Pros and Cons of a Listening Room Being a Sealed Box

[Ron Resnick]

Ideally, should a listening room be a sealed box (meaning a room with a roof and a floor and four continuous walls which can be completely closed with a door)?

Or are there any advantages to a listening room having one or more large openings on one or both side walls?

Is a completely closed room good because it allows a stereo system to "pressurize" the space?

Or can a room with one or more large openings on the side walls be advantageous by allowing excess sound pressure or standing waves to "escape"?

Do the answers to these questions depend on the size of the room in question?

 

[amirm]

An opening to the outside (e.g. open window) acts like a perfect bass trap. You will lose bass energy through it but also get less reflections.

With respect to an open floor plan, the larger space lowers the transition frequency and as a result, lowers your bass problems. As per above, you will need more bass output though to compensate. In other words, it is a good thing.

The reason to not do it is to keep the music in one place, and absence of power to fill the space. It is also much, much more difficult to model so all the rules about placement of subs and such get thrown out the window. This is why you see acousticians show a preference for rectangular spaces. Not because they are better but because they are easier to predict.

I am too dumb to know what is meant by "pressurizing" the room . Unless you are in a small car with thousands of watts, then you are not going to impact the pressure of anything in the normal room.

 

[Ron Resnick]

An opening to the outside (e.g. open window) acts like a perfect bass trap. You will lose bass energy through it but also get less reflections.

With respect to an open floor plan, the larger space lowers the transition frequency and as a result, lowers your bass problems. As per above, you will need more bass output though to compensate. In other words, it is a good thing.

The reason to not do it is to keep the music in one place, and absence of power to fill the space. It is also much, much more difficult to model so all the rules about placement of subs and such get thrown out the window. This is why you see acousticians show a preference for rectangular spaces. Not because they are better but because they are easier to predict.

I am too dumb to know what is meant by "pressurizing" the room . Unless you are in a small car with thousands of watts, then you are not going to impact the pressure of anything in the normal room.

Thank you for your reply, Amir.

I meant to describe a room with an open, but interior floor plan, not openings to the outside.

So you believe that a "closed box" is easier to treat acoustically, but that a room with large openings may have less need for acoustic treatment?

 

[amirm]

Hi Ron. A closed box is easier to *predict* not treat. For example if you have a rectangular room, we can predict where to put your speakers and listening position to reduce modal excitations. Once you open that floor plan in any way, such predictions become impossible without full computer simulation.

The frequency below which room modes become pronounced is proportional to volume. So once you open the space to a larger one, then you benefit in that manner. And your bass issues reduce. And if you are using acoustic treatment for that, yes, there will be some reduction of need for that. In my own large open space, all I had to do was use a bit of EQ and I was there.

 

[Rodney Gold]

ron , closed box for sure for symmetry an ease of treatment , but more importantly it will be a quiet room with no extraneous noise pollution and will also keep the music in..ie you can play at the level you like without disturbing the rest of the house.
Easy to control the liveliness of the room vs an open plan space .. no real aesthetic consideration or WAF to contend with with your own closed room

 

[Diapason]

My listening room is virtually a concrete box, and while it's nice not to disturb anybody else, it's a VERY difficult space for good sonics. Part of it is size, of course, but friends who have similar listening areas in more open-plan spaces seem to find it easier to get good sound.

 

[Rodney Gold]

What are the issues you have in your room?

 

[Diapason]

Standing waves, mainly. It's quite a nice little physics demonstration to play sine waves and go from virtually full cancellation to booming bass merely by moving a few feet!

 

[Rodney Gold]

Can be easily fixed with bass traps and or low bass DSP or better stil a swarm of subs

 

[FrantzM]

Standing waves, mainly. It's quite a nice little physics demonstration to play sine waves and go from virtually full cancellation to booming bass merely by moving a few feet!

Room treatment? Adverse to use multi-subs and DSP? Most any rooms benefits from both.

Sealed room has the advantage of being .. well .. isolated it becomes your cave, your sanctuary. A place where you retreat and are with the experience of listening to music. As many have pointed before it is easier to predict not necessarily to treat. THe corollary is that you are not bound by the constraints of pleasing another party (most likely) thus can delve into serious room treatment. In the bass however room treatment is never small, cannot be because of the long wavelengths involved. There, the best remedy is multi-subs and EQ/DSP something that has gotten a bad rap in purist circles but whose efficacy can be proved and repeated ad infinitum.

IMHO for what you are contemplating Ron, it would be better to go for a built-for-the purpose sealed room. A few months ago I was of the opinion that the room and its treatments would be independent of the speaker used. I am not so sure these days. I don't think the way you would treat the back waves of a dipole would be needed for a monopole , for example. Still in a closed room you can have well concealed built-in Helmhotz resonators and all kind of other room treatments and conceal them entirely.

 

[Diapason]

I've quite a lot of bass trapping in the room (GIK) and real improvements have come with added general "clutter". I have boxes of books in corners, and other miscellaneous crap, which has made a difference. It looks bad, but it improves the sound quite a lot. I experimented with DSP a while ago (a Copland amp maybe? Do a sweep, measure with a mic connected to amp, it sorts it out, real first steps stuff) and I liked what it did in some areas but felt it took away too much of that audiophile magic that probably isn't really real. One way or the other, I sleep better in my bed now without it. Recent visitors have expressed surprise that the room is no longer dominating proceedings the way it used to, so I'm happy that we're getting there, but it's still not ideal. It's only just over 9' wide too, which brings its own problems.

 

[bonzo75]

Ron, if your room can still be changed, just get Marty's ratios and treatments

 

[Diapason]

One huge advantage to having a sealed space is that the noise floor in my listening room is a LOT lower than anywhere else in the house, and that's a critical issue for me.

 

[Rodney Gold]

Sealed room has the advantage of being .. well .. isolated it becomes your cave, your sanctuary. A place where you retreat and are with the experience of listening to music.

That's it in a nutshell...

 

[GaryProtein]

Do air conditioning ducts make an otherwise "closed room" "open" because of the duct openings?

How much of an opening makes a room "open?"

 

[Ron Resnick]

Ron, if your room can still be changed, just get Marty's ratios and treatments

The dimensions of my room cannot be changed.

 

[Ron Resnick]

Do air conditioning ducts make an otherwise "closed room" "open" because of the duct openings?

How much of an opening makes a room "open?"

In my original question I envisioned doorway-sized openings and larger.

 

[GaryProtein]

In my original question I envisioned doorway-sized openings and larger.

I know.

I'm curious about smaller openings like 4-10" x 10" ducts and a 24" x 30" return.

 

[bonzo75]

The dimensions of my room cannot be changed.

Still get his treatments and advice - it is the only room I have been in that is producing bass control and super crescendos without overloading the room, with no negative side eff3ects like deadening the room.

 

[Steve Williams]

Still get his treatments and advice - it is the only room I have been in that is producing bass control and super crescendos without overloading the room, with no negative side eff3ects like deadening the room.

Marty's room is huge plus a pair of G213 v2 Gotham subs