Vibration Management
- Thread starter PeterA
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With Tony's excellent guidance, I reconfigured two spiked 20mm thick Panzerholz platforms for my Westminster Lab Rei mono blocs into Panzerholz tops suspended by the same 11lb / inch springs that Tony used in his project on top of two spare pieces of 20mm thick high-quality maple plywood. Because the Reis are front heavy, I drilled the four location holes in the bottom plywood to different depths in order to balance the Reis on the Panzerholz top. I don't have the measurement devices that Tony has, but I can tell you that this made a great sound even better -- improvements in depth, speed and clarity of bass and in clarity and resolution of mids and highs, plus an even greater sense of airiness that was already outstanding. Several hours of time in precision-drilling holes with a 3/4" Forstner bit and drill press, routing the edges, sanding the edges, staining them and applying 3 coats of satin polyurethane. Total out-of-pocket cost? About $18 worth of springs and shipping cost from McMaster-Carr. If you or a friend have the basic woodworking tools, making a spring-loaded platform is an inexpensive no-brainer.
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Interesting stuff you guys are posting here.
Did any of you ever consider the possibility that striking an object with another object i.e. a steel ball against the floor, isolation, absorption, springs, etc. might all be examples of executions belonging solely to the shock and impact methodology - not to any legitimate vibration mgmt. methodology?
Think of driving a 4x4 truck at 40 mph on a dirt back-road with chuckholes, washboard ridges, rocks, gullies, dips, bumps, etc.
This begs the question… What could your sensitive instruments possibly have in common with the violent shock and impact activities of a fast moving 3000 - 8000 lbs. vehicles’ suspension system? Are any of you really expecting your sensitive instruments to encounter chuckhole-like experiences?
If so, might it be even more telling to share one’s findings after measuring the vibrational influences on an amplifier or TT when struck with a sledgehammer?
Can somebody explain the mindset here?
Did any of you ever consider the possibility that striking an object with another object i.e. a steel ball against the floor, isolation, absorption, springs, etc. might all be examples of executions belonging solely to the shock and impact methodology - not to any legitimate vibration mgmt. methodology?
Think of driving a 4x4 truck at 40 mph on a dirt back-road with chuckholes, washboard ridges, rocks, gullies, dips, bumps, etc.
This begs the question… What could your sensitive instruments possibly have in common with the violent shock and impact activities of a fast moving 3000 - 8000 lbs. vehicles’ suspension system? Are any of you really expecting your sensitive instruments to encounter chuckhole-like experiences?
If so, might it be even more telling to share one’s findings after measuring the vibrational influences on an amplifier or TT when struck with a sledgehammer?
Can somebody explain the mindset here?
If you are wondering what happens if you drop your amplifier off the top of a 4 story building- would it affect the sound? I can assure you with utmost confidence that the impact will affect the sound of your amplifier.
Now that we all have had a good chuckle…
Think about pressing a key on a piano. The hammer mechanism strikes the triplet of strings and they vibrate at their resonance frequencies creating a sound. You do not hear a crash or a thump. The same holds true for a hammer striking a Xylophone bar. It rings at its tuned resonance frequency. Now imagine when I strike the floor with a steel ball the floor will ring at its resonance frequency, just like a piano string. That vibration travels into my equipment rack and into my amp, preamp, turntable, DAC, etc. And each of those preamp, amp, etc boxes- and my equipment shelves are going to ring or resonate at their respective natural frequencies as well as components inside those boxes. But when I isolate those boxes (amps, preamps, etc) on springs, those boxes remain silent- with the exception of airborne vibrations. So now I use some damping or cones on the boxes to help silence those airborne vibrations. The proof is in the listening.
When the speakers output vibration in rich harmonic tones that we call music, (Defining music is an entirely different debate, ie what is music to one person is awful noise to another) the room is energized. Every wall, window, piece of furniture and floor all respond to those vibrations by reacting at their resonant frequencies. If a piano is in the room, listen closely and you will hear the strings in that piano reacting to the music playing as well. That’s not even taking into account the reflections of the music off the walls, floor and ceiling.
