Hi fellow audiosexers!

I need help from you to solve an issue we have in our association where we want to do club parties.

We are in a building that is 13mx9mx4m that is situated at the basement of a 3 floors complex (I apologize if I don't use the correct terms but English is not my native language).

We have 2 Martin Audio W8 plus 2 Martin Audio W8S subwoofers in SALA1 (see attachment).

We received noise complaints from a neighbour that lives at the 3rd floor and from one that lives in the first floor, so just above us.

They feel vibrations in their apartments coming from the subwoofers.
We needed to cut circa 15 dBs to eliminate the problem but we want to do sound insulation to be able to do dj-sets at appropriate levels (max 105 dB A levels).

The construction of the building is made of very thick concrete and we suspect that there's some resonance going on in the pillars/ceiling/walls that make the low frequencies travel to the neighbours' houses.

We would avoid to do a room in a room because it would be not sustainable from an economic point of view for now, we don't have the amount of money necessary to do it and we don't know if the landlord would give us the permission to do this work.

What we had in mind was to completely fill the space with at least 100mm (200 mm is the goal) of high density (150 kg/m3) mineral wool panels directly glued to the walls/ceiling to help the vibrations not going through the structure.
In a second time we could do sound treatment to have a better sound inside but for now sound insulation is the absolute priority.

I made simulations with a software called Insul (version 9) and we should have an improvement of circa 25 dB at 63 hz doing this.

The strange thing is that mineral wool alone gives a better noise reduction that if I put a layer of 12.5 drywall in front of the mineral wool (in the 63/250 hz range).

Assuming that this is correct we would cover the mineral wool panels with fire resistant fabric so that fibers would be contained inside the fabric .

We would use a decoupled wall/ceiling only where necessary just to hang fixtures.

We would want to not do a floating floor because of price but we are concerned of possible floor to walls/pillars low frequency transmission that could nullify our efforts.

My question is: doing this would result in an attenuated low frequency transmission or is simply a waste of time?

Putting a layer of 200mm mineral wool (150kg/m3) outside a window (we don't use it) resulted in an improvement where you could clearly hear a person talking and loud bass to virtual silence (a person screaming is not heard and loud bass became almost inaudible).

From this surpringly good result I thought that maybe this could be a good strategy.

I attached the cadastral plan for you to have an idea of the situation.

"SALA1" is where we have the Martin Audio sound system (3 meters circa from the wall).

In "SALA2" we have 2 15 inches subwoofers and 2 10 inches speakers that we use at low volumes just to have some music in the bar room but this don't create problems.

I should add that we don't want to build a room in a room in SALA1 unless there's no other choice.

Thanks for your attention!

 

I live in a high-rise building myself and the bass actually creeps up several floors, or rather it causes everything to vibrate.

Sometimes the person responsible can do something about it by repositioning the speakers. You can also place the subwoofers and speakers on tennis balls and away from the wall. There needs to be a thick carpet under the subwoofers. Old carpets on the floor also work wonders.

Bass can only be insulated by using a lot of insulation material. 12 - 20 cm.
The "Steico flex wood fiber insulation board - 120x 40 x 2000" costs €22.98 / m².
Unfortunately, all of this is very expensive. The Rockwool insulation materials made of stone wool are non-flammable.

The best thing is of course to put 2 layers of plasterboard in front of it. Plasterboard starts to vibrate and this reduces the noise somewhat.
Actually, there should be 2 cm of space between the wooden frame and the wall, i.e. a doubled wall. Since you have little budget, you should concentrate on the wall and the wall directly next to your neighbor.

It's best to ask your neighbor, after the first layer of insulation, whether he would be willing to do a hearing test.

Noise barriers must actually be approved by the landlord because the room will also be smaller and the heating costs will be calculated differently. Lamps should be removed and replaced with floor lamps because the noise seeks out the weakest spot, the cable, and transmits the sound. Also plaster cracks etc. beforehand! You can also work on the floor later.

 

With it being a full concrete building, the building fabric will reflect more of the transmitted sound then it will absorb.

So unless the sound is only a problem for them when they open their windows & doors, what is causing the problems will be vibrations from the speaker cabinets transmitted directly into the surfaces they touch.

Are the 2 Martin Audio W8 & 2 Martin Audio W8S subwoofers standing on the floor? If yes then mount them on something that keeps them away from the walls or stand them on something. Isolation pads, raised floor, even super thick carpet will be an improvement.

Marshall amps are on casters so that most of the vibrations from the cabinet is lost in movement before reaching the floor and disturbing others in the building who can't hear the music.

if the sound is audible outside and that is the problem, do something to your windows.

To save others looking, are these your speakers?
https://martin-audio.com/downloads/archive/datasheets/W8Sdatasheet.pdf
https://martin-audio.com/downloads/archive/datasheets/W8datasheet.pdf

Rubber grommets and silicone sealant stops that cracking. Floor lamps are a bad idea in a night club, Pub or bar. They'll get knocked over and broken.

