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In Reply to: RE: Baffled about computer power posted by Jaundiced Ear on June 14, 2013 at 22:16:31
I'll tell you what I will try to do when I have time, but its really inconvenient. I will directly measure the jitter on my bench through my USB converter with and without the power supply.
However, if the problem is the system and power grounds etc, this may not show it.
Follow Ups:
Ah! So it's another one of those flabbergasting differences that leaves no measurable evidence of itself? It's amazing how often those things turn up!As an "audio engineer," doesn't it bother you that you cannot demonstrate, much less explain, such a dramatic change in the sound of your system? I mean, this should be trivial to investigate, right? All you did was swap out a power supply and that resulted in your being "flabbergasted." You post your claim on the internet, and when I ask you to show us what you heard suddenly it's "inconvenient" to actually do so? You've got to find time? Holy Cow! This sounds like a major breakthrough in audio play back. You tell us that a trivial change to your playback system left you flabbergasted and yet you've know curiosity about how it works?
What kind of engineer are you? Are you one of the "let's find out how the world works" kind or are you one of the "let's find out how to make money" kinds?
Edits: 06/16/13
What kind of physicist was Einstein? He did not have all of the answers, only those for specific situations,. Physicists are still trying to come up with a single set of equations that model the entire universe.
Just because you are an engineer does not mean that you have all of the answers. I could spend untold days and weeks trying to get to the bottom of this and maybe learn nothing. What benefit is it to me? I will not make any more sales and the recommendations will probably not change. I would be better off to spend this time designing new products. I am not a research lab. maybe my XMOS isolated interface will answer some of these questions. I think this is a better use of my time.
Now you've gone and done it!
But asking cogent questions isn't too bad of a second place...
Thanks for the very interesting observation.
Rick
You said were flabbergasted by the increase in dynamics. OK. How about you run a track, heck, thirty seconds of a track through Audacity twice, once with and once without the new power supply and show us the increase in dynamics. It really would take you untold days and weeks to do that?
" How about you run a track, heck, thirty seconds of a track through Audacity twice, once with and once without the new power supply and show us the increase in dynamics."
You are making the facile assumption that the eye/brain/mind hears like measurement apparatus. I suppose that might be true if the measurement apparatus had the computing power of a human brain and was programmed with advanced artificial intelligence software capable of musical and acoustic scene deconstruction. This is not how Audacity works.
Perceptions such as musical dynamics are high level constructions done in the mind from subtle clues. Musical dynamics is not some kind of short term RMS average. Another example is musical pitch. The subjective pitch depends on additional factors than the periodicity of a waveform. There are sound sequences which some listeners interpret as rising pitch while other listeners interpret the same sound sequences as falling pitch. My wife was a musician and she focused on musical ideas, or as she put it, "What the musicians were thinking." She was not terribly interested in subtle sonic details such as occupy the minds of audiophiles and recording engineers. (I recall the last time I asked her to comment on components. I was evaluating amplifiers at the time.)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
"You are making the facile assumption that the eye/brain/mind hears like measurement apparatus."
Actually, I would say that the Mind hears things quite differently than a measurement apparatus would.
"I suppose that might be true if the measurement apparatus had the computing power of a human brain and was programmed with advanced artificial intelligence software capable of musical and acoustic scene deconstruction."
In other words, if the measurement apparatus had a Mind. I hope you aren't asserting that Minds are infallible in their sensory perceptions. Certainly the ones with which we are familiar are not. Indeed, the Human Mind is so notoriously fallible in that regard that we have an expression for when one perceives something that does not exist: we say "you imagined it."
"This is not how Audacity works."
No indeed. Audacity doesn't have an imagination. Unlike the Human Mind, Audacity cannot imagine things that don't exist and then display them. It can only display what was actually played.
"Perceptions such as musical dynamics are high level constructions done in the mind from subtle clues. Musical dynamics is not some kind of short term RMS average."
I'm not sure what you are trying to say here. Are you claiming that dynamics exist only as an abstraction in our Minds? Are you saying that Audacity will show no difference between a chord struck on a piano as ppp and the same chord struck as fff?
