Heavy curtain for acoustics?

[Trezl]

I have a 22x11 front room of the house that is partitioned into a home theater on one side and my office on the other.

The home theater is 12x11. I'm thinking of installing a retractable curtain at the point of partition for acoustics when we watch movies.

Will there be much help from something like that, or will I still get a lot of reflection from the office even with the curtain drawn? Is there a certain type of curtain that I should look for?

I've attached a picture of the room setup to look at. There are two pillars right at the partition as shown in the picture as the walls jutting out of the middle of the room.

At that point, there is actually a 1ft section of wall that comes down from the ceiling, so I think installing a curtain rail along the wall would work pretty easily.

I'm not concerned with quieting the sound, just making sure the sound inside the HT space is as nice as possible. I hope to add acoustic treatments to the room eventually as well.

I appreciate any thoughts you all might have.

 

[Pyrrho]

The curtain would absorb sound. It might help with your acoustics, though the first thing to ask yourself is whether or not there is currently a problem with acoustics. I recommend that you try something first to see for yourself whether something along those lines would help. Get a couple of tall friends to hold a heavy blanket at approximately the place where you are thinking of installing the curtain, and listen to your system, and then immediately compare with it not being there, with the exact same disc playing the exact same part. That will be a cheap way of getting an idea of what it is likely to do for you.

Basically, the heavier the curtain, the more sound it will absorb, though there is a limit to what such a thing will do, and whether it is beneficial or not is going to depend upon other factors that I cannot know from what you have said. Try the blanket with a couple of tall friends, and if it seems to help, then go ahead with the project, but if it does not seem to help, then don't bother.

 

[jostenmeat]

Trezl, the best setup would be to have it lengthwise, having the HT stuff centered on the left. This will give you better symmetry, giving you the best chances of having similar response from both left/right, and would get you off the back wall. I've often seen b pape really highlight the need for getting off the back wall, to get away from muddying/collecting bass there, and if impossible, load it with broadband absorption. Or, you can put couch feet on sliders too, to help you get away.

Lengthwise is nice, because the overlapping/intensity of modes is reduced, and in this case, quite a bit (double). However*, since one dimension is exactly double the other, you will have some modes that will be particularly intense no matter what.

A problem that can happen with curtains is that all of a sudden the sound is "deadened", yet is still not any clearer, because modal issues with the bass still make it unclear. Curtains will only absorb HF, hardly your midrange, let alone your bass waves. I would do curtains if you feel that you have issues with the HF, less using measurements to see for sure. Just some thoughts.

Likewise with the viewpoint of Pyrrho, I've always believed in the concept of adding to taste. Some will say that you will not get meaningful differences with just a couple/several panels, whereas others say it's still immediately noticeable and beneficial. A person like b pape will often advise to put panels directly behind the speakers for SBIR, but I'm pretty sure in this case he would advise the backwall first. If it was me, I'd investigate the corners at upper left, and lower left, especially if I find that those corners/sides are energizing the left side of my soundstage too much. Good luck.

 

[Trezl]

Thanks for the thoughts tonight very much appreciated.

The problem with lengthwise (which I've thought of, is the current door placements just don't allow it to work right. The TV is at the only place in the room that has a flat wall without door or window.

The room isn't exactly cut in half either, the side that is currently set as the theater section is about 1-2' longer than the other half. The existing pillars keep the room that shape.

I do plan on acoustic panels on the walls over time as well. Was curious thoughts on what a curtain might do. The "deadening" you mention is something I've noticed in some rooms, and I didn't realize curtains would really only effect HF.

Pyrrho, thanks for the idea on getting some friends with a thick blanket as a first test. I'll try that before I spend any money on something.

 

[jostenmeat]

Thanks for the thoughts tonight very much appreciated.

You're welcome.

The problem with lengthwise (which I've thought of, is the current door placements just don't allow it to work right. The TV is at the only place in the room that has a flat wall without door or window.

If a door is blocked, of course not! However, if say only one window is partially blocked by the TV or something, I might still consider it, depending on how important audio is to you. If you live in a dark area, or that wall is the only wall that allows in significant light, etc, nevermind. But, my PJ screen is covering a window. I have other windows that I can reveal, then open, in the room. In fact I can roll up the screen too (but I never do).

The room isn't exactly cut in half either, the side that is currently set as the theater section is about 1-2' longer than the other half. The existing pillars keep the room that shape.

Now, while I don't exactly understand the pillars and their limitations they incur, desired starting point for listener is 38% room length, doesn't matter front wall or back wall. If 22 ft, that is either 8.36' from front or back. b pape has mentioned this number can drop to as low as 33% with the inclusion of non-axial modes. But, ballpark is good, no one sits with their head in a vice. Just stuff for your mind to chew on.

Finally, I have a friend who just doesn't put the time in understanding much of AV, yet is building a basement entertainment area, replete with projector theater, pool table, etc. He already got a 65" plasma with my help. Even after explaining things as if to a child, multiple times (and he's actually extremely bright), he still fails to do the most basic settings for his plasma, whether 24p, defeating NR, etc.

Well, I won't twist my friend's arm, it's whatever he wants. But, when I explained the HUGE difference of having his theater lengthwise, as opposed to exactly how you have it (left side), he explained that there is a window he didn't want to cover up. I told him he can get a tab tensioned, or Dalite HP screen. He still doesn't want to do it. I said ok, just realize that is a huge first compromise if you care about HT. He said it will have more than one purpose than HT. I explained the pool table can be behind the seating, as he would not want to be up against the back wall anyways. The PJ could be further back, over pool table, doesn't matter if the throw works out. And he LOVES my HT. I guess he really likes that window or something, even in the basement. After he saw what a big difference my recent visit made after tweaking his video, I am wondering if he will heed my advice or not. I really have no idea if he will. I just wanted to share that story.