door seal calcs

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door seal calcs

Postby Bob » Fri Mar 12, 2004 10:23 am

Over in http://www.recording.org/cgi-bin/ubb/ul ... 01420.html?
there's some quicky multi-frequency transmission-loss estimates of a couple of really heavy DIY door systems.

Obviously more accurate modeling (more coincidence layers for example) is possible to get better predictions of the effects. And of course the door jamb framing and other flanking is also ignored.

But I'm more interested in the seals. What are some good frequency/TL numbers for
a) cheap compression seals
b) four-sided-magnetic seals

And what's the easy technique to appliy those numbers against a door ?

(Just curious)
Regards
Bob Golds
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Postby Eric.Desart » Fri Mar 12, 2004 1:41 pm

And what's the easy technique to appliy those numbers against a door ?


Listening to what the supplier says, then subtracting somewhat.
For the rest testing.

It's hardly possible to calculate this correct.
A gap is as well a filter as a resonant channel.

On a good door one uses good rubbers and better two (if you use only one door)
And mostly the treshold is the most sensitive part.

Eric
Last edited by Eric.Desart on Fri Mar 12, 2004 5:13 pm, edited 1 time in total.
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Postby Paul Woodlock » Fri Mar 12, 2004 4:58 pm

Greetings bob

I wouldbn't bother trying to get figures for this.

As Eric says, it must be a nightmare trying to calculate it.

Do what I did. Just make it thick and heavy as possible with TWO seals.

Do it bank vault style like I did, and even the threshold isn't a problem, as it's exactly the same as the jambs. ( note in my piccies I routed in some aluminum angle on the threshold jambs to hold back the wear from walking over it. )

I also made sure the gap between the frame and the wall was COMPELTELY sealed with 'Gripfill' filler adhesive.

You have the piccies! Build one! :)


Paul
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Postby Bob » Fri Mar 12, 2004 8:16 pm

Hi Paul

Gripfill' filler adhesive.


Gap Filler ! What an excellent idea ! With the gap being smaller, the effects will be less.

(I know you're talking about between the frame and the walls, but I'm talking about between the door and the frame -- I wonder how durable this stuff is)

Sort of like that silicone idea of Eric's a couple of months back where he stuck silicone and then closed the door until it set, when the door was opened the seal was perfect right down to the imperfections.
Regards
Bob Golds
"The only thing we regret in life is the love we failed to give."
"Be a rapturist -- the backward of a terrorist. Commit random acts of senseless kindness, whenever possible" - Jake Stonebender
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Postby Rod Gervais » Fri Mar 12, 2004 8:52 pm

Eric.Desart wrote:
And what's the easy technique to appliy those numbers against a door ?


Listening to what the supplier says, then subtracting somewhat.
For the rest testing.

It's hardly possible to calculate this correct.
A gap is as well a filter as a resonant channel.

On a good door one uses good rubbers and better two (if you use only one door)
And mostly the treshold is the most sensitive part.

Eric


Eric is right on with this - for professional studio doors i use 2 good (General Motors) rubber gaskets - plus a magnetic weatherstrip - and work my butt off on the door bottoms to try to get a good seal.

Paul - i understand what you're doing - but we could not do anything like that in a commercial establishment here - we would not come even close to meeting the requirements for the Life Safety/Building codes - or the "American with Disabilities Act" (ADA) - so for us this isn't a code compliant installation - and that is always an issue.

But it is a beautiful thing you've constructed.

Rod
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Postby Bob » Fri Mar 12, 2004 11:08 pm

Eric is right on with this - for professional studio doors i use 2 good (General Motors) rubber gaskets - plus a magnetic weatherstrip - and work my butt off on the door bottoms to try to get a good seal.


The multiple seals scare me because I'm worried that it'll make the door hard to open and close. I have two doorways that will see a fair bit of traffic, although not as much as a professional studio.
Regards
Bob Golds
"The only thing we regret in life is the love we failed to give."
"Be a rapturist -- the backward of a terrorist. Commit random acts of senseless kindness, whenever possible" - Jake Stonebender
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Postby giles » Sat Mar 13, 2004 6:51 am

i posted some sketches on the old yahoo forum for door & frame construction for a room in a room type construction; some of you may have encountered this problem; the walls in a room in a room construction are typically not as vertically rigid as normal walls & then they have to support abnormally heavy doors which when open exert a lot of strain on the wall; with close fitting this can cause the door to drag on the floor when opening & closing. the solution for this is to fit a small wheel on the face at the bottom of the door. a corresponding replaceable wear track can be placed on the floor. this is a classic detail that you sometimes see in older buildings; Lorie Anderson did some installations once replacing the wheel with a magnetic recording head and a strip of mag tape on the floor with little phrases recorded on the tape so the door sort of spoke whenever you opened & closed it.
i observed a nice detail on the stage doors of the singel theatre in antwerp; this was a heavy duty felt strip routed in all the way round the edge face of the door & sticking out about 5mm; it snugged into the frame beautifully.
G
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Postby Eric.Desart » Sat Mar 13, 2004 7:28 am

Hello Giles,

The idea of this felt, is based on splitter silencers.
I described it before too for the underside of a door.

