View Full Version : Loudspeaker isolation
Hi all.
I am sure this sort of thing must have been discussed before, but after a few fruitless searches I thought I would post a topic and see what happens. (Please direct me to a suitable thread if one already exists somewhere.)
It's the age old question of using floor standing speakers in apartments, and the need or desire to isolate the speaker from the floor to some degree to try and limit structure-borne vibration. Many years ago, when my dad first moved in to the apartment I now own, we were having a bit of a musical evening when a pal (user talisman2 - Alf) put on the Enigma CD he had brought. The Castle Chesters my dad had at the time sprung to life, as you might expect. As did Betty the neighbour downstairs who was leaning on the doorbell. An experimental solution of a marble slab under each speaker was deployed with success. Betty never complained again.
Last year, however I did have a complaint from the current neighbour downstairs. I was being cast as some kind of noise nuisance, which led to meetings with and visits from the noise abatement officer at the local council. I had switched to some cast cement plinths, and I have now switched back to the original marble (with my current CDM9NTs that I have had for 15 years). All has been quiet since, but I occasionally get paranoid and end up with a nervous hand on the remote control.
My thoughts have been turning to a perhaps more substantial platform - nothing too tall (I hate adding too much height) so I have been looking at a number of solutions:
1) Sandwiching sorbothane between two solid sheets (perhaps the marble I already have) - I have been looking at sheets of sorbothane or perhaps the flat discs (but not hemispeheres) on Amazon and this looks like a not-too-costly proposition.
2) Something like the Auralex monitor pads - would they do the same job for floorstanders as they do for studio monitors - preventing (or minimising) vibration from the cabinets into the surrounding structure.
3) I also saw some granite plinths made to order online - would granite do anything different/better than marble?
I have seen the Townshend speaker bars on the web, which look like a brilliant solution (virtually suspending the speakers n the room) but at £1000 for four seems a bit drastic.
Be glad to hear anyone's experiences / thoughts / ideas on the topic...
Thanks all. :)
It's a tricky one this to get right as there's two main considerations: Coupling of various frequencies with structural elements causing resonance and noise transmission, and isolation of the noise levels themselves.
It's often an issue where isolation and coupling are conflated to mean the same thing, when they're really two different things entirely.
If you start by coupling your speakers to the floor effectively, then you equally effectively couple noise transmission, especially in the range of fundamental frequencies (harmonic resonance) of the flooring itself, and thus transmit to the walls too. Unless this is dampened in some way, that is transmitted as noise and usually the frequencies are the lower ones which are not absorbed and converted to heat energy unless heavily damped at those frequencies.
If you seek to effectively isolate the speakers, then two things matter. Firstly the method chosen (materials) and secondly the speaker positioning. If the speakers are positioned on a room mode which creates standing waves boosting those frequencies, and they coincide with the problematical ones for transmission to the apartment below, then the isolation will be far less effective as the speakers are essentially increasing room borne vibrations at that frequency point. Generally speaking, keeping speakers clear of corners and siting in 2 or 3 pi space usually results in a less problematical set up but it also depends on the structural nodes of the supporting floor and walls. Its not possible to accurately assess where a node (a point of minimum or zero amplitude with frequency) exists without some fairly advanced structural engineering assessment! (finite element analysis is usually employed) and as we're talking hifi and domestic rooms, that level of assessment is not going to happen.
One practical way, with the help of your neighbour is to try several speaker locations, and play some music which has plenty of bass throughout the lower frequencies at the same level (do not alter this). You'll find a location for the speakers which minimises the transmission of noise. It is important to couple the speakers at this point using spikes...do not isolate them. When the location of minimal noise intrusion is found, you have found a point close to a structural node, so whilst you minimise structural resonance issues you still need to work on absorption of the problematical frequencies which is often not possible for the lowest frequencies without some considerable structural alterations!
At that point, remove the spikes and isolate the speakers by using something like sorbothane underneath onto marble plinths or chopping boards, and sit those in turn on some polystyrene or Aurilax with a different (perhaps ply or MDF) board, carpet lined, underneath so that you create a sandwich, and simply sit this on four rubber feet onto the floor. Adopting a laminate solution is important to filter out as many frequencies as possible. You wont ever filter the very lowest frequencies as the wavelengths are too long in the lower bass registers and will simply travel through, but you will get some form of attenuation.
Then re-play the music at the same level and ask your neighbour if that is acceptable, and tweak the volume until they are happy. You should find a happy compromise hopefully if you adopt this method, but it will always be a compromise in an apartment unless the floors are made with noise isolation and vibration isolation in mind.
Ive got thick old concrete floors covered in thick rubberish underlay and thick dense carpet. I cant cause vibration from jumping in front of tt with a vibration tester on top, so am presuming it doesnt transmit much. Dunno though in techy terms
My understanding is that you can make as much noise as you want between 0900 and 2300 hrs and they can't legally touch you. Is this not correct?