Put all these vibrations and reflections together and now our stereo sounds about as good as a high school band at a basketball game. Isolation, room treatments and damping is a must to achieve good and proper sound from our stereo systems. For me, systematic processes for controlling mechanically transmitted vibrations, room reflections and finally airborne vibrations is how I achieve my goals.
Now that we all have had a good chuckle…
Think about pressing a key on a piano. The hammer mechanism strikes the triplet of strings and they vibrate at their resonance frequencies creating a sound. You do not hear a crash or a thump. The same holds true for a hammer striking a Xylophone bar. It rings at its tuned resonance frequency. Now imagine when I strike the floor with a steel ball the floor will ring at its resonance frequency, just like a piano string. That vibration travels into my equipment rack and into my amp, preamp, turntable, DAC, etc. And each of those preamp, amp, etc boxes- and my equipment shelves are going to ring or resonate at their respective natural frequencies as well as components inside those boxes. But when I isolate those boxes (amps, preamps, etc) on springs, those boxes remain silent- with the exception of airborne vibrations. So now I use some damping or cones on the boxes to help silence those airborne vibrations. The proof is in the listening.
When the speakers output vibration in rich harmonic tones that we call music, (Defining music is an entirely different debate, ie what is music to one person is awful noise to another) the room is energized. Every wall, window, piece of furniture and floor all respond to those vibrations by reacting at their resonant frequencies. If a piano is in the room, listen closely and you will hear the strings in that piano reacting to the music playing as well. That’s not even taking into account the reflections of the music off the walls, floor and ceiling.
Put all these vibrations and reflections together and now our stereo sounds about as good as a high school band at a basketball game. Isolation, room treatments and damping is a must to achieve good and proper sound from our stereo systems. For me, systematic processes for controlling mechanically transmitted vibrations, room reflections and finally airborne vibrations is how I achieve my goals.
For a minute there, it almost sounded like you were catching on. But alas...
BTW, one easy solution to your specific problem could be to refrain from striking steel balls against the floor while listening. I mean, who does stuff like this and why?
I'm starting to lose count of the number of preconceived narratives you're introducing here. Let’s just stay on topic with the biggie - shock and impact, so as not to muddy things.
The proof is indeed in the listening. You may be pretty confident with your measurements, verbiage, level of understanding, still pics, etc but that doesn’t mean everybody else is too. How are you at producing and posting an in-room video to support your passion for the shock and impact methodology that ought to be out of scope for your sensitive instruments?
Even more preconceived narratives. Don’t get me wrong. I’ve little doubt that you employ some good systematic discipline to your efforts and on its face, I’m sure most everything you and others claim here makes logical sense to most. But only on its face.
Nevertheless, what do you suppose is the probability that what you might consider systematic processes are actually a bit more willy-nilly or flying-by-the-seat-of-your-pants type processes that you attempt to approach systematically?
Regardless, you’re obviously no luddite. Why not post an in-room video or two so we can at least get an audible glimpse how your measurements, pics, and words line up with your sonics? If your videos are at least in the ballpark of your words and pics, congratulations. If not, then maybe there’s hope for me?
BTW, you never answered my question which was…
What could your stationary sensitive instruments’ unwanted resonant energy possibly have in common with the violent shock and impact activities of a fast moving 3000 - 8000 lbs. vehicles’ suspension system?
A car body sits on four springs just like my isolation platforms that I designed and built. Only difference is the car uses much bigger springs and has dampers, ie shock absorbers to limit the velocity of the wheels in the up/down direction. That is a critical safety feature not needed on a stationary platform in a home stereo system. If you were to remove the shock absorbers from the vehicle and then push on the vehicle it would bounce up and down at about 3 Hz.
You still feel bumps in the road because, 1) The shock absorbers remove some of the isolation provided by the springs, 2) The uneven road surface overwhelms the suspension system or 3) The vehicle encounters the bump at or below 3 Hz. The best example I can think of is to try riding in a basic two wheeled trailer that lacks any suspension down a road for a bit and you will quickly realize just how important a suspension system is. Also keep in mind that auto designers must balance isolation with a feel for the road. Too much isolation and no road feel could lull someone into an unsafe driving situation.
Ok, I will make some videos demonstrating what I am talking about. I just didn't want to bore everyone with too much detail.
Thanks for the notes and videos, Tony. Great to hear that you designed and built your own racking system as sometimes that's the best way to go, right?
When I suggested posting a video or two I meant of a music playback presentation in your room. Your first video included just a snippet of music that sounded pretty good actually from what I could tell. But it was quite short and I'm unfamiliar with the music to boot. Not to mention that I've no idea where the recording mic was positioned in relationship to yoru room and speakers.
Idealistically, the microphone should be reasonably close to the listening chair dead center so as to give a video listener a glimpe how you might hear the presentation from your chair. For example. My iphone is roughly 3 ft in front of my ears and there's a few more sonic issues at that location than mine but it seems to work well enough. Would you mind taking a crack at another video of a challenging music piece with that perspective in mind?
I'd like to pose a few questions for you to cut to the chase a bit.
1. Of the 3 primary sources of unwanted vibrations i.e. floor-borne, air-borne, internally-generated, which of these 3 sources is your system's biggest enemy?
2. What is your best evidence to support that belief?
3. If floor-borne and air-borne vibrations are doing their best to enter your components wouldn't internally-generated vibrations already captured within the component be doing their best to exit your components? After all, all energy seeks to travel away from their point source, right?
4. Here we have unwanted mechanical energy trying to get into the compoent while simultaneously other unwanted mechanical enrgy trying to exit the component. To minimize potential sonic harm resulting from any/all vibrations, do you apply the same principles, designs, executions, etc. to all unwanted vibrations regardless of whence they originated?
BTW, thus far we appear to be polar opposites in our understanding / views.
thanks,
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First, I am unwilling to make a video of my system playing music with my iPhone. I see that as just silly. If you want to hear my system in person, I am agreeable to that. An iPhone video will show that yes, it makes music but that's all it can do.Thanks for the notes and videos, Tony. Great to hear that you designed and built your own racking system as sometimes that's the best way to go, right?
When I suggested posting a video or two I meant of a music playback presentation in your room. Your first video included just a snippet of music that sounded pretty good actually from what I could tell. But it was quite short and I'm unfamiliar with the music to boot. Not to mention that I've no idea where the recording mic was positioned in relationship to yoru room and speakers.
Idealistically, the microphone should be reasonably close to the listening chair dead center so as to give a video listener a glimpe how you might hear the presentation from your chair.
For example. My iphone is roughly 3 ft in front of my ears and there's a few more sonic issues at that location than mine but it seems to work well enough. Would you mind taking a crack at another video of a challenging music piece with that perspective in mind?
I'd like to pose a few questions for you to cut to the chase a bit.
1. Of the 3 primary sources of unwanted vibrations i.e. floor-borne, air-borne, internally-generated, which of these 3 sources is your system's biggest enemy?
2. What is your best evidence to support that belief?
3. If floor-borne and air-borne vibrations are doing their best to enter your components wouldn't internally-generated vibrations are already captured within the component be doing their best to exit your components? After all, I think all energy seeks to travel away from their point source, right?
4. Here we have some unwanted mechanical energy trying to get into the compoent while simultaneously other unwanted enrgy trying to exit. To minimize potential sonic harm resulting from any/all vibrations, do you apply the same principles, designs, executions, etc. to all unwanted vibrations regardless of whence they originated?
BTW, thus far we appear to be polar opposites in our understanding / views.
thanks,
Your questions are thought provoking and challenging, so I will do my best to answer.
1) Floor borne vibrations are the biggest problem. Isolation of the speakers and then the amps, preamps, DAC, etc all provided dramatic improvements in the sound.
2)Clarity, imaging, well defined bass, deep bass that goes through the floor are the improvements that I found very apparent with spring isolation. I isolated my previous speakers with spring platforms and was amazed at the improvement in clarity and bass. Then later I tried the Isoacoustic Gaias on my speakers. While they do not isolate perfectly like springs, they improved the sound even more. I use those spring isolation platforms now on my subwoofers in my HT system. The bass is very deep and clear now in my HT system. I highly recommend that tweak. And that leads to your next question.
3) I believe that the bulk of internally generated vibrations in components- except for speakers, turntables and CD drives come from the power transformers. That's only my semi-educated guess. Therefore, components need rubber dampers and spikes/cones to drain that energy away. I learned for myself first hand with my speakers and recently with my preamps and amps. I think the Gaia feet on the speakers provide some amount of damping/energy drain along with isolation. They have them tuned or balanced between both for optimum sound. Too much damping colors the sound while complete isolation has no downside with some exception when energy cannot drain. I found putting the front of my preamps on cones and leaving the back of the preamps on their rubber feet provides a good balance of energy drain and damping. The preamp sounds faster when not resting on all four rubber feet. However, don't forget that the base the preamp is sitting on is perfectly isolated. I also found the type of material for that base makes a difference in the sound. I tried Delrin, bamboo and Acia wood. Of the three, I like the Acacia wood for the preamps.
4) Room acoustics are just as critical as vibrations. The room has to have balance. Too much damping and the music sounds lifeless. Too little damping and the music is muddied and blurred. In addition, highs can sound harsh and sibilance out of control. I worked for several months on my room acoustics. I have corner bass traps, absorbers on the front wall behind the speakers and diffusers on the ceiling. I worked several days with the diffusers placing them in various locations- same for the absorbers. Interestingly, I was at Hifi Buys in Atlanta last summer where I traded in my 5SE for the 6SE preamp. I was listening to their top system in their best room. I remarked about the amount of reverb in the room. The sales person told me of an app for my phone called Impulso. It requires you to place your phone at your listening position and then pop a balloon at the speaker position. The app analyzes the room to see if the decay is too fast or too slow. I'm proud to say that my room measured almost perfect. I managed to do that by ear. I'll be the first to say I was more lucky than good.
See plot of my room decay measurement below. Always good to find ways to calm my audio neurosis.
I find it fairly easy to follow Tony's explanations and his approach to vibration control.
Personally I don't like springs but prefer to use string suspension for audio, ideally combined with a rollerblock style ball bearing footer.
I make my own, and roller blocks are a pain to make and set up, so I usually just stick with my rope suspension footers.
Perhaps I didn't read back far enough in this topic, but what does the suspension system of a truck, or even a mountain bike, have to do with vibration control in audio gear - or in any other device for that matter?
In vehicles, the shock absorption is mainly controlled by the dampers, not the springs; vibration control is a completely different topic, and not done well by any 4wd trucks - of all vehicles - to say the least.
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I apologize for my lengthy response below and regrettably it’s also incomplete. But when talking about vibration mgmt. we’re talking about the greatest performance bottleneck in all high-end audio. IME, nothing else comes remotely close.
IMO, superior forms of isolation implies a complete severing of the mechanical / electrical energy conduit. For example. I have a table lamp and one sure-fire way to ensure no energy ever gets to the lightbulb is to take a pair of scissors and severe the lamp cord. Instant isolation. No waiting for further improvements down the road because in a moment in time that lightbulb is instantaneously 100% isolated from electric current.
Would you agree that this is a good-enough analogy of a genuine act of isolation from an energy source?
Two important notes:
1. To the best of my knowledge, all energy seek first and foremost to travel away from its point source.
2. Just because a mfg’er calls their rubber products dampers or calls their spikes/cones isolators does not necessarily make it so. In fact, it’s usually just an indicator that they too are caught up in common misunderstandings (preconceived narratives?). Often times one must analyze the design, materials, executions, etc. to determine which camp a product genuinely belongs. IOW, we must stop assuming everybody knows what they’re talking about – IME, more so with vibration mgmt. than any other sector.
Anyway, so already we’re polluting the isolation methodology with the energy transfer methodology and vice versa, right? IOW, we’re now mixing two opposing methodologies. Isn’t this like trying to mix light with dark, on with off, hot with cold, etc?
Doesn’t the isolation methodology in its purest form work best all by its lonesome? Likewise, doesn’t the energy transfer methodology in its purest form also work best all by its lonesome? Don’t both of these methodologies each belong in their own basic laws of nature/physics camp? Are not these two methodologies polar opposites of each other?
If the answer is yes, then what in the world are we doing trying to create some sort of hybrid of both as our final/best solution?
1. If in our endeavors we realize a genuine sonic improvement, does that automatically imply we are on a superior path and methodology?
2. Is it possible for those on an inferior path to also realize sonic improvements?
3. What is the best and perhaps only way those on an inferior path when embracing inferior methodologies can realize genuine sonic improvements?
4. From an isolation purist perspective what does an object become when sufficiently damped?
5. From an energy transfer purist perspective what does an object become when sufficiently damped?
6. From an intermixed methodologies hybrid perspective what does an object become when sufficiently damped?
I’m not an engineer but I am a fundamentalist. So in my case I choose what I think is the superior methodology and if performance was absolutely paramount to me (it is), then I do my reasonable best to ensure I never cross methodology streams. Only then might I stand a chance to achieve maximum benefit that methodology has to offer, right?
Hopefully it becomes a bit more apparent when we intermix two primary methodologies, not only have we cut the potential performance legs out from underneath both methodologies, we’ve also just created a bottomless hybrid rabbit hole. IOW, much like a box of chocolates, we’ve zero clue what the hybrid’s results may be.
And that’s not even yet taking into account our ability to somehow apply only superior forms of managing the intermixing of two polar opposite methodologies aka interoperability skills.
I had a longer response here but to keep it shorter I’ll just say… Like everybody else, it seems you’re doing your reasonable best to keep ALL unwanted resonant energy captured at the component to remain trapped within the component, regardless of its source.
The BIG question is why? Are you aware that once unwanted resonant energy is captured at the component, regardless how it got there, then doesn’t the component (and its internals) become the new point source for this unwanted resonant energy?
Back to floor- and air-borne vibrations. No matter what we do, will at least some unwanted floor- and air-borne vibrations still reach the components? According to your steel ball exercise the answer is obviously yes.
What is the natural behavior of energy again? To travel away from its point source.
What is the natural behavior of energy when its ability to travel is impeded?
BTW, I have a punch line that should help clear some/all of this mess up but I've a few more notes to share and hopefully some of this here is thought provoking.
Understood. In-room videos obviously do not capture the entire gestalt of the in-room experience so likewise on its face, videos can logically seem silly. But that doesn’t mean in-room videos via smartphone are silly to everybody. So even though you may think an in-room video is silly, must that prevent you from sharing an in-room video for others who may find some value?
The term isolation probably ought to be a bit better defined because though simple sounding on paper (on its face), as we can see isolation in high-end audio covers numerous as opposed to singular potential concepts including damping, absorption, weight, etc. as well as numerous as opposed to singular principles, designs, materials, executions, etc.
IMO, superior forms of isolation implies a complete severing of the mechanical / electrical energy conduit. For example. I have a table lamp and one sure-fire way to ensure no energy ever gets to the lightbulb is to take a pair of scissors and severe the lamp cord. Instant isolation. No waiting for further improvements down the road because in a moment in time that lightbulb is instantaneously 100% isolated from electric current.
Would you agree that this is a good-enough analogy of a genuine act of isolation from an energy source?
Good examples but I’ll address at another time.
