Isolation

[Ali Tait]

Interesting video that was posted on PFM, nice to see some actual measurements-

https://youtu.be/32DrKCqLWkk

Seeing the good results with the tough cones, I had a hunt online and have bought a set of these to try-

https://www.vital-parts.co.uk/m6-x-10mm-anti-vibration-conical-buffers-weight-rating-98kg-12585-p.asp

Lots of options on there, so you'll find something to suit, and not pricey either.

[CageyH]

Interesting, but he does not take into account the loads that the various devices have been designed for.

[Ali Tait]

Yes, looked at weights when I ordered, and hardness of the rubber.

[Barry]

At least he kills off the myth that spikes isolate vibration. I once asked a mechanical engineer who worked in the same research laboratory as I did, why spikes are used to isolate vibrations. His answer, believe it or not, was "you can't transmit a force through a point". Well spikes are not infinitely sharp points, they have a very small but finite contact area; otherwise they wouldn't be able to support whatever is put on them against the force of gravity.

As to rubber or compliant isolation devices, the important figure is the resonant frequency of the supported mass with the compliance of the support device. Just as with the cartridge - arm resonance the resonance frequency is important, and so it is with mass isolation. In this case the isolated mass should have a resonant frequency of around 3Hz.

When it comes to commercial audio items, I trust and rely on what support feet the manufacturer has chosen to use. None of my kit uses spikes, and I'm not troubled by rumble or any other low frequency interference. But to be fair, the speakers I use have a rapid roll-off below 50Hz, asymptotic to 18dB/octave.

[Chris]

Hi Barry,
Is there any easy way of calculating the resonant frequency or should I take the weight of my speaker and divide it by 4 feet and use the chart on the web page ? I see the smallish cones can be either for approx 7 kilos per foot or nearer 10 kilos. Assuming my boxes are around 25 kilos, is it better to leave a percentage in hand i.e. go for the 10k cones ?
Thanks,
Chris

[Barry]

I would choose the AVM1096 version. Each can support a 6.9kg weight, so four will support 27.6kg, giving you a 10% margin.

To calculate the resonant frequency you would need to know the compliance of the rubber supports. Whilst they quote the hardness of the rubber, I do not know how to relate that to the compliance. Again, whilst they quote the amount of compression (2.5mm) each cone suffers under the maximum load, one would still need to know the Hooke's constant for the rubber.

But what you suggest would seem to be the best plan of action.

[Chris]

Thanks Barry, I´ll get the bathroom scales out just to check my Wd25T floorstanders. All I know is that at my age they get heavier every time I move them.

[Barry]

Thanks Barry, I´ll get the bathroom scales out just to check my Wd25T floorstanders. All I know is that at my age they get heavier every time I move them.

LOL, I know what you mean! I use a pair of B&W DM2A speakers with my TV. I had to move them recently and was dismayed to find how heavy they appeared to be.

[Barry]

Have you measured the weight of one of your speakers yet? What did the weight turn out to be?

I have worked out how to calculate the resonant frequency of your speakers when supported by the above rubber cones. A 'back of an envelope' calculation suggests a figure of 6.6Hz, which should be satisfactory.

[SLS]

I've become a Stack Audio junkie. Have 5 of their products. They measure well in this video. If they made pizza I'd probably order some.

[Jimbo]

Interesting video that was posted on PFM, nice to see some actual measurements-

https://youtu.be/32DrKCqLWkk

Seeing the good results with the tough cones, I had a hunt online and have bought a set of these to try-

https://www.vital-parts.co.uk/m6-x-10mm-anti-vibration-conical-buffers-weight-rating-98kg-12585-p.asp

Lots of options on there, so you'll find something to suit, and not pricey either.

Saw that video sometime back and got me interested too. Good luck with the cones, I will be interested to see how you get on.

Recently been evaluating stuff under my speakers including spikes, rubber feet and some “fashionable “ isolation feet. The rubber feet have sounded the best so far!

Sorry no graphs or measurements :)

[Macca]

I've become a Stack Audio junkie. Have 5 of their products. They measure well in this video. If they made pizza I'd probably order some.

I had a home demo of them but whilst I can't definitively say there was no change there was not the obvious benefit many people have experienced.

Maybe due to the speakers being very large and heavy, and the floor being concrete, I don't know.

