Granite slabs under yer speakers...

[synsei]

Not a new tip granted, I'm sure there are many members who use these under their speakers or speaker stands, the thing is they tend to be rather expensive items if bought through the usual channels. Being the miser that I am, I sat down to ponder whilst listening to some music. Then it struck me, I have a bloody great slab of granite sat here doing absolutely nothing, measuring 450mm x 300mm x 65mm. With that I fired up t'internet and began looking for stonemasons in my vicinity who could trim it into two 300mm x 300mm x 30mm slabs. This turned out to be harder than I thought. Of the three close by, two didn't have saws rated to cut granite and t'other didn't have a big enough workbench (?). So I looked further afield and stumbled upon a monumental stonemason in Rothwell, Northants called A.J Mills, so I got straight onto the blower and explained what I needed done to the proprietor, Alan Mills.

A pleasant chap is Allen and he listened patiently while I explained what I needed him to do and what the two smaller slabs would be used for. Once I had finished he said he would be able to both cut the slab to size and polish the resulting two smaller slabs,

"...but, why bother?", he remarked. "I make gravestones for a living and there are always offcuts knocking about the workshop.", "Why bother cutting up a perfectly good slab of granite when I'm sure I could find you a couple of offcuts that would be suitable for the job?"

At this point I started to worry that this project was going to turn out to be too expensive, after all I had some granite already and the whole point of the exercise was to save some dosh. Tentatively I asked Allen how much he would charge for two, polished, 300x300x30mm slabs. I was totally astounded when he fired back that they would be 20 quid apiece.

So, the moral of this story is this: If you are looking for granite slabs to sit under your equipment, contact your local monumental stonemason coz ya never know, he just might want to make something for the living for a change... :)

p.s. Picking them up on Friday... :cool:

[realysm42]

If I remember how you've described your listening room/conditions to me, I think these could provide a substanital improvement over just stands, I was happy with what slabs of those exact measurements did for me!

Tighter bass and more expressive treble were the main effects. Less energy going into the floor means more being directed at the listened :)

[synsei]

Pop over to my Gallery thread Martin. I couldn't find your thread about speaker ballast so I posted up my findings in my own thread dude ;)

[The Grand Wazoo]

Granite never worked under speakers for me. But under TT's, amps, CD players, phono stages...... yes.

[realysm42]

Since getting my Franc platforms, the granite is mine is now under my sub, dac and psu for the dac, I like not having to sell/remove items :)

[synsei]

My listening room has a suspended floor Chris so it's kinda necessary to cut down on floor born vibrations ;)

[The Grand Wazoo]

OK, I understand.
However, when I tried this for myself for the first time (back in about 2002/3), it was in a room with a floating hardwood floor lying on a suspended softwood one. The speakers (floorstanders) sounded better than anything else I tried when they had 2 sheets of 8mm steel plate bolted to their bases & sitting on domed studs rather like the heads of mirror screws.

Just my experience.

[synsei]

That's interesting Chris. I'll see how I get on with granite for the moment (after all I have ordered them now) and if the slabs don't cut it then I'll look into the steel option. Presumably I'd need to bolt the steel to the bottom of the Atacama stands if I go down that route.

[hifi_dave]

IMO, the granite/marble slabs have to be sufficiently massive to damp down resonances and vibration. The little kitchen cutting boards have little effect under speakers but work well under equipment.

[Spectral Morn]

IMO, the granite/marble slabs have to be sufficiently massive to damp down resonances and vibration. The little kitchen cutting boards have little effect under speakers but work well under equipment.

Agreed.

However granite rings so good quality slate would be a better, all-be-it a more expensive option.

[The Grand Wazoo]

Never tried chopping boards under speakers - mine are too big for that!

[StanleyB]

I am wondering what kind of inscription you would have on a piece of granite from the grave yard. Maybe "Here rest my beloved B&W DM2" ?

[Gazjam]

Used to have a "marble slab" under my Rega Planar 3 turntable with the engraving;

"In loving memory of John M Dixon"

The Girlfriend's Dad was a stonemason and had some reject marble in the workshop :)

(True story)

[brian2957]

Had he spelled the guys name wrong :doh: I was given a slab of marble recently , I'll be checking it in the morning !!!!

[PLINIUS]

That's interesting Chris. I'll see how I get on with granite for the moment (after all I have ordered them now) and if the slabs don't cut it then I'll look into the steel option. Presumably I'd need to bolt the steel to the bottom of the Atacama stands if I go down that route.

