Density is crucial.Loner said:
Then double gypsum or more.
osb´+ gypsum is also not too bad. But it depends on where you set the "bar" regarding sound insulation.
Sealing all joints (ceiling, floor) is one of the most important things to consider.
Then the question is what double gypsum to gypsum + OSB provides, as in your case. Approximately half of this degradation... one might guess.
Now I don't know what dB Zankan is talking about, sound energy, or sound level, or if there might be even more variants. But often 3 dB is a fairly significant change. 1 dB (in sound level if I recall correctly) should be clearly audible as a difference.
Personally, I would hardly, due to sound damping, sacrifice all the advantages that OSB + gypsum offers compared to double gypsum, in terms of hanging various things, etc. Or, well, it depends, a laundry room, a listening/home theater room, or something else special maybe....
Now I don't know what dB Zankan is talking about, sound energy, or sound level, or if there might be even more variants. But often 3 dB is a fairly significant change. 1 dB (in sound level if I recall correctly) should be clearly audible as a difference.
Personally, I would hardly, due to sound damping, sacrifice all the advantages that OSB + gypsum offers compared to double gypsum, in terms of hanging various things, etc. Or, well, it depends, a laundry room, a listening/home theater room, or something else special maybe....
Once upon a time when I was young and studying, we were informed that if you double the power, like from a 60W amplifier to a 120W amplifier, or have a vacuum cleaner at 1000W and add another one at 1000W, you would change the sound level by 3dB, which would just fall within the threshold of hearing a difference. Which I relied on for a long time when someone criticized the low power output of the stereo. If you now shatter my worldview and say that 1 dB should be a clearly audible difference, you will crush my illusion, do you really want to do that... :eek:Mikael_L said:
- M
Yes, it's more confusing than you might think, since it varies depending on whether you're talking about sound pressure, sound power, sound intensity, etc. Start by reading a bit here. http://sv.wikipedia.org/wiki/Decibel Wiki doesn't have to be 100% truth either, one can consider.
But I recognize your reasoning, that double amplifier power = 3 dB higher sound (-pressure, -intensity, or whatever it might have been in this case). And that 3 dB would be a noticeable difference but not much more... This was also my "truth" when I sold car stereos.
I probably won’t sort out the whole truth about dB myself either. I'm just dropping some information that there might be more aspects, so you can research by your own need and interest.
I crush illusions easily, worldviews are harder...
But I recognize your reasoning, that double amplifier power = 3 dB higher sound (-pressure, -intensity, or whatever it might have been in this case). And that 3 dB would be a noticeable difference but not much more... This was also my "truth" when I sold car stereos.
I probably won’t sort out the whole truth about dB myself either. I'm just dropping some information that there might be more aspects, so you can research by your own need and interest.
I crush illusions easily, worldviews are harder...
If you instead build a wall with an air gap between the studs, like gypsum+OSB+metal stud&Roxul+air gap etc...
Aren't the benefits greater than doing double gypsum on a wooden stud?
Aren't the benefits greater than doing double gypsum on a wooden stud?
Okay, let's sort this out... When we talk about walls, we talk about the reduction of sound levels. Speech at 70 dB - 40 dB wall gives 30 dB on the other side assessed against a given curve A, B, or C. A is the one that applies in the normal case as it is adapted to the ear's ability to absorb sound at normal sound levels.
A 10 dB change is a doubling, 2 dB is a noticeable difference.
But to put it in context, you can say that 70 dB is the level we normally speak at. Then comes the next aspect, frequency. The human ear perceives sound at roughly 0 dB theoretically; we could hear when an air molecule hits the eardrum, which luckily it doesn't. But let's say we have a hearing threshold at 0 dB across the entire frequency band, then we are extra sensitive at 4000 Hz (i.e., rustling leaves in the forest) while we have a threshold of 20-30 dB at 64 Hz. This can be compared to the cursed invention of the loudness curve on an old classic graphic Eq. Thus, a reduction of sound should be measured against how the ear perceives sound. Then come aspects like impulse noise and others that play a role, but these are nothing that exists in the normal case in a dwelling.
Creating a double stud construction entails two things:
1) You separate the framework to reduce flank transmission.
2) You lower the natural frequency of the construction since the distance between the oscillating masses becomes longer.
This results in better sound reduction at lower frequencies and subsequently at higher frequencies since gypsum loses about 3-5 dB in a given frequency/octave band in harmonic overtones from the lowest frequency. I'm not entirely 100% sure on the exact figures for the last part.
A 10 dB change is a doubling, 2 dB is a noticeable difference.
But to put it in context, you can say that 70 dB is the level we normally speak at. Then comes the next aspect, frequency. The human ear perceives sound at roughly 0 dB theoretically; we could hear when an air molecule hits the eardrum, which luckily it doesn't. But let's say we have a hearing threshold at 0 dB across the entire frequency band, then we are extra sensitive at 4000 Hz (i.e., rustling leaves in the forest) while we have a threshold of 20-30 dB at 64 Hz. This can be compared to the cursed invention of the loudness curve on an old classic graphic Eq. Thus, a reduction of sound should be measured against how the ear perceives sound. Then come aspects like impulse noise and others that play a role, but these are nothing that exists in the normal case in a dwelling.
