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[rgobrasil]

Hi, everyone! I´m new to this forum and very glad i found it, this soundproofing subject can be so confusing!  I really need some help, can someone please enlighten me??

So this is my problem: I live in a new building with pretty thin walls, I guess. My downstairs neighboor is driving me nuts with his very loud TV every other day untill very late at night (not to mention my upstairs neighboor but that deserves a totally independent topic...  ). Sometimes I turn on my airconditioner and it´s enough to cover the noise, sometimes it doens´t help. Cars and trucks passing right under my window very early in the morning also bother me so I´ve decided to address both problems and thought about soundproofing my bedroom window and floor for a start.

Well, I had two different companies estimate the costs of a soundproof window and was offered two different configurations:

1) window #1 is a 3mm glass (something a little bit thinner than a 1/8" glass) laminated with PVB to another 3 mm glass + 9 mm of dehidrated air (something a bit thicker than 1/3" of air space) + a simple non-laminated 4 mm glass (1/6" thick);

2) window #2 is a 3mm glass (something a little bit thinner than a 1/8" glass) laminated with PVB to another 3 mm glass + 6 mm of dehidrated air (something a bit thinner than 1/4" of air space) + a 4 mm glass (1/6" thick) laminated again with PVB to another 4 mm glass

Both windows are made of aluminum and stuffed with some sort of soundproofing material (fiberglass, I think...).

Well, I´ve read everywhere that the thicker the air chamber the better the isolation but I´ve also read that quadruple glass windows isolate sound better than triple glass ones... So now I really don´t know which one to choose! I know quadruple glass windows may be an overkill but if they really isolates sounds better than the triple ones due to the extra layer of PVB and glass even though the dehydrated air chamber is thinner I´d definitely choose the quadruple one.

So what do you say, what blocks sound best: a bigger air chamber or an extra layer of PVB and glass??

Thank you so much for your attention!!

Cheers,

Renata

[Randy S]

When the dead air space is that small mass would be the dominate factor.. Check and see what the STC and OITC rating the companies provide for the windows..

[rgobrasil]

Hello there, Randy!

So the triple glass window seller states it´s a 35 db reduction of the noise... plus there are many people in Brazilian forums that state having instaled their windows and being really satisfied. But, wow, aren´t those expensive! I´m not sure what an impact would a reduction of 35 db mean... Is that little or is it good enough?

The quadruple glass seller doesn´t have an "offcial" number to give me... I just visisted their showroom and they told me they haven´t lab tested their windows yet... Plus I can´t find anyone on the net that has installed their window, so I´m assuming they´re new on the market. Their windows is cheaper (not cheap, just cheaper then the other one) but I think it´s risky, despite the good glass configuration they don´t seem very well sealed.

I´m kind of leaning towards the first one, unless I can find some other reputable brand with a reasonable price. Seems hard... Maybe I´ll just get another regular window with thicker laminated glass installed over the existing one. It won´t do the whole trcik but at least it won´t cost me an arm and a leg!  My street is pretty quiet, it´s just the random noise (that seems a lot louder exactly because my street is pretty quiet!) that bothers me...

Thanks for your help once again! :-)

[rgobrasil]

All right, so I´m back with two other windows options (exact same price fo both) and from a reputable vendor. 

Window #3: solid glass, no air chamber - 4mm glass + 2mm of some sort of acoustic resin+ 6 mm glass + 2 mm resin + 4 mm glass (claimed to reduce sound in 43 db and to be better at blocking low frequency noises than the ones with air chamber);

Window #4: quadruple glass with air chamber - 3 mm glass laminated to another 3 mm glas with this 2mm acoustic resin + 9 mm dehydrated air chamber + 3 mm glass laminated to another 3 mm glas with this 2mm acoustic resin (claimed to reduce sound in 41 db).

I´m pretty much not considering the first two windos of this post anymore since these two seem better and are cheaper than window #1 (but more expensive than #2). So, between windows ## 3 and 4, considering they are exact same price, which one do you think is best?? I don´t want to be naive and rely my decision solely on the numbers the vendor is giving me, I actually want to try to understand which one would be better considering sound isolation principles...

Thank you in advance for any input!

[Randy S]

When they post a reduction of decibel I would be concerned considering most likely you will not see that value of reduction across the range of frequencies ...what do they provide for STC rating (sound transmission class) or OITC (outside inside transmission class) ?

Remember that on single stud construction if you achieve a 41+ STC rating that will be the highest you can get without getting into double wall construction.

[rgobrasil]

Actually, Randy, what they gave me was not really a reduction in db but actually a measure called Rw. I have no idea how that compares to STC and I don´t believe that here in Brasil people actually measure materials STCs because no one seems to know what I´m talking about when I ask. However, I will ask this vendor because I haven´t yet.
 
And here´s what I found for a definition of Rw:

ISO 717/1 defines a standard contour and a procedure for fitting the contour to the measured sound reduction indices to determine a single-number rating of a sound transmission loss spectrum. This rating is called the Weighted Sound Reduction Index (Rw).
Unlike the STC contour, the Rw contour is defined over a slightly lower frequency range of 100 Hz to 3.15 kHz.
The contour fitting procedure requires that:-

the sound reduction values be determined to one decimal place
the contour be raised in 1 dB increments to a point where the average deficiency over the contour frequency range is as close to, but not exceeding, 2.0 dB.
if an 8dB or larger deficiency exists in the sound reduction index data, then the deficiency amount in dB and the frequencies at which they occur must be reported.
The average deficiency is the sum of all deficiencies in all frequency bands divided by 16, the number of 1/3rd octave frequency bands spanned by the contour.

The actual Rw value is equal to the fitted contour value at 500 Hz.

[Randy S]

yes I understand the meaning of weighted reduction, and actually that would be considered a better scale when dealing with low frequency noise like traffic.
So based on the information you have provided from the window company I think option #3 or #4 would be viable choices for single wall construction.