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In Reply to: Re: Good point. Next question: posted by Ted Smith on February 12, 2007 at 17:10:43:
I just picked on RF noise, as it is impossible to completely eliminate it and its effects. The best we can do it get it down as far as possible.Another major problem is acoustic vibration: equipment, wires, AC outlets. All equipment IME is susceptible to degradation from acoustic vibration, but it is easiest for non-technical audiophiles to visualize the problems inside vacuum tubes. The elements are made of very stiff and light bits of metal and wire. Just hold one up to your ear and tap gently on the envelope. Motion of the elements with respect to each other modulates the signal by changing the element spacings.
If applying dampers to the tubes improves the sound, doesn't that suggest the setup before the damping application was not fully resolving the signal? A similar question applies to improvements in sound from tweaking, say, CD transport supports or AC outlets. If we can hear that something not part of the signal has gone away by making such a change, then it follows that the artifacts were audible prior to the change and were distracting us to some extent.
While a more detailed and formal discussion of the definition of "resolution" would allow for ability to detect truncation errors in a system that is not presenting all the information due to a variety of issues, I think it is fair to say that one way to be sure a system is fully resolving all the information on Redbook CDs includes showing that no conceivable tweak can make an improvement in the sound when the system is playing CDs.
Follow Ups:
Hi.CD, DVD-audio or vinyl, & whatever programme sources are ALL potentially or actually affected by EMI/RFI, mechanical vibration & the like. It's a matter of the interference frequency & magnitude which may be made audible or not.
Given same listenng environment & same mating hardwares, all programme producers, e.g CD or DVD-audio, are subject to the same level of resolution depreciation if any.
Tweaking can something found effective to reduce the harmful audio effects due to those unseen noise invaders.
Even for IDHTs (indirect heated tubes), I put on my homebrew damper onto the tubes of my phonostage & power amp driver stage to kill possible microphonics.
A warning: don't overdamp any tubes. It can damp out liveliness of the music all together. I learnt it the hard way.
c-J
HowdyBut the fact that not all causes of loss of resolution sound the same puts a big monkey wrench in the works. I'm pretty darn sure I can tell microphonics, from bit truncation, from ground loop hum, from ...
All audio systems have finite resolving power, and some physical mechanism is responsible for the limit. If a system is well-tuned and makes pleasing music, I don't think what particular mechanism limits the resolution will be apparent, even if the resolution limit prevents full reproduction of the details present on Redbook CD. Chances are good that several mechanisms would have about the same degree of influence in such a system, so it would take a lot of careful experiments to distinguish them.There is an analogy to optical microscopes. I used to use these quite a lot in my professional work as a semiconductor engineer. Visible light wavelengths range from 400 to 700 nm. It used to be a commonplace bit of folklore that optical systems could not resolve features on the order of the size of the wavelengths used to illuminate them. I still recall the surprise I felt when I was invited to look at some 500-nm line-space pairs, fabricated with e-beam lithography, with a newly designed inspection microscope. Not only could I see the features, I could see details in them. This microscope cost $50,000 in 1980.
The point of this story is that resolution limits are not hard and fast. We can hear details below the resolution floor, just as we can hear signals below the noise floor. The question remains, are the details presented with adequate realism to keep them in the context of the program? Will additional details from a hi-rez source add to the musical enjoyment, or will the distortions (in a broad sense of the word) added by the playback system make them irritants?
HowdyI understand all of your words but in my experience hi-res sources win in low res systems and in hi res systems. But I don't know if this means I agree with or I am in conflict with your statements :)
I've only heard hi-rez formats at shows, and have not liked any of them.People whose audio judgments are more exact than mine have told me they also have not heard music from hi-rez sources.
I'm trying to comprehend the conflict between these and observations like yours. Hi-rez formats deliver more information, so, if audio systems could resolve the extra information, why would everyone not prefer hi-rez? In my experience with tweaking my system, I keep finding more honest detail in the Redbook format as I reduce the effects of vibration and RF noise. Perhaps at this point, I should try hi-rez, but the cost of a player comparable to my Wadia 861 is daunting.
HowdyThere are a lot of players that fail to deliver hi-res IMO, and a few that do better than expected. If you're ever in the Seattle area look me up. I could show you some music and you could offer your insights about possible improvements in my system. (We could also visit inmate MikeL whose system is always interesting.)
As to your questions: I've seen a lot of systems that have taken, shall we say, "interesting routes" to fixing some of their problems with Redbook. When you then give them a higher res source it's extra detail could simply be masked by these warts or even in some cases the extra hi freqs could have non-liniar effects in their systems. A simple example is the number of people using TacT or the equivalent which may indeed help their systems. When you give it an analog or DSD sourced input however you may loose more than you gain... I could go on, but you get the idea.
For a while after I first experienced SACDs I was a hi-res bigot but as I've improved my system I now see that Redbook has a lot to offer and that it has more detail and music than I ever expected, but still in my experience it's always a shadow of hi-res in a system similarly tweaked/optimized.
:)
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