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sound insulation in terraced house

Discussion in 'Home Cinema Buying & Building' started by mystic_bertie, Mar 26, 2005.

  1. mystic_bertie

    mystic_bertie
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    i am moving to another house soon, one i have bought which is around 47 year old so hopefully the walls will be quick thick, its a mid terraced house.

    I want to know how to prevent sound annoying the neighbours, everywhere i have stayed i have had complaints about the music/movies i play needing turned down even though it was not that loud the bass just seems to travel through modern houses so easily. Anyway i was wanting to know if there is any measures can be taken to help me play my music at a decent level without annoying anyone. I dont want to go to great expence but what is the most effective way of soundproofing without too much hassle or cost.

    I intend to lay down laminate flooring in the living room (14' 10" x 12' 10") so would it help if i used the thick green felt sheets rather than the thin white foam stuff. Does carpet and underlay do a better job of keeping the sound from travelling? Or is there no difference between laminate flooring and carpet?

    My system at the moment is a sony davs-880 which is the one with the 4 tall slim floor standing speakers, centre speaker and subwoofer box on the floor. I know the speakers themself wont be creating any bass but any suggestions what i can do with the subwoofer box to reduce the bass travelling.

    any suggestions on sound insulating greatly appreciated

    also is there any way i could measure the level of bass i can play ie try different levels to find what is noticable by my neighbour then use the meter to measure the level of bass and try and not go above this level, would this work ?
     
  2. Gary Lightfoot

    Gary Lightfoot
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    Bass is always tough to stop as it moves through things it touches, so you have to isolate the room or add mass to make it harder to travel.

    If you want to reduce the sound travel, treating the floor is one small part - you need to do more to the walls, and that means adding a new wall between you and next door. Cheapest way is to build a 4x2 wall frame an inch away from the existing wall, fill it with rockwool and finish off with two layers of plasterboard. THat will reduce your room size by 6 inches. Seal all edges with silicon to prevent and sound travel through air gaps. Do that before adding any skirting or coving.

    Do a search and you should find some more in depth instructions for soundproofing the wall.

    Chatting with the neighbours could help, and finding what the levels are like should give you an idea of how much the sound needs reducing etc.

    Gary.
     
  3. PIG JOE

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    If you have suspended wooden floors then build yourself an acoustic platform for your sub. Most neighbour problems are the result of sub bass booming through the floor.
    Its usually all they can hear! Very easy platform is a concrete slab from B&Q £1.38, bond to this with 'no more nails' an acoustic ceiling tile. Before you stick the tile to the slab cut 4 holes to hold 4 squash balls (1 at each corner). Make the hole so that the ball just sits in it and not goes through it. Spray the slab & tile satin black (or whatever colour) That's it, for less than a Tenner. Sit the sub (best on spikes) onto 4 x 1p coins, onto the slab, onto the balls. My sound improved so much, tighter bass with no boom and the neighbours now hear next to nothing! I'm using the MS 309 sub by the way. Hope this helps
     
  4. Gary Lightfoot

    Gary Lightfoot
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    Hi PJ,

    Got any pics of that? I made an Auralex 'Gramma' sub platform using MDF and high density foam (just like the Gramma), and it cost me almost nothing. I was using a paving slab with wood and rubber strips before that, but I like the sound of your idea better. :)

    Gary.
     
  5. mystic_bertie

    mystic_bertie
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    gary thanks for the reply, as much i i would like to prevent the bass travelling i dont fancy reducing the room by 6 inches, i like the idea of doing some cheap simple things to make the improvements. i also like what pj has suggested .

    pj do you have any pics of your platform and does it matter where you position it ie is it best away from a corner or wall to reduce the sound travelling?
     
  6. PIG JOE

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    Sorry don't have any pics. Not much to see really, just a slab sprayed black!!
    I'll take some pics at the weekend showing the sub on the platform to give some idea.
    The sub is sited in the corner, facing forward (towards the screen) along the ajoining wall and angled into the room. I have no choice on position, it's the only place i can site it, it's also out the way and not to much on show.
     
  7. Gary Lightfoot

    Gary Lightfoot
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    Hi Mystic,

    Here's a link to some pics of my 'grammas':

    http://www.avforums.com/forums/showthread.php?s=&threadid=127788&perpage=15&pagenumber=2

    PJ,

    I'm not 100% on how the squash balls are made to not fall through th eholes - I imagined the slab would be sitting on them through the holes in the MDF so that's why I'd love some piccies. :)

    I've two slabs that I can use for my subs from before, so I'd love to have a go at making your platforms since I have everything except for the squash balls.