Otherwise how does it work if the house next to you is being renovated and there is banging and hammering all day long?
Anyone who lives anywhere other than a detached house needs to accept that they are going to hear all sorts of noise from their neighbours, of which music is just one. If they really can't cope with it then the problem is theirs and they need to look at moving somewhere more suitable for them.
Granted we have probabaly all experienced at some point a neighbour taking the piss, but in most cases (like this one I suspect) it is just a music enthusiast listening at a reasonable volume at a reasonable hour. Some folk seem to think they have a divine right to peace and quiet, they need to accept that is not the case.
Ive got thick old concrete floors covered in thick rubberish underlay and thick dense carpet. I cant cause vibration from jumping in front of tt with a vibration tester on top, so am presuming it doesn't transmit much. Dunno though in techy terms
That's true Grant but transmission of bass frequencies is something else. They can pass through concrete floors without imparting any resonance vibration in the floor itself, so whilst your speakers may not impart any floor borne vibration to the rest of your kit at those frequencies, they might still be heard next door/underneath/above you.
Sure Paul... Itll go through walls easily as they aint thick, before the floor causes any trouble alas. Ive only one neighbour and i try to only use stereo whe he is out.
My understanding is that you can make as much noise as you want between 0900 and 2300 hrs and they can't legally touch you. Is this not correct?
Otherwise how does it work if the house next to you is being renovated and there is banging and hammering all day long?
Anyone who lives anywhere other than a detached house needs to accept that they are going to hear all sorts of noise from their neighbours, of which music is just one. If they really can't cope with it then the problem is theirs and they need to look at moving somewhere more suitable for them.
Granted we have probabaly all experienced at some point a neighbour taking the piss, but in most cases (like this one I suspect) it is just a music enthusiast listening at a reasonable volume at a reasonable hour. Some folk seem to think they have a divine right to peace and quiet, they need to accept that is not the case.
Not really.. Unreasonable noise for extended periods is not on and can be dealt with. Obviously renovation work is allowed etc but thats classed as a nes noise. Playing a stereo full blast all day and evening etc isnt
My understanding is that you can make as much noise as you want between 0900 and 2300 hrs and they can't legally touch you. Is this not correct?
Otherwise how does it work if the house next to you is being renovated and there is banging and hammering all day long?
Anyone who lives anywhere other than a detached house needs to accept that they are going to hear all sorts of noise from their neighbours, of which music is just one. If they really can't cope with it then the problem is theirs and they need to look at moving somewhere more suitable for them.
Granted we have probabaly all experienced at some point a neighbour taking the piss, but in most cases (like this one I suspect) it is just a music enthusiast listening at a reasonable volume at a reasonable hour. Some folk seem to think they have a divine right to peace and quiet, they need to accept that is not the case.
Not exactly.
Noise, in this context, is defined as any unwanted sound, and whether it constitutes a nuisance or not can be quite subjective, so there are guidelines in place as to those limits. Statute determines injurious noise as that which is detrimental to a person's welfare or health under the Environmental Protection Act, specifically 79(1)(g) and (ga) of the 1990 Act.
Additionally, "Noise Nuisance" is defined as "an unlawful interference with a person's use or enjoyment of land or of some right over, or in connection, with it".
As you can see, the determination is not a one size fits all but would depend on the circumstances of the person affected as much as anything. It is for the Local Authority to take into account individual circumstances when assessing whether the degree of nuisance is interfering with someone's use or enjoyment, or is deemed injurious to health or welfare. In such circumstances, they may serve a noise abatement order, and court enforcement would follow, presumably with a police presence if that order was deemed to be broken.
At the end of the day, it boils down to reasonable behaviour on both sides. If you play loud music all afternoon for example, but it might be a one-off, then that is unlikely to be considered as unreasonable. If you regularly party late into the wee hours and in doing so keep your neighbours from sleeping, you're likely to be slapped with a noise abatement order. Similarly, if they can't hear their TV in the evenings as your music is so loud, you might be paid a visit and asked to turn it down to reasonable levels as a first step. Its just common courtesy to behave reasonably. When looking at moving into a flat, it's always worth checking first how your enjoyment of loud music might affect others.
Noise from say construction sites is regulated more tightly where time limits may be imposed on works as well as dBA levels measured at the site boundary (usually 65dBA for most silenced kit in residential areas but this will rise for things like mini-piling and angle grinding etc).
Having said all of that, if someone bangs on your door and says that just because they can hear your music you should turn it down, as long as the music isn't being played at unreasonably loud levels, or interfering with their enjoyment or welfare, they can politely be told to "jog-on". It's a fact of life that if living in apartments, you're unlikely to be cocooned from noise unless your apartment is designed with that in mind.