Certainly £1K worth of improvement just wasn't there.

[Pigmy Pony]

I've got £6.40 worth of 'improvement' heading my way :)

https://img.kwcdn.com/product/fancy/c1c4f077-22c5-4af5-8da9-efa50ca1435f.jpg?imageView2/2/w/800/q/70/format/webp

[Barry]

That's probably all you need to pay. You can always put the £993.60 towards some cables.

[Ali Tait]

Saw that video sometime back and got me interested too. Good luck with the cones, I will be interested to see how you get on.

Recently been evaluating stuff under my speakers including spikes, rubber feet and some “fashionable “ isolation feet. The rubber feet have sounded the best so far!

Sorry no graphs or measurements :)

Just fitted them to the speakers a few days ago, though I also put stacks of granite slabs on block paving bricks to raise the speakers up as the tweeters are at the bottom of the driver line up due to the TL design-

https://i.imgur.com/A4bA8SP.jpeg

Definitely a big improvement.

[Jimbo]

Just fitted them to the speakers a few days ago, though I also put stacks of granite slabs on block paving bricks to raise the speakers up as the tweeters are at the bottom of the driver line up due to the TL design-

https://i.imgur.com/A4bA8SP.jpeg

Definitely a big improvement.

Looking good Ali and I am sure the granite slabs help too. I have something similar under mine but I might be upgrading via a trip to the local graveyard stone mason!:)

[Macca]

Just fitted them to the speakers a few days ago, though I also put stacks of granite slabs on block paving bricks to raise the speakers up as the tweeters are at the bottom of the driver line up due to the TL design-

https://i.imgur.com/A4bA8SP.jpeg

Definitely a big improvement.

No-ones ever going to look at that and accuse you of not taking audio seriously!

[Pigmy Pony]

No-ones ever going to look at that and accuse you of not taking audio seriously!

Especially when you see all the big holes in his patio :)

[SLS]

Just fitted them to the speakers a few days ago, though I also put stacks of granite slabs on block paving bricks to raise the speakers up as the tweeters are at the bottom of the driver line up due to the TL design-

https://i.imgur.com/A4bA8SP.jpeg

Definitely a big improvement.

I can see a Stack LAN Regenerator in there!
I have one of them, mat, stabiliser, Auva 50 (speakers) and Auva EQ (under phono stage).

I also use Kridon Image under my t/t (can see some of those?) and Isoacoustics pucks.

[Ali Tait]

LOL it’s my man cave so I can do what I like. Good for films too on the 100” screen. :-)

[Ali Tait]

I can see a Stack LAN Regenerator in there!
I have one of them, mat, stabiliser, Auva 50 (speakers) and Auva EQ (under phono stage).

I also use Kridon Image under my t/t (can see some of those?) and Isoacoustics pucks.

Yes got one recently, good bit of kit.

[Macca]

LOL it’s my man cave so I can do what I like. Good for films too on the 100” screen. :-)

And the holes in the patio are barely a minor inconvenience. It's all worked out fine.

[Ali Tait]

Kiridon image?

[Ali Tait]

And the holes in the patio are barely a minor inconvenience. It's all worked out fine.

Had some things to bury..

[Pigmy Pony]

What are the speakers Ali? They look pretty big.

[SLS]

Kridon is a chap who sold many thousands of very high-quality machined aluminium feet, mainly for Garrard and other vintage turntable projects. I have a set under my 301. I spoke to him recently and he was about to get back selling on eBay, but seems to have shut up shop.

[Lawrence001]

He's also into photography, the name Kridon Image goes back to before he started selling the feet.

[Ali Tait]

Kridon is a chap who sold many thousands of very high-quality machined aluminium feet, mainly for Garrard and other vintage turntable projects. I have a set under my 301. I spoke to him recently and he was about to get back selling on eBay, but seems to have shut up shop.

Ah ok thanks, Angus (Phonomac) made the plinth for me, the feet came with it.

[Ali Tait]

What are the speakers Ali? They look pretty big.

They're IPL Acoustics S5TL, big transmission line design. Got them for a good price as the cabinets, whilst solid, looked dog rough. Colin Topps reveneered them for me and built the external crossovers sitting on top. Thread here-

https://theartofsound.net/forum/showthread.php?74658-IPL-Acoustics-S5TL