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Re: Audio Rack
CanesFanInVA #441948 04/08/21 02:35 AM
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Nope, it's not BS. Onkyo holds many patents for anti-vibration designs. Here is one:

https://patents.google.com/patent/US7773373

Of note is the following excerpt:

"The function of the vibration-damping structure of the AV amplifier will now be described. With a configuration as described above, when the power of the AV amplifier is turned ON, a voltage is applied to the main transformer 52 and the sub-transformers 53 and a current flows therethrough. As a current flows through the main transformer 52 and the sub-transformers 53, these components vibrate slightly. Moreover, the exhaust fans 54 are rotated by a driving circuit (not shown) to also vibrate slightly. As the main transformer 52, the sub-transformers 53 and the exhaust fans 54 vibrate slightly, these vibrations are transmitted to the component accommodating chassis 45 on which these components are mounted.
Since the component accommodating chassis 45 is fastened to the sub-chassis 25 so as to be partially in contact with the sub-chassis 25 via a plurality of fastening members, the vibrations of the component accommodating chassis 45 are attenuated while being transmitted to the sub-chassis 25. Similarly, since the sub-chassis 25 is fastened to the main chassis 11 so as to be partially in contact with the main chassis 11 via a plurality of fastening members, the vibrations of the sub-chassis 25 are further attenuated while being transmitted to the main chassis 11."

There's more interesting reading below the above excerpt that describes the nasty effects of these vibrations on the audio signal.

Norimasa Kitagawa and the rest of his crew wouldn't make this up. These guys do nothing, I mean absolutely nothing in their lives but eat and breathe this stuff all day and all night.

P.S. I remember reading that Onkyo had a heck of a time with vibration modelling. They'd introduce stiffening in one area only to discover that reflections from the stiffener resulted in more complex vibrations that created more problems. This is one reason a well-designed EI transformer is preferred over a toroidal transformer for power supplies. The EI transformer is less likely to vibrate particularly with a DC component on the powerline.

Last edited by Mojo; 04/08/21 02:57 AM.

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Re: Audio Rack
CanesFanInVA #441949 04/08/21 04:21 AM
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Ok they state that vibration gets into the audio path somehow ... they don't say how ... guessing maybe connectors rubbing, mag fields interacting, open air inductors moving, poor solder joints?

Next .. Why they are going to these lengths ... is it audible or to get killer specs ...

I just find the whole thing over the top ... The only time amp vibration annoys me is when the transformer audibly vibrates the case. But ... maybe some of you have actually have experienced this.

Re: Audio Rack
CanesFanInVA #441951 04/08/21 04:38 AM
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Certainly any time a powered passive or active component vibrates in an electric and magnetic field, parasitic voltages and currents will arise. Electromagnetic fields are everywhere. In fact, all matter including biological matter, is nothing more than an electromagnetic field condensate living in an electromagnetic field. What that electromagnetic field really is no one knows but it appears to be a practical abstraction that we make use of.

A manufacturer like Onkyo, surviving with razor thin margins, would never add parts to a design that are unnecessary. Rather, they optimize the design and that's a much tougher engineering feat than manufacturers who use 50 pounds of steel for their chassis.

For patent purposes, they only say as much as they need to and no more:

"When the AV amplifier is powered ON, the power transformer 90 and the exhaust fan 91 start vibrating, and the vibrations are transmitted to the lower chassis 82. Then, the vibrations are transmitted also to the signal processing board 88 and the amplifier circuit board 89, which are fixed on the upper surface of the lower chassis 82. Vibrations of the power transformer 90, etc., influence the audio signal being processed by the signal processing board 88 and the amplifier circuit board 89. Specifically, the audio signal is contaminated with vibration-induced noise, which affects the quality of the sound output from the speakers."

I think, but can't be sure, that any parasitic noise detracts from the perceived soundstage and imaging and also leads to listening fatigue. Transformer hum is certainly very noticeable but there is other, less noticeable noise that likely gets to us and we don't even know it.

Last edited by Mojo; 04/08/21 04:42 AM.

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Re: Audio Rack
CanesFanInVA #441952 04/08/21 11:31 AM
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I give, Mojo. So, are you putting your gear in restraints? 2x’s preference is a good solid rack.
Don’t think that would eliminate any internal shaking but externally it’s tied down smile

Re: Audio Rack
Mojo #441953 04/08/21 12:34 PM
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Originally Posted by Mojo
I think, but can't be sure, that any parasitic noise detracts from the perceived soundstage and imaging and also leads to listening fatigue. Transformer hum is certainly very noticeable but there is other, less noticeable noise that likely gets to us and we don't even know it.
I’ll guess that in any well designed unit it’s just part of the noise floor ...

Re: Audio Rack
CanesFanInVA #441954 04/08/21 02:16 PM
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There is the theoretical noise floor, the noise floor measured in a lab and the noise floor in the final installation. I'd love to see what the noise is generated within a receiver when turned up and speakers and subs are blaring right at it. Then add to that other environmental noise like EM.

BTW, I haven't gone to any special means to shield my gear from any kind of noise. My cables are like spaghetti. The only thing I've done is route power carefully and not stack the DSPs and amps.

Last edited by Mojo; 04/08/21 02:18 PM.

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Re: Audio Rack
CanesFanInVA #441957 04/08/21 08:31 PM
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Tubes can go microphonic as they age, so maybe...

But the rest I dunno. Far bigger fish to fry when designing a space. smile

By far ventillation is key. Rest is bonus.

Re: Audio Rack
CanesFanInVA #441962 04/09/21 01:46 AM
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Ventilation! Yes sir! Some tubes more microphonic than others, from the git go.

Frying fish ... never in my house.


Enjoy the Music. Trust your ears. Laugh at Folks Who Claim to Know it All.
Re: Audio Rack
rrlev #442070 04/12/21 11:14 PM
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Originally Posted by rrlev
Ok they state that vibration gets into the audio path somehow ... they don't say how ... guessing maybe connectors rubbing, mag fields interacting, open air inductors moving, poor solder joints?

Next .. Why they are going to these lengths ... is it audible or to get killer specs ...

I just find the whole thing over the top ... The only time amp vibration annoys me is when the transformer audibly vibrates the case. But ... maybe some of you have actually have experienced this.

Rich, it might interest you to know that something as minor as the length of your ear or nose hairs affects your listening. Andrew said so in his latest video. I have a nose hair trimmer but unfortunately I busted it as I tried to jam it into my ear. So now I'm in a bit of a panic. This could be why I am only hearing 5 violins.


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Re: Audio Rack
Mojo #442075 04/13/21 12:31 AM
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Originally Posted by Mojo
[quote=rrlev]I busted it as I tried to jam it into my ear. So now I'm in a bit of a panic. This could be why I am only hearing 5 violins.
Did it get stuck? And is it still running?

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