Vibrations, audio components, and sound

[microstrip]

Maybe the subs frequencies aren't exciting the solid state components? I can absolutely hear what type of support my Ayre MX-R's are on...

John,

We need an open mind to understand the problem of vibrations in electronics. Electronic systems feel the vibrations in a different way from our fingers ...

The subject has been exhaustively reported the past by many audio designers who care about these effects. People have assembled the same circuit amplifiers using thick non resonant heat sinks and flickery ringing heat sinks and found they sounded quite different. Specialized audio component manufacturers, such as Mundorf from Germany supply data on vibration sensitivity of their components.

But, yes, they do not supply blind test evidence and the reported effects can not be easily measured with a PC soundcard and some cheap software, because the effect of vibrations is delayed in time.

 

[PeterA]

The subject has been exhaustively reported the past by many audio designers who care about these effects. People have assembled the same circuit amplifiers using thick non resonant heat sinks and flickery ringing heat sinks and found they sounded quite different. Specialized audio component manufacturers, such as Mundorf from Germany supply data on vibration sensitivity of their components.

But, yes, they do not supply blind test evidence and the reported effects can not be easily measured with a PC soundcard and some cheap software, because the effect of vibrations is delayed in time.

Does this not suggest that electronic components are sensitive to vibrations? Speaking of heatsinks, have we not all heard them resonating when a sudden handclap is made near them? I certainly have, but I don't know if that is also heard in the amps' output.

This discussion of whether or not one can hear the effect of isolation platforms under SS amps reminds me of the disagreement we had earlier in another thread about whether or not one can hear SS amplifiers warm up during the first hour or so after being turned on. Some hear it, others deny it. Nelson Pass writes that warm up is audible, but I have not read anywhere what he thinks about vibrations reaching or within his amps.

I am going to think about how I can devise an unsighted test of my amps to see if I can hear the effect of both warm up and the inflated vs deflated Vibraplanes. I will say that when I added steel ballast plates to my Vibraplanes and had a friend over to listen, he immediately heard a difference, not noticing (seeing) the new thin black steel plates or any other change to the system. He simply said, "Wow, what did you do to change the sound so dramatically?"

I will add that reading the skeptical comments about effects does have me wondering about trying to conduct a bunch of unsighted tests in my room. It would be nice to simplify things by removing things if they don't in fact have an audible effect.

 

[jfrech]

J Hi, first you should ask a friend to pick up your pre amp say, while you are unsighted.
You have to pick when you hear a difference, the human body is an extremely good isolation device ,so it 'should' be easy to spot.
But it has to be unsighted.
Read the Microphony thread I linked to !
Keith.

Keith, I read that thread. Very interesting and thanks for posting it. I think it captures one aspect for sure. His last sentence below all the graphs was interesting also.

 

[rbbert]

As far as speakers go, this analysis by Gary Koh is useful

http://www.whatsbestforum.com/showt...ing-with-particular-reference-to-loudspeakers

 

[microstrip]

(...) I will add that reading the skeptical comments about effects does have me wondering about trying to conduct a bunch of unsighted tests in my room. It would be nice to simplify things by removing things if they don't in fact have an audible effect.

Skeptical founded comments are always welcome. However measurements taken with an accelerometer placed on or in close contact with the surfaces or box of the electronic equipment are not a proof of inaudibility of anything.

Remember that before conducting unsighted tests you have to carry successful positive tests to "calibrate" your system.

 

[microstrip]

The accelerometer is used to measure the amount and frequency of the vibration, the proof of the pudding is the spectral analysis of the output of the device being tested.
If there are no extra spuriae on the plot, at the frequencies that the unit vibrates , them no noise is being transferred to the output.
Microphony II and III are worth reading.
Keith.

It is known that the spectral analysis of the output in no proof of the pudding. It is why these differences are commonly called "small differences". You need very special dedicated measurements to measure it. Otherwise no one would buy Audio Precision or similar high price, high quality programmable testing equipment.

Can you point me a link to a particular post that is worth reading in the threads you refer? Such ambiguous references do not prove anything. BTW I do not want to prove or proof anything, you are the one who has all the certainties and I am now the skeptical ....

