Has anyone used Herbie Gliders on their SDA SRS?

Polar

my wife is beyond tired of the cardboard I threw under my SRS when I brought them home, so I promised her I'd get them on some proper footing. I would like to do isolation feet instead of spikes, so someone pointed me to Herbie's Audio Lab to look at their Threaded Stud Gliders. I think they'd be perfect for the job - and priced decently at $17 each - but I would like to hear from anyone who's used them.

Also, I believe the SRS takes 1/4"-20 studs, but what length would be appropriate? Herbie makes these in lengths from half-inch to 2 inches long.

pitdogg2

What no link? Rookie😜

https://herbiesaudiolab.com/collections/loudspeaker-rack-decoupling-and-isolation/products/threaded-stud-glider


I can tell you what you don't want, you don't want something that's going to allow your loud speakers to move. Just the basic steel gliders that Polk put out with their big SRS speakers, even in my very low pile carpeting my 2.3tl's would slide enough to mess with the soundstage.
Those look like they have some sort of Teflon or slick plastic and I bet for sure that they would move pretty easily.

Gardenstater

They are filled with "dB Neutralizer". I wonder if it is sorbothane.

Polar

Gardenstater wrote: »

They are filled with "dB Neutralizer". I wonder if it is sorbothane.

Thats one of the things that popped into my head. A lot of times these unique audio tweaks are just repurposed industrial materials that DIY types can use and enjoy a significant savings.

How do Herbie's audio/video feet compare to other "soft" footers?

From that linked article:

"Soft polyurethanes like Sorbothane and Norsorex lack the reflexive counter-punch needed to fight microphonics and have a tendency to produce ill-defined bass and some high-frequency loss or false emphasis."

If they're looking for "reflexive counter-punch in a shock-absorbing insert, I gotta wonder if these guys are on the wrong track with their substance. The best way to minimize vibration is to reduce reflex. For instance, when Sorbothane became commercially available for running shoe inserts, Dr. Scholl's came out with their own material that was significant better at absorbing rebound when compared to Sorbothane.

In Herbie's defense, I imagine that they want somewhat of a rebound vs the mass applied by the speaker, so that it offers a static height under compression thats about one=half the original material thickness.

Thats a subject for another day.

Anyway, it's not Sorbothane. I just don't know whether thats bad or good.

Polar

pitdogg2 wrote: »

What no link? Rookie😜

I have no excuse... I have failed as a poster, but I'll try to make it up to the forum. Starting with the above post, which contains both a link and a quote, and this sentence contains gratuitous italics. I will of course continue to improve if you're willing to work with me!

pitdogg2 wrote: »

I can tell you what you don't want, you don't want something that's going to allow your loud speakers to move. Just the basic steel gliders that Polk put out with their big SRS speakers, even in my very low pile carpeting my 2.3tl's would slide enough to mess with the soundstage.
Those look like they have some sort of Teflon or slick plastic and I bet for sure that they would move pretty easily.

Are you still driving your speakers with the Aragon? Maybe thats the reason they're moving - all that current is making them levitate.

I've got these speakers sitting on cardboard sheet, on a hardwood floor, and they don't move too easily, even driven by a mildly upgraded M1.0t. The only time they move is when my wife vacuums behind them. Carpet can be abrasive to certain things but pretty slippery for metal. Perhaps the original steel gliders do just that - glide - on carpet?

Gardenstater

Reflexive Counterpunch LOL LOL. That's a riot.

For a helical spring loaded with a mass, to get a resonant frequency of around 2 Hz, which is significantly low enough to give good isolation for audio equipment, you need 3 in. of compression under load relative from the no load condition, and you need there to still be some free compression available still.

Viscoelastomeric isolators like sorbothane use different math but they have to be pretty darn soft for typical audio equipment and they have to be a certain height to cross sectional area to get the resonant frequency low enough. I seriously doubt that a tiny amount of sorbothane in Herbie's Gliders can accomplish that. So called isolators like Herbie's Gliders are using a combination of dampening and isolation but the result is that it doesn't really isolate for all of the audio frequencies. For the lower frequencies it will actually amplify. The science is unescapable.




There's a sorbothane calculator somewhere that I had a link to.

Found it:

https://www.sorbothane.com/technical-data/design-guide-calculators/vibration-calculator/

Polar

Gardenstater wrote: »

Reflexive Counterpunch LOL LOL. That's a riot.

For a helical spring loaded with a mass, to get a resonant frequency of around 2 Hz, which is significantly low enough to give good isolation for audio equipment, you need 3 in. of compression under load relative from the no load condition, and you need there to still be some free compression available still.