It's a very good tip Dave, inexpense, non-perminant & very effective in eliminating the sympathetic resonance between floor & speaker cabinet. Construction of peoples homes varies considerably, so does the amount of
improvement.

[Macca]

Used to have a "marble slab" under my Rega Planar 3 turntable with the engraving;

"In loving memory of John M Dixon"

The Girlfriend's Dad was a stonemason and had some reject marble in the workshop :)

(True story)

Reminds me of Alan Partridge's theory about using granite tombstomes for the work surfaces in luxury kitchens. Although as he rightly pointed out you would need to place them with the engraved surface face down otherwise they will collect crumbs...

[The Black Adder]

I was once shown a cd player and an amp with a lump of granite built in to the bases.. Can't remember what kind though. Expensive as far as I can remember. I think it was at a dealers house K4POG or something... Great bloke too. :)

[Spectral Morn]

I was once shown a cd player and an amp with a lump of granite built in to the bases.. Can't remember what kind though. Expensive as far as I can remember. I think it was at a dealers house K4POG or something... Great bloke too. :)

Ancient Audio or the brand Wilson Benesch distributed for awhile Audio Net http://www.audionetusa.com/

[icehockeyboy]

Anyone ever put a granite jobbie on top of their CD player?

A few years ago it was fairly popular, I tried it, and at the time beloved it helped. :scratch:

[isuckedmandelsonslemons]

I've spent the last few months experimenting with lots of different materials under and over bits of kit. I've also tried all sorts of sound isolation spikes. I'm convinced that granite gives a slight 'ring' when placed beneath a CD player and does nothing when placed on top.

After months of experimentation my equipment sits on a solid oak rack with 50mm solid oak shelves. I'm convinced this is the best solution so far but the experiments continue.

[Macca]

I have a plastic coated metal weight sat on top of my CD player - 10 kilos - I am convinced the player sounds better with it. I have taken it off a few times thinking 'this is nonsense' but it always goes back on. Doubt I could tell the difference blind, though.

[stupinder]

We have suspended floors and I found a big improvement with the following set up.
From floor to speaker.
Kingspan foam block stuff
Paving stone
wine boxes filled with dried sand
speakers

like this - you can just about make it out in the corner. Clearly the the wine boxes need to be of a good quality and I found I got a much rounder and full bodies sound using Pomerol on the bottom with a bog standard Bordeaux on the top.

http://i342.photobucket.com/albums/o433/Stupinder/ROOM/lefthand010612.jpg

[synsei]

I'm getting a feint hint of raspberries, lavender honey and huge dollops of BLOODY LOUD MUSIC!!!! :D

[stupinder]

I'm getting a feint hint of raspberries, lavender honey and huge dollops of BLOODY LOUD MUSIC!!!! :D
hehehehe. To put it into perspective the drivers on the floor are 15" and the ones atop the Victors are 8".
I do listen quite loud...PARDON WHAT!!!
If I enjoy my new speakers when they arrive next week the Victors may well go up for sale....perhpas (Mrs Stup' really doesn't want me to flog them as she loves them with bass heavy music)

[synsei]

Oh I bet they do bass very well, 15" drivers are where its at. Shame I can't get such monsters into my listening room or I might be tempted if you put 'em up for sale. The DM2's pretty much dominate the room with their wee 8" ones... :lol:

[stupinder]

Oh I bet they do bass very well, 15" drivers are where its at. Shame I can't get such monsters into my listening room or I might be tempted if you put 'em up for sale. The DM2's pretty much dominate the room with their wee 8" ones... :lol:
don't panic the drivers in the Victors are only 12". Sound lovely at low volumes but can really shift some air when asked to...
S

[synsei]

I wonder if they'd work well with a T-Amp? :D

[stupinder]

I wonder if they'd work well with a T-Amp? :D
They do - ive run em succesfully with a sonic Impact Mk 2 T amp - in a smaller room (office) they were mental :-)

[walpurgis]

Municipal quality concrete paving blocks (the type local authorities use) work well under speakers and are way cheaper than natural stone. The 400x400x60mm size are pretty heavy and inert enough.

I have a pair and used them for years.

The thing to watch with any concrete or stone block is that they all retain some moisture and will eventually rot your carpet or damage wood flooring, it happened to me, so use some means of lifting them slightly. Spikes or cones etc.

