Go for the faraday cage.
Seriously though, if Rob Watts seems convinced that small vibrations in the DAVE, caused by external sound waves from speakers, or rumble from other sources, can affect the sound from DAVE, it is thought provoking. My instinctive response is no-way! but I am open minded enough to wait with interest, to hear what he discovers when he performs tests, when he returns from his current far east tour.
This has started me thinking about the implications - if it is possible that even the influence of the tidal conditions can be heard via DAVE, then what is the true noise floor? Can DAVE detect the passage of the earth through the solar magnetic field (including periods of solar flares?) - seriously it does raise the question as to whether there is a correlation between the experiences of DAVE users on this thread, and whether the the sun was more active than usual?
I am just adopting the scientific method, and exploring the possible consequences of some of the recent comments on this thread - but only Rob has the measuring and test equipment, to provide real data.
Listening to music seems simple compared to this.
Those who don't care at all about the science of sound or vibration control and would prefer to simply go back to enjoying music, feel free to completely ignore this post.
It would appear that for many, vibration control for headphone listening is a voodoo concept not worthy of serious discussion but, personally, I, too, like to understand how to explain certain observations that are not easily explained. I don't claim to be an expert on vibration control but I am indeed intrigued by comments Rob and other experts in the field have made as I am by my own observations that have been reproduced by others (not necessarily with the DAVE but other electronics similarly housed in heavy billets of aluminum). Personally, the idea that tidal conditions and solar magnetic fields can routinely influence SQ is a bit far fetched. Nor am I convinced that the SQ differences that are heard with devices like Stillpoints are predominantly due to external environmental forces. Based on my discussions with those more knowledgeable and experienced in this field than myself, internal resonances produced by any and all electronic components have at least as much to do with it (and this would include cables and speakers since they pass electricity). In other words, the enemy is
within and this would potentially explain how differences can be heard in a headphone system.
Shuttlepod's assessment that in his system, after speakers, vibration control seems to make the most difference with his power supplies and line conditioner, seems to be an assessment mirrored by many. This has puzzled me but the best explanation that has been provided to me is because AC, as an alternating or oscillating current, is vibrational by nature and so draining away and dissipating the secondary vibrations that occur as a consequence can lead to noticeable improvement in SQ. Of interest, with my HFC MC-6 Hemisphere line conditioner, I found no significant benefit with my vibration control devices, however, could this be due to the gelatinous matrix present within the Hemisphere that was designed to quell internal resonances or the Furutech NCF receptacles used that contain mechanical dampening compounds? Snake oil? I'll leave that for others to decide but the point is that many of these manufacturers are claiming that the troubling resonances are coming from
within.
Regarding cables, as you go up the chain to the more expensive cables, it no longer becomes about metallurgy. At some point, it typically becomes about RF shielding and vibrational dampening. Purist Audio Design, for example, makes a $10k mains cable filled with liquid ferox designed to serve as both an RF shield and mechanical dampener. Similarly, HFC incorporates some type of mechanical dampener in their cables, both for their power and signal cables and some of these manufacturers have suggested to me that they are trying to buffer against internal vibrations as much as they are external forces. As for a headphone cable being microphonic, maybe @JaZZ and I are talking about different things and maybe I am misconstruing what is happening but with the stock cable that came with my Noble Kaiser 10 IEMS and even with the Silver Dragon that I use for it now, if you tap the chord with your finger or the chord brushes up against something, like your neck, you get a clearly audible rustling or thumping noise and so the way I am interpreting this is that there is clearly an impact on the electrical signal with the transmission of vibrational energy against the cable by local forces that has nothing to do with speaker output or reflections from nearby furniture.
Regarding how vibrational control could impact the DAVE for headphone listening, my own theory (and I could be completely wrong) is that once again, it has more to do with internal or local forces rather than any blaring external forces. To be upfront, during this recent evaluation of vibration control devices, my testing was performed almost exclusively with speakers (>99%); not because I didn't believe my findings weren't applicable to headphone listening but because in the past 6 weeks, I have done almost no headphone listening with my DAVE for various other reasons (and in a few days, I will explain those reasons). At the same time, because my speaker listening has more recently been a
low volume affair, it's hard for me to imagine that these low volumes are creating any significant external sonic forces that would impact the DAVE much differently than headphone listening...but who knows? Nonetheless, while it's easy to imagine how a thunderous subwoofer could eventually penetrate through the protective anti-resonant properties of the thick billet of aluminum that the DAVE is housed in, exactly how does this mighty fortress protect the DAVE against its own internal resonances? As I stated in my report, power supply components -- as they charge and discharge, capacitors, resistors, ICs and output devices in the signal path
all vibrate as they pass the audio signal and while these individual vibrations may be small, because they have the ability to locally and much more directly act on the signal (similar to me lightly running my finger down my headphone cable and inducing a rustling noise), it may not take much for these internal forces to impact SQ. This is the theory that makes the most sense to me.
In my report, I mentioned that mechanical isolation boils down to the 3Ds --
dampening,
drainage, and
dissipation. In my own simplistic way of thinking, it was easy to grasp the importance of first "D" but not the 2nd and 3rd "D" and yet the latter 2 "D"s may be more important, especially with headphone listening. When you're trying to guard against external vibrations, like a car would want to do against a bumpy road, then a dampening mechanism like shock absorbers become important. But when you're trying to free a component of the negative impact of its own vibrations, then drainage and dissipation of these vibrations become much
more important. Based on my own reading, solid billets of metal are very effective drains or conduits but unless there is some way to dissipate this vibrational energy (either as heat or work) in sufficient quantities, there will be no
net flow of vibrational energy away from that component and this vibrational energy gets transmitted back to the component. When we're talking about dissipation through heat, for this transfer to occur, you generally have to couple the conduit with a dissimilar substance capable of drawing or absorbing that vibrational energy away from the conduit. And so while the DAVE's large aluminum chassis is probably serving as a very effective drain, how is the vibrational energy being dissipated? I suppose some of this vibrational energy could be dissipated through heat exchange between the chassis and the surrounding air. Dissipation could, in theory, also be occurring through the rubber footers beneath the DAVE. Given the greater surface area of the Black Raviolis, these may be even more effective dissipators and indeed, as I put my finger against one of these Black Raviolis, they are quite warm. With ball-bearing devices like Stillpoints, dissipation doesn't occur through heat as much as it does through work, usually in the form of rotation of the ball bearing(s) within. Which is better? My own experience has shown me that it depends. For devices that generate large amounts of horizontal vibrational energy (like speakers, large transformers, CD players), Stillpoints are supposed to be better. For devices where the vibrational energy is more vertical, the rubberish footers that dissipate energy through heat can be just as effective if not more so.
Again, these are just my own observations and impressions and you may disagree. As before, does the DAVE itself greatly benefit from mechanical isolation in a headphone system? In my system, the answer is no and so I don't think I'm disagreeing with anyone here. But is there
zero benefit? My ears don't tell me that and I feel comfortable standing alone in this claim if need be. Once again, and this should have been my concluding statement all along, the real benefits lie not in isolating the DAVE but in the cumulative impact of mechanically isolating all parts of your audio chain and given how the DAVE combines three components in one, this need not be a difficult or necessarily expensive ask.