    Gary.
     
  8. PIG JOE

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    The holes in the tile (not MDF) are made smaller than the size of the squash ball and not drilled quite all the way through. The ball then just sits into the hole with aprox 2/3 of the ball exposed, you can push the ball into the hole ,this will grip it while you position the platform. The platform can not be moved about as if it were on wheels so you need to get it as near as to where you want it and then gently tweak it. Attached is a simple diagram, I think?.
     

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  9. oaklandraiders

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    Yo

    I think its a cunning plan to increase B&Q sales !
    I';ve got the Gramma platform which works fairly well, but I'm tempted by this slab idea.

    John
     
  10. PIG JOE

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    No not B&Q! Iv'e got a deal going with the squash balls company.
    They sell sell then in packs of 3! (best price i found was £4.49)
    and of course you need 4 so have to buy 2 packs!!
     
  11. Gary Lightfoot

    Gary Lightfoot
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    Hi PJ,

    Gotcha!

    I was imagining the tile to be thinner, so I couldn't see how the ball wouldn't hit the bottom of the slab. The drawing is perfect, thanks. :)

    I might NMN some MDF on the top and cover the whole thing in carpet to tidy it up - the slabs I have are a little lumpy bumpy on one side, so the extra MDF will help flatten it out and give the spikes something to dig into. When I had the sub on the slab before, it was tricky getting it to be perfectly stable. If I moved it, it took a while to get it stable again. Where'd you get the accoustic tile from? I have some 18mm MDF that might do the trick instead. What do you think?

    I can see a Squash Ball PowerBuy happening sometime soon though... :)

    GAry.
     
  12. Tenex

    Tenex
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    FYI it's not green felt but compressed paper boards - while they do make a difference the difference is not great. Carpet is always going to be a better sound insulator than laminate but if you can't live with carpet then consider a large rug - the large laminate surface will reflect a lot of sound and a rug will break it up somewhat. Similar effect to hanging curtains - carpet and curtains - not popular products any more ;) maybe next decade ...

    I've always wondered if it would be worthwhile laying laminate over existing carpet ...

    But truly the only way to eliminate sound/noise transmission is as someone above pointed out: mass.
     
  13. nicd14

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  14. Tenex

    Tenex
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    I can understand that but laying over existing floorboards produces more bounce than you'd expect. If the carpet & underlay were laid on a solid (concrete) floor I'd still give it a go.
     
  15. stevefish69

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    On my KEf 2010 i use a slab of Marble which has 3 Mitchell's tenderfeet spikes underneath which couple the marble to the floorboards. I did try Squash balls 1st but found the 2nd option better. I also have a 25Kg weight which lives on top to hold the whole lot down.

    Never had a complaint from the neighbours since doing this, and have noticed that the Partition walls don't vibrate quite as much
     

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  16. PIG JOE

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    Hi Gary sorry for the late reply, not sure about MDF, my theory is that the tile absorbs unwanted tones, would the MDF be to dense? By the way i called it an acustic tile but i think it's just a good old suspended ceiling tile that i aquired from work!
    Interesting to read 'stevefish69' comments, you see my theory, and it is only that, is the sub on it's spikes sits on the slab, concrete or marble, you have now created a false floor and the sub should operate as the manufacturer intented. Now you need to isolate the sub and platform from the real floor, my thinking is that the tile, squash balls and air gap does just this. Surley if you put the slab on spikes and then onto the floor some of the boom and rumble is transfered back into it? Also what's the idea behind the big weight on top of the sub??
     
  17. Gary Lightfoot

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    Hi PJ,

    Thanks for the tile info.

    I also have the same thoughts about isolation and would have thought the squash balls would be more effective than the spikes to isolate the subs vibrations form the floor.

    I think spikes are designed so that the sub becomes coupled to the floor and so only the speaker cone moves, converting more movement into sound rather than losing some by the box moving the opposite way to the speaker. The extra weight helps to do that. I think it also helps to tighten the sound as there is less box movement to 'muddy' the bass.