[isuckedmandelsonslemons]

Municipal quality concrete paving blocks (the type local authorities use) work well under speakers and are way cheaper than natural stone. The 400x400x60mm size are pretty heavy and inert enough.

I have a pair and used them for years.

The thing to watch with any concrete or stone block is that they all retain some moisture and will eventually rot your carpet or damage wood flooring, it happened to me, so use some means of lifting them slightly. Spikes or cones etc.

I'm hoping this tip gets a five star rating in What hifi. I have several hundred of these I'd like rid of.

[Andrei]

So, the moral of this story is this: If you are looking for granite slabs to sit under your equipment, contact your local monumental stonemason coz ya never know,


I quite agree synsei (or is it Dark Lord?). I live in Napier, a town of some 60,000 and I easily found a a granite supplier. It is a local firm that makes kitchen benchtops from granite or marble. The cost was NZ$120 - say £60. You can see it at

http://theartofsound.net/forum/showthread.php?t=21090

which is the welcome gallery. As you say this is from offcuts from larger projects. There were a couple of dozen colours to choose from. In my case I use it partly to put some mass under the turntable; and also to help level the surface, as it is easier to level the granite than the turntable.

[synsei]

That Marantz is lovely, good choice of colour for the granite too ;)

[Peter Galbavy]

At one point I did phone a number of seemingly local stonemasons but they all turned out to be retailers and didn't produce anything. That's North London for you.

In the end I went with a 5-pack of 300x600 porcelain floor/wall tiles and put 5 small pea-sized lumps of BluTak between each pair building up a sandwich. I have a stack of black ones in the AV room and beige in the music room. Works out about £20 a pack from Homebase for the generic stuff.

They work. And they provably work. I ran Audyssey room correction before and after in the TV room and the post-calculation graph showed a major taming of the 80Hz boom in the room.

[Richiebuoy]

So I looked further afield and stumbled upon a monumental stonemason in Rothwell, Northants called A.J Mills, so I got straight onto the blower and explained what I needed done to the proprietor, Alan Mills.


Now there's a name from the past, Alan Mills, a nice bloke, did you know that Alan was the singer on the massive one hit wonder "Do The Hucklebuck" by Coast to Coast...... Unfortunatly Alan broke with the band just before it made the charts and some other guy mimed it on TOTP's.....

[synsei]

:lol: I got my rocks off an honest to goodness pop star :lol:

Seriously though, he is a top bloke and we had quite a long discussion about music and hifi once I told him what I wanted the granite for ;)

[RichB]

Mine were 7.50 a each from argos... Granite worktop savers. They really worked on my regas. I put a couple of pennies under the front spikes on the speakers, really tightened up the sound. Bass is all there but really sweet and natural, no vibrations into the sofa as before. Not a lot of money lost if they didnt work and I could always use them in the kitchen. My mate uses a couple with some rubber floor tile wedged in between to tame his Roksan Darius'. It was his tip and i'm pleased I tried it.

[pwood]

Putting your speaker on a granite tile or slab makes a difference to the sound of that I am in no doubt. i was so convinced it was better I left things thinking it was an improvement. How wrong was I ! . In my case and Im not saying it will be the same for everyone as rooms and speakers are different the sound was on placing my Ruark Talismans on them more immediate. Thats something after years of being a hifi fan I now know is to be treated with caution. i took them off and noted the sound was more of a whole less in yir face. Tried the same with a few mates and none of us bar the one living in a flat that needed the bass calming have the granite underneath anymore prefering the warmer less HIFI like or in plain English more musical sound.

Had the same sort of experience in mass loading my speakers as well. Funnily enough my new speakers dont have the facility to add mass to them.

[synsei]

Below are my Hafler and Thorens TD160mkII sitting on home made equipment supports. These are granite worktop savers purchased from The Range for £10.99. The turned, brass, gold plated isolation feet and cups were bought from Gear City in Hong Kong for £9.99 for a set of four. I have three of these supports in total so they stand me at £20.98 each which is a helluva saving over a commercial product ;)

http://i1019.photobucket.com/albums/af316/Sgtgrash/Hifi%20Stuff/HaflerGranite.jpg

http://i1019.photobucket.com/albums/af316/Sgtgrash/Hifi%20Stuff/Thorensongranite.jpg

[guy]

A local stonemason let me have a 1" thick slab of stone (not sure what, dark colour but no layers so not slate, think it may be granite) from his waste skip. I gave one of his machine operators a fiver to cut it in to two equal slabs of about 300 x 400mm and drilled three holes in to each slab to araldite adjustable spikes in to place.