Creating a double stud construction entails two things:
1) You separate the framework to reduce flank transmission.
2) You lower the natural frequency of the construction since the distance between the oscillating masses becomes longer.
This results in better sound reduction at lower frequencies and subsequently at higher frequencies since gypsum loses about 3-5 dB in a given frequency/octave band in harmonic overtones from the lowest frequency. I'm not entirely 100% sure on the exact figures for the last part.
Okay, let's clear this up...again.
When talking about a wall's sound properties, one usually refers to the reduction index, R. This is a measure of how much a partition wall can dampen sound passing through it, and the unit is dB. Sound reduction is usually measured in third-octave bands from 50-3150 Hz, where the mentioned summary value R is calculated and frequency-weighted according to given rules. The weighting curves A, B, C, and D used in other sound contexts have nothing to do with the reduction index.
An increase in sound level by 1 dB is barely noticeable, meaning a person with normal hearing can, if they listen very carefully, perceive the difference. For sound to be perceived as twice as loud, the sound level needs to increase by about 10 dB.
The ear's hearing varies depending on frequency, which means that we can perceive two tones of different frequencies as differently strong even though they have the same sound pressure. It is further complicated by the fact that this frequency dependence looks different for various sound pressure levels. If we look at the hearing threshold, the weakest sound we can perceive, it is about 5 dB at 1000 Hz. To hear a bass tone of 60 Hz at all, the sound level needs to be about 35 dB, while a sound level of about -4 dB is sufficient to hear a tone at 4000 Hz (note the minus sign).
When building a wall with a double stud frame instead of a single one, direct transmission is reduced (not flanking transmission!). If we imagine a traditional gypsum wall with a single stud frame, it looks like this: When a sound wave hits the wall's gypsum board on one side, it is set into motion. The resulting vibrations propagate to the studs, which in turn causes the gypsum board on the other side of the wall to start moving and thus also generating sound. With a double stud frame, the direct connection through the studs from one side of the wall to the other is broken. Sound cannot be transferred through the wall frame’s studs here. A double frame is very effective in terms of sound insulation.
It is true that increasing the distance between gypsum boards lowers the wall's natural frequency, but this has no connection to whether single or double studs are used. A 120mm stud gives, for example, a larger distance between the boards than a double stud frame 2x45mm with a 10mm free air gap does. The natural frequency itself does not say anything about the wall's reduction index.
When talking about a wall's sound properties, one usually refers to the reduction index, R. This is a measure of how much a partition wall can dampen sound passing through it, and the unit is dB. Sound reduction is usually measured in third-octave bands from 50-3150 Hz, where the mentioned summary value R is calculated and frequency-weighted according to given rules. The weighting curves A, B, C, and D used in other sound contexts have nothing to do with the reduction index.
An increase in sound level by 1 dB is barely noticeable, meaning a person with normal hearing can, if they listen very carefully, perceive the difference. For sound to be perceived as twice as loud, the sound level needs to increase by about 10 dB.
The ear's hearing varies depending on frequency, which means that we can perceive two tones of different frequencies as differently strong even though they have the same sound pressure. It is further complicated by the fact that this frequency dependence looks different for various sound pressure levels. If we look at the hearing threshold, the weakest sound we can perceive, it is about 5 dB at 1000 Hz. To hear a bass tone of 60 Hz at all, the sound level needs to be about 35 dB, while a sound level of about -4 dB is sufficient to hear a tone at 4000 Hz (note the minus sign).
When building a wall with a double stud frame instead of a single one, direct transmission is reduced (not flanking transmission!). If we imagine a traditional gypsum wall with a single stud frame, it looks like this: When a sound wave hits the wall's gypsum board on one side, it is set into motion. The resulting vibrations propagate to the studs, which in turn causes the gypsum board on the other side of the wall to start moving and thus also generating sound. With a double stud frame, the direct connection through the studs from one side of the wall to the other is broken. Sound cannot be transferred through the wall frame’s studs here. A double frame is very effective in terms of sound insulation.
It is true that increasing the distance between gypsum boards lowers the wall's natural frequency, but this has no connection to whether single or double studs are used. A 120mm stud gives, for example, a larger distance between the boards than a double stud frame 2x45mm with a 10mm free air gap does. The natural frequency itself does not say anything about the wall's reduction index.
Oh, what an interesting thread! I have a question that I hope someone can answer:
The boy's bedroom is next to the kitchen, so he wakes up easily if we do the dishes or make noise with something else. The wall consists of building board-studs-building board, which means it's a really poor sound-insulating construction. The simplest way to make it somewhat better is to put a plasterboard directly against the building board in his room (since we're re-wallpapering anyway), but how do I make it really good? A stud at the floor and ceiling, vertical studs on this, and then OSB+plasterboard? Or are there better alternatives?
The boy's bedroom is next to the kitchen, so he wakes up easily if we do the dishes or make noise with something else. The wall consists of building board-studs-building board, which means it's a really poor sound-insulating construction. The simplest way to make it somewhat better is to put a plasterboard directly against the building board in his room (since we're re-wallpapering anyway), but how do I make it really good? A stud at the floor and ceiling, vertical studs on this, and then OSB+plasterboard? Or are there better alternatives?