 

[microstrip]

Alan used extremely expensive measuring kit , he is an engineer specialising in vibration in aircraft engines.
If the 'noise' can't be measured in the output then it's isn't going to be audible.
Search for posts by Be718
Keith

Microphony II
http://www.pinkfishmedia.net/forum/showthread.php?t=174650&highlight=Microphony

Microphony III
http://www.pinkfishmedia.net/forum/showthread.php?t=175165&highlight=Microphony

I asked for a direct link to useful relevant information that can be debated, the signal to noise ratio of these confused threads is beyond my patience threshold. Sorry. And I would find more relevant to this thread if the poster specialized in vibration in atomic force microscopes.

No one is saying it can not be measured - I said it can not be measured by the simple way you suggested.

 

[PeterA]

Keith, it might be useful if you just dropped the particular quotes into this thread for easy access and future discussion.

I've been thinking about testing my amps with the Vibraplanes inflated and deflated. Moving them off of the units is out of the question, especially for quick A/B unsighted listening. Even simply deflating them is time consuming and difficult to do unsighted. If I could find a friend to set it all up while I left the room, it would not be double blind and there is the problem of the inability to switch back and forth quickly. I'll keep thinking about this. Does anyone else have a suggestion as to how to best test whether or not the amps' output changes with the isolation or not without the use of expensive test equipment that I don't have?

I think this is why the typical audiophile is left to simply listen over time to see if he can notice any changes. I realize that this method is open to criticism, but at the moment, it is all that I have besides reading other peoples accounts and threads like Keith is suggesting.

 

[amirm]

Keith, it might be useful if you just dropped the particular quotes into this thread for easy access and future discussion.

I've been thinking about testing my amps with the Vibraplanes inflated and deflated. Moving them off of the units is out of the question, especially for quick A/B unsighted listening. Even simply deflating them is time consuming and difficult to do unsighted. If I could find a friend to set it all up while I left the room, it would not be double blind and there is the problem of the inability to switch back and forth quickly. I'll keep thinking about this. Does anyone else have a suggestion as to how to best test whether or not the amps' output changes with the isolation or not without the use of expensive test equipment that I don't have?

You could stick four blocks of wood under the four corners of Vibraplane to lift it up? That would defeat its damping pretty good and can be done in 15 to 20 seconds I imagine if your amp is not too heavy. Put a curtain in front of the set and have your friend come and go, sometimes doing this, sometimes not and see what the results are.

I think this is why the typical audiophile is left to simply listen over time to see if he can notice any changes. I realize that this method is open to criticism, but at the moment, it is all that I have besides reading other peoples accounts and threads like Keith is suggesting.

It is not just open to criticism. In the science thread that we are, it is of no probative value. It is as good as not having done the test.

 

[amirm]

I asked Micro the same question, is there any published data to show,that low level vibration from the unit itself, or transferred structurally or through the air ,is audible on the output of any solid state equipment?

I searched the AES library yesterday. The only papers on this topic were from late 1970s to early 1980s and all on turntables (putting aside the loudspeaker ones that are not the topic here). This indicates total lack of any interest to conduct such tests, meaning no one expects any audible effects to be there.

 

[PeterA]

I asked Micro the same question, is there any published data to show,that low level vibration from the unit itself, or transferred structurally or through the air ,is audible on the output of any solid state equipment?
presumably someone must have suggested to you that your solid state equipment would sound better is isolated?
Keith.

I don't know the answer to the first question. To the second question, yes, a gentleman in Germany with Lamm SS amps suggested that I try Vibraplanes under my Pass amps. He heard a difference with his and suggested that I try it. I already knew that it improved the sound of my turntable, so I went ahead and tried it. I heard an improvement, and a further one when adding the steel ballast plates to optimize the load.

I'm not saying that it can be measured. I'm not sure. MikeL has an active Herzan under his preamp or DAC and noticed a difference also. What I would like to know is if replacing the stock Pass Labs rubber footers with coupling devices will improve the sound further. I did notice a difference when placing Stillpoint Ultra 5s under the amps, but it was unclear to me if the difference was also an improvement. I decided not to buy the Stillpoints.

 

[DaveC]

It is not just open to criticism. In the science thread that we are, it is of no probative value. It is as good as not having done the test.