 

Sorry for the double post but if you have the budget to make big changes.

Add a ceiling and mount all the speakers in the ceiling with insulation behind.

Lots of speakers above the head of the guests will give the same over all audible volume in the room while actually being quieter and with fewer spots of high intensity.

So less chance of transmitting through the building.

 

not strange .the wool eat the waves ,the drywall reflects .
you could put a thin layer of black spraypaint on the wool and it will still be absorbing but it must be really thin .if you put the wool into blackpainted drywall profiles it may be look acceptable .
im speaking of stonewool plates not rolls .

and no matter how good you install drywalls ,if bass staticly and long working on them they will begin vibrate cause they made from softish gipsum...even planked 3 times i guess...

 

Last edited: Nov 23, 2024

the biggest problem are the subs if they are 18" they are way to overpowered
for that size room + the waves they produce are really effective @ 30m away
that could be the biggest problem!
But even with room in room say 15" subs would be tough to control.

the next problem with insulation is fire security, you could get problems with
Insurance & safety regulations!!
check your local guidelines to be sure

If you train your dj's to be very mindful & convince them quality over loudness
THEN the 2 W8 with 12" or 15" should be very good, maybe not in an empty room
but a full room should be fine

 

xs/the box in frankfurt had subwoovers as long as the dancefloor ,7 meters or so and room was 9 metrs or so but no living appartments above .

you sure mate this is done with woofers ? would need real thru ceiling wall anker screws i could imagine and super special wire/chains or rubberband

 

Last edited: Nov 23, 2024

No, when i wrote that I was thinking with this room size and the ceiling height it'd be easier to get the sound wanted from 8 no. 12'' speaker cones or smaller ceiling mounted.

Put the ceiling in with a void of about 250mm to pack with insulation. Assuming the average person is 2000mm tall, the travel distance for the sound will be only 1750mm so you can keep the volumes down. and still sound loud to the listener. Use a EQ to reduce the high frequencies & give the low frequency intense sound your looking for.

It's a loosing battle trying to get sub woofers to spread evenly accross a room when the crowed is inches from the equipment. The people at the front absorb most of it so the volume ends up needing to be massive to reach the back or center of the audience, depending on how you place the equipment.

What we really need to know is the limits on resorces to help find the right solution.

If budget is tight then the only way is to during the day send someone to the top of the building and play a slow frequency sweep through the sound system to find what fequencies make it up the building and cut them out.

It'll effect some songs sound but it's cheep.

 

just remember that the person who made complaints, may continue to do so if they hear "anything". Spending a lot of money might not end your problem. Also, don't forget all the heating/air conditioning duct work will carry sound, as if you were piping it directly in to your neighbors'.

 

Update: the neighbour invited us to his house and we did some tests. With subwoofers at full throttle his floor was clearly vibrating but it was just to test, we don't need that much bass for our parties and it will be out of law (over 120 dbA at 3 meters circa) .

We did test frequencies with a sine wave generator at 1hz steps from 25 to 200 hz (long process) and with actual club music and we found that it's not one or more specific frequencies causing the bass to be audible but a broad spectrum so it's not possible to equalize offending frequencies.

Mids and highs were entering from his windows and this is caused by the fact that we have poor insulation from our entrance wall (made of glass) and emergency door especially in green (the violet one is main door), which is thin and light. I'll attach a scheme of the building just to make you understand more (I just can't draw lol so I don't know if you can understand anything.

Our neighbour is at the 3rd floor on the right of our space and above "SALA 2". "SALA 1" has a roof on top of it, the buildings are only above "SALA2".
For now there are no other residents, last year there was one just above SALA2 and he complained about bass frequencies but now he moved in Argentina so for now we only have this neighbour, other apartments are private studios of lawyers etc... so not a problem because they're not used at night.


We found a compromise with our neighbour at a volume that is less than 10 dB what we would want to have, even just 5/6 dB more would be sufficient (even just 3/4 dB more would make an appreciable difference) .

The volume at which we found a compromise is circa 24 dB less than with the bass at full throttle. At the volume we would want to achieve his floor was not shaking but bass, as well mids/highs, were too much audible (for him but I understand it given that he sleeps there).

It was not clear if bass was coming more from the windows or from the floor but I guess it's a combination of the two.

Now what I have to understand is: how can we achieve a reduction of 10/12 dBs (just to keep it safe) or at least 6/8 dBs?
Filling all the space (glueing panels to walls/ceiling/doors etc...) with high density (150 kg/m3) and thick (from 10 to 20 cm) mineral wool
would meet our goal?

I know that we have to create an air tight space and I think that we could succeed in doing so but I can't understand if mineral wool alone would suffice or not (even if 20 cm thick).