Viscoelastomeric isolators like sorbothane use different math but they have to be pretty darn soft for typical audio equipment and they have to be a certain height to cross sectional area to get the resonant frequency low enough. I seriously doubt that a tiny amount of sorbothane in Herbie's Gliders can accomplish that.\

There's a sorbothane calculator somewhere that I had a link to.

Fantastic, a materials scientist - I'm glad I posted!
Is that 3 inch a constant for all helical springs and all mass applications? Was I close on my statement about the static height under compression?
Finally, would you think the resonance of the material is whats at play here (the lower the resonance, the higher the threshold is to get energy across is)? I had supposed it was a standing-wave structure inherent to the material (under stress) that causes a cancellation. Or are these the same thing, just approached from a different angle?

Gardenstater

For a 6" unloaded spring that gets compressed under load by 3" then you would be close with that ratio of 2:1 but it isn't really a ratio thing. The 3" compression just happens to be the result when you do the math for compression springs for 2 Hz resonant frequency.

What is at play is the spring constant K (Force per unit displacement), which isn't just a function of the material properties but also the physical shape and size of the spring (or elastomer). A typical coil spring has virtually no internal dampening. Elastomeric materials have dampening factors that reduce the amount of amplification on that graph I posted, but it is harder to get the properties and shapes and sizes needed to get the resonant frequency to be low enough. So most of those devices result in some amplification (with dampening) that somebody might actually thinks sounds better in their particular system but it isn't true isolation because the resonant frequency is too high for audio equipment.

F1nut

There's a reason the OP is listed.

Polar

Gardenstater wrote: »

For a 6" unloaded spring that gets compressed under load by 3" then you would be close with that ratio of 2:1 but it isn't really a ratio thing. The 3" compression just happens to be the result when you do the math for compression springs for 2 Hz resonant frequency.

Thanks for the insight.

Gardenstater wrote: »

What is at play is the spring constant K (Force per unit displacement), which isn't just a function of the material properties but also the physical shape and size of the spring (or elastomer). A typical coil spring has virtually no internal dampening. Elastomeric materials have dampening factors that reduce the amount of amplification on that graph I posted, but it is harder to get the properties and shapes and sizes needed to get the resonant frequency to be low enough. So most of those devices result in some amplification (with dampening) that somebody might actually thinks sounds better in their particular system but it isn't true isolation because the resonant frequency is too high for audio equipment.

This reminds me of vehicle suspension physics. The common perception of shock absorbers is that they absorb road shocks, but they don't. The springs are what absorb the bumps, the shock absorbers then convert the oscillation of the springs to heat.

An idea occurs to me: If I can get the Herbie's Lab guys to post here, would you be interested in a point/counterpoint with them? I think we could all learn a lot.

Gardenstater

The stiffness of the springs is what controls the amount of vibration transmission that you get when a bump of a certain height is hit at a certain speed that puts you in the isolation part of that graph I posted.

Without damping factor in the struts, the vibration that gets through would cause an oscillation that would take a long time to dissipate, and if it was near the resonant frequency it could become violently unstable.

That'd be interesting for a non scientific audio product company to debate the science when they have no 3rd party laboratory testing behind their product.

Edit - actually strictly speaking, the damping factor of the material enters into the amount of transmission too. It would be more accurate to say that the stiffness effects the frequency at which you transition from amplification zone to isolation zone, which is the point of 0% isolation and 0% amplification.

Polar

Gardenstater wrote: »

The stiffness of the springs is what controls the amount of vibration transmission that you get when a bump of a certain height is hit at a certain speed that puts you in the isolation part of that graph I posted.

Without damping factor in the struts, the vibration that gets through would cause an oscillation that would take a long time to dissipate, and if it was near the resonant frequency it could become violently unstable.

That'd be interesting for a non scientific audio product company to debate the science when they have no 3rd party laboratory testing behind their product.

Thank you George. I hope I can convince someone from Herbie's Audio Labs to show up here. People should be able to defend their products, so either they're going to stand some correction or they're going to satisfy people enough to drive their sales. Either way, we win.

Gardenstater

It's kind of a no win situation because they will undoubtedly fall back on the stance that .....we don't need to test because we have lots of testimonials from satisfied customers who liked the way their systems sounded afterwards. Testing will probably only hurt their sales and that's why they don't do it. There is no way to talk the science with them when they won't do the testing. They will stick with the pseudoscientific marketing lingo and continue to make money.

A company like Towshend Audio is another story however.