I understand what you're saying but in the end it's a personal judgement. Where the thread resides makes no difference to me.

In science terms, couldn't it be the equivalent of an untested hypothesis? That's pretty much my view on it...

hy·poth·e·sis
h??päTH?s?s/
noun
noun: hypothesis; plural noun: hypotheses

a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

 

[amirm]

I understand what you're saying but in the end it's a personal judgement. Where the thread resides makes no difference to me.

That's fine but makes a difference to everyone else who is here. We created this forum to avoid subjective observations being offered as proof points. So we can't go back on that or there would have been no reason to create this forum. There is currently a parallel thread in the non-science forum and these observations can go there.

In science terms, couldn't it be the equivalent of an untested hypothesis? That's pretty much my view on it...

hy·poth·e·sis
h??päTH?s?s/
noun
noun: hypothesis; plural noun: hypotheses

a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

In generic science, sure. In audio science, no. As I mentioned, the implicit position of audio science is that this is not a worthy subject of investigation because almost assuredly, such subjective observations are due to personal biases, as opposed to any indication of audible difference.

If isolation is needed for whatever reason, the designers of such expensive equipment should have included it in their products. If their stated fidelity cannot be achieved otherwise, they better be front and center about it in their marketing material and manuals.

All of this said, as I indicated, I plan to perform some testing as I think it is useful to have data to discuss rather than general position.

 

[PeterA]

You could stick four blocks of wood under the four corners of Vibraplane to lift it up? That would defeat its damping pretty good and can be done in 15 to 20 seconds I imagine if your amp is not too heavy. Put a curtain in front of the set and have your friend come and go, sometimes doing this, sometimes not and see what the results are.

Amir, Thank you for the suggestion, but if you were to look at the photo of my front wall in my system page, you would see the challenge. My amps weigh about 140 lbs, the steel ballast plates weigh another 136 lbs, and the Vibraplanes each weigh 150 lbs. That's 426 total, all in a tight space. The speakers have to be moved for good access to these items. I could put wood blocks under each side leaving perhaps an 1/8" and then just deflate them a bit. That would be quicker. But then, that is not the same as having them on the bare floor boards. I think the massive steel and birch ply platforms, even not inflated, would offer some insulation from floor borne vibrations, given the mass and different materials. But I will consider making the effort.

It is not just open to criticism. In the science thread that we are, it is of no probative value. It is as good as not having done the test.

Yes, I appreciate this distinction, and don't want to drift further toward listening impressions and the discussions that would follow. Measurements would be more appropriate in this forum, but I can't take them and I don't know if there are any published ones showing audible distortions anyway, as Micro has asked. So, perhaps I can not really add anything further of substance to this thread which is attempting to get scientific answers to the questions about different vibrations on different components. I think I will just read what others can share about the science behind this.

 

[microstrip]

I searched the AES library yesterday. The only papers on this topic were from late 1970s to early 1980s and all on turntables (putting aside the loudspeaker ones that are not the topic here). This indicates total lack of any interest to conduct such tests, meaning no one expects any audible effects to be there.

Fortunately it was of interest to Mark Levinson designers. Quoted from the ML no32 Reference Manual (surely not on the AES library).

The Nº32’s casework is extraordinary even by Mark Levinson standards, and, like the other aspects of its design, reflects an uncompromising approach. Its chassis is a custom aluminum casting, machined and finished with a conductive Irridite (clear chromate) coating. This design approach assures a rigid, stable environment in which vibration and microphonic effects are controlled.

I hope it was not a typographic error ...

 

[DaveC]

Fortunately it was of interest to Mark Levinson designers. Quoted from the ML no32 Reference Manual (surely not on the AES library).

The Nº32’s casework is extraordinary even by Mark Levinson standards, and, like the other aspects of its design, reflects an uncompromising approach. Its chassis is a custom aluminum casting, machined and finished with a conductive Irridite (clear chromate) coating. This design approach assures a rigid, stable environment in which vibration and microphonic effects are controlled.

I hope it was not a typographic error ...

And Sony, with their higher end chassis and footer designs used for the ES series components.

