Vibration Management

[Taiko Audio]

Hmm, I think I'll pass on bolting stuff to platforms
Not poss w my tt for a start

I think your turntable would be heavy enough to couple to the platform by function of mass. I was more thinking along the lines of something lightweight like a T+A Dac 8 DSD

 

[KlausR.]

Vibrations excite an object in multiple directions, the 3 axis I can measure are vertical (height), horizontal 1 (depth), horizontal 2 (width).

Sounds like an accelerometer. Would this sensor not be affected by the sound wave itself? Apparently Stacore had precisely that problem, see #108.

Klaus

 

[spiritofmusic]

Taiko, which brings the chat around to what Lloyd LL21 has done in mass loading his components
Or is the consensus that bolting gear to support shelves is a TOTALLY different venture to this option?

 

[Taiko Audio]

Sounds like an accelerometer. Would this sensor not be affected by the sound wave itself? Apparently Stacore had precisely that problem, see #108.

Klaus

It's called a vibration analyzer, it measures displacement, acceleration and velocity. Sensor precision is mainly influenced by mass.

 

[Taiko Audio]

Taiko, which brings the chat around to what Lloyd LL21 has done in mass loading his components
Or is the consensus that bolting gear to support shelves is a TOTALLY different venture to this option?

I think I need to clarify something here. We are discussing 2 different modes of action:

1) Isolation from the floor where the top plate of the (active) vibration platform attenuates floor vibrations and hence supplies a more quiet shelf to place your component on.
2) Cancelling out vibrations of the component itself placed on top of the active vibration platform, I intentionally did not bracket active here as you may have noticed. For the platform to be able to counter vibrations of the component it needs to be able to MOVE the component in counter phase to the vibrational nodes. Hence it needs to be rigidly coupled to the platform and be able to be excited to move in counter phase. Mass loading is a way to "couple" the component to the platform, so is "bolting it on". I don't know what LL21 uses mass loading for but you could also use it to reduce ringing times of a component, change its self resonance, etc. This is however a different function of mass loading them I'm discussing

 

[KlausR.]

It's called a vibration analyzer, it measures displacement, acceleration and velocity. Sensor precision is mainly influenced by mass.

Does the the analyzer generate output when you place it at say 3 m from the loudspeaker and play a tune? If so, does the measuring protocol prescribe to measure a baseline to be deducted from the actual measurement?

If you have to fix the head of the sensor to the device to be analyzed, like shown for instance for the Erbessd analyzser, does this not modify the vibration behaviour of the device and hence the readings?
Klaus

 

[spiritofmusic]

Taiko, I love it when engineers use emoticons
It's good to gaze upon the huddled masses LOL
Whether we smile or cry is in yr remit
Better than lighting a fire and praying to the Gods, as the audiophiles in 10000BC prob did

 

[microstrip]

why would audio components be any different than what is being targeted in those tutorials? it's not any different. follow the steps outlined. the tools offered in those tutorials are good enough for world class laboratories.

but I will allow Emile (Taiko) to explain.

You need to know the fundamentals of how vibrations affects sound quality before drawing any universally accepted conclusions in this matter.

We can have at less several possibilities - vibrations due to feedback of loudspeakers, vibrations of the whole room structure, vibrations induced by other components in the equipment and vibrations due to the electrical signals in the component it self. Unless you know precisely what is the contribution of each type and how they rank, and which you do want to address, you do not know what you should measure. Just picking measurements because they are useful for other very exigent applications does not help to understand what is really happening.

People often forget that an useful measurement must correlate with what is being tested and that in order to establish such correlation we often need to dig deep in the subject.

Just MHO.

 

[Stacore]

You need to know the fundamentals of how vibrations affects sound quality before drawing any universally accepted conclusions in this matter.

We can have at less several possibilities - vibrations due to feedback of loudspeakers, vibrations of the whole room structure, vibrations induced by other components in the equipment and vibrations due to the electrical signals in the component it self. Unless you know precisely what is the contribution of each type and how they rank, and which you do want to address, you do not know what you should measure. Just picking measurements because they are useful for other very exigent applications does not help to understand what is really happening.

People often forget that an useful measurement must correlate with what is being tested and that in order to establish such correlation we often need to dig deep in the subject.

Just MHO.

+1
We use measurements to asses the technical performance and correctness but then the main tests are listening.
Put it simply: measurement is about one to few parameters max, listening impression is highly multidimensional.
I'd love to have at my disposal a lab which would reliably measure the transfer curve in the whole audio range
plus a trained listening group to correlate the measurement with listening impressions (sth. similar that has been done e.g.
with the harmonic distortion spectrum). Maybe one day...

Cheers,

 

[BlueFox]

One area I think being overlooked is that sound is simply the vibrations of air molecules. If your audio gear and rack are also vibrating then that is affecting the air molecules. This would collide with the vibrations from the speakers and add distortion to the sound.

At least that's my hypothesis. I realized that while wondering why the stereo sounded so good late at night. Then I realized all the outside ambient noise was gone, and it occurred to me that the air was still and only carrying the music. Granted, some postulate that the power is cleaner at night, and while that might be true, my power is clean all the time, and at night the air is also clean.

 

[Mike Lavigne]

You need to know the fundamentals of how vibrations affects sound quality before drawing any universally accepted conclusions in this matter.

