Speaker Isolation Feet/Stands

[Julian Walker]

Good Evening All,

I hope everyone is well!

After building a kitchen/diner extension that nearly killed me, I've resurrected an old audio set up I bought over 30 years ago. The speakers are Celestion and still sound pretty good however I've got them sat on the wooden floor and they could do with a bit of isolation treatment. They measure about 240mm wide x 240mm deep x 450mm high.

I don't want to raise them up anymore than I have to (6" max) so I'm wondering if anyone can recommend a suitable isolation foot/pad/stand that not's going to break the bank. I've had a look a quite a few options online but would appreciate any educated advice.

Many thanks all and a very Merry Christmas to you all

Jules

[Hugh Robjohns]

I like the IsoAcoustics Iso-Puck devices for the kind of application you're describing.

The size and number required for each speaker depends on the weight of the speaker...

https://isoacoustics.com/pro-audio-isol ... ck-series/

[Dynamic Mike]

I bought the IsoAcoustics speaker stands shortly after they were reviewed in SOS and been very pleased with them. However in the past I've used a couple of layers cut from a camping sleeping mat with pretty good results regarding isolation. You'd easily get a couple of layers from a single mat cut to size & at around £8 from Argos etc. it won't break the bank.

[ef37a]

My Tannoy 5As sit on two tall narrow CD cabinets made of MDF and are stuck down with 4 blobs of Blu Tac each. This not only secures the speakers from being accidentally toppled but I am pretty sure Btac allows near zero sound transmission?

Or, get some 50mm foam and sandwich it between two layers of 19mm MDF/chipboard/ply. Copydex is the "cleanest" contact adhesive and plenty strong enough.

I am sure the fancy, expensive isolators ARE worth the asking price?

When I was in the network hardware game they got into "Power Poles" extruded Aluminium channels that could be loaded with standard electrical/data outlets. They could be cut with perfectly square tops and bottoms and plates fitted. I have long thought they would make excellent speaker stands? Each could have a mains and audio outlet making for a very tidy setup. I have a few 'odd ends' loaded with 13A outlets as 'diss' boxes.

Dave.

[Drew Stephenson]

What works is going to depend on the speakers in question and the spring constant of the medium. It's why decent isolation units will always have a weight specification. Too light or too heavy and the speakers won't be getting the material into its springy zone.

[Tomás Mulcahy]

I am not convinced isolation is necessary. Speaker cabinets are very rigid, especially ones from a reputable brand like Celestion. So there is no perceptible vibration that needs to be isolated. It is the drivers that vibrate. The vibrations travel through air, where loudspeakers are concerned.

Look at this video, it's pretty obvious.

And read this, where he concludes that at best the effect is broadband and 20-30dB down.

[ef37a]

What works is going to depend on the speakers in question and the spring constant of the medium. It's why decent isolation units will always have a weight specification. Too light or too heavy and the speakers won't be getting the material into its springy zone.

Yup, it's a Spring-Mass-Damper system and will only isolate frequencies at or above the system resonance. "Harmonics" Innit!

Dave.

[Wonks]

The material can be too springy with not enough load, and fully compressed (so not springy) with too much load, so you need speakers within the ‘Goldilocks’ weight zone so that speaker vibrations are absorbed rather than reflected back to the speakers. (Despite the mention of Goldilocks, do not use porridge for this).

[ef37a]

The material can be too springy with not enough load, and fully compressed (so not springy) with too much load, so you need speakers within the ‘Goldilocks’ weight zone so that speaker vibrations are absorbed rather than reflected back to the speakers. (Despite the mention of Goldilocks, do not use porridge for this).

But! You could use wet Wheatabix as a glue? Almost impossible to shift once dried in the bowel!

Dave.

[Wonks]

But! You could use wet Wheatabix as a glue? Almost impossible to shift once dried in the bowel!

Dave.

Was that a deliberate typo, or are you now very constipated?

[The Elf]

I'm willing to bet these do a similar job to those fancy-pants isolator spikes:

[Wonks]

Look at this video, it's pretty obvious.

Putting sand on the top and sweeping through the audio spectrum would be a much better test than a single bass frequency a long way from the glass’s and any cabinet resonant frequencies.

It’s impossible for the cabinet material not to move at all, the question is at what frequencies and by how much.

[Hugh Robjohns]

Julian says " I've got them sat on the wooden floor and they could do with a bit of isolation treatment."

...so I'm assuming he has a real, physical problem with unwanted audible vibration that he's seeking to address, rather than a random desire to spend money...

It might be that the speakers are causing the floor to vibrate, or maybe the floor contact is uneven allowing the speaker to vibrate. I don't know... but efficient isolation would solve the problem, whatever it is.

And Tomás, not all speaker cabinets are totally rigid and perfectly damped. Some just because they're cheap and nasty, and some because they are designed not to be!

I don't know what Celestions Julian has, but some used the BBC design principle of thin walled cabinets where the panel vibrations were intended to contribute constructively to the overall sound!

As for your videos... the first one with the sub... that unit has TWO speakers located on opposite sides of the cabinet specifically designed to cancel out the inherent vibration created by a single driver! Rather than making your point, it actually does the opposite by highlighting what needs to be done to remove cabinet vibrations!

I'll not comment on Ethan's article, save to say confirmation bias...

Foam pads or sheets can certainly work quite well but, as Wonks explains, you need to get the foam into its optimum spring range which would mean experimenting with different foam density and pad sizes.

The Iso-Pods are designed for specific load weights, and you optimise the isolation by varying the pod model and number of pods under the speaker. Not cheap, I agree, but effective and easy.

Alternatively, sorbothane spheres and small furniture castor cups or thick disc washers can work very well!

And finally, Dave, blutak hardens over time. It's ideal for keeping speakers on top of stands, but its not effective at vibration isolation in the long term.