    That's how I believe it to work, but Steve seems to have results that prove the opposite, so I wonder if there is a link to a scientifc explanation of what's really happening?

    Gary.
     
  18. mattym

    mattym
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    the energy needs to be stopped from reaching the floorboards, the smaller the footprint the less energy wil be carried, , a heavy weight on top will stop more vibration going through, i think thats whats happening anyway...my tests on the pads im working on suggest that the smaller the footprint, the less the vibration travels....though i could be completely wrong, im only guessing!
     
  19. Gary Lightfoot

    Gary Lightfoot
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    Hi Matt,

    Sounds reasonable to me. :)

    I'd love to find a definitive explanation though, something like a white paper on the subject.

    Gary
     
  20. mattym

    mattym
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    me too!
     
  21. Gary Lightfoot

    Gary Lightfoot
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    I've googled, and a lot of results suggest that isolation such as foam rubber etc will de-couple the sub from the floor and reduce transmitted vibrations. Nothing was an official clarification though.

    I can see how spikes couple the sub to the floor, and therefore increase the mass of the sub's 'container', but it's still sending the vibrations into the floor. Maybe the extra mass and the weight are ensuring the speaker cone transfers all its energy into sound rather than transmitted vibration. Just a guess though.

    For soundproofing, you need mass and isolation to prevent sub bass travel - a concrete floor (huge mass) that is the foundation for many houses will transfer the sound of a ball being bounced quickly and easily into the adjoining houses. Only cutting the concrete between houses to make a gap (isolatuon) will stop the transfer. I think that's why I'm inclined to go with the theory of rubber as isolation rather than spikes, but some of the practical experiences mentioned here seem to contradict the theory.

    Who else is confused? :)

    Gary.
     
  22. mattym

    mattym
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    im confused, but thats nothing new. I know that we have some of the most dense rubber ive ever seen that we use for a couple of our products, its so heavy its unreal!

    Gary, posted the package today, expect it in 3 -5 days! :D
     
  23. Gary Lightfoot

    Gary Lightfoot
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    Thanks Matt,

    Will let you know when it's arrived.

    Gary.
     
  24. karkus30

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    It makes sense if you think about it from another angle. Remember those experiments you did at school with a weight and a spring, well thats whats going on and your talking about one frequency and one material. Its down to acoustic coupling and damping. Now Im not an expert, but if you think like that you can sort of apply it to the sub. Stick it on wooden floorboards and it transfers the vibration, stick it on a rubber pad and it still transfers at certain frequencies, both through the pad (probably as a thump) and through airbourne vibration. Stick it on a concrete slab on the same floor and stick a heavy weight on top, still transfers, just different frequencies.

    Sub bass is one of the hardest things to damp, it is great at travelling long distances and can breech virtually any material. This is the reasons motor manufactures spend millions on careful design. Ultimately you need heavy dense materials of different masses, seperated by materials that absorb different frequencies.

    To understand how difficult this all is. Imagine matey boy with his Nova, sat at the bottom of your street with his cheap sub booming away..........you can still hear it, doesnt matter if his windows are down or up, the sound still travels. Thats with rubber tyres (sort of like squash balls) connected to a solid high mass surface and a dense block of 10 inches of brick and 50 yards seperating you.

    So, two options are left. One is to stop the sub causing a thump, so that should require a big heavy sub and some way of stopping it sliding around on the floor.............so, use spikes, high mass through small surface area results in a high coefficient of friction, hey presto the sub more or less stays put. You cant eliminate the airbound vibration, so the only thing left is to keep the volume low. Alternatively you can coat your whole room in an inch thick sponge rubber and dangle the sun from a high tensile cable anchored to an isolating platform.
     
  25. eviljohn2

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    :eek: :eek: :laugh:
    It would have to be a very high tensile cable to hold the sun up! ;)

    Otherwise a very sensible and helpful post. We do essentially need to divide the "noise" into 2 categories - airborne and structure borne. We can't do a lot about the airborne as that's precisely the effect we're trying to achieve (an airtight room would be ideal but don't listen too loud with too big a sub or you'll burst your eardrums!) but by isolating the subwoofer cabinet from the floor (and subsequently any other solid matter in the room) we can help quite a lot. This is where things like Gramma platforms or home-made isolation slabs come in as discussed in this thread. The next point that's well made is with regard to resonance if we shake something at it's resonant frequency it is going to bounce all over the place no matter what we do so the only thing to do there is glue the objects down. And then fill the walls with as much and vibration absorbing material as possible.