My thinking was that my Rega Elas did not fully penetrate the carpet to keep the speakers in full contact with the solid floor beneath. The mass of the slabs in conjuction with the spikes ensured that the carpet was pierced, and the concrete below became a path for energy transmission.

Once in place it became obvious that vibrations from the speaker cabinet now had somewhere to go, rather than competing with the movement of the cones- just placing my hand on the speaker with and without slabs in place demonstrated a massive reduction in speaker cabinet vibration with the slabs in place.

Coupling the speakers more effectively with the floor has made an inprovement in clarity of the speaker at all volume levels and frequencies in my opinion. Well worth a few hours work/playing, and at very low cost.

Guy

[YNWaN]

A local wholesaler of granite supplied me with two custom made 30mm thick pieces of granite for my speaker crossovers to sit on; polished top and edges, I specified the exact size and granite type - £23 each.

[Tarzan]

l come to this thread by chance, as l have put Granite chopping boards under my speakers, and this did improve matters, however l then removed them and put the said chopping boards under the intergrated amp and CD Player and blow me this makes a further improvement!:cool::scratch:

[realysm42]

A local wholesaler of granite supplied me with two custom made 30mm thick pieces of granite for my speaker crossovers to sit on; polished top and edges, I specified the exact size and granite type - £23 each.

Its funny, I wanted to get some granite cut to size a while ago, the guy quoted me £150 a slab :lol:

Jokers...

[YNWaN]

Yep, the price does vary enormously.

[seoirse2002]

Its funny, I wanted to get some granite cut to size a while ago, the guy quoted me £150 a slab :lol:

Jokers...

There's a place in Wandsworth that will do it for you from offcuts much cheaper than that.
Ill get his number for you:)

[realysm42]

Cheers man, that would be helpful for future projects!

[Thing Fish]

The problem it appears to me with all these granite slabs is that they tend to come in a max of 30mm thickness. As mass is the objective I would have thought at least 50mm or even thicker would be needed?

I am looking at some concrete paving slabs that Travers Perkins sell singly they are 450 x 450 x 50mm thick and can be painted or housed in wood as desired.

[The Grand Wazoo]

Monumental masons will have some seriously thick granite - take a look in your local graveyard & see what's available!
Note: I am not advocating some sort of hi-fi related grave robbing exercise!

[realysm42]

I know nothing of physics, but isn't mass relative?

Its a crude example but an inch of granite would be better than a metre of bean bag, for example.

Its also incredibly inert material. Its not the best solution but its a cost effective way of giving effective isolation.

[Thing Fish]

Monumental masons will have some seriously thick granite - take a look in your local graveyard & see what's available!
Note: I am not advocating some sort of hi-fi related grave robbing exercise!

Thanks Chris, Good idea. I've fired off an email to a London based stonemason and await a reply...:popcorn:

[Wakefield Turntables]

Right a simple lesson in basic science. To stop vibration it DOES NOT matter how much something weighs it's how the substance oscillates. A stiff material will not vibrate whilst something of less stiffness will vibrate, oscillate and general be a bit of a bugger at limiting its ability transmit vibration. Carbon fibre is extremely stiff, and consequently why companies use it to make tonearms and high end plugs. No doubt someone will pickup on my post and correct me. I'll get really techy (pardon the pun) but cant be arsed.

Regards and love

Andy.

[Wakefield Turntables]

Just found this. http://en.wikipedia.org/wiki/File:Passvibcomp.jpg Its a useful way of getting your head around how various techniques can be used to get rid of specific bands of Hertz. So granite will control specific Hertz levels but it might not be the best way of improving your speakers.

[The Grand Wazoo]

As I've said on AoS several times before, I've never found granite to have a great effect under speakers. Lots of other components, but not speakers. I've had far better results with sheets of a few mm thick steel plate screwed onto the underside of floorstanders.

[synsei]

Monumental masons will have some seriously thick granite - take a look in your local graveyard & see what's available!
Note: I am not advocating some sort of hi-fi related grave robbing exercise!