[Tomás Mulcahy]

I never said imposible to vibrate or totally rigid. I said very rigid. Perhaps the misunderstanding indicates confirmation bias Interesting about the thin walled Celestions Hugh, how were they mounted?

I accept the glass of water is problematic, I just thought it was a good simple example.

Isoacoustics have data comparing their unit with spikes, but no data comparing it to no isolation mounting. It’s a bit suspicious not to have a control in such a test. That is why I am not convinced there is an audible improvement. At least Ethan has somewhat useful data showing this.

Getting back to biases, it’s extremely difficult to test this perceptually. Floyd Toole did some amazing work with speaker comparisons but as far as I know they never tested mounting while he was with Harman.

[Hugh Robjohns]

Interesting about the thin walled Celestions Hugh, how were they mounted?

At the corners.

That is why I am not convinced there is an audible improvement.

I've worked on more than enough home studios over the years to know that a great many do have speaker/shelf vibration problems, and I know what sorts those problems out. I don't need convincing there's an audible improvement in those situations.

But given a good, solid speaker mounted sensibly on a good solid stand set up properly, there will be no practical vibration problem and obviously no improvement from using any form of (completely unnecessary) isolation.

None of my speakers here use isolation of any form.

At least Ethan has somewhat useful data showing this.

Somewhat meaning not at all, then?

I don't know where to begin with his experiments, there's just so much obviously wrong in the basic experimentation process. But for starters, he claims the top of the table resonates — something he demonstrates by tapping upon it — and says this should be excited by vibration transferred from the speaker... and then he places the speaker on that resonant surface, instantly both loading and damping it and thus completely defeating the planned experiment.

Moreover, his measurements are only of the bass driver's frequency response (and while we're on that subject, the DPA4090 is NOT a precision measurement mic, and the charts showing the claimed HR824 bass response were not made by him in his test system, so they're irrelevant too!).

Surely, any sensible, competent, educated, and rational engineer trying to assess the transfer of vibration, would use an accelerometer fixed to the table to measure the precise amount of vibration reaching it with and without the different isolation platforms in place?

His experiment is trying to detect some possibly very low level resonances added to the full output from the speaker, when it's clear that the natural experimental variations between different attempts changes the response more than enough to hide that anyway!

So no... it's really not 'somewhat useful data'. It's highly misleading and entirely set up to 'prove' the point he wants to prove, which is (arguably rightly) bashing audiophoolery while ignoring the real science.

[Tomás Mulcahy]

But given a good, solid speaker mounted sensibly on a good solid stand set up properly, there will be no practical vibration problem and obviously no improvement from using any form of (completely unnecessary) isolation.

None of my speakers here use isolation of any form.

Same here. I am not sure it is widely understood that there is "obviously no improvement from using any form of (completely unnecessary) isolation".

Somewhat meaning not at all, then?

That's a valid critique. So we have no data at all on what happens without isolators. We don't need it

[ef37a]

"And finally, Dave, blutak hardens over time. It's ideal for keeping speakers on top of stands, but its not effective at vibration isolation in the long term."

Does it Hugh? I didn't notice that when I peeled it off their bottoms after they had been on wall brackets for a good five years!

In any case, I did not claim Bt was some miracle "absorber" just that it breaks the hard surface to hard surface contact and prevents any rattles getting through. Not that this was a problem for me. The CD towers are 19mm MDF, very rigid and well loaded with CDs i.e. quite 'massy'.

'Ee did want cheap!

Dave

[ef37a]

But! You could use wet Wheatabix as a glue? Almost impossible to shift once dried in the bowel!

Dave.

Was that a deliberate typo, or are you now very constipated?

Not sayin'

[Wonks]

Max/SSG always used blutac on the monitors on his studio installs.

[Hugh Robjohns]

As do I... but only to keep speakers in place, not as isolation.

[Wonks]

Indeed. Always on very solid stands.

[ef37a]

Indeed. Always on very solid stands.

As mine are.

Dave.

[Hugh Robjohns]

I am not sure it is widely understood that there is "obviously no improvement from using any form of (completely unnecessary) isolation".

Indeed... but then few people have a good grasp of acoustics and vibration, even so-called audio professionals.

But the rule of thumb is simple enough: if you put the speaker on something than can vibrate, it would be worth trying isolation to see if it helps. And the more solid the stand, the less likely you'll need isolation.

That's a valid critique.

So we have no data at all on what happens without isolators.

Well, I have... both on solid stands and on less solid shelving and table tops....

[Tomás Mulcahy]

Well, I have... both on solid stands and on less solid shelving and table tops....

Publish it

[SafeandSound Mastering]

I use the neoprene squash pucks here for BM6P (thick wooden sand filled stands made by my late father who was a carpenter) and he also made my 5 legged PMC IB1S monitor stands, super rigid. The PMC stands are on paving slabs and then pucks as they meet the top of the stand.

I chose them based on weight of respective monitors and it just seems to me to make sense to stop unnecessary vibrations transferring wood on wood. It seems to me that otherwise the stands (or other surfaces that a speaker maybe on) may become some form of potentially resonant extension of your cabinets (beyond merely air bourne acoustic transfer which would be less efficient than direct coupling). With the pucks the monitors kind of float in the air a bit.

I turned them up to a good old level and held the stands and the were not appreciably vibrating in sympathy so the contribition to what I hear at the drivers to ears directly sweet spot is essentially nothing. (no desk or gear in between me and the 3 drivers of the speakers. (I sit to the side and turn my head)

They were not expensive and I have not over thought them. Empirical test of stands vibrating less when clasped with a hand than before suggests it helped slightly. Not scientific by any means but it feels a little like a belt and braces thing to do. Sometimes 'feels right' seems to matter.