Steve,
I just read this post of yours:
http://www.johnlsayers.com/phpBB2/viewt ... tion+glass
And had a couple questions.
1. I always thought that using a double wall system, the wider gap at the top is the *preferred* way off mounting glass?
2. I'm going to have two pieces of glass 3'X6' - one 1/2" thick and the other will be 3/8" thick. Is this the right glass for the window size?
3. After all this confusion, I'll ask this - using my double-wall, what would be the BEST setup for a 3X6 foot window: thickness, angle-direction, larger gap at top or bottom, etc... ??
Studio Glass Confusion
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BradJacob
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Studio Glass Confusion
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- Brad
www.theSecretSystemBand.com
"...over the years, 'the-blues' has raised many children..."
- Brad
www.theSecretSystemBand.com
"...over the years, 'the-blues' has raised many children..."
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knightfly
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1. I always thought that using a double wall system, the wider gap at the top is the *preferred* way off mounting glass?
http://www.audio-muziek.nl/audiotechniek/acoustics.pdf
2. I'm going to have two pieces of glass 3'X6' - one 1/2" thick and the other will be 3/8" thick. Is this the right glass for the window size?
This is more dependent on the REST of the wall; you want the mass of the glass in each side of a wall to match, or slightly exceed, the mass of the gypsum; since glass weighs about 3 times what gypsum weighs, then a wall with two layers of 5/8 rock on one side should have 1/2" glass on that side. If the other side has the same, it's not ideal; doing this will make both halves of the wall exhibit identical weaknesses (same frequency) - so it's better to make one side with more mass. Your 3/8 and 1/2" glass, if you have different weights of drywall on one side, should follow; IOW, the lighter mass side should get the thinner glass. If both sides of the wall have identical layers of drywall, then it doesn't matter which glass goes on which side.
3. After all this confusion, I'll ask this - using my double-wall, what would be the BEST setup for a 3X6 foot window: thickness, angle-direction, larger gap at top or bottom, etc... ??
From the standpoint of isolation, no tilt at all; this gives wider air gap between panes, so maximises the mass-air-mass performance. From the standpoint of OPTICAL glare, etc, it depends on lighting, angles, etc - From an in-room standpoint, on the CR side if your rear wall will be heavily absorbed it's less important that the window be tilted. Tilting down (wider top) can redirect early reflections into the rear of the console, where a 3-4" absorber can be placed; OR, window can be wide at the bottom and the ceiling absorber will help take care of those reflections. It's nearly impossible without elevation views and some protractor time to figure out which will be better for YOU - things like how close the console is to the window, height of the window, height of your head, etc.
Thickness; covered earlier...
Be careful when reading answers to other posters; there may be peculiar circumstances that already exist, that I've tried to help them overcome (or at least mitigate) without costly tearouts... Steve
http://www.audio-muziek.nl/audiotechniek/acoustics.pdf
2. I'm going to have two pieces of glass 3'X6' - one 1/2" thick and the other will be 3/8" thick. Is this the right glass for the window size?
This is more dependent on the REST of the wall; you want the mass of the glass in each side of a wall to match, or slightly exceed, the mass of the gypsum; since glass weighs about 3 times what gypsum weighs, then a wall with two layers of 5/8 rock on one side should have 1/2" glass on that side. If the other side has the same, it's not ideal; doing this will make both halves of the wall exhibit identical weaknesses (same frequency) - so it's better to make one side with more mass. Your 3/8 and 1/2" glass, if you have different weights of drywall on one side, should follow; IOW, the lighter mass side should get the thinner glass. If both sides of the wall have identical layers of drywall, then it doesn't matter which glass goes on which side.
3. After all this confusion, I'll ask this - using my double-wall, what would be the BEST setup for a 3X6 foot window: thickness, angle-direction, larger gap at top or bottom, etc... ??
From the standpoint of isolation, no tilt at all; this gives wider air gap between panes, so maximises the mass-air-mass performance. From the standpoint of OPTICAL glare, etc, it depends on lighting, angles, etc - From an in-room standpoint, on the CR side if your rear wall will be heavily absorbed it's less important that the window be tilted. Tilting down (wider top) can redirect early reflections into the rear of the console, where a 3-4" absorber can be placed; OR, window can be wide at the bottom and the ceiling absorber will help take care of those reflections. It's nearly impossible without elevation views and some protractor time to figure out which will be better for YOU - things like how close the console is to the window, height of the window, height of your head, etc.
Thickness; covered earlier...
Be careful when reading answers to other posters; there may be peculiar circumstances that already exist, that I've tried to help them overcome (or at least mitigate) without costly tearouts... Steve
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Julián Fernández
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knightfly
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since the two materials are close to the same weight per unit thickness... Steve-
Julián Fernández
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Some guy is selling a cheap laminated glass (1cm thick)...
Is a big problem to make both leafs of the window of the same thickness..? I already read John´s tip:
It is essential that the two sheets of glass be different in thickness.
The thing is, i don´t have much money and it´s a good glass... what would you suggest?
Is a big problem to make both leafs of the window of the same thickness..? I already read John´s tip:
It is essential that the two sheets of glass be different in thickness.
The thing is, i don´t have much money and it´s a good glass... what would you suggest?
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knightfly
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With 1 cm thick glass, two panes set 100mm apart, you would have a coincidence dip in TL at around 1300 hZ; this dip would lower the TL in that range by about 5 dB, which would be about 3 dB worse than if one of the glasses were THINNER by 3mm!! (using a thinner glass on one side would decrease the damage of this coincidence dip by that much)
One thing that needs to be watched in isolation glasses or walls, is having a SHIFT in the amount of TL at one specific frequency; this will almost always cause the wall to sound "weak", because of the non-uniform response of the wall at that one weak spot. You are better off having a smooth (but not as good) TL curve than one with peaks and dips, in other words.
Maybe you know someone who would be willing to buy two thinner, cheaper glasses and trade you for one of your thicker ones? This would benefit both persons - that way, each would have (say) one 10 mm and one 7mm glass.
IF not, two of that thickness glass, while not ideal, would give pretty good isolation; just be aware that there may be a slight weakness at around 1300 hZ as I mentioned... Steve
One thing that needs to be watched in isolation glasses or walls, is having a SHIFT in the amount of TL at one specific frequency; this will almost always cause the wall to sound "weak", because of the non-uniform response of the wall at that one weak spot. You are better off having a smooth (but not as good) TL curve than one with peaks and dips, in other words.
Maybe you know someone who would be willing to buy two thinner, cheaper glasses and trade you for one of your thicker ones? This would benefit both persons - that way, each would have (say) one 10 mm and one 7mm glass.
IF not, two of that thickness glass, while not ideal, would give pretty good isolation; just be aware that there may be a slight weakness at around 1300 hZ as I mentioned... Steve
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Julián Fernández
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Thanks KF! The thing is that the leafs will be set 200mm apart (because of the insulation design)... Is that even worst? (using the 1cm thick glasseS)
Still thinking about angling or not the glasses... I read the Acoustic Myths pdf and your advice (and John´s too)... My recording room is 4x3mts and the CR 3x2.4mts. The window will be at least 1x0,8mts. I understand the benefits for angling (reflections and so), and no to (better insolation)... I´m only would like to know your opinion in this case.
Still thinking about angling or not the glasses... I read the Acoustic Myths pdf and your advice (and John´s too)... My recording room is 4x3mts and the CR 3x2.4mts. The window will be at least 1x0,8mts. I understand the benefits for angling (reflections and so), and no to (better insolation)... I´m only would like to know your opinion in this case.
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knightfly
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