That's a dead good recommendation that. After grave consideration t'is where I sourced mine from. Since they were laid to rest under my Atacamas church organs sound so funereal. I've seen the light ;)

[Wakefield Turntables]

That's a dead good recommendation that. After grave consideration t'is where I sourced mine from. Since they were laid to rest under my Atacamas church organs sound so funereal. I've seen the light ;)

Im glad youve laid that to rest, sounds like its was a biblical undertaking getting the slabs under your speakers.

[Reffc]

Bit late I know but I'll jump in here because there's so much leaping before looking that folk are getting some seriously good exercise!

To say that stiff materials do not vibrate is wrong, plain and simple. They do, even carbon fibre does (but at high frequency, plus tonearms are made of a matrix which is wound specifically to lessen the amplitude of the frequency and pull it out of the sensitive mid range). The stiffer the material, the higher up the frequency band it vibrates, so the trick is in finding a material that has it's resonant frequency above the audible spectrum or below it.

Granite does vibrate, in fact, it's pretty good at transmitting vibrational energy but but is also self damping, so it's effectiveness, or not, will depend on the amplitude of the vibrations as well as the frequency.

Slate has a similar density but due to its sedimentary grain structure, it has far better self-damping properties, so makes a better material for plinths (for example) than granite.

The stuff you see sold as granite chopping boards or granite worktops rarely is granite by the way. It's a composite which uses granite chippings (a by-product of the aggregate business) which is compressed with a cementitious compound to form a composite like a concrete. Most chopping boards you buy are made from this composite.

Now to less dense materials. To say that less dense materials are no good as isolators is also quite wrong. It depends entirely on their make up. Materials such as sorbothane are much lighter than slate for example but they are designed to convert vibrational energy to heat energy. Most foams and other similar lightweight insulating materials dissipate vibrational energy as heat, due to vibrations causing movement of the cell structures which lose that energy as heat.

Consider many studio speaker stands used for isolation...they do not use heavy granite, they use foam wedges which can be bought commercially from places such as Studiospares. A Polystyrene sandwich with a neoprene or closed cell foam filling is a pretty good and pretty cheap isolation material.

The idea behind granite and even paving slabs as a good idea for placement under speakers is not so much related to their isolation properties, as it is to coupling the speakers to a high mass substrate which helps to mass load the speaker via the coupling spikes (spikes couple, not isolate). This in turn transmits vibrational energy which has its amplitude dropped by the mass and self damping of the slab. It still vibrates, but because the amplitude is lessened in the slab, less is transmitted to say floorboards below. Foam platforms are equally as effective, if not more so because they isolate rather than couple.

[Thing Fish]

Nothing is ever certain as the variables such as our ears/room acoustics and the like all play a part in the overall sound.

But as we all know we are all tweakers and I for one enjoy that aspect of our hobby.

There is no harm in trying different stuff. We are all intelligent people with access to google and I for one am certainly aware of coupling/decoupling, room acoustics and the like having spent 2 years at the School of Audio Engineering.

What works for one won't always work for another and vice versa that's a given.

I for one will tweak away until my hearts content.

[Wakefield Turntables]

Bit late I know but I'll jump in here because there's so much leaping before looking that folk are getting some seriously good exercise!

To say that stiff materials do not vibrate is wrong, plain and simple. They do, even carbon fibre does (but at high frequency, plus tonearms are made of a matrix which is wound specifically to lessen the amplitude of the frequency and pull it out of the sensitive mid range). The stiffer the material, the higher up the frequency band it vibrates, so the trick is in finding a material that has it's resonant frequency above the audible spectrum or below it.

Granite does vibrate, in fact, it's pretty good at transmitting vibrational energy but but is also self damping, so it's effectiveness, or not, will depend on the amplitude of the vibrations as well as the frequency.

Slate has a similar density but due to its sedimentary grain structure, it has far better self-damping properties, so makes a better material for plinths (for example) than granite.

The stuff you see sold as granite chopping boards or granite worktops rarely is granite by the way. It's a composite which uses granite chippings (a by-product of the aggregate business) which is compressed with a cementitious compound to form a composite like a concrete. Most chopping boards you buy are made from this composite.

Now to less dense materials. To say that less dense materials are no good as isolators is also quite wrong. It depends entirely on their make up. Materials such as sorbothane are much lighter than slate for example but they are designed to convert vibrational energy to heat energy. Most foams and other similar lightweight insulating materials dissipate vibrational energy as heat, due to vibrations causing movement of the cell structures which lose that energy as heat.