 

[Mike Lavigne]

I don't know the answer to the first question. To the second question, yes, a gentleman in Germany with Lamm SS amps suggested that I try Vibraplanes under my Pass amps. He heard a difference with his and suggested that I try it. I already knew that it improved the sound of my turntable, so I went ahead and tried it. I heard an improvement, and a further one when adding the steel ballast plates to optimize the load.

I'm not saying that it can be measured. I'm not sure. MikeL has an active Herzan under his preamp or DAC and noticed a difference also. What I would like to know is if replacing the stock Pass Labs rubber footers with coupling devices will improve the sound further. I did notice a difference when placing Stillpoint Ultra 5s under the amps, but it was unclear to me if the difference was also an improvement. I decided not to buy the Stillpoints.

for those who need visual proof; the Herzan (and a few other active devices) does have a screen which allows you to observe the noise that is being attenuated as it is happening. basically it's an LCD with a number of straight lines which get 'disturbed' both vertically and horizontally depending on the degree and duration of the resonance sensed by the piezo-electric sensors. you can clap your hands, or thump the gear, or shelf, or rack, or jump up and down on the floor.....and you will see the noise/feedback visually. you can play a piece of music and observe it; and then play the same music with the speaker and amps off and observe it, to see the difference. you can just sit there and observe 'ground noise' making the lines very slightly 'squiggle'.

will every system get the same benefit from such a device? no.

does every system (and every piece of gear) deal with noise? of course. but is it always audible? no. and you have to listen in a specific context to say what the benefit, if any, that there would be to any type of treatment.

in the research/medical environment using electron microscopes there is a 100% predictable benefit to active isolation. it's logical that there would be. and since you can see it with your own eyes it's hard to deny.

 

[Mike Lavigne]

Indeed it shows that the device is attenuating vibration, but it does not prove that any vibration still present is being heard through the audio output of the device being supported.
Keith.

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.

this was when I first got my MM7 speakers with 86" tall, 750 pound bass towers, 8 feet from my tt.

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.

so that is a turntable example.

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.

denial is not a River in Egypt. it's the state you are in.

or you are a troll just pulling on chains.

 

[blutto]

....find below a post by Gary Koh from the thread mentioned up thread....

-------------------------------------------------------------------
"
Quote Originally Posted by Phelonious Ponk View Post

Gary, surely if you've built coupling or isolating into your speaker systems you've measured the effects? Besides, nothing ends that what's audible vs what's measureable never-ending debates more effectively than solid evidence.

Tim
Yes, I measured while doing the design to optimize. But I didn't take high resolution screenshots, and the changes were more audible than measurable and there will be those who will argue that the measurements shown will not be audible. Even if I were to post the measurements, the problem is that you can't fight an opinion even with solid evidence.

------------------------------------------------------------------------------

....and the reason this is so ( and this comes from a convo I once had with a B & K rep ) may be because the ear/brain can actually listen way down into a noise floor whereas most instrumentation brick walls at the edge of the noise floor ( and this added level of "insight" can in certain circumstances exceed 50db )....

-------------------------------------------------------------------------------

....and there is one more thing that I think should be considered....in the "study" that Keith leverages his argument on is a line that should give everyone pause who believes that "study" to be gospel truth..... the line says Note this is on the amps top cover which is essentially a thin sheet easy to excite. The vibration on the internal components may be even lower. ( the top plate of the amplifier was the part that was the focus of the measurement )....so essentially no part of the amplifier which actually does any amplifying work was measured....

....so to draw hard and fast conclusions from that "study" would be the equivalent of inferring the acoustic characteristics of rooms in a house from the measurement of the roof....yeah its interesting, but ????....


Cheers

 

[DaveC]

We know that electric signals can cause mechanical vibration in transformers, wires, capacitors, etc... In fact one of Clarity Cap's main goals in developing their new(ish) MR capacitors and others in their line is vibration control:

"The crucial factor to emerge was the effect that mechanical resonances within a capacitor have on sound quality and the importance of reducing or controlling a capacitor’s sonic output."

http://www.claritycap.co.uk/products/mr.php

There's also the fact that mechanical systems can be modeled using the exact same differential equations as electric circuits, it seems reasonable that if electric resonance can be so easily converted to mechanical that the opposite could also be true.