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Stopping floor vibration


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My listening room has 19mm thick tongue and grove hardwood floor on timber Joists. I believe the floor likes to sing along with the music. 

Im using Martin Logan Ethos Speakers that have powered bass and a downward facing Passive radiator.

i placed the speakers on 450x450 pavers resting on 10mm thick closed foam and it changed the sound a lot. 

To re sort the sound, ( yes there are those that think Panel treble/ midrange won’t match cone bass, however, this to me suggests that it is not as simple as that) I moved the speakers further from the wall and adjusted the powered bass. ( my vague memory says I increased it). 

So I believe there is still more to be gained by isolating the floor. Maybe bigger pavers( to spread the load), thicker foam, or maybe springs under the speakers?

Any ideas?  Thanks John D

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If you could position the speakers on top of the joists you would minimise the sympathetic resonance. Or have the “platform” you sit the speaker on straddle a joist or two then use layered damping to isolate the speaker and top layer of platform as much as possible from the floorboards. 

 

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This is one concept of vibrations which may affect your gear which not everyone will agree with:

 

http://www.barrydiamentaudio.com/vibration.htm

 

Basically your floorboards are putting vibrations into your speakers (and gear) so affecting sound. These vibrations come up via the soil, building foundations, walls, joists, floorboards then your gear. An extreme example of this to give you a feel of the idea would be someone drilling the road immediately outside your property.

 

Isolation will therefore help prevent these vibrations entering the gear. Some will understandably debate whether these vibrations can really affect the sound. All I can say is that I have used the ball bearing devices mentioned, and the inner tube idea, and they both improve the sound, but in quite subtle ways, certainly not 'night & day'. I now use expensive Symposium products, probably not worth the cost, but the improvements aren't easily obtainable elsewhere. Other products, like those of Townshend and Finite Elemente work the same in my limited experience.

 

The improvements are 'less smeared transients', meaning crisper percussion, piano and plucked guitar for example.

 

To continue your experiments, why not just use the foam and remove the pavers? You could of course also ask Martin Logan if they have any views on this.

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I had a floor similar to yours @Sparkle, but I had the advantage of renovating the room.  I pulled up the old carpet and put another 1000 or so flooring screws into my 19mm floor panels.  Then I laid another 22mm layer on top of the existing and in between I used Green Glue.  I also went nuts with the screws making sure I went all the way through both layers of chipboard and into the joists.  Part of my goal was to minimise the sound transmission down to the rooms below, hence the Green Glue and extra mass of flooring.  Just walking around the room the difference is profound.

 

But low frequencies are difficult or impossible to stop from going through walls and floors in a domestic environment (you can't make them heavy enough to stop 20-40Hz) so the next step was to stop the speakers from directly "activating" the floor.  Speaker vibrations directly coupling to the floor is the most efficient mechanism of this happening, and all speakers vibrate so I have physically decoupled the channels from 500Hz down from the floor.  For the subs I have used pneumatic isolators which are expensive but they really do work wonders for the low frequency stuff (my subs weight 400kg each).  100Hz - 600Hz I used some less expensive industrial machine mounts that do a good job from about 30Hz.  Hope this helps.  I can give more information if you are interested. 

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10 hours ago, Black Orange said:

Have a look at Auralex SubDude. They are designed to isolate subs and should work well in your situation. I have not used them myself but always read favourable reports. 

 

https://www.storedj.com.au/auralex-subdude-ii-sub-isolation-platform

@Mike13 uses them. I use these:

https://www.svsound.com/products/soundpath-subwoofer-isolation-system

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Guest Peter the Greek

@acg provides good advice in my experience.

 

This is a structural problem, the house reacts to certain frequencies. Putting the speakers on something etc is a complete waste of time.

 

Is the T&G directly attached to joists or is there a layer of chip board?

 

The best approach is more nails/screws. But that means you need to have the floor refinished.

 

How old is the flood?

 

If there is no chip board, you could glue and screw chip board between the joists to add strength. A difficult process and may not yield great results. You'd use a structural adhesive, not GG, chip board provides decent damping (sort of) - the aim here is not soundproofing,, rather stopping vibration noise

 

 

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Sadly when I built the house I wasn’t thinking of Hifi,.  If I did I would have definitely put 19 mm yellow tongue particle board on the joists first, then overlaid it with the tongue and grove polished hardwood floor. Had I done that, I probably would have cheated and used 12mm overlay instead of 19mm, probably not making things much better. 

