Looks measurable to me. I'm looking for proof that unmeasurable levels of audible range distortion (created by ultrasonic range issues) are detectable by the ear as indicated by this statement:

Still waiting for that evidence. Of course if a device produces artifacts in the audible range for any reason it will be, ah, potentially audible. What I'm looking for is evidence of distortion in the ultrasonics that produces audible distortion that's impossible to measure. Not likely IMO.

Charlie: if its not measurable, then it is not there. And, with test equipment being so accurate these days, if you can't measure it, then you can't hear it.

You can take that to the proverbal bank!

Couldn't agree more. You're preaching to the choir on this one.

Shawn,

Pretty interesting read though in every case there was doubt given on whether Rupert was jumping to conclusions. Though it does bring up some thought of whether these type of differences might well cause some distortion in the audible range.

doc: I read, somewhere, that the human ear can't tell differences of less than about 1 dB. For the sake of argument, lets make that 1/5 of a dB.

You don't think that modern test equipment can measure to less than 1/5 of a dB in the audio spectrum?

I think that we are beginning to discuss an area that is much like discussing audio speaker cables. That is: some people just do not understand the RLC properties of cables and spend $1000s on cables needlessly.

I think it's very plausible that this might be the case. Where I stop drinking the kool-aid is when someone asserts that audible distortion is unmeasurable. The bottom line for me is that either there is audible (and thus measurable) distortion, or not. Cause is a secondary concern.

There's always the argument that scientific knowledge isn't fixed and that we don't know everything and that therefore it is possible that there are types of distortion, or complex wave interactions that cannot be measured with current equipment, but that show up as artifacts to the human ear.

Which is why people buy into various products that either make unsubstantiated claims, or claims based on pseudoscience or just plain bull shiitake.

Kind of like trying to argue with someone over whether aliens have visited earth. You can make the arguments about theory of relativity and how mass can't even begin to approach speed of light, let alone go faster, but the believer will always come back with, "yeah, but how do you know that there isn't some phenomenon or technology that will allow us to do that, but that we haven't discovered yet?"

Anyhow, my point is that it's very difficult to disprove that which is beyond knowledge...which a lot of these types of claims are.

It's really pretty simple. Science is about what we presently now know about the natural world around us. We can change it later when we learn something new but it's what we know for now. It also allows us to design things and have them work in predictable ways. Granted that there can be arguments between scientists about interpretation. What might or might not be discovered is, however, not science, it is the presently unknowable. It could be supernatural, spiritual, metaphysical, but it isn't science. Science can neither prove nor disprove the possibilities that have been raised here. Engineers , designers, and fact-based critics can only operate in the realm of reality and what is known--that is to say that they can only use the best available science. Until there is evidence the possibilties are mere idle speculation--granted it is speculation that sells a lot of high end equipment. As I have noted before, a well designed doubleblind test can ferret out real from imaged effects. The fact remains that some gear sounds better than others and we don't have a good quantitave handle on explaining that. I agree with some of the thoughts here to the extent that some gear sounds good and others don't even with similar specs. But I would strongly encourage all to keep to the facts and the cold engineering science. Decisions made on what could be will almost invariably be worse than those based on fact. That is the underlying strength of western rationalism that has underpinned our society since the Renaissance. It's not that science is always right or that it can explain everything, it's simply the best way we have of understanding natural phenomena and is more likley to be right than any other form of explanation or understanding. In recent years our society has lost our respect for the scientific method, for fact, for truth and a lot more. Can we at least be rational about our audio gear? Of course not! Why should that be any different? I think I'll go buy some expensive wires....ooppps I meant "interconnects."

A double blind test is a kind of experiment; if it's independently verified, then it's science. I doubt there's a case where a group could hear a difference (scientifically demonstrated) and a difference could not be measured. It seems more likely that one of the following would be true:

• A difference is clearly measurable but it's not immediately clear which component(s) of the difference are audible
• A difference is clearly measurable but the difference doesn't make the test subjects or test administrators happy

The former explains the cases where something "sounds better" although it has "similar" specs. We aren't looking closely enough at the measured differences, and companies like Harmon Intl. use this as a means of making real useful progress in understanding what matters.

