Sealing doorways...does it make a difference

[Jeff5347]

My question is in regards to all doors in our theater rooms. I have 3 doors. 1 to get downstairs, 1 to the furnace room and 1 to the washroom. At the bottom of each door i have an gap of 1/4 to 1/2 inch depending on the door. Also in all doorways i have small felt dots that "shim" the door from the frame so i dont get rattles. My ask is does having the open air gaps compromise the pressuring of the room for bass. I was think of getting seals all the way around the frame and at the threshold to essentially airtight the room. Am i overthinking this? Would sealing the doorways incease the pressurization of the room or would it be wasting money and time on no diiference at all.

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[PENG]

My question is in regards to all doors in our theater rooms. I have 3 doors. 1 to get downstairs, 1 to the furnace room and 1 to the washroom. At the bottom of each door i have an gap of 1/4 to 1/2 inch depending on the door. Also in all doorways i have small felt dots that "shim" the door from the frame so i dont get rattles. My ask is does having the open air gaps compromise the pressuring of the room for bass. I was think of getting seals all the way around the frame and at the threshold to essentially airtight the room. Am i overthinking this? Would sealing the doorways incease the pressurization of the room or would it be wasting money and time on no diiference at all.

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It will affect the lower range frequency response for sure. If you use room EQ you should leave the door in the same position when you use the system, before running auto setup.

 

[Danzilla31]

My question is in regards to all doors in our theater rooms. I have 3 doors. 1 to get downstairs, 1 to the furnace room and 1 to the washroom. At the bottom of each door i have an gap of 1/4 to 1/2 inch depending on the door. Also in all doorways i have small felt dots that "shim" the door from the frame so i dont get rattles. My ask is does having the open air gaps compromise the pressuring of the room for bass. I was think of getting seals all the way around the frame and at the threshold to essentially airtight the room. Am i overthinking this? Would sealing the doorways incease the pressurization of the room or would it be wasting money and time on no diiference at all.

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I'm actually in the process of doing my home theater now and all doors will be sealed yes it does help with pressurizing the room and as PENG stated will help your low end response

 

[Jeff5347]

As of now i have no seals on the doors. Just door and frame. I do have Rew and when using audessey i always keep the room closed. I havent tried to see results with 1 ir so doors open. My thought is the lower freq being able to pressurize a room, if there is a gap that is like broken pipe...that would reduce pressure in effect reducing the effect of the bass. So your thought as well is too gasket seal every door to disable any leaks and increase pressure? Would even that 1/2 gap on the bottom of the doors have that noticeable of effect?

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[Danzilla31]

As of now i have no seals on the doors. Just door and frame. I do have Rew and when using audessey i always keep the room closed. I havent tried to see results with 1 ir so doors open. My thought is the lower freq being able to pressurize a room, if there is a gap that is like broken pipe...that would reduce pressure in effect reducing the effect of the bass. So your thought as well is too gasket seal every door to disable any leaks and increase pressure? Would even that 1/2 gap on the bottom of the doors have that noticeable of effect?

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My experience is the more air tight the room can realistically be the better off you are. But more experienced members can probably better explain it

 

[Swerd]

Before you seal any doors, think about heating & cooling air flow. Where are the supply and return ducts located? If you seal the doors to your theater room, will you be cutting off the normal air flow that your furnace/AC air handler depends on?

I've heard of people who seal doors to prevent sound from leaking out and disturbing people outside of the room. But not to help with bass performance inside the room.

Sound in the room is created by waves of air, moving to and fro. Although we often use the phrase "pressurize the room" for bass frequencies, it's wrong to think about it as the same as water or air pressure inside a pipe.

 

[PENG]

Before you seal any doors, think about heating & cooling air flow. Where are the supply and return ducts located? If you seal the doors to your theater room, will you be cutting off the normal air flow that your furnace/AC air handler was designed to handle?

I've heard of people who seal doors to prevent sound from leaking out and disturbing people outside of the room. But not to help with bass performance inside the room.

Sound in the room is created by waves of air, moving to and fro. Although we often use the phrase "pressurize the room" for bass frequencies, it's wrong to think about it as the same as water or air pressure in a pipe.

I would leave the door open, my point was simply that when you run auto set up you should then also leave the door open.

It is up to you to choose what works better for you, but be consistent.