PS: I'm way jealous of those cools italics you use when you quote. How do you get them?
I don't believe that the measurement apparatus has to have a "Mind" to pull out various subtle effects. It just needs better algorithms, and these may require new knowledge about how humans listen to musical sounds. It may also need more processing ability than is practical, but I think this is likely to be less of an issue, given that processing need not be done in real time. The biggest problem to date is hardware, especially A/D converters and DACs.I don't think we would normally talk about measurement apparatus "hearing" something. It's not even clear what it means for a person to "hear" something. There are experiments that show that people can change their behavior based on the presence of sounds that they are not consciously aware of. (The same thing can apply to visual stimuli. The effect can be even stronger with other senses, such as smell.)
What someone hears as musical dynamics does not come just from the amplitude of the waveform, e.g. as captured by an RMS measurement. Other information is also used, such as the tonality and the pattern of attack. The mind does this automatically as part of interpreting sound. This is a basic skill that probably evolved along with our species. It is important to distinguish between high volume caused by a very high output source that is distant vs. high volume caused by a moderate output source that is nearby. There is a lot of automatic processing taking place that tends to abstract properties of sonic objects independent of their location in the acoustic environment. This is why musical instruments sound the same when sitting at different places in a live concert, even though the waveforms may be markedly different due to acoustic effects.
Something as simple as striking one note on a piano is not actually so simple. The listener will hear different sounds in terms of the pianist's touch. In addition the note will be interpreted as loud based on apparent distance (e.g. pattern of direct vs. reverberant sound) and distortion (e.g. intermodulation of the sounding board of the piano caused by "banging"). Other musical aspects such as tempo are also influenced in complex ways, e.g. a normal tempo in a small recital hall might be perceived as excessively fast in a large concert hall. In certain times of music, such as French Impressionist music, perception of tempo may even depend on the specific tuning of the instrument, as there can be an artistic relationship between beat tones and thet timing at which notes are played. (James Boyk has written on this subject of tempo and hall reverberation. I noticed the tempo effects of beat tones while learning to play some Ravel piano compositions.)
I format my posts by typing in text that includes basic HTML tags. The Asylum software passes these on and puts them in the web pages that it sends to your browser which then displays them with appropriate formatting (e.g. italics). You can see what I typed when I want italics by viewing the HTML source code for this page. (In Firefox you see source code off the Tools/Web Developer menu.) It is also possible to include HTML hyperlinks in the text. As you can see, it's not necessary to use any special software to create web pages. All the hard work is done in the web browser. You can use the "Preview Message" button to ensure that your post looks the way you like before sending it off.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Edits: 06/18/13
Thanks for your response. I appreciate your kindness in explaining to me how you format your posts. I thought perhaps I was missing some option within the Asylum's software that would all you to quote other posts and to format your text. Your post is a relief as it explains why I cannot find options that are routine in other fora.
With regard to the substance of your post, I suspect that we are talking past one another which naturally could lead to misunderstanding. While most of us use our stereos to listen to music, the fundamental issue here is reproduction of sound.
None of us are listening to live musicians. All of us are listening to transducers creating vibrations in air. However magical the original performance, it has been captured as a waveform and after passing through our stereos that waveform dictates what the transducers will do. The bad part is the waveform is far from perfect. The good part is the waveform is consistent. Transducers don't have minds of their own. The do what the waveform tells them to do, no more and no less. Our stereos may only reproduce a shadow of the original event, but they can reproduce the same shadow again and again.
That consistency is the basis of my argument. However modest the playback equipment, it is still consistent. Clock radios don't wake up one day and sound like mega buck systems in acoustically treated rooms. Every day they still sound like clock radios. Likewise, fancy systems don't suddenly sound like clock radios. Setting aside room acoustics, if my stereo starts sounding different it's either because of a change in my mind or because the transducers are moving differently than they were before. I'm not interested in how mood changes or a snifter of brandy can affect the sound I perceive coming from my stereo. What I'm curious about is the case where the transducers moved differently than before.