We can have at less several possibilities - vibrations due to feedback of loudspeakers, vibrations of the whole room structure, vibrations induced by other components in the equipment and vibrations due to the electrical signals in the component it self. Unless you know precisely what is the contribution of each type and how they rank, and which you do want to address, you do not know what you should measure. Just picking measurements because they are useful for other very exigent applications does not help to understand what is really happening.

People often forget that an useful measurement must correlate with what is being tested and that in order to establish such correlation we often need to dig deep in the subject.

Just MHO.

from my perspective, Taiko is taking the same through approach to high end audio music reproduction resonance optimization, that his team took to create the SGM music server. it's not only science, but science and listening. and lots of out of box thinking added on. and using the best possible tools science can offer as well as materials science and any other tools that can be brought to bear.

I can say I am very excited to have peeked behind the curtain on what is being done.

 

[Stacore]

It should have become obvious that I do not believe in results from sighted listening, which is what is done in 100% of the cases. So without controlled listening tests I have no reason to believe that some arm-cart combos sound bad indeed. But that’s me.

This very much depends on what is your objective in audio and what do you expect from your system,
if you have a well developed inner sound reference or you have to rely on external reference points, etc etc.

Cheers,

 

[Taiko Audio]

Does the the analyzer generate output when you place it at say 3 m from the loudspeaker and play a tune? If so, does the measuring protocol prescribe to measure a baseline to be deducted from the actual measurement?

If you have to fix the head of the sensor to the device to be analyzed, like shown for instance for the Erbessd analyzser, does this not modify the vibration behaviour of the device and hence the readings?
Klaus

No it does not generate much if any output signal hanging in free air, although I admittedly did not try this as I would use a microphone for that purpose.

It functions by mass coupling to a surface.

There will always be a noisefloor you have to deal with in any type of measurement you take.

Taiko, I love it when engineers use emoticons
It's good to gaze upon the huddled masses LOL
Whether we smile or cry is in yr remit
Better than lighting a fire and praying to the Gods, as the audiophiles in 10000BC prob did

Gosh that made me feel special for a minute there

 

[KlausR.]

One area I think being overlooked is that sound is simply the vibrations of air molecules. If your audio gear and rack are also vibrating then that is affecting the air molecules. This would collide with the vibrations from the speakers and add distortion to the sound.

I just made a simple experiment: laboratory stand with clamps, sheet of paper free hanging from the clamp, distance to woofer 20 cm (8 inch), played Flim & the Bs "Tricyle" track 1, volume knob at 3 pm (active speaker, woofer amp 400 Wpc). With the impulsive sounds the lower end of the sheet vibrates, observed with the naked eye. At 1 m, it doesn't. Then took a paperthin piece of copper foil, 20 cm from the woofer, no movement at all.

I frankly don't think that the housing of an audio component, which is substantally thicker that my copper foil, and not placed directly in front of the woofer but to the side and often above, has the slightest intention to move.

Klaus

 

[spiritofmusic]

Taiko, you guys ARE v special
Seriously
Anyone who can have a major part in designing digital gear ie the SGM that has nudged me T-H-I-S close to relinquishing vinyl as my source of choice, is pretty damn special
If you ever talk to Barry/Blue58, he'll tell you a dozen plus exposures to yr stellar unit is doing just that

So, Mike L's interesting news on active isoln hitting another level is linked to yr work?
Hmm, the mystery deepens...

 

[KlausR.]

This very much depends on what is your objective in audio and what do you expect from your system,
if you have a well developed inner sound reference or you have to rely on external reference points, etc etc.

My objective in audio and expectations from my system are that they play the tunes I like with as little addition/subtraction/distortion as possible, within my budget of course. It took me one year to know what is important in vinyl replay, it tool me another year to know what's important in loudspeakers. During my research I came across "The Great Debate" and that was a turning point, audiowise.

Klaus

 

[KlausR.]

No it does not generate much if any output signal hanging in free air, although I admittedly did not try this as I would use a microphone for that purpose.

If it does when throwing music at it, you'd have to get the baseline before doing the actual measurement. That should be possible, so yes, it would be interesting to see how the housing of an amplifier behaves when struck with sound waves from a subwoofer.

Klaus

 

[Taiko Audio]

Taiko, you guys ARE v special
Seriously
Anyone who can have a major part in designing digital gear ie the SGM that has nudged me T-H-I-S close to relinquishing vinyl as my source of choice, is pretty damn special
If you ever talk to Barry/Blue58, he'll tell you a dozen plus exposures to yr stellar unit is doing just that

So, Mike L's interesting news on active isoln hitting another level is linked to yr work?
Hmm, the mystery deepens...

Thank you, much appreciated! We're working on several very interesting projects but a little mystery makes life so much more interesting doesn't it?

 

[Taiko Audio]

If it does when throwing music at it, you'd have to get the baseline before doing the actual measurement. That should be possible, so yes, it would be interesting to see how the housing of an amplifier behaves when struck with sound waves from a subwoofer.

Klaus

You'd be amazed. I'll look into a small demo somewhere in the next few days.

 

[KlausR.]

You'd be amazed. I'll look into a small demo somewhere in the next few days.

Ik ben benieuwd. Take your time, next week I'm out of office.

Klaus