 

[Jeff5347]

Well as luck or unlucky has i went to get some doorjam seals but my out side floor is concrete. The jams even at their smallest are to big to fit under the door so thats scraped. I can seak around the door at least. In the whole house is radiated heat ao no ducts anywhere. To do it right id have to shave the doors and put threshholds with seals on the floor instead of the door. Floors are a bit uneven so they would bind opening otherwise. Kinda feels like more work than the reward would be

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[Rob_z]

You can look into a surface automatic door bottom like the Pemko 4131CRL if you can mount it on the push side of the door. Spring loaded seal drops when the door is closed and no need to undercut the door any further and can seal up to about 3/4”.

 

[ryanosaur]

Not saying its wrong, but this entire idea feels more like a red herring, distracting from things in-room that can make a much bigger difference to your acoustic payout. Unless of course your room is so dialed in that the possibility of that .1% improvement from sealing up your doors is the audio equivalent of the money shot you need.

That said, since the topic is Low Frequency... What is your Room Volume? You've got it closed, obviously... What and how many subs are you running? Are your L/R Mains capable of Full Range?

 

[Speedskater]

While an opening totaling only a few square inches can really mess-up sound transmission, but lets leave pressuring the room out of it.

 

[Danzilla31]

Before you seal any doors, think about heating & cooling air flow. Where are the supply and return ducts located? If you seal the doors to your theater room, will you be cutting off the normal air flow that your furnace/AC air handler depends on?

I've heard of people who seal doors to prevent sound from leaking out and disturbing people outside of the room. But not to help with bass performance inside the room.

Sound in the room is created by waves of air, moving to and fro. Although we often use the phrase "pressurize the room" for bass frequencies, it's wrong to think about it as the same as water or air pressure inside a pipe.

That's a good point I forgot to mention that I actually had to add a return duct to the room because walling it off and sealing it like that without that extra return duct was going to seriously affect the air flow in that room

 

[Jeff5347]

Room is def not dialed in. Working on making some acoustic panels as well. Just looking to do things to help with bass. Dont get me wrong the bass is very good. L and R are athena AS F2 floor standers and i run 3 hsu subs. 1 vtf3 mk3 and 2 vtf1's. With running rew i noticed leaving all 3 doors open i had a 3 db increase at around 14hz vs closed. Now im not basing anything off that due to all these subs are not capable of 14 hz. The vtf3 which i have is set for max ext is said to go to 18. My room is 12w x 26L x 7h. I know the height really is my enemy w 7 ft but....
As for sub placement my current setup for now with rew tests ive determined is at its best.
Im not able to leave the upstairs door open as the wife would have a fit
I also get what Ryan said about this could be a long shot hopeful idea.
Heres an of the top question as i am just getting into measuring with rew and finally getting subs that can actually play real bass notes. I have a cubby in the back of the room that i had to seal up as it was open to the furnace room. Its just a storage area of abou 3ft h by 2.5 w by 2.5 ft deep. Could adding a bunch of quilts to fill the cubby act as a make shift bass trap

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[PENG]

Not saying its wrong, but this entire idea feels more like a red herring, distracting from things in-room that can make a much bigger difference to your acoustic payout. Unless of course your room is so dialed in that the possibility of that .1% improvement from sealing up your doors is the audio equivalent of the money shot you need.

That said, since the topic is Low Frequency... What is your Room Volume? You've got it closed, obviously... What and how many subs are you running? Are your L/R Mains capable of Full Range?

Sealed or not should not make much difference other than noise contamination if applicable. The difference in bass response between with the door wide opened and totally shut (again, sealed or with small air gaps) could be quite significant.

 

[Trell]

Sealed or not should not make much difference other than noise contamination if applicable. The difference in bass response between with the door wide opened and totally shut (again, sealed or with small air gaps) could be quite significant.

I'm not sure that I understand you, as English isn't my mother tongue, but are you saying that small (how small?) air gaps would not in a material (audible, that is) way affect the bass response?

 

[ryanosaur]

Sealed or not should not make much difference other than noise contamination if applicable. The difference in bass response between with the door wide opened and totally shut (again, sealed or with small air gaps) could be quite significant.