If our transducers move the same way they did before, our stereo will sound the same. Any actual change to the sound of our stereos must be because the transducers moved differently than before. If they are moving differently than before, it must be because the waveform that told the transducers what to do is itself different. If that electrical waveform is different, then that difference should be measurable. When audioengr says he is flabbergasted by the change in dynamics wrought by a new power supply, then his transducers must be moving differently than they were before. How else could his stereo manifest this change? If his transducers are moving differently then perforce the waveform controlling the transducers must be different as well.
It should be trivial to detect whether or not actual differences to the waveform exist: do a null test between them and see what pops out. If audioengr were to do such a test we'd be able to see the difference and it's scope. Then we'd have something to discuss. Until then we only have a single anecdotal claim and that to me is nothing to get excited about.
With all respect, can you explain to me where my reasoning leads me astray?
Everything changes all the time. Even if the transducers move identically, the sound waves will be different in the room because the air temperature, pressure and moisture will be different. There can be other acoustic changes, such as open/shut doors, curtains, etc. Your electronic equipment is subject to electromagnetic interference and power line noise. Both of these are far from constant.
What you hear depends on where you sit. Unless your head is clamped in a vise your ears will pick up different sounds even if the air waves in the room weren't to change. If you sit bolt upright in a hard chair you will be taller in the morning than in the evening. Finally, what you hear will depend on the condition of your body, how much alcohol is in your blood, your general state of health, your mood, etc.. What you notice will be determined by how you direct your attention during the listening session which will depend on your experience as a listener and your ability to concentrate. On top of that if you play the same song twice you won't have the same reaction to it as it will no longer be unfamiliar. You may hear more details because of this, or you may hear fewer details because you have become bored.
It's not for nothing this place is called an asylum. :-)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
LOL! I agree, there's a reason it's called the asylum.
Still, in your reply you seem to be talking about ephemeral, intermittent, transitory, and most importantly, trivial changes. I'm trying to keep the discussion focused on the type of change that truly makes it worthwhile to pull out your wallet and put money on the table. Why should I buy any new component if all changes are the same and changes bombard us from all directions all the time? On the other hand, if I'm going to part with money, I want to be darn sure that what I'm buying will actually provide meaningful, positive, consistent change to my stereo. Despite my moniker, I'm a pushover for that kind of change. Show me what you've got makes an actual improvement and I'm willing to listen. Third party testimonials don't count.
How everyone spends their own money is their own business. I tend to do things the same way you do, namely big dollars will require big improvements. Other people may have more money to throw around or may get ego satisfaction from throwing money around. I have found that often the "big differences" in components are not so big in that they are less than the changes that one can get from proper set up. But then as a retired person I have plenty of time to fool around. If I were a busy and high paid professional I might view things differently.
Those ephemeral differences may grate over time, so they should not be trivialized.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Gee, we agree on more than I would have guessed a week ago. I think we live in a golden age of audio. I think even modestly priced gear can be capable of excellent performance. I think the majority of inmates on this board likely already have gear that provides excellent performance and would be far better off experimenting with room treatments than swapping around DACs or preamps. I also think the majority will continue to swap out gear rather than change their rooms.
In our little house, I don't have a dedicated room. The occasional in and out is still appreciated, so one has to keep the wife happy. You can only go so far with room mods.
I was unable to see your setup listed, but I do know what Tony has. I bet he would be very impressed with some of the DACs in the $6500 to $7000 price range. Not that products like the Mytek aren't good sounding, but the improvement in sound with some of these more expensive DACs is substantial.
I suspect the weakest parts of my Mytek are the op-amps in the IV and output circuitry. (I have bypassed the op-amps in the analog volume control.) However, there are even more op-amps in my powered Focal monitors, so I'm not sure how much there would be to gain in this dimension without throwing around lots of money. The other problem with the Mytek is that it uses the stock SABRE chip filters, which aren't so great, particularly at 44/16. However, I upsample in my computer to 176/24, 192/24, or DSD128, effectively bypassing the SABRE chip filters.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Going from no music to music is a big difference for me. I think I'll get a new preamp; the Ayre KX-R. After all, I'm still working :-)
Edits: 06/19/13
"Ah! So it's another one of those flabbergasting differences that leaves no measurable evidence of itself?"
