Hello:
I have a home studio, it sounds decent, but I´m having low frequency impact noise comming from the streets.
It did not happen before becouse the streets were made of asphalt , now the treets was rebuilt whit concrete.
It ´s very hard and it transsmit the noise to my studio.
The noise floor in my recording room is 25 db, when a bus croos the streets Makes noise( boom toc toc ), and the noise is about 6 to 8 db louder.
In my control room the noise floor is about 33db and wne the bus croos the streets the noise is 6 to 8 db louder.
Should I float my floor and walls?
I´ve read a STC for a 12mlm Gypsum Board is 15 db for 125 hz.
That´s enough soundproofing for solve this problem?
The recording room is 7 meter long, 5 meter wide, 4,30 meter hi.
(sorry about my english i do speak spanish)
Thanks!
LOW FREQUENCY IMPACT NOISE
Originally posted at johnlsayers.com, topic 15917.
Your sound issue is transmited sound through the earth, floor and walls.
Can you tell us more about the studio and its construction?
IS it in a bedroom or was the studio purspose built.
Walls?
Floor?
I believe there is a Spanish speaking section in this forum.
Like Ms. lilith_envy said, some of the issue is with the direct earth connection. Other things that will increase sound is that generally speaking, when roads are re-worked they get wider, and wider means the sound will get closer to your area. A heavy connection like concrete, if it is bedded on a hard earth connection, can move directly into your structure via the rock or frozen ground.
"I´ve read a STC for a 12mlm Gypsum Board is 15 db for 125 hz.
That´s enough soundproofing for solve this problem?"
What you are trying to say, I assume is that the transmission loss value at a specific frequency is relevant to your case. The Sound transmission Class (STC) of a piece of sheetrock is not given in reference to that piece of material. And in the hunt for isolation, mass is the determining factor, so a 1/2 inch (12 mm) would give less results, a lower stc and a reduced transmission loss, than 5/8 inch (16 mm) of mass would.
The loss(transmission loss @ 125 Hz) is a product of the thin sheetrock, one sheet or multiple sheets, it's still there:) like a window that is open and the frequency can move in or out of it,
You are wanting to attack the 50 Hz and lower area, this is not an stc thing but a product of the density of the material and how well it can support a barrier from low frequency.
That``s exactly wath happens, here are a sample , normalized to 0 db. So how can I solve or minimize this problem.? Do youy need more information? Thanks!!Like Ms. lilith_envy said, A heavy connection like concrete, if it is bedded on a hard earth connection, can move directly into your structure via the rock of frozen ground. "
can you localize where the sound is coming in? the walls/ceiling? a window? vents? floor? if you have (get) a contact microphone (or mechanic stethoscope, although the mic will let you record and analyze the frequency content) and put it on the concrete floor - what are you getting? same for walls windows ducts, etc etc
Yes ! it comes from ceiling the most, walls, and floor, i´ve tryed the contact microphone, and the same frome avery where.More or less db. the noise is there. Here are the sample recorded. And a picture showing the frecuency analisys Any solution,? please!!!! :( :( :( :( :( thanks!!!can you localize where the sound is coming in? the walls/ceiling? a window? vents? floor? if you have (get) a contact microphone (or mechanic stethoscope, although the mic will let you record and analyze the frequency content) and put it on the concrete floor - what are you getting? same for walls windows ducts, etc etc
It structural in it's transfer - depending on your options to build a decoupled room within the existing space, or not.
Yes I know that. I could built a decoupled Room. I can not built a concrete floating floor , but I do can built a wooden floating floor. The Q is how much, do I need to do for isulating those 6 to 8 low frecuency db.It structural in it's transfer - depending on your options to build a decoupled room within the existing space, or not.
Can we get a picture of this room...I'm thinking a window or a door is making this issue.
if it comes from the ceiling area first, then it(sound) has to travel a longer path or comes from overhead, typically it will be the floor/wall assembly and any window aperture involved.
to isolate the 60-80hz effectively you need to have a natural resonance down around 20-25hz (basically 1/3) (which should be possible using say 12mm 30 hardness neoprene rubber or Sorbathane under the isolation wall framing). then you need to decouple the floor and ceiling - preferable the ceiling uses the decoupled walls for support so it's separated from the structure, and the floor use a damped membrane approach. you'll also need mass to ensure the actual wall and ceiling assembly resonance is low enough so 2x 16mm drywall. the air gap between the isolation walls and exterior is lightly filled with 15-24kg/m3 insulation.
Sounds Good Glenn...can we get the data on that to interpret how this actually works from a verified testing area?
