Noisy ceiling

Hello Naim members,

Wondering if anyone has encountered house ceiling noise issues and whether they have found a way to solve it. I am facing noise issues such as rattling noises and vibrations. The ceiling is gypsum ceiling which hides away the drainage pipes and ducts, and the AC ducting, above that is concrete ceiling.

When playing at 9’oclock with songs where the frequency drops below 100 Hz, the ceiling emits vibrations and noise. I played a sweep frequency from 50-100 Hz, you cannot see the ceiling shake or vibrate, however you hear the vibrations and rattling noises very clearly. There are two AC ceiling vents, one of them is just above the speakers and second is just above the listening position.

Actually, this makes a good prank to scare people in the dark with ceiling noise when playing a low frequency sweep :grin: :ghost:

Has any of the forum members experienced such as issue and found a way to solve it?

I thought of ceiling acoustic treatment (such as diffusion panels/absorption panels), but doubt this will help since I feel that the noise is caused by sound signals traveling through the AC ducts and false ceiling, and being amplified in the space between the concrete ceiling and the false ceiling (height i guess is at least 50cm).

If you play a sweep function above 100 Hz, say 100 to 500 Hz, you do not hear the noise anymore.

My chain of though is to install acoustic rockwool insulation such as Knauf Acoustic Sound Ultimate above the false ceiling and a layer of acoustic gypsum such as Soundbreak XP below the ceiling. I am not sure if this will solve the problem, or whether i will just be spending money and getting no benefit (snake oil).

Appreciate some input to solve this mystery…

Assuming you have safe access to the space, I think you need to find what’s resonating and either brace it or damp it. If it’s the ac ducting, just putting a hand on it will probably identify it as the culprit.

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That is also my reaction - whether the ceiling itself or something within. From the description it should not be hard to locate if access is possible. The question is, is access possible?

Cheers guys, that was my feeling as well, and was broken down do the following steps:

  1. Isolate noise on the AC duct by using AC duct thermal rock wool insulation, and using rubber to isolate joints
  2. Install 50mm acoustic rock wool above the gypsum all over the ceiling (perhaps 15m2)
  3. Replace the current gypsum with a two later acoustic gypsum

The problem is that I have no access to the ceiling, to do so, i would need to remove the AC grille which is not possible since it is plastered into the Gypsum, so to remove the AC grille, I will have to cut the AC grille.

I am attaching a picture for easier reference.

There are different products to use depending on the sound isolation concepts, main concepts are:

  1. Decoupling
  2. Damping
  3. Mass
  4. Absorption
  5. Resonance
  6. Conduction

And products to use are:

Acoustic gypsum boards
Acoustic gypsum tiles
Decoupling clips
Noise proofing compound glue
MLV (Mass Loaded Vinyl)
Ceiling tiles sound barriers

Was wondering if someone has gone through this exercise and their experience, and whether it is best to just apply simple acoustic treatment techniques or go all the way in, problem is, the current gypsum will need to be broken down for any alterations, so whatever adjustment i do will be best to be done once.

I guess i would not have had this problem if I had no gypsum ceiling, however this is not a choice due to concealed ducts, pipes, and AC ducting.

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I assume no option fir access from above?

If you’re going to have to do something drastic to get in there, then maybe it might be worth some prior investigation with a stethoscope or similar while playing a stimulating note, to try to track down if there is a particular location: if localised the amount of work needed to get at it may be reduced.

IIRC Naim were using ceiling treatments at last year’s Munich show and they were very successful; Indeed, I though the sound was really good. It might be worth mailing them and asking about what they used.

I remember they had a room treatment company involved at Bristol show as well this year, so well worth contacting Naim.

Hi Hani.
Unless it is the whole expanse of the ceiling vibrating I think it could be difficult to actually find the culprit without major surgery.
To make a ceiling per se making vibration noises is of course likely to be the result of low frequency pressure build up in the room itself causing in your case the weakest link ( the ceiling) to vibrate.
If you are actually hearing an in-room bass lift, I would measure it for amplitude/ frequency and treat your areas behind the speakers with absorption ( tex GIK monster bass traps) starting with the corners. I am fully aware that this option won’t be likely to suit the aesthetics of your room, but to me actually looking at the cause ( now you know the effect) is the logical place to start.
I would phone up GIK acoustics UK and have a chat with Lucas ( technical advisor) and email him some pics. Good luck Peter

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I’m sure acoustic treatment will be a good idea - but make sure you fix the rattle first!

Thanks Richard, will either e-mail Naim directly or ask my Naim dealer (i am in Dubai) to mail them.

Hani, if you direct your question towards Jason Gould, he should know the details.

I have indeed done my REW measurement and e-mailed Lukas from GIK, he has recommended Soffit bass traps which will even dampen further compared to the Monster traps, i am considering the portable version since this is my living room and happy wife = happy life :slight_smile: , but Lukas was not able to confirm how much effect they will have since i do have a considerable bass build up.

You do not feel it in the majority of the music, however you do feel it when the bass really drops low, and I am not talking rap or drum & bass, just regular music such as Together for The XX from the Fiction album. The songs sounds amazing until a huge bass build which starts at 1:28.

