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Vibrational Effects on Digital Audio

Wes

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There is a lot of discussion in the audiophile press and forums about how vibrations (say from a cooling fan for a PC) can affect the SQ from a DAC.

I thought this might be a fertile ground for discussion, so here it is...
 

pkane

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There is a lot of discussion in the audiophile press and forums about how vibrations (say from a cooling fan for a PC) can affect the SQ from a DAC.

I thought this might be a fertile ground for discussion, so here it is...

The Beach Boys were aware of this issue, as evidenced by: "I'm pickin' up good vibrations"
 

Inner Space

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There is a lot of discussion in the audiophile press and forums about how vibrations (say from a cooling fan for a PC) can affect the SQ from a DAC.

I thought this might be a fertile ground for discussion, so here it is...

My country place has a 10-mile drive over washboard dirt, gravel, rocks, roots and packed snow, and then I get to a level, paved two-lane recently redone with smooth new blacktop. My truck's CD player doesn't change SQ. So DACs are probably safe from cooling-fan vibes.
 

PierreV

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That's a severe issue indeed.
My bits were so shaken that, every time I played "Money, Money, Money" by Abba, they reshuffled the stream into bitcoins.
Fortunately, I found an objective solution: gimbals. My DJI Osmo is a perfect fit for the KTB.

1614562633638.png
 

BillG

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There is a lot of discussion in the audiophile press and forums about how vibrations (say from a cooling fan for a PC) can affect the SQ from a DAC.

Those of us who have worked in computer science and information technology professionally for decades shake our heads in disbelief at all the myths propagated by certain unscrupulous manufacturers (and the naive audiophiles who take every sales pitch they present as truth) regarding digital audio.

These aren't turntables and tube amps we're dealing with here, it's data. I could slap my DAC with a rubber hammer all day long and it still wouldn't affect the sound quality.
 

chris719

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Well, a lot of electronics now are using high-k MLCCs in power supplies, decoupling, and even voltage reference filtering. Certainly you can come up with tests that will show the piezoelectric effects of these caps. I just highly doubt they are of real concern in audio. Even if there was a measurable contribution in a specially designed test, it seems highly unlikely to apply to real use cases.
 

curiouspeter

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Quiet! The audio industry will collapse if people realize that a $10K DAC is indistinguishable from a $100 DAC. You can sell a $10K DAC without some isolation feet. :p
 

pozz

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Some devices are microphonic. Not that I know much about the causes but @March Audio posted a few videos:
 

amirm

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I tested for vibration a long time ago. Volume controls are by far the highest source of such effect. Cable connections can be responsible as well.

I am game doing more testing but need a test platform which I can dial in the level and frequency of vibration. Thought of building something out of a woofer and such but just haven't had time. Anyone can think of a ready and cheap solution?
 

Blumlein 88

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This might be a subject @Frank Dernie has some useful knowledge to contribute.

Well unless he tells us to bolt our ADC/DACs into an F1 car and drive it around a track. If that is the suggestion I volunteer to be the test pilot. :)
 

Mnyb

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Paint shaker/mixer ? When you buy paint and they mix it in the store , the clamp the can to a machine to mix the pigment and base paint ?
 

Chrispy

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The audiophile press being largely shills for such products, hard to know what their input means.

ps having had digital gear going offroad several times I'm not worried about it at all at home.
 

Mnyb

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The audiophile press being largely shills for such products, hard to know what their input means.

ps having had digital gear going offroad several times I'm not worried about it at all at home.

The company I work for , who builds a lot of VSD drives quite large digital things . In a steel mill or paper mill you definitely can feel the whole floor vibrate in some electrical rooms where the equipment lives.

It’s only in the marine version with ship propulsion and oil rigs we take special anti vibration precautions .
 

Chrispy

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LOL audiophilia can be debilitating.... :)
 

Vovgan

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I am game doing more testing but need a test platform which I can dial in the level and frequency of vibration. Thought of building something out of a woofer and such but just haven't had time. Anyone can think of a ready and cheap solution?

How about putting a DAC on a table over a subwoofer? This will be the maximum amount of vibration any DAC will realistically experience in any stereo/HT setup. I have not noticed any deterioration in sound quality, even though my subs where sometimes moving left and right during the battle scenes in movies before I put silicone strips under their velvet-laid feet.
 

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Frank Dernie

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This might be a subject @Frank Dernie has some useful knowledge to contribute.