One problem right off the bat is that rubber in and of itself acts as an isolator not a damper while spikes/cones are not isolators but are energy conduits allowing energy to travel. One object potentially impedes or traps energy's ability to travel while the other potentially expedites the transfer of energy away from its point source.
Two important notes:
1. To the best of my knowledge, all energy seek first and foremost to travel away from its point source.
2. Just because a mfg’er calls their rubber products dampers or calls their spikes/cones isolators does not necessarily make it so. In fact, it’s usually just an indicator that they too are caught up in common misunderstandings (preconceived narratives?). Often times one must analyze the design, materials, executions, etc. to determine which camp a product genuinely belongs. IOW, we must stop assuming everybody knows what they’re talking about – IME, more so with vibration mgmt. than any other sector.
Anyway, so already we’re polluting the isolation methodology with the energy transfer methodology and vice versa, right? IOW, we’re now mixing two opposing methodologies. Isn’t this like trying to mix light with dark, on with off, hot with cold, etc?
Doesn’t the isolation methodology in its purest form work best all by its lonesome? Likewise, doesn’t the energy transfer methodology in its purest form also work best all by its lonesome? Don’t both of these methodologies each belong in their own basic laws of nature/physics camp? Are not these two methodologies polar opposites of each other?
If the answer is yes, then what in the world are we doing trying to create some sort of hybrid of both as our final/best solution?
Fair enough. Based on what you describe above, when one mixes (think pollutes) two otherwise pure methodologies, what kind of results ought one genuinely expect? Here’s a few more questions for you…
1. If in our endeavors we realize a genuine sonic improvement, does that automatically imply we are on a superior path and methodology?
2. Is it possible for those on an inferior path to also realize sonic improvements?
3. What is the best and perhaps only way those on an inferior path when embracing inferior methodologies can realize genuine sonic improvements?
4. From an isolation purist perspective what does an object become when sufficiently damped?
5. From an energy transfer purist perspective what does an object become when sufficiently damped?
6. From an intermixed methodologies hybrid perspective what does an object become when sufficiently damped?
I’m not an engineer but I am a fundamentalist. So in my case I choose what I think is the superior methodology and if performance was absolutely paramount to me (it is), then I do my reasonable best to ensure I never cross methodology streams. Only then might I stand a chance to achieve maximum benefit that methodology has to offer, right?
Hopefully it becomes a bit more apparent when we intermix two primary methodologies, not only have we cut the potential performance legs out from underneath both methodologies, we’ve also just created a bottomless hybrid rabbit hole. IOW, much like a box of chocolates, we’ve zero clue what the hybrid’s results may be.
And that’s not even yet taking into account our ability to somehow apply only superior forms of managing the intermixing of two polar opposite methodologies aka interoperability skills.
I had a longer response here but to keep it shorter I’ll just say… Like everybody else, it seems you’re doing your reasonable best to keep ALL unwanted resonant energy captured at the component to remain trapped within the component, regardless of its source.
The BIG question is why? Are you aware that once unwanted resonant energy is captured at the component, regardless how it got there, then doesn’t the component (and its internals) become the new point source for this unwanted resonant energy?
Back to floor- and air-borne vibrations. No matter what we do, will at least some unwanted floor- and air-borne vibrations still reach the components? According to your steel ball exercise the answer is obviously yes.
What is the natural behavior of energy again? To travel away from its point source.
What is the natural behavior of energy when its ability to travel is impeded?
We’re straying off topic with this section so no comment.
BTW, I have a punch line that should help clear some/all of this mess up but I've a few more notes to share and hopefully some of this here is thought provoking.
Right away I want to clarify something. The properties of rubber makes it primarily a damper, ie the rubber converts mechanical energy into heat. Rubber can isolate as well by absorbing energy but only in specific frequency ranges dependent upon material properties such as hardness, shape and the load placed on it. And also note that the damping and isolation properties of rubber are nonlinear. That makes it difficult to predict how it will perform. And the nonlinear nature of rubber can cause what we hear as colorations. So yes, rubber can function as an isolator but with these aforementioned caveats.