Thanks for the interesting and thought provoking posts. When the 'dispute' happened (I was aghast as the last thing I want to be is a nuisance neighbour) I tried to press the officer from the council as to what was deemed acceptable and she wouldn't be drawn - citing instead this idea that it is 'ruining the enjoyment' of the property. I was shocked at this as, to me, this is licence for the skilled and devious to turn on the waterworks and make life very difficult for someone just trying to live their life. This all happened some time ago, though, so I'm pretty sure everything's ok - and I'd rather let sleeping dogs lie than go in and do dance music tests.
I have some thinking to do about mounting speakers - they've always been spiked on to the marble plinths so I think the change to rubberised style feet is one easy thing to try (and makes sense as you're effectively on a hard surface and not trying to pierce the carpet).
Thanks again - good food for thought. :-)
hifinutt
13-07-2016, 21:41
the Townshend stands are excellent
sometimes they come up s/h and they often have 20% off at the shows like whittlebury
the Townshend stands are excellent
sometimes they come up s/h and they often have 20% off at the shows like whittlebury
They do look rather interesting but the cost, even discounted, is prohibitive.
http://www.townshendaudio.com/wp-content/uploads/2013/10/Townshend-Seismic-Isolation-Bars-for-speakers-and-sub-woofers-980x650-1-980x650.jpg
Ammonite Audio
14-07-2016, 06:30
They do look rather interesting but the cost, even discounted, is prohibitive.
But if you do really need to isolate the speakers from the floor structure, there's really nothing to touch the Townshend products. They do isolate fully, unlike rubber sheet, sorbothane balls/pads etc.
Code Acoustics
16-07-2016, 11:39
Hi Malcolm,
Really interesting topic! We've been playing with this a lot recently.
Townend do a really good video on speaker isolation:
https://www.youtube.com/watch?v=dW9-r83IvhI
We love what they had done with their isolation, but it's an expensive solution. We tried to come up with something say 2/3's as good for a 1/3 or the price. This is our first go:
http://hifipig.com/wp-content/uploads/2016/07/code_nwas_2016_1s.jpg
One thing that's crucial is the load needs to be correct for the Sorbothane. Too much load and the Sorbothane amplifies (!) the vibrations. Too little load and it doesn't do a great deal.
The hemispheres were not great (if you put them under the speaker). Unless your speaker is perfectly balanced, which most aren't, they'll tilt.
But personal opinion is it's well worth the effort, particularly isolating bass vibration from the floor. It doesn't completely decouple the speakers from the floor, but perhaps a 60% decoupling. The bass becomes dryer and more defined. Far less boomy. But crucially, you'll annoy your neighbours far less!
I've bought some Sorbothane discs - eight of them - 2.25" diameter and 0.25" thick. They just arrived today and I haven't installed them yet. Speakers are B&W 804S.
The plan is to place the discs between two sheets of marble. In my mind (probably wrong or at least over-simplifying) the upper layer of marble would help to spread the speaker's load a little. If it's a disaster I've only wasted £32. :-/. I can't make up my mind on using four or five discs per speaker at the moment.
The professionally designed solutions like yours or Townshend's are interesting - and if it means playing music/movies or not (or not moving house) then a more significant investment may be worth it in the longer term.
(EDIT: Thanks for the replies, by the way...)
Let us know how you get on.
Code Acoustics
17-07-2016, 20:36
Hi Malcolm,
The key is to make sure the load is in the operating window of the Sorbothane you've specified. If not, just add / remove pads until you're in the window. In the technical guidelines Sorbotha say it's the amount of 'bulge' you have that's important. i.e. best to have 10 discs of lower load rating, than say 3 discs of higher load rating.
Luckily, the clever chaps at Sorbothane have already worked this out! I couldn't find the info for the discs, but it must be out there. I've included data on the other types of Sorbothane:
http://www.vibrationmounts.com/RFQ/VM01032.htm
http://www.vibrationmounts.com/rfq/VM110804.htm
You'll see on the RHS column, there is a specified load window for each mount.
Between two slabs of marble sounds really good. As long as you're in the load window, I'm sure you'll notice a significant improvement.
P.S. our solution is not in the same league as Townsend. They actually use a spring, that's surrounded with a Sorbothane type material. We'll hopefully pursue this when we have a bit more time and money.
Hope this helps, best of luck!
https://www.amazon.co.uk/gp/product/B0042U8P9C/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
Hmm - I wonder if I need to do some more research and return these discs - the spec says each disc supports between 240 and 480lb - each 804 weighs 62lb according to B&W's spec sheet... I was originally looking at a sheet of sorbothane cut to size, but read that several smaller discs would work better for the bulge factor, but I fear I may be underlie ding these. :-/
Simon_LDT
18-07-2016, 08:18
Damn, those flat discs take a lot of weight, that's a minimum 109kg per pad!
