I am developing some vibration reduction feet named the Vibration Black Hole (VBH) for Vera-Fi Audio. It uses several stages of viscoslastic gel damping combined with changes in material density (aluminum to stainless steel to nylon) to produce mechanical impedance mismatches that enhance the loss of mechanical energy transmission. The feet are 50mm in dia and 33mm high. They are designed to be used with spike feet that contact a conical depression in the small black nylon pisto st the top. Self adhesive spike can be provided for installation on the bottom of the piece of gear. The feet work not only in the axial direction but also laterally (radial).
I set up a test to measure the attenuation of an impact to a table that is then transmitted to the plinth of a TT. By instrumenting the plinth with a piezoelectric transducer, we can measure the transmitted energy from a mechanical impact to the table. I use a special instrumented hammer fitted with a calibrated transducer (PCB Piezotronics, ICP Impact Hanmer). This way, we can quantity the hammer impact energy for accurate comparison.
This is the VBH:
Here is the setup - LSA TT, Owon digital Oscope, PCB Piezotronics ICP hammer and signal conditioner, disc piezoelectric transducer mounted on plinth.
The piezoelectric transducer is mounted to the plinth with 3M thin double sided tape at the 1/3 and 1/3 position to avoid the vibrational nodes:
This is the instrumented PCB Piezotronics ICP hammer:
Here is the Oscope trace without the VBH. Yellow trace is hammer strike energy and blue trace shows the time response of vibrations in the plinth:
Here is a closeup of the VBH installed with a spike foot under the stock feet:
Here is the Oscope trace with VBH. Note that the hammer energy is approximately the same at around 24.6Vpp. The transmitted vibration is reduced in amplitude but more importantly, the high frequency resonances are smoothed out. The VBH will help to dissipate impulsive energy (taps, bumps, etc,):
I set up a test to measure the attenuation of an impact to a table that is then transmitted to the plinth of a TT. By instrumenting the plinth with a piezoelectric transducer, we can measure the transmitted energy from a mechanical impact to the table. I use a special instrumented hammer fitted with a calibrated transducer (PCB Piezotronics, ICP Impact Hanmer). This way, we can quantity the hammer impact energy for accurate comparison.
This is the VBH:
Here is the setup - LSA TT, Owon digital Oscope, PCB Piezotronics ICP hammer and signal conditioner, disc piezoelectric transducer mounted on plinth.
The piezoelectric transducer is mounted to the plinth with 3M thin double sided tape at the 1/3 and 1/3 position to avoid the vibrational nodes:
This is the instrumented PCB Piezotronics ICP hammer:
Here is the Oscope trace without the VBH. Yellow trace is hammer strike energy and blue trace shows the time response of vibrations in the plinth:
Here is a closeup of the VBH installed with a spike foot under the stock feet:
Here is the Oscope trace with VBH. Note that the hammer energy is approximately the same at around 24.6Vpp. The transmitted vibration is reduced in amplitude but more importantly, the high frequency resonances are smoothed out. The VBH will help to dissipate impulsive energy (taps, bumps, etc,):
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Can be any piece of equipment actually. A lot of amplifiers and preamplifiers can benefit from reduction of vibration and mechanical noise. Tube amps and preamps that are susceptible to microphonics for example or amplifiers that might have mechanical vibrations from trafo mangnetostriction effects. Or to isolate speakers and let them float above the micro vibrations of a floor or desk (if desktop mounted).
About same energy as using knuckles to knock on a wooden door to let someone know you are outside the door.
Here is a video to illustrate the typical force and sound it makes.
I could send you an early beta-production set. It won’t have the nice packaging etc yet. The feet will sell for $199 for a set of 4 including the aluminum spike feet that attach to whatever piece of equipment you have. If your gear has spikes already then they won’t be needed.
They should be available for sale as production run in 6-8 weeks.
Here is a video to illustrate the typical force and sound it makes.
I could send you an early beta-production set. It won’t have the nice packaging etc yet. The feet will sell for $199 for a set of 4 including the aluminum spike feet that attach to whatever piece of equipment you have. If your gear has spikes already then they won’t be needed.
They should be available for sale as production run in 6-8 weeks.
A review of VBH just came out.
https://www.stereotimes.com/post/vbh-1-vibration-reduction-feet-vera-fi-audio-by-greg-voth/
Nice photos in article:
https://www.stereotimes.com/post/vbh-1-vibration-reduction-feet-vera-fi-audio-by-greg-voth/
Nice photos in article:
Another review of the VBH just came out.
https://positive-feedback.com/reviews/hardware-reviews/vera-fi-audio-vbh-1/
https://positive-feedback.com/reviews/hardware-reviews/vera-fi-audio-vbh-1/
Nice product - you're going to have some "line card" within the next few years, as you keep coming up with stuff.
I didnt see this post when it first came out. I have to wonder why the cheezy piezo pickup, with the waaaay more pro hammer and its associated preamp? I thought the piezo has to bend to generate voltage, so are you getting a ripple wave going across the TT plinth surface?
Anyway, I'd recommend using one of the Dayton exciter transducers in reverse as a pickup. (if not a "real" accelerometer commensurate with a second one of those PCB preamps) That's going to get whatever THUD makes it through the isolator feet; due to the stationary momentum of the magnet. The very tiniest one will have a higher self resonance than is ideal, but the medium size ones are a bit better in that regard. I bet you have those just kickin around.
I can see it's a tough measurement to make.
I didnt see this post when it first came out. I have to wonder why the cheezy piezo pickup, with the waaaay more pro hammer and its associated preamp? I thought the piezo has to bend to generate voltage, so are you getting a ripple wave going across the TT plinth surface?
Anyway, I'd recommend using one of the Dayton exciter transducers in reverse as a pickup. (if not a "real" accelerometer commensurate with a second one of those PCB preamps) That's going to get whatever THUD makes it through the isolator feet; due to the stationary momentum of the magnet. The very tiniest one will have a higher self resonance than is ideal, but the medium size ones are a bit better in that regard. I bet you have those just kickin around.
I can see it's a tough measurement to make.
The piezos have different modes and can be tailored. I have some bending ones but the cheap (guitar pickup) discs are axial mode (they work in compression or tension in 1 dimension). Bending them will also make a signal. I do indeed have a bunch of dynamic exciters lying around.
I might have some accelerometers lying around somewhere - but really, the piezo is a nice transducer despite being cheap. Great sensitivity and very light weight.
I might have some accelerometers lying around somewhere - but really, the piezo is a nice transducer despite being cheap. Great sensitivity and very light weight.