One example of the latter was a test where (sure enough) tube lovers could identify and prefer the sound of tube amps and the measurable difference was (drum roll) the tube amps in question had slight (but barely audible) levels of even order harmonic distortion. This apparently meant that that group of listeners preferred the sound of a little distortion, which, needless to say, didn't sit well within the group itself.

The limits of human hearing are, at an extreme level, set by the physics of pressure wave propagation, diameters of the atoms involved and the 'sound pressure' produced by Brownian motion. Measurements in the electrical domain prior to the transducer suffer no such limits and may be orders of magnitude more precise.

If humans could hear much better, we could hear how warm the room was. Not very useful.

I am a newbie here. But I want to touch two points. My setup first:

Sony CD/DVD DVP-CX985V (hate it)
Denon AVR-2105 (drives center and surrounds)
Outlaw 2200 monos X2 (drives mains)
Polk LSi15
Polk LSiC
Polks RTi28 surrounds
SVS sub PC-Plus 20-39 (newest addition down to 16hz)

The Outlaw 7500 looks intriguing to me. I could buy it and use the 2200's for Surround BACKS. Or, I could bi-amp the LSi15's. But as it is, the LSi15's are rated at 250 max watts. I like moveis, but I love music! Classical and rock! My system benefits greatly from the addition of the 2200's and obviously the soumdstage is off because Denon is driving half the system. But in stereo, everything is great. The SVS sub may seem useless, but it ebbs into my next issue. With certain classical recordings (particularly large orchestral ones in rooms) the mics picked up "building" sounds and sometimes air. What showed me this? The SVS subs! It exposed too much!

My background: I am a violinist and composer. As part of my education, I had to take a class in physics/acoustics. That it was a POS at the time, but now things are really making sense to me. I cannot and will not presume to know 1/8th of anyone here so forgive me if what I say is common knowledge. Since what I am going to talk about is attempting to fuse real acoustic with solid state technology, it may not translate at all.

Let's say a violin plays his open G sting (the lowest all by itself. It is actually playing a fundamental and everynot in a harmonic series. And brass player could tell you those right away. In my example, the first note (fundamental) is the G, then the series of harmonics above (not always audible seperately) D, G, B, D, F, G > infinity

There's an Algebra function where the curved line (forgive me for not going to my books and checking) runs parallel into the Y or X axis and your eye will say that it will touch of you just followed it longer (off the paper perhaps) but mathematically it is impossible because a "0" cannot be in a certain part of the equation. Above, you noted the "F" in the series based on a G. Above that the harmonics get into the inaudible range and to dogs . . . they must hear some atonal stuff!!!
In that series, you also noted that the series at the first part outlines a harmless G Major chord. Andyone else playing a REAL B or D note would fit in well. Remember, that THEIR notes are also kicking off their own harmonic series notes. The obvious here is why #1 minor keys sound so "dark." They don't jive with nature's physics. #2 pianos are intentionally out of tune. M3's, M6's and M7's are all sharp. Nature, in fact, to OUR ears eventually shows it is out of tune. On an ocsilliscope (sp?) play a A1 and an A5 at the same time. The A5 will sound HORRIBLY flat. Yet orchestras do the equivalent of this all the time and make it work. You want to here the harmonic series yourself? Have a piano? Go to it. Press down the peddle that let's the note go on for a time. Make sure the room is utterly quite. Stick your ear as close to the box as possible. Hit only ONE note in the middle of the piano somewhere. Your ear will slowly discern the upper partials of the harmonic series. It will be kind of like looking at those crazy puzzles that turn out to be a saiboat or something after you look at it and then go into "blurry" mode.

How does this have anything to do with anything. Well, these harmonics at any performance are being picked up by the mics. They are being recorded. Many modern speakers, pre-amps, and amps (and even sources) claim to reproduce well outside the 20hz-20Khz range. Why? What more are they giving you? On my computer, I can record a perfect sin wave at 16hz. I heard and felt something. What did I hear? My math says that 16hz should be like a C#/Db. Did I hear an upper partial in the 20hz range? How complex must all of this seem to a processor.

Which takes me back to this story above about 48-50Khz anomoly. Without my interpretation of it first, I'd like you to consider what I said.

p.s. I am also torn between an all 2200 system or a 7500 amp system.