them and they work fabulous. They are trimmed in red oak with a Pearl White Metallic paint. I also used Dirac Live room correction which is a full suite application on my NAD M17v2.

[BrandonB]

You can never tell acoustic performance by visual appearances.  Curtains/blinds are minimally effective.  One of the best materials for absorption is Owens Corning 703 high density fiberglass as used by GIK (see their circle here).  Thicker the better, shoot for 4 inches. 

For diffusion you can't beat painted quadratic 3D blocks of wood but they're heavy and only effective down to 1100 Hz for 7.5 inch deep panels. 

Warning:  vendors tend to over sell their products.  Start with a small set, focus on first reflection points.  The room shouldn't be small or squarish, it is the 2nd most important component of the system (after speakers).  My room was 8ft x 13ft x 21ft (Fibonacci ratios) and without treatments performed well.

Thanks for the info.  My room is close to fibonacci 10x14x21.  So that is nice to know!

[william2001]

Curtains have at least some absorption if the densitiy is high, draped for more fullness, and mounted away from rigid surfaces where the particle velocity is higher.  But still not very effective compared to the already mentioned standard materials.... rigid fiberglass and Rockwool.

[Photon46]

When we installed Pottery Barn's heavy velvet blackout drapes over four large windows in a rather good size living space (replacing lighter weight curtains) there was a noticeable change in the way high frequency sounds decayed in the room. They can be acoustically useful if that is your issue but they aren't going to affect anything below the very highest frequencies.

[daopi]

I didn't try this but I am contemplating to do it:
Curtains are installed on rods and some mounts accept multiple rods. I am thinking on the second rod, behind the one visible in the room, to hang, centered at ear level, some ceiling tiles with high NRC and CAC ratings (like USG Mars). They are light, not messy like fiberglass boards and can be easily hidden behind the the curtains. The good ones are not cheap thou...

[BrandonB]

I didn't try this but I am contemplating to do it:
Curtains are installed on rods and some mounts accept multiple rods. I am thinking on the second rod, behind the one visible in the room, to hang, centered at ear level, some ceiling tiles with high NRC and CAC ratings (like USG Mars). They are light, not messy like fiberglass boards and can be easily hidden behind the the curtains. The good ones are not cheap thou...

You might have something here.  My first reflection from one of my Oticas is a window.  I could hang some absorbtion tiles like a curtain.

[PumaCat]

You might have something here.  My first reflection from one of my Oticas is a window.  I could hang some absorbtion tiles like a curtain.

Jus a suggestion for your consideration: you'd be better off using a proper acoustical panel from GIK Acoustics at your 1st reflection point on the window. Even the 2" GIK Impression series of panels would be a big improvement over curtains or a generic absorption tile; they are very effective and also attractive-looking as well as affordable, and the 2" thick foam-backed panels only $79. Also, you can just set it on the window sill at the 1st reflection point; easy-peasy.  I have them at my 1st-reflection points in my listening area, on both the left and right side walls. Cheers.

Link here: https://www.gikacoustics.com/product/impression-2inch-acoustic-panel-diffusor-absorber/

Cheers.