Consider many studio speaker stands used for isolation...they do not use heavy granite, they use foam wedges which can be bought commercially from places such as Studiospares. A Polystyrene sandwich with a neoprene or closed cell foam filling is a pretty good and pretty cheap isolation material.

The idea behind granite and even paving slabs as a good idea for placement under speakers is not so much related to their isolation properties, as it is to coupling the speakers to a high mass substrate which helps to mass load the speaker via the coupling spikes (spikes couple, not isolate). This in turn transmits vibrational energy which has its amplitude dropped by the mass and self damping of the slab. It still vibrates, but because the amplitude is lessened in the slab, less is transmitted to say floorboards below. Foam platforms are equally as effective, if not more so because they isolate rather than couple.

Yes, I know all materials vibrate, where in my post does it say that they dont? You explained this quite well and use good examples. Problem is most people dont get the logic of removing Hz ranges out of the equation and I think thats why most people get such weird and wonderful results.

[Reffc]

Yes, I know all materials vibrate, where in my post does it say that they dont? You explained this quite well and use good examples. Problem is most people dont get the logic of removing Hz ranges out of the equation and I think thats why most people get such weird and wonderful results.

Err, Andrew...you said that a stiff material will not vibrate ;) Perhaps not what you meant, but it was what you said:


Right a simple lesson in basic science. To stop vibration it DOES NOT matter how much something weighs it's how the substance oscillates. A stiff material will not vibrate whilst something of less stiffness will vibrate, oscillate and general be a bit of a bugger at limiting its ability transmit vibration. Carbon fibre is extremely stiff, and consequently why companies use it to make tonearms and high end plugs. No doubt someone will pickup on my post and correct me

I agree though that experimentation is the key as quite often some materials on their own will not isolate very well but mix them with others and the cumulative effect is that laminations of different things can be very effective. Any lamination of different materials alters the resonant frequency, so if wanting an effective isolation platform, I usually build a sandwich of materials usually with a damping material between them which helps dissipate vibration.

[Wakefield Turntables]

Err, Andrew...you said that a stiff material will not vibrate ;) Perhaps not what you meant, but it was what you said:



I agree though that experimentation is the key as quite often some materials on their own will not isolate very well but mix them with others and the cumulative effect is that laminations of different things can be very effective. Any lamination of different materials alters the resonant frequency, so if wanting an effective isolation platform, I usually build a sandwich of materials usually with a damping material between them which helps dissipate vibration.

:oops: yep you've got me. :lol: no material is perfectly stiff, well picked out! I think your correct re multiple laminations I do something similar when I'm trying to slow down impact velocity and increase pressure redistribution when I'm messing around with severely mangled feet!

Here's and interesting question for you. Do you think it could be the speed of how we drop the hz range in the first layer of lamination which gives the tendency to cause some materials to "ring"?

[Reffc]

:oops: yep you've got me. :lol: no material is perfectly stiff, well picked out! I think your correct re multiple laminations I do something similar when I'm trying to slow down impact velocity and increase pressure redistribution when I'm messing around with severely mangled feet!

Here's and interesting question for you. Do you think it could be the speed of how we drop the hz range in the first layer of lamination which gives the tendency to cause some materials to "ring"?

I'm not really expert enough to answer that properly Andrew but I equate the term "ringing" with resonance in a stiff material which corresponds to upper mid/low HF.

I have done some limited measurements using different materials when developing a design for Garrard Turntable plinths and found that some materials exhibit similar resonant frequencies and amplitudes, but differ a lot in how well damped they were (ie the duration of the "ring" if you like).

Amongst the worst performing materials in terms of duration of resonance was plain mdf...truly bad. Used for speaker cabinets it needs to be pretty well braced to avoide problems with larger speakers (floor standers for example, of which most are manufactured from MDF panels). Yet laminate it with Birch Ply and the resulting composite out-performs either of its parent materials. The resonant frequency can also be proportional to the panel size with some materials. I have made my front speaker baffles from this laminate of ply/MDF precisely because it pulls down the resonant frequency for the panel by dint of mass/density and the amplitude and duration of panel vibration are reduced.

I think I'd need to understand your question better to attempt to answer it but I understand it as:

does pulling down the frequency in Hz of a panel using an appropriate first lamination selection inadvertently lead to greater ringing in the second/remaining laminations which may have a higher resonant frequency on their own?