Well unless he tells us to bolt our ADC/DACs into an F1 car and drive it around a track. If that is the suggestion I volunteer to be the test pilot. :)
I was actually the first person to run a digital data recorder on a F1 car.
We considered analogue recorders but the ones I had used before, FM data recorders running 1" tape, were almost as heavy as the car.
A clever German engineer who designed the first microprocessor controlled ignition system for the Cosworth DFV made a rather splendid little FM data recorder using a Uher portable cassette recorder mechanism with a 4-track head and his build FM electronics. He designed it for testing his ignition box on the car but we got him to make one for us to test differentials. One track was reserved to record the modulation frequency so we could use its output in the demodulator to comensate for speed fluctuation due to car movement. We recorded throttle opening and 2 output shaft speeds for diff comparisons.
Even with the demodulation from a channel of the recorder we often had to throw away data because of excessive tape speed fluctuations causing the demodulator to drop out. We gave up trying to get consistently useful data.
Once we had a digital recorder, a one off made by an enthusiast who worked on instrumenting nuclear bomb tests (!) who fancied starting his own business, we got useful data.
There were zero vibration related performance shortcomings in the data. All the vibration related problems were mechanical, like cracked pcb tracks, intermittent contact in sockets and so forth. The biggest limitation was with the RS 232 interface the data download speed was slower than real time, and wired, so the driver got impatient during downloads, generation 2 used plug in memory, a 256 kB memory card was over £1000 iirc back then.
Interestingly the same guy worked for me right up to the first prototype active suspension controller - I wrote the spec, he assembled OEM hardware into a box and wrote the code.
Analogue systems were neither accurate enough nor robust enough, in the data corruption sense, for use on F1 cars.
We did have problems to resolve with digital systems but they were to do with transducer choice, anti-aliasing, data rates, hardware cost and availability and download speeds.
The only vibration related difficulties were mechanical damage.
 

wwenze

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The electrical effects of the fan likely overshadows this... because I've heard that before

We might need to decide on an upper limit, because anything shaken enough can have audible effects. Loose connectors at the very least.

I tested for vibration a long time ago. Volume controls are by far the highest source of such effect. Cable connections can be responsible as well.

I am game doing more testing but need a test platform which I can dial in the level and frequency of vibration. Thought of building something out of a woofer and such but just haven't had time. Anyone can think of a ready and cheap solution?

Those bass shaker things that you attach to seats and etc. Add your passive speaker test rig to it. :D

https://www.amazon.com/AuraSound-AST-2B-4-Shaker-Tactile-Transducer/dp/B0002ZPTBI

I wonder if AP can do IMD with one channel controlling the bass shaker and another channel doing the speaker as per normal. Then we can do reviews of decoupling foam and stands. Bam, another thing this website can review. Also another myth to bust (Effect of "special stands" or spikes or whatever)
 
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Matias

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I tested for vibration a long time ago. Volume controls are by far the highest source of such effect. Cable connections can be responsible as well.

I am game doing more testing but need a test platform which I can dial in the level and frequency of vibration. Thought of building something out of a woofer and such but just haven't had time. Anyone can think of a ready and cheap solution?
Stack the DUT on a subwoofer enclosure playing 50 Hz?
 

mjvbl

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Well, a lot of electronics now are using high-k MLCCs in power supplies, decoupling, and even voltage reference filtering. Certainly you can come up with tests that will show the piezoelectric effects of these caps. I just highly doubt they are of real concern in audio. Even if there was a measurable contribution in a specially designed test, it seems highly unlikely to apply to real use cases.

I'm powering a PC mainboard using a 16-24V DC to ATX PSU board, it appears to be well made, but it has super bad ceramic capacitor whine and clicky sound depending on the CPU load. I think it also produces some constant tone lower in amplitude, when I put ears close to it, maybe something 4-8kHz. When I connect a cheap pair of USB powered speakers to the mainboard, the speaker reproduces that same tone that can be heard acoustically from the PSU board.

Okay this isn't what the question is about, I think it's just funny as it seems to me that maybe in this extreme case one part of the system is producing mechanical vibration via the low grade ceramic capacitors and feeding it back to itself immediately, sort of?

But I think C0G/NP0 type ceramic caps are actively recommended for audio applications. A post here says they're also very low distortion:
https://electronics.stackexchange.c...0g-or-film-in-loud-enviornments/495609#495609

TI highlight better resilience to vibration for some of their oscillators:
https://www.ti.com/lit/an/snaa296/snaa296.pdf

But the worst one in that report is a SAW oscillator. Not sure that's something that would be used for a DAC.
 

charleski

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The company I work for , who builds a lot of VSD drives quite large digital things . In a steel mill or paper mill you definitely can feel the whole floor vibrate in some electrical rooms where the equipment lives.

It’s only in the marine version with ship propulsion and oil rigs we take special anti vibration precautions .
This reminds me of ads that say you need an AC power conditioner because they use them in hospitals ... with no mention that the hospital has an MRI machine down the hall that’s spitting out tons of noise.
 
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