Sealed Room vs Open Room

[Uniquely]

I created a thread about this before, but was unable to find it in a search. My HT room can be completely closed off, but does have three doors that open into other areas of the house. I have found that there is a noticable difference in sound if any of my doors are opened. My cats can open the doors themselves (something they taught themselves in their quest to murder my oscar and plecostomus.) I can always tell when one of the cats has let themselves in, because I can hear the change in sound when the door opens, even though I did not see or hear the door itself open.

When I previously asked about the audiological principles that would cause a sealed room to sound so different from a room that is open to other areas of the house, the idea that it could sound different was pretty much pish poshed by the majority of responders. I'm not familiar with any of the principles that would cause the difference that I hear in my own set up, but most of us pretty easily accept that things like wall treatments, curtains, throw rugs, and even things as simple as throw pillows can affect the overall sound quality of a room; so I was a bit by baffled by the dismissal of the idea that a sealed room could offer audiological advantages over an open room.

Surely there must be some audiological theory that explains the difference I hear in my own setup between when the room is sealed and when it is open to other areas of my house. Experts?

[Beta Man]

"Pressure"

Same reason a sealed sub would sound different from a ported one.

Although, with your room treatments etc... I'm surprised you have "that" noticeable of a difference with just one door open..... that door perhaps is a reflection point

[Uniquely]

Originally Posted by Beta Man

"Pressure"

Same reason a sealed sub would sound different from a ported one.

Although, with your room treatments etc... I'm surprised you have "that" noticeable of a difference with just one door open..... that door perhaps is a reflection point

Location of the doors probably has everything to do with it, since both of the doors that the cats can open are in the rear corners. Mostly my treatments are for decoration. The ones on the back wall are to hide the speaker wire for my rears.

The ones on the doors however, I hope are audiologically useful. My idea in hanging them on the doors was twofold, to reduce sound travel between the two rooms, because my wife's HT is on the other side of those doors; and because in each rear corner there is a pair of doors at a 90 degree angle from each other. My hope is that putting treatments on the doors reduces sound bouncing back and forth between each of the hollow doors. One day I want to get some nice heavy doors, at least for the two doors that open into my wife's HT. There are FIVE doors total in that room Two into the great room that my wife uses, a coat closet, a door into my utility room, and the front door of the house.

[Beta Man]

in order to dampen the sound traveling between the rooms you should try some foam weather stripping in the door jam.....

Sound does travel through the "cracks" but also sound is transfered from one hard surface to another, so much of the sound is likely traveling between where the door meets the trim around it.

[Uniquely]

Originally Posted by Beta Man

in order to dampen the sound traveling between the rooms you should try some foam weather stripping in the door jam.....

Sound does travel through the "cracks" but also sound is transfered from one hard surface to another, so much of the sound is likely traveling between where the door meets the trim around it.

Good idea. That would probably make it harder for the cats to open them too Smart little boogers even learned how to twist the door knobs.

[jomari]

beta pretty much explained it well enough so we wont go that alley no more. pressure is what makes a sealed room more 'intense' compared to an open layout - less dispersion of sound, less reflections, less to deal with. no need for acoustic treatments placed on the refridgerator.

on the other hand, when we talk about doors, he's also got that covered. i guess the only thing id like to add is that most dedicated HT rooms use either a double door and/or a very heavy door (i dunno what you call em, i think its a vault door). its more of isolating the room instead of room reflections and the like. keeping the sound in, and preventing it to leak out into the open areas.

oh, nice new entertainment unit there rob... wheres the flippin mopads ive been tellin you about!

[Uniquely]

Originally Posted by jomari

oh, nice new entertainment unit there rob... wheres the flippin mopads ive been tellin you about!

I spent all my money on the unit

[Big Daddy]

It is all about interaction of waves with the room boundaries (wall, ceiling, floor). In most rooms, you are not listening to your speakers, but rather you are hearing your room. For example, put a subwoofer in a corner against two walls. In that corner, all room modes will be energized and the subwoofer will be very loud (perhaps too much of a good thing). Now, move the same subwoofer to a corner with an open door on each side. All of a sudden, the same subwoofer will lose some of its oomph. Finally, put it in an open area (middle of the room) and in a very short time you will want to return the subwoofer to the manufacturer.

[HAMP]

Hey robinandtami,

I had 4 openings without doors with the sound system I had in my apt and I wanted so bad to hear my set-up in a somewhat sealed room. The two subs did a wonderful job, I just wanted so bad to hear in a closed area.

