Interesting link on hifi stuff (2)

I think you're too harse in your criticism. His biggest faux-pas is presenting opinion as fact, but this a very common failing. That aside, here are a few excerpts I agree with :

"is often accompanied by a resonant peak, which can add ringing and a boost in level at that frequency. Therefore, designing a transducer to respond beyond 20 KHz. is useful because it pushes any inherent resonance past audibility"

"there is nothing inherent in gold that makes it sound better than a clean connection using standard materials"

I would also say to JCaudio, that, often basic theory does not explain all of the strange quirks of audio, but fuller theory, including, most importantly, the effects of real-world constraints and imperfections, will always explain audio effects. I get quite upset when people suggest that we should ignore the theory and use our ears. In fact we should do both ... use our ears then develop the theories, to back them up.
Also we should blind test more often. There are many subtle and unusual effects in audio that have surprised me, but there have been just as many "emperor's new clothes" over the years.

TWL : agree ... but I'd like to think that we're in the business of critiquing such web pages, not trashing them. In general I find your posts very interesting and I'm quite keen to listen to a low power valve amp with high-efficiency full range drivers (my system is Spica Angelus w/solid state), since I have never had the time or money to play with valves/lowthers. However there are a couple of salient point in that chap's web page so I thought I'd draw them out.

JCAudio. I have never experimented with power cords, and I expect that whether they change the sound of a system is heavily dependant on how transparent the system is. My system may or may not benefit, so I'll try one someday. That said, I think that the effects of RFI, inductance, capacitance, and the filtering of noise which the component drives back out onto the power supply (particularly cheap CD players !) are all factors which could cause a power cord to make an audible difference, and which should be measurable. I'm interested in the postings of P. Qvortrup, since he raises issues I'd never really considered with respect to impedance matching, valve amplification, DAC filtering. However I respect that he raises these issues in a scientific way, pointing to physical, measurable effects.

I am very very skeptical of ANY product that does not explain the physical phenomena in its marketing and I'm convinced that there's plenty of snake oil and fairy dust out there, but equally there are plenty of real second-order effects, not immediately obvious to the pure theorist. I am interested in trying to separate the two, because my budget is very limited, and I don't enjoy being parted from large amounts of cash !

JCAudio .. no I'm not saying that. What I'm saying is that if you can't immediately explain why your ears hear a difference it's because your theory is not good enough.
Take an example ... digital cables. Basic theory says it's just ones and zeros, and that, so long as the cable is not so poor as to cause the two to be mistaken by the DAC then you'll hear no difference.
But we do hear a difference.
So the more advanced theory looks at the eye pattern of the signal, considers jitter, cable bandwidth (limited by capacitance and inductance), RFI, and impedance matching, and shows that the optimal eye pattern (which really means low jitter in lay terms) is actually quite hard to achieve, and will certainly alter the overall sound.
So I think you misunderstood me. I am not saying that we should measure audio by specs .. of course not, we should measure it by grins :-). That said it is important to strive to understand what are the phenomena at work that put the grins on our faces, so we can make those grins wider and available at lower prices.
I'm an engineer, but I'm a practical engineer. Engineering is about optimal performance at the right price. A wonderful sounding HiFi that costs $100,000 is about as much use as a chocolate teapot to the general population. A slightly less wonderful sounding system, that still sounds very good, but retails for $1000 is going to bring much more pleasure to many more people. However it is also a much more challenging engineering task, only accomplished when one has a very sound technical understanding of what makes a hifi work well.

Lastly I cannot believe that there is anything that the ear can discern that is not measurable. The frequency response, dynamic range and phase sensitivities of the human ear are hardly so great as to present problems with measuring equipment.
When people find no measurable effect I suspect they're measuring the wrong thing. e.g. measuring bit errors on digital cables ... of course the bit errors don't change. But the DAC requires timing information along with the bits and timing info. probably does change.