"Measured" is not the same as "measurable". In related cases differences have been measured by people, but they have adequate patience, knowledge, skill and equipment.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
"...If the difference is inadubile, then it cannot be heard."
Huh? How is this a statement (poor spelling notwithstanding)? It's like saying "if the thing is invisible then it cannot be seen". No sh$t.
I've not always agreed with Steve's conclusions, but he always seems to get to them with a plan and with a documented path. He has already said he is working on it....he simply asked (in this thread) a question as he readies his own tests. The risk, of course, is that someone, like yourself, will not read the whole thread and come to a conclusion that is unfair. IOW, give him some freaking time! What is your hurry? If you need a quick conclusion, let us know your own tests and results.
As far as my own comments, I am not an engineer or proper scientist, so I rely on others, usually. But I am not afraid to ask the stupid questions. Discovery is a dangerous thing; one is often labeled a heretic. And in computer audio it seems that there is way more to discover than has been discovered.
Whoops! That line wasn't really intended to be part of the post. I was "thinking out loud" while fiddling with the "signature" option when I typed that and obviously didn't proof read carefully.Still, you may think it's an obvious tautology, but it sure doesn't seem to be obvious to many of the inmates. This thread is a classic case: a "flabbergasting" difference with no bother given to actually showing a change in the output waveform. I would simply blow it off if it was a regular inmate making the claim, but in this case it's being made by a self professed "audio engineer" who makes his living peddling kilo buck audio add-ons that supposedly deliver these same types of experiences. I think it's fair to hold audioengr's claims to a higher standard.
And what is that claim? Not that the new power supply reduced hum or distortion, but that it made a flabbergasting improvement in dynamics when using Async USB interfaces. Now to me, a flabbergasting improvement in dynamics means that the loud parts are noticeably louder and the soft parts are noticeably softer. For something to be noticeably louder, it must of necessity be louder. For something to be noticeably softer, it must of necessity be softer. In other words, audioengr is saying that changing the power supply effectively remasters all the music passing through the Async USB interfaces. That to me is an astounding discovery, and not something to just be tossed off as a casual curiosity.
Hey, I salute the man for making this breakthrough. I'm just asking that he share it with the rest of us. As I said, we can't travel to his listening room, but he's an audio engineer: how about posting some files on line to demonstrate his discovery? It should be trivial to demonstrate that the loud parts are now actually louder and soft parts are now actually softer. I suggested Audio Diffmaker, but heck, he could just post some Audacity screen shots showing the differences between the output waveforms that the new power supply caused. Wouldn't you like to see that? Isn't that the sort of thing that an audio engineer could toss off in a few minutes?
On the other hand, if the wave forms show no differences in the dynamics before and after the power supply swap, or only show trivial changes below the level of audibility, then how on earth can the changes even be audible much less flabbergasting?
Edit: My above post assumes that the signal provided with the original power supply was "correct" so that the new power supply must somehow be remixing the sound to create the flabbergasting changes. However, it may be the case that the original output was somehow defective and "incorrect" in which case the new power supply may simply be making the output "correct." However, even in this case it should be simple to demonstrate the actual changes to the output brought about by the new power supply.
Edits: 06/16/13
Changing a 88/24 sound file by adding dither noise (+- one bit in the least significant position) has been described as "completely trashing the sound". This may be a bit of an exaggeration, but the point remains that a difference was heard between two almost identical sound files. (This is far from a unique observation.) Please note that the noise floor of the "24 bit" ADC in a typical sound card is around 17 bits of resolution. In other words, the sound card doesn't hack it as a piece of measurement apparatus in any discussion as to what people can or can not hear. It is about 60 dB out of where it ought to be, following the general rule that a piece of measurement apparatus (sound card) should be ten times better (20 dB) than the device under test (ear/mind/brain).
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Right. It could be different amount of noise coming into the DAC/preamp/power amplifier supplies and not necessarily anything coming from the USB port.
Edits: 06/15/13
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