With Insul software (a prediction software used in architectural) I have some strange results in regards to mineral wool use that I want to make you see: it would seem that we should not only succeed but exceed our goals but something seems not right.

Everywhere I read that mass and decoupling are the first thing when it comes to isolate low frequencies but this simulations tell another story.

Here's a simulation I made with Insul starting with a simple concrete wall:


How can it be that simply glueing 10 cm of 60 kg/m3 of mineral wool to an existing wall (read to all the walls/ceiling etc...)we should expect 10 dB reduction at 63 hz?

How can it be that simply glueing 10 cm of 150 kg/m3 of mineral wool to an existing wall (read to all the walls/ceiling etc...)we should expect 26 dB reduction at 63 hz?


How is it that simply adding a sheet of 12.5 cm drywall to the layer of mineral wool (the 60 kg/m3 in this screenshot) the transmission loss will be not only nullified but 5 dB less than with only concrete at 63 hz?


If what this software says is true we should solve all our concerns just glueing mineral wool panels (covered with fire-resistant rated acoustic transparent fabric to incapsulate the fibers) to existing walls/ceiling/door and just make a resilient channel bar to attach our 8 fixtures (4 moving heads and led bars).

How is it possible that if I raise the thickness of concrete from 152 to 252mm so 100 mm of concrete instead of 100 mm of mineral wool the trasmission loss is only 4 dB more than 152mm concrete (this seems right according to mass law), so 6 dB less than 100 mm of 60kg/m3 mineral wool and 20 db less than 100 mm of 150kg/m3 mineral wool (this is what I don't get)? I will upload the 252mm concrete screenshot in the next post because I already made 5 attachments that is the maximum possible here.

How can it be that mineral wool do this fantastic job? Too good to be true?

What I know from having it done is that 20 cm of 150kg/m3 outside of a 1x1m circa window just pressed in the cavity did a wonderful job as I described in the first post but I don't know if that result would work with bass inside the structure (from our walls/ceiling to our neighbour that is 3 floors above us).

The mineral wool on the window stopped very effectively airborne sound.
Would it be the same with structureborne sound?
Is it structureborne sound what our neighbour is hearing?

I know that this is a very long post so thanks in advance for anyone reading it all.

Budget is low for now (max 5000 euro) and we will not change our audio system. We know that mids/highs are the easiest part of the issue so I'm not focused on them.

So our question is: We just want to know before doing anything if mineral wool would suffice (as the simulation is showing) or if the only solution would be a room within a room to gain 10 dBs (minimum 5/6 dBs) of headroom at low frequencies.

 

this is the 252mm concrete simulation that I couldn't attach in the previous post. Notice the difference between 152+100mm more concrete and 152mm conrete plus 100 mm of mineral wool. Is this software wrong or right?

 

bump
@Sinus Well

 

You are mixing/Confusing Mass & Density
Take for instance material like basotec, while (depending on thickness) is fine for absorbing
frequencies above 150-200, its brutally reflective in the lower register
because its much denser than rockwool

like i said, you would be much safer with a smaller BASS DRIVER
in terms of db you could be more than 50% reduction in transfer* (*outside sala)
dont have the equation at hand, maybe 20db, without much loss on the
dance-floor!!! with 12" driver that is, which is also much more direct*
for the audience (*meaning: feeling the bass)

to double your deficiency with the rockwooll you should also leave an air gap
10-15cm ideally everything above 5 still ok
+ you can also reduce naturally occurring room modes/feedback
using available websites (just need to input size of the room)
it will give you exact room modes (freq)!!!

 

you need 1/4 wavelength absorbers, that is e.g. for 50hz 343 m/s / 50 / 4 = 2,14 m thick absorbers so it's not feasible.

the size of the speaker does not matter, only spl and frequency matter for this. 130 dB from an 15" woofer are exactly the same as from an 21" woofer. the smaller speaker has to compensate with excursion for smaller cone area to achieve the same level.

setting a 40-50 hz highpass may help a little. you can also try to add 2 additional subs and position and dsp / phase align them in a way that they cancel out at your neighbours location. it may be difficult to get them aligned with mains then though. or try a cardioid setup. https://electrovoice.com/media/downloads/wp_subwoofer_arrays_v04.pdf

you can not create an airtight space btw. because people may want to breathe.

 

Last edited: Nov 29, 2024

Just complain about the neighbour about too loud sex noises!

 

i give up

 

Have you considered using Rational Acoustics SMAART software at all? It is somewhat commonplace software in sound reinforcement cases. The Suite version includes SPL mode, which as you probably can guess is for monitoring and adjusting dB SPL tailored to the physical space; rather than trying to change the space physically. It is on version 9, and v9.1. can be found for both PC and Mac. Check it out, maybe it would be useful for your current scenario. https://www.rationalacoustics.com/pages/smaart-home