[jomari]

Originally Posted by Big Daddy

It is all about interaction of waves with the room boundaries (wall, ceiling, floor). In most rooms, you are not listening to your speakers, but rather you are hearing your room. For example, put a subwoofer in a corner against two walls. In that corner, all room modes will be energized and the subwoofer will be very loud (perhaps too much of a good thing). Now, move the same subwoofer to a corner with an open door on each side. All of a sudden, the same subwoofer will lose some of its oomph. Finally, put it in an open area (middle of the room) and in a very short time you will want to return the subwoofer to the manufacturer.

im flattered big daddy is teaching more about acoustics, aside from subwoofers 101...

as mentioned earlier Rob, its also about 'pressure'. confine your home theater in a smaller space, the 'better' the performance (acoustics aside)...

think of it this way,

compare your current living room,

versus a hangar.

larger space means more work for the speaker to perform properly, what more the subwoofer right?

[Hammie]

If you want the best sounding experience out of your room, you will need the THX Certified doors.

[Uniquely]

Originally Posted by Big Daddy

It is all about interaction of waves with the room boundaries (wall, ceiling, floor). In most rooms, you are not listening to your speakers, but rather you are hearing your room. For example, put a subwoofer in a corner against two walls. In that corner, all room modes will be energized and the subwoofer will be very loud (perhaps too much of a good thing). Now, move the same subwoofer to a corner with an open door on each side. All of a sudden, the same subwoofer will lose some of its oomph. Finally, put it in an open area (middle of the room) and in a very short time you will want to return the subwoofer to the manufacturer.

Thanks Big Daddy..... good explanation. I chose this room, because I hoped that the ability to close if off would help with sound.... and I think it has. But I really had to sacrifice with the shape of the room. We all have our obstacles (well most of us ) when it comes to room shape, or the ability to close it off, or any number of factors I guess.

I know I'm going OT in my own thread, but one thing I have been thinking about lately is how wide my soundstage is. The room is about 30 ft wide and only about 12-14 feet deep. I was thinking about the Onkyo and Yamaha receivers that are able to provide either extra width or height to your front sound stage with two extra speakers. I've been contemplating if it would benefit me to add two bookshelf speakers to the higher shelves of my entertainment unit's side towers. Any thoughts on that?

I'm actually pretty happy with where the sound is at right now, but I guess we always seek to improve.

[Uniquely]

Originally Posted by HAMP

Hey robinandtami,

I had 4 openings without doors with the sound system I had in my apt and I wanted so bad to hear my set-up in a somewhat sealed room. The two subs did a wonderful job, I just wanted so bad to hear in a closed area.

I don't know if it's the sealed room, or the fact that I just don't crave bass the way I did when I was a kid, or more likely both; but when I level calibrated my speakers with an SPL meter for the first time, I had to set the sub about 7db's below the rest of the speakers. It was just too boomy... of course they say that about Klipsch subs anyway.

[Big Daddy]

Originally Posted by robinandtami

Thanks Big Daddy..... good explanation. I chose this room, because I hoped that the ability to close if off would help with sound.... and I think it has. But I really had to sacrifice with the shape of the room. We all have our obstacles (well most of us ) when it comes to room shape, or the ability to close it off, or any number of factors I guess.

I know I'm going OT in my own thread, but one thing I have been thinking about lately is how wide my soundstage is. The room is about 30 ft wide and only about 12-14 feet deep. I was thinking about the Onkyo and Yamaha receivers that are able to provide either extra width or height to your front sound stage with two extra speakers. I've been contemplating if it would benefit me to add two bookshelf speakers to the higher shelves of my entertainment unit's side towers. Any thoughts on that?

I'm actually pretty happy with where the sound is at right now, but I guess we always seek to improve.

About 10-12 years ago, my HT room was a bit narrow and I used to to own several Yamaha top-of-the-line receivers. They supported height channels and many DSP options. I really liked them and used to play with the different options. Some people find them too gimmicky.

Another option is to use two side surround speakers on the right and two side surrounds on the left. That is the option I use today and I really like the enveloping sound. My Denon receiver supports this option and calls them surround A and surround B. This is in addition to rear surround speakers. During Audyssey calibration, it goes through surround A first, then surround B, and finally surround A+B. Even with an SPL meter, I can adjust their levels individually.

The easiest way to open up your sound stage is to use bipolar front speakers. Definitive Technology super towers are bipolar. They completely fill the room with sound and make the HT experience so much better. Once you get used to bipolar front and/or surround speakers, you will never want to go back to standard direct speakers.

[Uniquely]

Originally Posted by Big Daddy

About 10-12 years ago, my HT room was a bit narrow and I used to to own several Yamaha top-of-the-line receivers. They supported height channels and many DSP options. I really liked them and used to play with the different options. Some people find them too gimmicky.

Another option is to use two side surround speakers on the right and two side surrounds on the left. That is the option I use today and I really like the enveloping sound.

I don't have enough room depth to add more sides. I think my layout is reverse of what yours was. The room is much wider than it is deep.