This was the reason why I want to treat the culprit first before I go for portable root treatment such as bass traps and diffusers.

I still think I have a major issue with the gypsum ceiling since when I climbed up the ladder and literally plugged my ears to the AC grille (needed a bit of an acrobat movements to do that), i could see or hear in this case that the main culprit is in the gypsum ceiling, hence the reason i am leaning to changing it, but my question here is, how, what is needed, and to what extent?

thanks @Richard.Dane, will contact him, and hopefully he can shed some light, cheers.

If your system is exciting a resonance in the ac, you might be able to reduce it by having damping baffles fitted to the inlet and outlet; however ac ducting is usually big flat planes of undamped galvanised steel, so the best solution there is applied damping.

Bottom line - see if you can get some advice from an ac designer that works with recoding studios before you rip the ceiling down. You might still need intrusive work, but at least you will be addressing the root cause.

Architectural acoustic design won’t hurt either. It needn’t be ugly.

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Hi Hani
I’m not sure that your idea of applying sound insulation is going to work. In general, it’s always best to tackle the source of the problem rather than trying to insulate it.
The problem you have is that the aircon duct that is causing these vibrations has to remain open to the room. You cannot insulate your ceiling and leave a large hole in that insulation, as the noise will still come out of the hole.
If you are prepared to consider acoustic gypsum, that means you would be replacing the existing ceiling, so you have nothing to lose by making large holes in it. Then you can identify any loose or vibrating ducts etc. and deal with them. You may be able to use self adhesive bitumen sheets on any aircon ducts, like those that are used on cars to deaden vibrations in the bodywork. Any loose pipes can be secured by fixing them with support brackets.


Hi ChrisSu, I do agree with you, it is best to tackle the problem, however the issue is once the gypsum has been completely replaced, it is not possible to make any alterations unless you have to breakdown, again, the entire gypsum. It would have been easier if it was a false ceiling with tiles (what i currently have in my kitchen), you can easily remove one tile and you can see everything around and allow you to carry out tests, but with a gypsum board which feels like one piece, not much can be done without having to break it down. Even the AC grille cannot be removed since it is plastered into the ceiling.

I expect adding an acoustic plenum box to the grille, using rubber or acoustically damped couplings instead of rigid ones, using acoustic foam wrapped around the duct, etc…, may help reduce duct noise.

Leaving a loose end, even if 1mx1m open, is a good idea you can sneak to take a better look and see what is going on inside incase the sound does not dampen. I feel this is going to be one heck of a journey.

Let the journey begin :slight_smile:

Hi Hani.
Soffit bass traps are very very good, I am using 2 myself. Assuming you are willing to accommodate room treatment my reason for suggesting slightly shallower bass traps ( Soffit bass traps are 420mm square) is the distance from your stylish portal openings to the front wall. This is where absorbers are very likely to go. Thomas has used these behind his Magicos to great effect and it even looks rather nice.
My thought is to place a 150 mm panels = monster bass traps here and cover both corners with a floor to ceiling height curtain say a quarter Into your front wall. This could leave half of your front wall still exposed in the middle between your Focals. The free wall would then lend itself to a lovely large painting, which you colour wise could tie into the colour of say a beautiful silk curtain design. Nobody would ever think that this just wasn’t a part of the design of your classic style room and neither know, that your acoustic treatment is hiding behind them.
Just a thought… :grimacing: ATB Peter

If you take the drastic action of breaking through the ceiling, I think you will find that vibrating panels in the ducting are fairly easy to identify. Once you have cleared away the dust (there will be lots of it, probably not only in that room!) I would try playing some music again. If you just hold your hand against the duct, you should be able to feel it vibrate, and if you fix a damping panel to it, you will be able to tell immediately if it is having an effect. So you will need to play music in the room during the works. Then you should be able to rebuild the ceiling, confident that the problem has been solved.

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Bass traps in the room will only solve the vibration issue occurs at a frequency where you currently have a bass peak, and if you will never in normal music playing reach the same sound level out of desirability. If those hold true, bass traps conceivably could stop the problem as well as tame the in-room bass problem you describe. Of course, if you are able to arrange home trial of bass traps, returnable, then that would be an obvious no-loss thing to try first, and worry about the room aesthetics if they seem to be the answer.

You can’t do much about the physical size/shape of traps, other than seek GIK’s advice and/or experiment to find the best compromise, however you can have them in any colour fabric, whether to match or contrast, and even have an image of your desire on them (they can do that with many of the panels not advertised as “art” panels).

Hi PeterR,
My plan was actually to have portable room treatments which I can store in my storage room and bring out when needed. The Soffits are very good and they do go very low in frequency (down to 40Hz), hence installing them like a virtual wall was what i was aiming for, however Lukas from GIK has confirmed that the Soffits work best when in a corner and not just behind a speak. I am still talking to Lukas to find the best option for mobile room treatment, and in case I do need to hang something, it should be subtle and blends seamlessly with my living room.:slight_smile: