Vibrations, audio components, and sound

[microstrip]

The Finite ELemente Resonator device http://www.finite-elemente.de/englisch-1/hifi-accessories/functioning/ was designed by a known team from the Dortmund University of Applied Sciences and Arts http://www.fh-dortmund.de/borchert/index.php. They have a publication on it, but it is written in German

 

[microstrip]

Classe Audio

"Microphonics, caused by component vibration and magnetic interference from the passage of electric current through them, has plagued audio designers since the beginning of recorded sound. Isolation is the key. At Classé, we begin with a unique front-end circuit topology that mechanically decouples vibration-sensitive components from all sources of vibration. In addition, our transformers rest on a specially designed plate to draw magnetic fields away from the circuitry."


Boulder

"Every critical audio circuit board in the new 3050 is framed in an innovative, custom machined, aerospace-grade aluminum housing rather than screwed to a plate. Vibration damping material is then sandwiched between the circuit board and the frame in order to eliminate even the tiniest mechanical resonances that could have any possible effect on the clarity of the musical signal."

Jeff Rowland

"The control of resonances is very important, especially in the preamplifier itself. Rowland takes a high-mass structure, which is very difficult to move, and further isolates the circuit board within, so that it is not influenced by any outside vibrations. Around 1985, he noticed that as he started putting more screws in the circuit board and tighten it down more, it would sound better, "more dimensional and quieter."

"Normally we don’t think of the contribution of microphonics on solid-state equipment, but as our circuit topologies become more perfect and ideal, then we have to start paying more attention to these other higher-order effects – the contribution of vibration and movement on the actual circuit itself."


Wikipedia on microphonics

"With the advent of solid-state electronics (transistors), this major source of microphonics (tubes) was eliminated but smaller sources still remain.

The ceramic EIA Class 2 dielectrics used in high-K capacitors ("Z5U" and "X7R") are piezoelectric and directly transform mechanical vibration into a voltage in exactly the same way as a ceramic or piezoelectric microphone.[2] Film capacitors using soft (mechanically compliant) dielectric materials can also be microphonic due to vibrational energy physically moving the plates of the capacitor. Likewise, variable capacitors using air as a dielectric are vulnerable to vibrations moving the plates. Capacitors using glass as the dielectric, while quite expensive, can be made to be essentially nonmicrophonic.
Wiring and cables can also exhibit microphonics as charged conductors move around, and various materials can develop triboelectric ("static") charges that couple to the electronic circuits."



Disclaimer - Just FIY - no AES science at all!

IMHO the subject is not deeply studied because the economic interest on the high-end market is too small to pay for research and the basic principles are empirically known by high-end designers.

 

[Phelonious Ponk]

The science of audio forum seems to be rapidly defending into subjectivist speculation.

Tim

 

[DaveC]

IMHO the subject is not deeply studied because the economic interest on the high-end market is too small to pay for research and the basic principles are empirically known by high-end designers.

I agree. I think the subtleties of how mechanical vibration effects electronics wrt small scale vibration is a non-issue in most applications except audio. It seems closer to the issues dealt with by users of sensitive measurement devices and high magnification microscopy. An indication that this is true is the fact Herbie's sells their products that have been developed for audio to such industries. I don't know the details but I do know he has customers that use his products for applications other than audio.

 

[DaveC]

The science of audio forum seems to be rapidly defending into subjectivist speculation.

Tim

I totally disagree. The opinions and design philosophies of folks who are at the pinnacle of their craft seem relevant. Sony, Boulder Amplifier, Clarity Cap, Rowland, Classe, etc.. all seem to hold positions that affirm the importance of controlling mechanical vibration in audio systems. One of the issues with "Audio Science" is that much of the research is done by private businesses who do not share the results of their experiments in order to maintain a competitive advantage.

 

[PeterA]

The science of audio forum seems to be rapidly defending into subjectivist speculation.

Tim

Amir wrote that there is very little audio science on this topic, at least according to his search of the AES papers. I was hoping that someone would actual expand on my list of questions in the OP or attempt to answer them and correct me where my assumptions are wrong. I am somewhat disappointed that the science minded members have not contributed more to the discussion or supplied some data, test results or measurements.

Tim, I would ask this: In the other vibrations thread on the subjective side of the forum all sorts of claims were made about the science of vibrations and their effects. Why are those members not here in the Science Forum supporting their claims with science? That is why I started this thread: to learn something more about this topic beyond what I hear subjectively in my own system with my own solutions.

I would welcome contributions from Reid on Herzan and allvinyl from Stillpoints on this subject, even if only in general terms so as to protect their proprietary research.

 

[YashN]

a few years ago I had a number of Lps, particularly certain female vocal recordings, where I was getting what sounded like groove damage. in one case, a Cassandra Wilson recording 'Blue Moon Daughter', I actually purchased a very expensive second UK pressing from the UK, since I assumed my first one was damaged.

then I got the Herzan to replace the stock vibration platform from Wave Kinetics. those 2 pressings, and many others, now played perfectly. that apparent groove damage was feedback from my new bass towers.

It's one of the albums I use to test for proper bass reproduction, her voice is quite low herself, but there are really low drums and bass guitar and guitar and other percussions, which could sound all muddied in a lesser system. Songs like 'Love Is Blindness' and 'Death Letter'. Her cover of Neil Young's 'Harvest Moon' is not to be missed as well, although very different from the original one.

at that same time i received my new solid state darTZeel NHB-458 monoblocks. they have a designed in suspension for the electronics. the circuitry is actually suspended inside the casework to isolate it from ground based feedback. the amp ships with shipping screws which presses from each side to the inner guts to keep the amp stable during shipping. they are designed to be removed when in place and the holes covered with nice little gold plated screw in caps.

at first i played the amps and after a few hours i was noticing a mid bass bloat and some congestion in the mid range. i was mystified as to the cause. i checked over my system, then read the amp instructions. removed the shipping screws and all the bloat and congestion was gone.

This is interesting, because it is the kind of thing I classify as 'taken for granted' or 'ignored' in most systems. There is a majority of existing equipment that can be end-user improved with some care taken and some DIY skills for next to nothing and which can bring great results.

 

[YashN]

Sony, Boulder Amplifier, Clarity Cap, Rowland, Classe, etc.. all seem to hold positions that affirm the importance of controlling mechanical vibration in audio systems.

It looks like you could add Dartzeel (not too familiar with their particular spelling yet), and perhaps Goldmund and Townshend to that list.

I believe Shunyata, Furutech, Tripoint as well (for other types of components).

 

[NorthStar]

? https://www.gcaudio.com/templates/isolation devices.html

? http://wavekinetics.com/the-truth/

 

[amirm]

Classe Audio

"Microphonics, caused by component vibration and magnetic interference from the passage of electric current through them, has plagued audio designers since the beginning of recorded sound. Isolation is the key. At Classé, we begin with a unique front-end circuit topology that mechanically decouples vibration-sensitive components from all sources of vibration. In addition, our transformers rest on a specially designed plate to draw magnetic fields away from the circuitry."


Boulder

"Every critical audio circuit board in the new 3050 is framed in an innovative, custom machined, aerospace-grade aluminum housing rather than screwed to a plate. Vibration damping material is then sandwiched between the circuit board and the frame in order to eliminate even the tiniest mechanical resonances that could have any possible effect on the clarity of the musical signal."

Jeff Rowland

"The control of resonances is very important, especially in the preamplifier itself. Rowland takes a high-mass structure, which is very difficult to move, and further isolates the circuit board within, so that it is not influenced by any outside vibrations. Around 1985, he noticed that as he started putting more screws in the circuit board and tighten it down more, it would sound better, "more dimensional and quieter."

"Normally we don’t think of the contribution of microphonics on solid-state equipment, but as our circuit topologies become more perfect and ideal, then we have to start paying more attention to these other higher-order effects – the contribution of vibration and movement on the actual circuit itself."

I am unclear why you are quoting all of this. Vibration management in audio electronics has been a marketing feature list for many years. When I was at Sony back in late 1980s I recall reading our ES series brochure bragging about the same things you list above. And I am confident I can find similar mention in mass-market mid-fi equipment. So manufacturer mention is just that. It is not data.

But it does reinforce what I post which is if the designer thinks such matters are important, they need to deal with it in the device. And that is what those companies are saying they are doing. None are saying that their boxes don't perform well unless you put them on an isolation table which is the topic at hand. It would be heck of a statement to make after charging such a premium for their products.

I will address the second part of your post tomorrow.

 

[Goliath]

I am somewhat disappointed that the science minded members have not contributed more to the discussion or supplied some data, test results or measurements

Data and test results supporting what?

The real question here is - is there any supporting evidence to show that vibration widgets audibly change/affect the sound waves meeting the ears? For this, we need controlled tests, and to my knowledge, there is nothing available. Hardly surprising to those of us who are science-minded.

So as someone else rightly put it, absent any evidence outside "I heard it, I said so", this discussion has devolved into subjectivist speculation.

 

[Gregadd]

But it does reinforce what I post which is if the designer thinks such matters are important, they need to deal with it in the device. And that is what those companies are saying they are doing. None are saying that their boxes don't perform well unless you put them on an isolation table which is the topic at hand. It would be heck of a statement to make after charging such a premium for their products.

