agear, I think the state of our socialized knowledge is something like this: - There are plausible reasons why vibration reduction could work in solid state gear. A) Microphonics in the components, or B) You are actually hearing the preamp/DAC, etc. mechanically vibrate.
- There are known issues with tubes and things that move like turntables and speakers.
- There is almost no known electrical or acoustical measurements of vibration control being needed, or improving solid state gear in the audio/home environment.
- As far as I know, the only "evidence" is from listener impressions. This doesn't make it false, it just means we have not progressed from subjective to objective yet. I hope that comes in the future.
@georgelofi Point about being 100% sure your speakers are not moving in 3D space is right on. Not only must you isolate the vibrations of the cabinet from any other surfaces such as the floor, you have to ensure the cabinet doesn’t rock in response to the woofer movement, causing a dopler like effect to muddy the sound. Best, Erik |
Erik -- I have nothing to add to your comments, best take them up with Shunyata directly. That's far beyond the level of attention this deserves. :) Best, Erik |
As I've said before, testing and measuring the benefits of vibration control in home audio should be easy, and inexpensive. I've yet to see the loop closed.
Doing this work could lead to cheaper and better sounding equipment when we have definite, exact, nuanced information to guide our manufacturing choices. If any of this exists for audio, I've yet to see any of it.
Best,
Erik
|
1) Shunyata Dark Field Elevators for cable isolation
http://www.shunyata.com/images/technical_features/dfss-chart.jpg If the claim is that these images demonstrate the benefits of cable vibration isolators then I call BS. Notice please: - The time (5 ms/d) and voltage scale (50V/d). This is clearly a measurement of a 50Hz or 60 Hz/220V AC power line, not speaker or signal level.
- Where the noise is occurring, at the upper peaks. This is not floor or air-borne noise. It’s probably AC line noise possibly caused by a digital power supply on the line or transformer problems.
- The magnitude of the noise itself, around 50Vp-p but of very high (relative to 60 Hz) frequency. That kind of noise in the line or speaker would be audible if not damaging to components. In an AC line they are easy to filter.
- There are no measurements (in addition to the charts) provided.
- There is no description of the test conditions.
- Items 4 and 5 mean this test is irreproducible. No one can refute them because you can’t test under the same circumstances.
Charitably I would say they posted the wrong pictures. If you said these were pics for a 220 V power conditioner I’d say "Hey, it’s cleaning up something! I wonder how they tested..." Also please note, all these statements above (including BS) are in the engineering domain. All the attacks that follow will be personal, name calling, etc. Well, let them begin. I will always look forward to careful thought out replies like "Hey Erik, you missed this link which explains...." or "I like mine!" Those are all fine, I’m not challenging your subjective experience, just saying, those pics don’t make sense. Best, Erik |
@folkfreak 2) Grand Prix Audio racking systems -- which include a variety of
isolation methods including ball/cup feet exactly to deal with floor
borne vibration (Apex footers)
http://www.grandprixaudio.com/research
http://www.grandprixaudio.com/products/apex#product-features
Well at least these tests and measurements are a little better documented, but not really reproducible nor do they make any specific claims. The charts have no units at all. In the test results they make no measurements of improving sound quality just vibrations. Not at all the same thing. Material and Industrial engineers have had established methods for doing this for ages. Nice to see someone, anyone, in audio taking up this approach, but whether or not they are relevant to audiophiles is not demonstrated here. Best, Erik |
It is quite possible we are approaching the real problem the wrong way. What if the real issues are not that electronic signals are being contaminated by vibrations, but that we are hearing our equipment stands resonate? Same for cables. I could see them vibrating on the floor. Maybe we need quilts instead? :)
But lack of measurements leave this up in the snake oil and trial and error. We might as well be trepinating each other in the hopes of reducing headaches.
|
Hi @folkfreak
Anything mechanical and spinning has known susceptibility to vibration noise, including CD’s, DVD’s and of course phonograph players. I wouldn’t be surprised if CD players were susceptible to jitter or even flat-out read errors with enough vibration. Very few CD players have buffered, asynchronous outputs. The Sonic Frontiers, and Parasound players were some of the very few. As you probably know, some other boutique players use large memory buffers to play from.
However, with good clocks and buffers, this effect should be completely eliminated. So, I am completely skeptical of hard disk / USB 2.0 players having any such issues at all.
I’m also leaving the door open to electronics or even cables having vibrational susceptibility, but again, it’s so freaking easy to begin to measure this, and I’ve seen zero. Invariably some one points out to vibration isolation for laser measurements of gravity waves, or earthquake damping .... yes, they have problems... and you know what? They are freaking measurable!! That’s how they arrive at the optimal solution. If vibration control is a real issue then magazines should be testing preamps and platforms for it. Nada.
Best,
Erik
|
Remember that in audio, the FTC sets some standards, but doesn't measure the gear. It's up to the equipment makers to measure and make claims, and occasionally magazines test them to see how close they are to the specifications.
We are far from any of that I'm afraid. It's up to academia and manufacturers and even interested hobbyists to explore and then define measurement protocols since there is a complete lack of them in audio. If someday that happens, then maybe down the line we'll have legal standards for labels on racks like food nutrition content.
But for now I can claim my home made rack improves temporal cohesion and reverses digital blur by 40%.
Best,
Erik
|
@geoffkait
Then please tell me a model to mathematically describe the effects of microphonics and vibration. Lacking that, it IS trial and error and devoid of engineering. Weren’t you a few pages back arguing it was impossible to use basic engineering practices to stands? Perhaps it was another camp. Or we are stuck at trepination and therefore unable to develop even aspirin and ibuprofin for headache relief.
I’m sure there are makers who can test their stands and make them vibrate less. What’s lacking is an explanation and model for what of these characteristics makes an audio system sound better. That’s what I mean about the loop not being closed. You can take a course in loudspeaker driver design, where you would dissect and analyze everything from an AMT to a fan-based woofer and know how to put those numbers together to explain the subjective effects of your choices in materials, magnets and coil geometry. We have no such thing for vibration control in audio. Usually around here some one responds "But we don't need engineering...." and we go all the way back to making holes in customer's heads for pain relief.
They could sell a bazillion "vibration isolators" and it’s no proof to me of anything besides good marketing. Imagine even a light bulb being made today without a thorough understanding and accessibility of the sciences involved. Power, current, efficiency, materials and emitted light spectrum. Forget a light bulb, a chef’s knife has more science behind it than vibration control in audio.
Best,
Erik
|