I understand how it >might< perform, but I have no idea if it will or will not, and might actually be more work than needed with a deleterious effect in the end.
I think of placing a lot of weight on a basic structure...with no field testing on the neoprene as to the weight imposed, and I have to wonder, why even do it, what is my margin for error?
Brien - actually a reasonably high resonance frequency like that would be decoupled easily as described. calculating - there are a number of online resources to use to calculate it (Mason Industries, Sorbathane etc who provide isolation products for just this purpose and tables for calculating this) but when you get down to a target of ~40hz and less though the decoupling becomes much more dependent on precision...
Make sure there is no significant sub-60Hz frequency content. If they aren't properly configured, some spectrum analyzers may have difficulty showing low freq content for impulses.
Neoprene won't do much at lower frequencies due to the static deflection needed. If there is really low freq content then you're looking at needing a sprung floor with some serious static deflection.
I just put a C414 in the recording room, and began to record, I wanted to know what noise could to interfere in a typical xy strings recording session. If a can to minimize that low noise, about 10 db I suppouse could be right. Do im wrong?Make sure there is no significant sub-60Hz frequency content. If they aren't properly configured, some spectrum analyzers may have difficulty showing low freq content for impulses. Neoprene won't do much at lower frequencies due to the static deflection needed. If there is really low freq content then you're looking at needing a sprung floor with some serious static deflection.
In order to figure out how to mitigate the noise, you need to figure out what range of frequencies are ACTUALLY contained in the vibration intrusion. If the duration of the impulse is less than the duration of a cycle of a given frequency (say 20Hz for example, duration of 50ms), then your analyzer software may not recognize that there is content at that frequency. In other words, contrary to the spectrum you provided, there may be sub 60Hz frequency content. This may change the design that you will need to mitigate the intrusion. I would hate for you to go to the expense of building a floating floor to target 60Hz+ vibration, only to discover that the problem extends well below this. EDIT: I would get a proper evaluation done by a qualified acoustic engineer.I just put a C414 in the recording room, and began to record, I wanted to know what noise could to interfere in a typical xy strings recording session. If a can to minimize that low noise, about 10 db I suppouse could be right. Do im wrong?Make sure there is no significant sub-60Hz frequency content. If they aren't properly configured, some spectrum analyzers may have difficulty showing low freq content for impulses. Neoprene won't do much at lower frequencies due to the static deflection needed. If there is really low freq content then you're looking at needing a sprung floor with some serious static deflection.
I m collecting information,for the moment you can view some pictures I,ve posted before, viewtopic.php?f=2&t=9881Can we get a picture of this room...I'm thinking a window or a door is making this issue. if it comes from the ceiling area first, then it(sound) has to travel a longer path or comes from overhead, typically it will be the floor/wall assembly and any window aperture involved.
Thanks! It´s to hard to find a qualified acoustic engineer Here, The problem comes form the streets, when the buses cross the black line showed in the picture , the next cement block moves down and makes boomm!!! toc toc!!! Did you heard the mp3 sample i´ve posted, is it possible to make any analysis form that audio file? Thanks againIn order to figure out how to mitigate the noise, you need to figure out what range of frequencies are ACTUALLY contained in the vibration intrusion. If the duration of the impulse is less than the duration of a cycle of a given frequency (say 20Hz for example, duration of 50ms), then your analyzer software may not recognize that there is content at that frequency. In other words, contrary to the spectrum you provided, there may be sub 60Hz frequency content. This may change the design that you will need to mitigate the intrusion. I would hate for you to go to the expense of building a floating floor to target 60Hz+ vibration, only to discover that the problem extends well below this. EDIT: I would get a proper evaluation done by a qualified acoustic engineer.I just put a C414 in the recording room, and began to record, I wanted to know what noise could to interfere in a typical xy strings recording session. If a can to minimize that low noise, about 10 db I suppouse could be right. Do im wrong?Make sure there is no significant sub-60Hz frequency content. If they aren't properly configured, some spectrum analyzers may have difficulty showing low freq content for impulses. Neoprene won't do much at lower frequencies due to the static deflection needed. If there is really low freq content then you're looking at needing a sprung floor with some serious static deflection.
My own analysis using Steinberg Wavelab shows significant content down to below the audible frequency range (20Hz). I may not be doing it correctly, so perhaps other people here can validate this. Also, because the recording is an mp3, and I understand that mp3s can have accuracy problems in low frequencies, you may want to post a .wav for analysis. It looks like the road was not constructed well. Have you tried approaching the local authority to try to have some remedial work done on the road? You could say it is interrupting your sleep and ability to make money. I don't know how these things work in Argentina, but this could be a lot cheaper for you...Did you heard the mp3 sample i´ve posted, is it possible to make any analysis form that audio file? Thanks again
There is a better than average chance that the "toc toc" you hear is from the tires of the buss, which has a lot of weight, and the tire hits both sides of the joint in the road.