I actually use those myself under my speakers (between speaker and stand), had them for years. I don't like the idea or using blu-tak or attaching spikes or anything to the underside of my speakers hence why I got those. I'm basically using 3 pads which should be holding a minimum of 327kg with just 10kg!!
Anyhow, I do have the stands then spiked onto 2 granite blocks (which have blu-tak between those) and I don't seem to get any boomy bass or any bass issues with transferring to the floor. I don't know if this means anything at all really but I have tested by putting a glass of water on the bottom on the stand and playing the speakers loud and the water does not move at all, nada. Not very scientific I know.
I think I have found the correct sorbothane pads for my application, and they're actually 2" hemispheres which are quoted as 17-24lb loading per pad, which with four under each speaker puts me in the right range for my 804s.
https://www.amazon.co.uk/gp/product/B003IMODW8/ref=s9_acsd_hps_bw_c_x_8
They are hemispheres, which I was shying away from but I figure with the compression/squishing they'll be pretty steady.
Well, my sorbothane hemispheres have arrived - but I'll need a cooler evening and perhaps a second pair of hands before I'll want to heave the speakers about. One thing is for sure is that I'm entranced with these 804s.
Damn, those flat discs take a lot of weight, that's a minimum 109kg per pad!
I actually use those myself under my speakers (between speaker and stand), had them for years. I don't like the idea or using blu-tak or attaching spikes or anything to the underside of my speakers hence why I got those. I'm basically using 3 pads which should be holding a minimum of 327kg with just 10kg!!
Anyhow, I do have the stands then spiked onto 2 granite blocks (which have blu-tak between those) and I don't seem to get any boomy bass or any bass issues with transferring to the floor. I don't know if this means anything at all really but I have tested by putting a glass of water on the bottom on the stand and playing the speakers loud and the water does not move at all, nada. Not very scientific I know.
I'm not convinced by those quoted figures, which seem staggering. They could be used for isolating 801s perhaps? -- but I'm more than happy to have the hemispheres as a replacement. There was an interesting review on Amazon from someone who had put the discs under the legs of their bed, and they could no longer feel the trains passing by their house.
Ive a really big set of pads I got from Nigel that I guess could hande a car on them lol. not 100% sure they are sorbothane, but they would be great for big speakers. Ive got them under my moth cleaner, and it made a big difference to the vibration.
I think this is all rather promising - and will be good for my peace of mind that I've done as much as I can (short of £1k on the Townshend bars) to minimise transmission downstairs.
I must admit that although I've done a lot of experimenting in the last 30 years I've never really investigated the proper decoupling of speakers. However, I have had repeatably good results from the direct coupling of speakers so I am biased in that direction. I will give this idea more thought and apply fair investigation, but (like the majority of current speaker manufacturers) I tend toward the direct coupling of speaker vibrations to the floor.
100% Analogue
What category do mana platforms fall into ?
I must admit that although I've done a lot of experimenting in the last 30 years I've never really investigated the proper decoupling of speakers. However, I have had repeatably good results from the direct coupling of speakers so I am biased in that direction. I will give this idea more thought and apply fair investigation, but (like the majority of current speaker manufacturers) I tend toward the direct coupling of speaker vibrations to the floor.
100% Analogue
Do you mean good results from an SQ point of view or preventing/minimising vibrations outside of the listening room?
From a sound quality point of view.
-----
With Mana it depends what number of layers you use. If it is just a single base then it's mostly coupling the speaker to the floor. As the number of layers are increased a torsional element becomes introduced. However, altering the relative height of the bass driver to the floor will also have a strong sonic impact as will altering the listening axis of the tweeter.
100% Analogue
cheers,i made 2 platforms under each speaker,i may give just 1 a go and see if there's any difference.
In general, I'm not really a fan of the use of platforms under speakers (wood, concrete or granite for example) and would prefer the speaker just to be firmly spiked directly to the floor. However, many speaker spikes are a bit puny compared to thick carpet and underlay and aren't particularly well anchored to the cabinet. There also seems to be a bit of a fashion with some manufactures to provide spikes that are more like cones - fine if you have hard floors but useless if you have carpet.
There are two issues being discussed in this thread but under one banner. In my experience the bass is tighter, a bit dryer and easier to pitch if the speaker is closely coupled to the floor by spikes. However, this does cause a significant amount of energy to pass into the floor and it will transmit through the building. If you live in a flat, for example, this is likely to be a significant issue. In such a case soft mounting of the speaker will reduce the transmission of vibration (four valve springs with a concrete slab on top for example).
100% Analogue
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