Spring/mass systems isolate, are linear and therefore do not add colorations- I could be wrong but I cannot think of an example where that is the case. You can find some graphs online showing the response ratio of a spring/mass systems vs frequency. The response ratio peaks at the natural frequency and then drops off asymptotically towards zero. Rubber materials do not behave that way.
It is the nature of things to absorb vibrations and convert them into heat. In my video you can see the sinusoidal wave decay to zero after a few oscillations when I pushed on my preamp with my finger. That’s the hysteresis in the spring wire absorbing that energy and converting it into heat- and also the spring wire outside diameter rubbing against the wood down in the holes which is friction being converted into heat. And then I have tubes and class A amps converting electricity into heat. No wonder my room gets hot.
Spring/mass systems isolate, are linear and therefore do not add colorations- I could be wrong but I cannot think of an example where that is the case. You can find some graphs online showing the response ratio of a spring/mass systems vs frequency. The response ratio peaks at the natural frequency and then drops off asymptotically towards zero. Rubber materials do not behave that way.
It is the nature of things to absorb vibrations and convert them into heat. In my video you can see the sinusoidal wave decay to zero after a few oscillations when I pushed on my preamp with my finger. That’s the hysteresis in the spring wire absorbing that energy and converting it into heat- and also the spring wire outside diameter rubbing against the wood down in the holes which is friction being converted into heat. And then I have tubes and class A amps converting electricity into heat. No wonder my room gets hot.
Alternatively, one could use accelerometer measurements to quantify the vibrations, and also some thumping tests to determine if certain equipment is microphonics.
Without any of that it is somewhat like faith to “correlate” things.
I have a couple of new videos. First one shows my amp isolation- as before, with vibration data...
The other video shows my cable risers.
drive.google.com
drive.google.com
The other video shows my cable risers.
Amp isolation.MOV
drive.google.com
Cable isolation.MOV
drive.google.com
Tony,
Can you speak to the choice of spring rate as a function of equipment / shelf mass?
Eg - a 75kg+ Amp & stand versus a 10kg DAC or server?
Thanks!
Can you speak to the choice of spring rate as a function of equipment / shelf mass?
Eg - a 75kg+ Amp & stand versus a 10kg DAC or server?
Thanks!
...nice work on the cables, which are always a challenge. I am working on that problem myself, having just purchase new gear, requiring a new set-up. Thanks for posting.
Nice !I have a couple of new videos. First one shows my amp isolation- as before, with vibration data...
The other video shows my cable risers.
Amp isolation.MOV
Cable isolation.MOV
The natural frequency is a function of the square root of spring rate over mass. You can find some calculators online that will solve for natural frequency by inputting mass and spring constant. Using metric system is easier. English units for mass are tricky. Because it is a square root function, it takes large changes in the ratio of K/m (spring rate/mass) to appreciably change the natural frequency.
For example, the (4) 11 lb/in springs supporting my Preamp which weighs about 40 lbs including the weight of the board it sits on yields a natural frequency of approx 3 Hz. That is ideal. If I were to double the spring rate to 22 lb/in say, then the natural frequency only increases to 4.6 Hz. That is still pretty good and the stiffer springs are a little easier to implement because the platform will not lean as much due to weight distribution.
The springs that I used for my amp stands were originally used with my previous speakers that weighed 175 lbs each. These amps weigh 110 lbs or 150 lbs, I think. Not quite as heavy and so the natural frequency is up around 5 Hz. The amps are still very well isolated and it makes a difference in the sound.
I'm a crusty old engineer more comfortable and used to using the English system of measurements. I lived and worked in Germany for a few years and mostly did my calculations using the English system and then converting to SI units. My German colleagues couldn't comprehend having to divide mass by g sub c. I find it perfectly natural. (Engineering humor)
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