Forgive me if I've misunderstood, but if I haven't and that is what was meant, then the act of joining two different materials together doesn't allow either to operate at their natural frequencies, rather the laminate is transformed by combining two materials which have different self damping and resonance characteristics to form a single unique panel which cannot exhibit the separate resonance tendencies of the parent materials. At least, that is how I understand it. It is a little more complex than this though as it also depends on how differing materials are laminated as to whether they react independently. Different ply woods react differently and have differing characteristics if the timber used is different, if the thickness changes (either of the timber or the total lamination) and depending on the glues used. For example, I selected a "lossy" high quality PVA for my speaker panels when laminating the sides which has very different properties to some other PVAs. It never sets hard and has excellent self damping properties as well as good density. The energy applied stretches the glue at microscopic level (vibration movement) and this in turn generates internal heat which is then lost. Its a common trick now used by major high end speaker manufacturers when assembling their cabinets (ie joints are designed as "lossy" joints which limits panel vibration).

[Wakefield Turntables]

Paul,

Great chat so far, I'm at work looking at some several knackered feet at the moment will read your post through and hopefully clarify some things!

Andy

[Daniel75]

guys,

slightly off topic but can someone tell me what is the benefit of creating granite "sandwich"? for example two slabs of granite with a cork between them?

Cheers

D

[Wakefield Turntables]

In a nutshell.

All things vibrate.
These vibrations are harmful for sound quality
Certain materials are very good at getting rid of nasty vibrations
Some materials are better than others
Granite is supposed to be good at getting rid of vibrations
With less vibration, equals, hopefully, better sonics :eyebrows:

BUT

As to a sandwich. Well the granite may still leak certain "vibrations" they may be at a Hz level which effects sound quality. Cork could possibly soak up these vibrations or reduce the Hz level even further. Ideally the Hz level should be so high that we can't hear it or so low that we can't percival it. A second layer of granite I suppose could be used to mop up anything that's left over. Hope that makes things a little clearer. :cool:

[Daniel75]

Thanks! This is much clearer now. I would assume that one could substitute cork with something cheaper like high density foam or chip foam or yoga blocks:) ?

D

[Wakefield Turntables]

Thanks! This is much clearer now. I would assume that one could substitute cork with something cheaper like high density foam or chip foam or yoga blocks:) ?

D

Yes you could try any material you wanted ;) and this is exactly what we are debating but with a little technicality added for good measure. Its not a hard concept to understand, we just use silly big words to explain everything, we really should keep it simples :lol:.

PS I will get back to this thread properly tomorrow when I have some time.

[losenotaminute]

Yes you could try any material you wanted ;) and this is exactly what we are debating but with a little technicality added for good measure. Its not a hard concept to understand, we just use silly big words to explain everything, we really should keep it simples :lol:.

PS I will get back to this thread properly tomorrow when I have some time.

I think my Ruarks have lead in the base of the stands, at least judging by the weight it must either be lead or very heavy steel. I would have thought for speaker stands the weight would make a difference as well as the stiffness and other physical characteristics of the material. Maybe that is just a naive view, buit with more weight, the less likely they are to move either through sound vibration or floor movement?

I was always think "the heavier the better" when it comes to hifi equipment, good rule of thumb.

[Wakefield Turntables]

I think my Ruarks have lead in the base of the stands, at least judging by the weight it must either be lead or very heavy steel. I would have thought for speaker stands the weight would make a difference as well as the stiffness and other physical characteristics of the material. Maybe that is just a naive view, buit with more weight, the less likely they are to move either through sound vibration or floor movement?

I was always think "the heavier the better" when it comes to hifi equipment, good rule of thumb.


Heavier is better doesn't always work.

How does your speakers weigh? Mine weigh approx 70kg. They are inert and I have never felt them resonate. Now think of a house wall. It must weigh tens of tonnes?? Outside my office window I noticed council workers were repairing a road, this was across the street. I also happened to notice the WALL vibrating. Now which weighs most the speakers or the wall? Mass is important but how the vibrations are handled is more important.

Now with regards your floor. It's an inanimate object unable of vibrating, it will only vibrate or resonate when an external source which causes resonance or vibration has been applied. This will them travel up your speakers. So the best solutions are to isolate or dissipate naughty vibrations. Sorry this is a bit basic.