Much in the same way when you are on a concrete road that has construction joints installed, the sound like that resembles a horse running on a hard surface is a by product of this typical construction.
I wouldn't think the road is moving downward that is visibly perceivable, but if it IS, this should be brought to someones attention as the other poster suggested.
it looks like most of the noise is above 30hz (which means you'd want to decouple down around 10hz which will be tougher with rubber...) but the main noise seems to be the 80hz and up (the spectrograph shows several bands).
I looked at the prospects...and they were dim. The tools provided required a high level of understanding from me as a user...on a broad scale, not many will get the reality to match their work. All that said, and all this additional product installed...there is still the fasteners from bottom plate to concrete that will make the flanking path and by pass the rubber. Let's assume we install some type of decoupled mechanism as we have previously discussed, at the specific points that a fastener needs to be installed. This product elevates the plate and will generate a void from the bottom of the plate to the existing concrete, until we hit another fastener installation point. Now my question is, if we can get passed the flanking path generated from the fastener and IF the cost of this product matches the builders budget, how is it supposed to support the plate with this very heavy load in the areas that are now free from contact of a solid substrate? I have yet to find a "roll" of this product that would accommodate this issue, and there has yet to be a price produced to support this is or would be a successful path to choose. There must be something to it or you would not keep mentioning it but by and large these products are for specific issues that mostly have little to do with a sound room type environment, they are simple "acoustical" in nature, but that is not a word wholly subscribed to the world of music...but more often simple to the field of generating less vibration from some specific piece of equipment that has to be brought under vibrational control. So I am asking for your insight into the use and how it will be beneficial to users of it. The long version, not the short one :)Brien - actually a reasonably high resonance frequency like that would be decoupled easily as described. calculating - there are a number of online resources to use to calculate it (Mason Industries, Sorbathane etc who provide isolation products for just this purpose and tables for calculating this) but when you get down to a target of ~40hz and less though the decoupling becomes much more dependent on precision...
Specifically to this build, let's consider the proximity to Chile, an area prone to earthquakes.
I would bet the building methods are different in that they most likely build like folks in Miami, Fl who fall pry to hurricanes on a regular basis...so they use mostly concrete.
The plates have to be bolted in Chile even on the interior walls....just something to consider as we expand this idea of decoupling via rubber.
Yes, here buildings are made of concrete and hard brick. When I began to build the sutiod , streets where made of asphalt . It was more flexible. The vibrations where damped by the asphalt it self. But the last year the street was made of concrete.Asaphalt was removed , the floor was compacted. I Showed this problem to the city engineer. I can fill the treet vibrating under my foots , and I can see the street moving down, its minimal 0,5 to 1 cm but is deep enough for making such as vibrations. But the city engineer take their time to solve the problem, and I dont know if the problem will come up again. So I have to think about two solution, one from the other from the city engineer,and the other building muy studio.Specifically to this build, let's consider the proximity to Chile, an area prone to earthquakes. I would bet the building methods are different in that they most likely build like folks in Miami, Fl who fall pry to hurricanes on a regular basis...so they use mostly concrete. The plates have to be bolted in Chile even on the interior walls....just something to consider as we expand this idea of decoupling via rubber.
so a couple of options exist - specialized products like Mason Industries which mount to the base and suspend the wall structure (such as ND), then the sides and top are stabilized with decoupled (isolating) sway braces such as WIC. the floor would still be the weak point and without a proper floating floor, the best bet would be a deep damped membrane floor and then plan on cutting off below say 30hz to eliminate any low or infrasonic noise. in the case of a roll product - you have some options for either completely underlying the frame with a soft rubber (assuming the higher freq is the target) or smaller sections sized to get the compression just right (so higher freq or simple impact noise - fair easy, lower freq or deeper impact levels - more work is needed) so you might cut the roll material into (example) 100mm squares and space about 600mm apart (again the wall ceiling room mass computations need to be done) but basically once you know the square unit area - weight it's actually relatively straight forward to compute the size. additionally, some times using thick foam or rubber tubes which can be cut to depth (say a 100mm tube with 25mm walls like pipe insulation) can be used effectively since their square area is a smaller cross section than a square or rectangle and then it's easier to get down lower in frequency (but not necessarily find a source for it). so i'd say step one is an accurate computation of the target room mass and weight distribution to determine how many Kg/cm we have to address.