Pit crossed my mind gluing particle board between the joists, but the 90mm timber boards need to grow and shrink with humidity, so I’m not game to possibly ruin the polished floor, which is in very good condition despite being 16 years old.. 

i noticed at the recent Lenehan Gtg he was using springs under his speakers.

His springs wouldn’t work for me as his speakers weigh 70kg and mine are around 20kg from memory.

i was thinking I could get lighter weight springs and mess about a bit?

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Springs are like the pneumatic isolators I mentioned but have no damping.  I would personally try these:

 

https://www.novibes.com/Compression_Mounts/Standard_Compression

 

You need to load them up near their maximum load, so 4 of the 45lb ones (52502 model) under each 70kg speaker should start to isolate from about 10-15Hz

I have them under the power supplies for my valve amps...they are an excellent product.  Once you buy eight and ship them to Aus and pay some GST they should set you back about $150 total. 

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Thanks gents. Agc , $150 is reasonably priced, tho a little hassle. 

Aperalim, the Townshend look neat, but starting at £1400 is a deal breaker.

i got an idea from looking at the Townshend ones.  

 

What a about a tick flat plate with big holes drilled in the corners slightly smaller than Tennis balls or similar?  The balls would insulate vibrations between the floor and the plate which the speakers are sitting on.

There are many types of balls to experiment with. Maybe Squash balls would absorb shock better?

rubber and air can make good suspension. 

Anyone tried something like this?

 

I just had at the Auralex Subdude. Cheap enough at $89 ( each I’m guessing)

its just a piece of 18mm mdf with a piece of 25mm absorbant foam underneath. 

I have something like this already. A piece of 40mm thick Concrete paver with a piece of 12 mm absorbant foam underneath. Cost about $5 each. 

Maybe I just need to double up the foam?

Still thinking.  

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On 08/08/2018 at 9:21 PM, Black Orange said:

Have a look at Auralex SubDude. They are designed to isolate subs and should work well in your situation. I have not used them myself but always read favourable reports. 

Hello Mr Sparkle, IMHO this is the best advice for your situation.

1 hour ago, Sparkle said:

I just had (a look) at the Auralex Subdude. Cheap enough at $89 ( each I’m guessing)

its just a piece of 18mm mdf with a piece of 25mm absorbant foam underneath. 

I have something like this already. A piece of 40mm thick Concrete paver with a piece of 12 mm absorbant foam underneath. Cost about $5 each. 

Maybe I just need to double up the foam?

Still thinking.  

It appears, above, that you are willing to try a DIY solution. Let us assume that the Auralex product is properly engineered for its duty, and not be cynical and say it is just any piece of wood over any piece of foam. I would therefore suggest that 'undesigned' DIY alternatives need to be relatively thicker and over-the top, using a hit-and-miss, belt-and-braces, try-and-try-again philosophy. This is unlikely to save any money, but I will testify that it can potentially be more rewarding. 

 

There has been some advice in this thread that you need to deal with airborne vibrations, assuming they are a major contributor to degraded sound quality. IMHO it is structure-born vibrations that are the real issue. Your speakers are the vibrating structure, so the best thing to do is to isolate them from other structures. Once this is done, airborne vibrations are so much less energetic that only large, lightly-supported surfaces are affected, such as window panes.

 

IMHO, and this is just my humble opinion, suggestions to reconstruct your floor are not warranted, as long as you have isolated your speakers physically. Hardwood floors are designed to carry heavy loads over small areas, so they are one of the stiffest large surfaces in your room, second only to brick walls or concrete basements, so, if you want to reduce large vibrating surfaces, start with windows, then ceiling, then progress to gyprock walls. Although, bear in mind, Floyd Toole has written that rock-solid boundaries in one's listening room are a dire idea. So, I have very mixed feelings about some of the advice, other than to isolate the speakers from the floor, and fix any obvious rattling that would be detectable by ear with a sine wave sweep signal. 

 

Regards

Grant

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Thanks Grant, for the time and energy you put into replying. 

Just to clarify my previous statement about Auralex Subdude11.  In their Specifications section Auralex says about their base materials “ .... features a functionally inert 3/4 “ velour covered mdf”...

3/4”=18mm. Over the last 20+ years I have sold $$$$$ of 18mm mdf, ( which stands for Medium Density Fibre board).  This is “ Just any piece of wood”. Probably what your speakers are made of, unless you can afford Aluminium or Carbon Fibre. 