[Reffc]

I think my Ruarks have lead in the base of the stands, at least judging by the weight it must either be lead or very heavy steel. I would have thought for speaker stands the weight would make a difference as well as the stiffness and other physical characteristics of the material. Maybe that is just a naive view, buit with more weight, the less likely they are to move either through sound vibration or floor movement?

I was always think "the heavier the better" when it comes to hifi equipment, good rule of thumb.

Yes,

heavier stands are a good thing and it should make a difference if your speakers are coupled to them, it helps lower the overall resonant frequency of the cabinets and also helps damp resonance amplitude. In general, weight is a good thing as mass loading is an accepted way of sinking vibrations. Again, whether it eliminates them is another matter as that is dependant upon the material's self damping properties.

[Gmanuk101]

I bought two granite chopping boards well a well know 2 queues store which was also similar to a greek ship.

I found under my spiked mission (sand filled) stands they made a little bit of difference, but since my floor is a suspended one it still vibrates even at low volume levels.

I am looking at maybe rubber or cork tiles for under the speakers as I doubt my landlady will allow polymer foam under the floor ;)

[Chops]

I bought two granite chopping boards well a well know 2 queues store which was also similar to a greek ship.

I found under my spiked mission (sand filled) stands they made a little bit of difference, but since my floor is a suspended one it still vibrates even at low volume levels.

I am looking at maybe rubber or cork tiles for under the speakers as I doubt my landlady will allow polymer foam under the floor ;)

I had the same problem regarding spiked feet into polished, suspended wooden floor making the floor 'sing'.

I found good ol' concrete paving slabs worked well but they couldn't stay for cosmetic reasons :rolleyes:. I used the thick green hardboard type material you get from DIY shops underneath them, which is sold to go under laminate flooring and I think it helped a little to isolate the floor further. I've now replaced the concrete with granite (not as good) but added SDS IsoFeet (http://www.sounddeadsteel.com/hifi.html) and RDC cones and cups between speakers and granite. Works a treat. I haven't measured floor vibration but it no longer seems to be acting as a sounding board.

Chris

[Reffc]

I bought two granite chopping boards well a well know 2 queues store which was also similar to a greek ship.

I found under my spiked mission (sand filled) stands they made a little bit of difference, but since my floor is a suspended one it still vibrates even at low volume levels.

I am looking at maybe rubber or cork tiles for under the speakers as I doubt my landlady will allow polymer foam under the floor ;)

Where suspended floors are concerned there's usually three options: use something far more substantial than a chopping board, say a 1 cwt paving slab (it can be painted gloss black!) and couple the speaker to that with spikes but ISOLATE the slab from the floorboards using something like sorbothane or squidgy closed cell foam. The other option is to cut out a portion of the floorboards and cast a concrete block to the substrate below (extreme but in a dedicated room can work really well) and the final option is to isolate just the speaker using sorbothane under the base, that or foam speaker supports (alternatively make thse by sandwiching polystyrene with rubber (cut up innertubes work well) and closed cell foam, to an overall thickness of about 100mm. I've seen these used to really good effect.

[Gmanuk101]

Where suspended floors are concerned there's usually three options: use something far more substantial than a chopping board, say a 1 cwt paving slab (it can be painted gloss black!) and couple the speaker to that with spikes but ISOLATE the slab from the floorboards using something like sorbothane or squidgy closed cell foam. The other option is to cut out a portion of the floorboards and cast a concrete block to the substrate below (extreme but in a dedicated room can work really well) and the final option is to isolate just the speaker using sorbothane under the base, that or foam speaker supports (alternatively make thse by sandwiching polystyrene with rubber (cut up innertubes work well) and closed cell foam, to an overall thickness of about 100mm. I've seen these used to really good effect.


brilliant thanks :) the floorboard cutting is not an option, so the paving slabs one is! out of interest where do I get the sorbothane from?

[Reffc]

brilliant thanks :) the floorboard cutting is not an option, so the paving slabs one is! out of interest where do I get the sorbothane from?

Try Ebay, lots of sorbothane on there!

[Wakefield Turntables]

I've got loads of sorbothane if you of need some

[MCRU]

I've got loads of sorbothane if you of need some

oo yes please, how thick is it and is it in sheet form?

thx :)

can you cut it to be a circle 260mm o.d with a small hole in the middle?

[Wakefield Turntables]

I can get you any thickness you like and yep it comes in sheet form!