In fact even when some gaps are still left the felt works as an absorber the same way as splitters do in ventilation silencers were one can completely look trough.

So for thick wooden doors it's a relative easy thing to integrate and it can solve problems caused by inaccuracies.

Eric
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Postby giles » Sat Mar 13, 2004 8:08 am

hello Eric,
lovely building, De Singel.
G
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Postby Paul Woodlock » Sat Mar 13, 2004 4:21 pm

giles wrote: Lorie Anderson did some installations once replacing the wheel with a magnetic recording head and a strip of mag tape on the floor with little phrases recorded on the tape so the door sort of spoke whenever you opened & closed it.
...G



Greetings Giles

Excellent idea!


Paul
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Postby Paul Woodlock » Sat Mar 13, 2004 4:24 pm

Rod Gervais wrote:
Paul - i understand what you're doing - but we could not do anything like that in a commercial establishment here - we would not come even close to meeting the requirements for the Life Safety/Building codes - or the "American with Disabilities Act" (ADA) - so for us this isn't a code compliant installation - and that is always an issue.

But it is a beautiful thing you've constructed.

Rod


Why Thankyou Rod :)

Although my place isn't and won't be a commercial facility, out of interest, what specifically would fail the codes?


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Postby Paul Woodlock » Sat Mar 13, 2004 4:26 pm

Bob wrote:
The multiple seals scare me because I'm worried that it'll make the door hard to open and close. I have two doorways that will see a fair bit of traffic, although not as much as a professional studio.


Greetings Bob

This is made easy by compression latches. ( sort of thing you find in big walk in fridges )


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Postby Rod Gervais » Mon Mar 15, 2004 4:16 pm

Paul Woodlock wrote: Although my place isn't and won't be a commercial facility, out of interest, what specifically would fail the codes?


Paul,

The sill detail would fail - in fact - it would be considered a trip hazzard - and would not meet the requirements for wheel chair access -

If you look at the Zero International Door Sills page i link to below (for example) you will see that only 4 of the 10 sills detailed on this page have the little wheelchair picture directly below the cut - that wheelchair indicates that the sill complies with the handicapped accessibility laws in the US - none of the other sills can be used where accessibility is required.

Take a look:

http://www.zerointernational.com/produc ... .asp?pg=14

When it comes to home studios - I always still design (or reccomend) that people construct in accordance with the codes - and the main reason for this is that sometimes (down the road) someone might want to begin to expand that room into a commercial business - and then would have to meet these requirements.

FYI - in the US - if a complaint is made to the Feds - a violation of the ADA can get you a $10,000 fine for each occurance - not anything i want to design someone into.

Rod
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Postby Rod Gervais » Mon Mar 15, 2004 4:19 pm

Bob wrote:
Eric is right on with this - for professional studio doors i use 2 good (General Motors) rubber gaskets - plus a magnetic weatherstrip - and work my butt off on the door bottoms to try to get a good seal.


The multiple seals scare me because I'm worried that it'll make the door hard to open and close. I have two doorways that will see a fair bit of traffic, although not as much as a professional studio.


Actually they close pretty easy - the magnetic strip helps with that - it does (however) take a wee bit more pressure to open them (once again due to the mag strip). Operation is not like normal doors.

BUT - this is to be expected with any super seal door assembly - the looser the fit the more air can make it's way through - and air movement translates to sound movement.

Rod
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Postby Eric.Desart » Mon Mar 15, 2004 5:17 pm

giles wrote:hello Eric,
lovely building, De Singel.
G


Hi Giles,
Do you remember those horible discussions about the alledged terrible acoustics in the beginning?
Conductors hated this hall, when recordings were made from orchestras.

The difference with people occupation and without was as such that they didn't want to use it for recordings.
That's solved for very long now.

Eric
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Postby giles » Mon Mar 15, 2004 8:24 pm

after many years of visiting i moved definitively to my real home(antwerp) in 92 so i missed the birth pains of de singel; as a performer i'm very aware of the difference between the soundcheck in an empty zaal and performance sound in a full zaal.
urbanists & architects rate the building very high. how was the accoustic "problem" resolved? it is used for recording now isn't it?
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Postby Eric.Desart » Mon Mar 15, 2004 9:05 pm

It was resolved with diffusers/reflectors and absorbers.
But the whole thing was simulated in prediction models. (KUL involved)

It has always been used for recordings. That's why in the beginning it came in the news.
It's rather sensational when everything is organized, cameras present, recording gear set up, orchestra present and then the conductor refuses to play.
So that's headline news :):):)

If something's good it take MANY years to spread the word. (Except when there is a big name connected to it, then it's declared good even when terrible).

If there are slight problems, but brought that sensational in the news, in 2 days the whole world (matter of speech) knows for 100% sure that the acoustics of this extremely expensive brand new Singel sucks. And everybody (even complete laymen) confirmed very convinced that they could hear this terrible acoustics (note that 99.99% never get the chance to hear music in an empty hall, so they hear problems not present when they are there. It was COOL to find the Singel bad)

Eric
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