Polar

I don't take sides in the audiophools vs meter heads thing. I really don't. I wish they all could take a step back and work together. The 'phools need to understand that the numbers are a great thing to frame the discussion. The 'heads need to accept subjectivity. But I understand the whole resistance to snake oil, and I wish the 'phools had some firmer footing there.

I like hearing from both sides. On one hand the math keeps people honest, but on the other hand there's subjective stuff that can't be quantified - or more properly, hasn't been quantified yet. I'm sure on a long enough timeline it would eventually be, but I don't know how expedient it would be to wait that long.

I don't know the Townshend Audio story, I don't think I've seen the name until you mentioned it. Is it interesting?

Gardenstater

Some videos from Townshend Audio explaining the science is what got me interested in vibration isolation for loudspeakers.

Subjective testing could be done comparing Herbie's Gliders with Townshend Audio platforms. That'd be interesting.

It is comparing two different products though because, even though they won't admit it, the Herbie's Gliders are al frequency dependent amplification/isolation device and the Townshend platforms are more of a pure isolation one.

Gardenstater

This company claims 3 to 4 Hz resonant frequency with the proper load and they have a before and after graph with an impulse excitation. Townshend Audio says 2 Hz or lower is what is needed if you want to isolate from low frequencies such as truck rumble on a nearby thoroughfare and the like. You can see in the graph that these don't isolate really well for low frequencies.



https://avroomservice.com/evp-2/

Owner of the company is clearly a no nonsense nice guy:

https://www.youtube.com/watch?v=s6Ucek7OqBg

Gardenstater

This video is a must view for all you spikeheads out there🤣

https://www.youtube.com/watch?v=dW9-r83IvhI

Polar

Ok, that last video is an eye ear brain opener.
George, you're a good resource. I think I'm going to nominate you for the position of Docent here at the Polk Vintage Museum.

xschop

"less thumpy, but more true"

Gardenstater

xschop wrote: »

"less thumpy, but more true"

"Townshend Podiums give me the bass I like.......dead on balls accurate" << Mona Lisa Vito

F1nut

LMAO...suckers

Gardenstater

You can hear the effect of adding a steel block underneath each podium where it couples maybe 30% and keeps the speaker from floating freely on the springs. Sounds pretty good but when it is removed it is like a veil is lifted.

https://www.youtube.com/watch?v=lzwafmSXkjw

xschop

F1nut wrote: »

LMAO...suckers

I'm a sucker for less distortion.

F1nut

xschop wrote: »

F1nut wrote: »

LMAO...suckers

I'm a sucker for less distortion.

Put your money where your mouth is. It'll cost you $2,175.00 to $4,000.00.

xschop

F1nut wrote: »

xschop wrote: »

F1nut wrote: »

LMAO...suckers

I'm a sucker for less distortion.

Put your money where your mouth is. It'll cost you $2,175.00 to $4,000.00.

LOL. Those were not a challenge to build. These were....

Gardenstater

Anyone can easily make their own DIY Townshend Podiums. A couple pieces of Birch plywood sized correctly for the height and center of mass of your speakers, 4 properly selected springs, and 3 cable ties for initial preload for each spring is all you need to see if it is something you can appreciate the improvements of. You will have to fuss a bit with initial setup to get the speakers and springs properly positioned so the speakers are level and each spring is getting equal load.

Townshend may not make ones large enough for something like the SDA SRS. I haven't really checked. Another issue for people who play them loud "might" be that the use of the bass brace might be a good idea, with a pivot pin at each end perhaps.

F1nut

xschop wrote: »

F1nut wrote: »

xschop wrote: »

F1nut wrote: »

LMAO...suckers

I'm a sucker for less distortion.

Put your money where your mouth is. It'll cost you $2,175.00 to $4,000.00.

LOL. Those were not a challenge to build. These were....

Totally different animal.

The Townshend spring mechanisms are vastly more effective at absorbing vibration than bearing or point devices

xschop

Correction....The Townshend spring mechanisms are vastly more effective at absorbing funds than bearing or point devices.

Gardenstater

Lest some LOLer get confused what I am talking about is something like this, which is one of the springs under my buddy Steve's turntable. We have done this to his Steve Deckert open baffle speakers as well, and they are abouit 5 ft. tall. I would add a bumper of some sort on the inside if I tried this on speakers with a center of mass as high up as the SDA SRS, to limit how far they can rock should a dog or cat launch themselves onto them or some other unforeseen happenstance.

F1nut

Gardenstater wrote: »

Hilarious

F1nut

xschop wrote: »

Correction....The Townshend spring mechanisms are vastly more effective at absorbing funds than bearing or point devices.

I can certainly agree about that.