 

On the other hand the foam part is much cleverer, and I would Never suggest that it was “Just any piece of foam”. I’m sure Auralex has put a significant amount of R and D into finding an Affordable yet Effective piece of foam.

 

The foam I’m using cost 100 yen per side in Daiso in Japan! Obviously not the best, but made quite a difference in “ cleaning up the bass”. 

If one Googles “Vibration absorbant foam”, there are some speciality foams which are quite expensive. Unsurprisingly, perhaps, used as insoles for shoes.  

Now, it’s my guess that these companies Really have an R +D budget to get to the bottom of unwanted vibration.  

 

I do do agree that DIY can end up a waste of money. It can also save money if it proves that the Concept doesn’t work, or better still that it does work and that the best Solution is a Commercially available one.  

 

Thanks for for your time Grant and I will continue my Investigation!!

 

 

 

 

 

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1 hour ago, Sparkle said:

Thanks Grant, for the time and energy you put into replying. 

Just to clarify my previous statement about Auralex Subdude11.  In their Specifications section Auralex says about their base materials “ .... features a functionally inert 3/4 “ velour covered mdf”...3/4”=18mm. Over the last 20+ years I have sold $$$$$ of 18mm mdf, ( which stands for Medium Density Fibre board).  This is “ Just any piece of wood”.

Hello, yes, I know what you mean. I think that my main point was about engineering a product vs stacking whatever materials come to hand. For instance, if you happened to be using one MDF grade from those listed on table 1 and table 2 (link), and Auralex carefully chose another, the acoustical result would be quite different.

 

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Probably what your speakers are made of, unless you can afford Aluminium or Carbon Fibre. 

My speakers are a Corian-based 3-layer CLD panel, that I designed from first principles. :)  Such are the trials and tribulations of the DIY-er. ;)

 

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On the other hand the foam part is much cleverer, and I would Never suggest that it was “Just any piece of foam”. I’m sure Auralex has put a significant amount of R and D into finding an Affordable yet Effective piece of foam.

Probably, but the real work is in developing the total product, such that the layers, however they behave individually, complement one another together. Which is what I mean about "engineering a product": for example, to design a 500mm platform, Auralex might, might, choose a different grade of MDF or foam than for a 300mm platform. OTOH it is also good engineering to make affordable products work properly ($89...not bad...), so it would not surprise me if they use the same material in many products, including cheap MDF! But, one hopes, they actually "engineered it" as a system. That is the only point I wished to raise, and I have probably raised it once too often now (sorry).

 

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The foam I’m using cost 100 yen per side in Daiso in Japan! Obviously not the best, but made quite a difference in “ cleaning up the bass”. 

If one Googles “Vibration absorbant foam”, there are some speciality foams which are quite expensive. Unsurprisingly, perhaps, used as insoles for shoes.  

Now, it’s my guess that these companies Really have an R +D budget to get to the bottom of unwanted vibration.  

Yes, but specific to the application. "Engineered." ?:sorry:  IMHO knowing that it works for sports shoes gives nothing more than a hint, that it might, or might not, work in a very different application. Even if it was properly designed into that application.

 

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I do agree that DIY can end up a waste of money. It can also save money if it proves that the Concept doesn’t work, or better still that it does work and that the best Solution is a Commercially available one.  

 

Thanks for for your time Grant and I will continue my Investigation!!

My pleasure. And yes, I also agree with your point that Auralex may not be well engineered, may not work well, and testing that assumption is a good thing! A good thing that begins with the purchase of at least one Auralex platform for testing. :)

 

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Hi Grant!  First of all I’m impressed that you made speaker enclosures from Corian .. I used to sell a competitor product and always planned to build DIY speakers from the material.. perhaps wisely in my case I never went through with it!!!

 

when I was younger, I used to get excited by products sold by certain companies. In the case of many of them, I found that when I visited the company, there appeared to be no designated R and D space.. the reality was that the really clever stuff happened in the mind of the Company Boss and/or his Assistant. 

 

Often just defining a simple idea and marketing it... I suspect nothing much has changed in many cases. 

I understand that Auralex has created an affordable product. I would love to borrow a pair and try to discern if their Engineering sounded better than dodgey DIY project based on Similar principles. 

I mean actually hear a noticeable difference, not needing audio microphones and Sophisticated software to tell me that I spent money wisely!!

Any photos of your Speakers?    John D

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Someone has suggested to me to have a look at Les Davis Audio discs.  
Has anyone used these? They are more affordable than other products.. 
 
Save your money - so subtle is any improvement to be hardly perceptible !
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