We seem to be in agreement on that. My comment was focused specifically on the quest to create an "airtight" room.
OP responded well in that he is learning REW and working with it to improve his overall situation. @Jeff5347, kudos to taking those steps!
My first recommendation is about your subs: plan on upgrading all subs to match your VTF3s. The VTF1s are by all accounts good, but they will limit your overall experience. Getting all subs matched will allow for easier and better integration as a whole. As you are already using REW, the next logical step is also employing a MiniDSP 2x4HD to fully dial in all 3 Subs.
You did not go into placement, and this concerns me a little. I am known to not agree with placing subs on the front wall and corner loading. I think these CAN be some of the worst locations. I've had great success placing my subs using the Subwoofer Crawl, alone. Each one is on a side wall, and neither is the same distance from either front speaker. Asymmetrical placement can be a much more powerful tool than any other approach, and this can be furthered by using REW to confirm and adjust, then use DSP to tailor the results even further.
To your question on Panels and Traps. Be careful. Improper use of such things will only be a waste of time and energy and may just as easily hurt your room rather than help. First, make certain your room is well appointed with comfy furnishings and some assorted KnickKnacks. Diffraction is your friend. Assuming you are already carpeted, that shouldn't be an issue.
I have most commonly seen bass traps employed on the front wall and in corners. I do not think your cubby will do anything. If you are truly experiencing excess bass energy, then I would first look at sub placement. Next, Gain and Level Settings. Then, and only then, would I consider trapping the room to minimize that energy. If you do need to go to that extent, consider that the cylinder traps are usually about 18" dia. to be effective. Also, the angled panels that go in the corners... again, these are usually 2'wide panels that eat up the corners of your room. anything smaller is, as I understand it, pointless.
I further applaud your willingness to build your own acoustic panels. Again, consider the goal and how you choose to employ them. Absorption alone can lead to an overly dead room. Perhaps consider a combo approach of Absorption/Diffraction on the front wall behind the speakers (unless slap echo is very prominent, and then tailor your FRP panels to meet the frequencies you need to attenuate, while being mindful that perhaps a diffraction/absorption approach may be suitable there as well.
Use your REW measurements to your advantage as you begin down this path, and reinforce your knowledge with a good acoustics handbook, as well!

 

[PENG]

I'm not sure that I understand you, as English isn't my mother tongue, but are you saying that small (how small?) air gaps would not in a material (audible, that is) way affect the bass response?

Yep, if the door is basically shut, not ajar, an inch or two gaps somewhere won't matter much. If the door is say, half opened, or fully open, the difference could be a lot. I know so not just by ears, but also by FR graphs obtained REW sweeps using my Umik-1 mic.

 

[Jeff5347]

Ryan. Thanks for all that info. I cant type right now but ill give a bit more info later. But to the sub talk. 1 sub behind the couch, 1 1/3 from the left on front wall and one on the right wall about 4 ft down

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[William Lemmerhirt]

@ryanosaur I just wanted to touch on something quick. I know your very quick to propose against corner loading, and front wall placement but it’s also very room dependent. In fairness this is something you’re also quick to mention. My point though, is corner loading and front placement also CAN be very effective. Especially on concrete with a vaulted ceiling like me. I’m pretty flat down to about 15hz. All 3 subs are corner loaded, and 2 are in the front. A couple things. While they are symmetrical in front, they are NOT symmetrical in respect to the whole space, and the left side ceiling is 9.5’ while the right side(only half the distance across the whole space) is 12.5’. Imo this makes it not symmetrical as my LP is 16’ away, but I have openings that carry well beyond that. I believe you’re on a crawl space, so basically suspended, and that can be nightmarish to deal with. Also, the narrow but very tall shape would dictate placement away from corners.I know you’ve mentioned turning your subs down after audyssey. I think that’s interesting considering most find the need to turn them up. Anyway just good for thought. Haven’t rapped with you for any. Maybe just needed some dialog lol.

For the op, the reason you get response at 14hz with the doors open is you’ve kind of enlarged the “enclosure”, or room. That allows the long waves to carry out of the room without doubling back into the room and messing with the FR. It’s kinda like the difference in a small subwoofer enclosure vs a large one.

 

[Jeff5347]

So heres some extra info. I have an 8 ft couch about 10 ft off the front wall. The front of the couch is at the 10 mark. I also have a love seat anout 6-7 feet behind the couch. The rear area is setup as a sudo reading area. On the front right is a built in bookshelf with blu rays and such.
I have to correct 1 sub. The vtf1 on the front. I said it was about 1/3 in from the left but i forgot it is in the front left corner. At least from rew graphs that is where all 3 subs and the main seem to produce the best "straight" line.
I did do a little test. I pinned 2 towels to each other then attached one set to my left and then right side at the mains reflection points. Now i did hear a difference i guess i would say less shrill. Maybe the highs werent as piercing if that makes sense. Now i will admit im a bass head and i know what i like but to say the towels on or off was better than the other im not sure.
Heres some pics of the room

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