Whether or not the attempts are effective is another matter. Many make the enxlosure a solid peiice of aluminmu, or mont the cirxuit bards on fubber gromets amd and use rubber devices to preven tube microphonicd. Many appear at shows with turntables mounted on an antivibration device.s

 

[Gregadd]

While there are definite issues of vibrations affecting mechanical devices, tubes, speakers, transformers, flexing pc boards, certain components, etc, the real issue is the common audiophile habit of taking a known scientific thing and trying to extrapolate it to what we can actually hear and at what point we cant hear it, ie at what point is it good enough to not be audible...the perpetual question indeed.

A few decades ago my friends and I did some tests with the then new idea that the heatsinks on power amps if you ran you finger across them you could hear them vibrate. So, we put the amp in another room, cranked the gain fully up, and while a guy tapped and brushed and ran his finger across the heatsinks we all listened, with young ears capable of hearing the flyback at 18Khz in a TV set, and we did not hear anything. Was that just that particular amp or what, hard to say, but you can do tests like this your self to determine if your system has these issues....just do it![/QUOTE
]

Now that is anecdotal evidence of which any audiophile subjectivist could be proud

 

[JackD201]

It's not unique to high end gear. My Pioneer CDJ-2000s are pro units meant for use in commercial clubs. Inside is a suspension system. Sure you might say it's for when you are using CDs but here's the shocker, when using USB sticks or USB from a laptop instead of discs excessive vibration causes the players to go into error mode which triggers the emergency loop function. The internal suspension is not enough. It's pretty common then for clubs to have rubber or sorbothane rails on which these are installed. We're not talking just about sound quality here, we're talking system failures in live performances. So much so that the suspension is present in the XDJ-1000 which is the version with no transport (USB, Ethernet only) and there are after market stands for these that have anti vibration pads too. Here's the thing, the vibration angle isn't in any marketing material. If you want to see the countermeasures you'll find them in the service manuals. Hyped for high-end? Perhaps. Needed? You can figure that out for yourselves.

That said I have come across components that to these ears are oblivious to what they're placed on. My old Levinson 3 series pre and dacs were pretty immune. The CH Precisions I have now are too. What do they have in common? They've already dealt with vibration from the get go. Mind you, I sell racks. Some of the costliest ones around. When I say you can forego the expense with CH and just recommend something really sturdy because these weigh a ton, that's less money in my pocket. The racks do however make a difference with everything else I carry.

Add to that reports here from two fellows who went from footers to racks where reinserting the footers between the new racks yielded no more changes in either direction. That kinda debunks the "mo' bettah" theory and that there is a point where observed difference go into "so small that I could just be imagining things, so off to audiogon you go territory".

Now the big question. What measurements would actually satisfy those that seek to refute the observations? I'd be really interested in seeing what methodologies they would employ.

 

[BE718]

I investigated a lot of this in another forum. A FM was claiming that he could hear very positive differences created by applying hard plastic (PEEK) screws and components to his equipment stand, all of which were apparently helping to "earth" and isoloate vibration away from the components.

Now, I work in vibration measurement and my FOO alarm went off. I chuckled to myself and decided to provide some actual vibration measurements of my kit and stand and other items to show just what was wrong with this thinking. I have access to vibration measurement kit from Bruel & Kjaer and others.

Needless to say the thread got somewhat heated at times. I can point people in its direction but the signal to noise ratio is very poor and it is very long. If people are interested I can re-hash it here trying to be a little more concise hopefully.


However to sum up, can equipment be microphonic? Yes it can.

Is that a problem for most kit (excluding turntables) in normal domestic environments? No.

Do many hifi stands actually isolate vibration? Nope.

 

[amirm]

I am interested to see the data and learn. So however you like to summarize, it would be great.

 

[BE718]

I am interested to see the data and learn. So however you like to summarize, it would be great.

I will get to work

 

[Blizzard]

One of these unit's are on my "to buy" list.


http://www.dytran.com/Model-5346A1-...Vibration-Sensor-Analysis-Software-P3045.aspx

 

[BE718]

One of this unit's are on my "to buy" list.


http://www.dytran.com/Model-5346A1-...Vibration-Sensor-Analysis-Software-P3045.aspx

Interesting however it is very limited in frequency range. I was very concerned where the manual states it has no aliasing filters built in. This is an important and fundamental requirement.

 

[Blizzard]

Interesting however it is very limited in frequency range. I was very concerned where the manual states it has no aliasing filters built in. This is an important and fundamental requirement.

What do you recommend? This one looks pretty cool. Wider frequency range as well. Can connect to mobile devices.

http://digiducer.com/