    Nothing new in the post I'm afraid but it often helps to hear things in a different way. :)
     
  26. Gary Lightfoot

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    Isolation can help stop the soundwaves travelin through walls - if you build a new wall away from the existing wall (4x2s, 2 layers of plasterboard with insulation in between for example), the air gap helps reduce the transfer through it - the bigger the gap the better. The mass of the plasterboard helps slow down and dissipate the sound, and the insulation helps with any in-wall resonance and some higher frequencies IIRC.

    Flanking transmission is the next problem and that can be reduced with isolation too - you build a room within a room starting with the floor. Using specific materials such as rubber mounting blocks, you can build the new floor on those (make sure it doesn't touch the surrounding structure) and then build the new walls on the new floor. Do the same with the ceiling onto the new walls. With nothing physically touching the outer walls or ceiling, and the floor isolated to a great degree via the blocks, you've kept most of the noise within the room.

    That's the principle of a 'room within a room' as I understand it anyway.

    The case with the car and it's boom box is the same as the bouncing ball on concrete - the concrete takes the sound with it, but you need to cut the concrete to stop it traveling. Do the same with the road and you won't hear the cars bass boom. Easier said than done I know. :)

    Gary.
     
  27. karkus30

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  28. Killahertz

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    I don't believe there is any one unifying isolation theory, rooms are just to different for one 'system' to work in all scenarios. The nearest we come is to seperate the requirements of a solid floor versus a floating floor.

    The primary goal should be one of stability. In order to attain maximal quality of function the drive unit needs to operate from an unchanging point in space. As a dynamic motion, however, this isn't necessarily simple - each action having an equal but opposite reaction, etc, etc. If we have a hard surface, and use a compliant footing then it is inevitable that the enclosure will move in response to it's driver's motion. Perhaps not by much, especially if the enclosure is very heavy, but move never-the-less. With a rigid floor, then, spikes are best for stability. In spiking the enclosure to the floor we couple vibrational energy to floor, which being solid heavy mass acts as a sink (a very low resonant frequency mass drawing energy which in trying to create motional vibration is dissipated as heat). This serves to aid the rigidity of the cabinet by reducing spurious vibrational motion, which will contain harmonic resonances that may very well be audible (and because of the (higher) harmonic frequency content, increasing localisable).

    A floating floor will readily accept, and release, vibrational energy. If we couple an enclosure direct to a floating floor then not only will the enclosure move (and hence destroy the primary goal of stability), but it will set the floor in motion - each perpetuating the other. A floating floor is unlikely to have a single resonant frequency, it is likely to have it's own sonic signature. This, however, may pale into (sonic) insignificance as the motion of the floor will generate mechanical vibration derived interference in itself, as well as structures that it connects to. Thus, if we use a decoupling (compliant) coupling, we cure the problem, don't we?. Well, if the decoupler is compliant, and truly effective (perhaps having viscoelastic properties), then we should at least limit the vibrational energy reaching the floor. This alone may be effective (it depends on the floor and other factors), as the primary source of colouration may be from vibration derived interference. On the other hand it may not be effective (especially if the decoupler isn't), and a compliant footed enclosure will still move, limiting the effectiveness of stability control. What is often necessary is a combination, a 'system' of coupling, decoupling, and mass. The aim being to simulate the sinking of a low resonant frequency heavy mass solid floor, yet retain the benefit of coupling to that mass. Numerous 'systems' and preferences exist, of which the simple sandbox is my personal recommendation.

    As it is I have a solid concrete floor, so don't need to consider such methods. As it is, however, my (MS309) subwoofer does sit on a concrete slab, but not for solidity or stbility. There are numberous wires and cables in the area, and the slab alleviates the inevitable issue with spikes going through carpet, and potentially through hidden cables. Plus, being a dow-firing design, I prefer the ports to be able to 'breathe' rather than disappearing into the carpet's pile. Oh, and just to reinforce my favouring the use of weight on top of the subwoofer enclosure, I use about 1CWT of solid green granite :eek:

    [​IMG]
     
  29. Gary Lightfoot

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    Nice rock. :)

    Good write-up too.

    Gary.
     
  30. PIG JOE

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    Cor blimey Killahertz !
     

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