How close to the real thing?

Atmasphere, there is no way that well-designed solid state amplifiers "tend to have these higher odd orders all the time. This is one of the reasons they tend to sound hard or bright. Now its important to note that these harmonics do not have to be very distorted, usually 100th of a percent are audible, simply because these harmonics are so important to the human ear." Total harmonic distortion, meaning any and all spurious frequencies away from the fundamental, is normally at about -70db or better, usually better, and there's no way that such low-level distortions could possibly cause amps to sound hard and bright.

The most likely cause of hard and bright sound are no-so-good speakers, that have too much upper midrange energy when driven by an amp with a low output impedance and flat frequency response. Connect a tube amp with a rising output impedance in the same frequency range, which will cause a roll-off in the overall response, and voila, hardness suddenly gone.

Irvrobinson, I would agree with you about those distortion levels, but certainly would not blame the speakers directly. I would suggest rather that the combination of equipment and setup is allowing other distortion mechanisms to intrude, into the electronics of amp and CD player, say. Typically the power supplies of much equipment are pretty hopeless in suppressing interference into sensitive areas, and this is the sort of thing that normal THD measuring never captures.

So, either you boost the quality of the power supply, as, say Naim does, or you cotton wool the power being fed to the gear with filters, special power cords, etc, etc.

Frank

How close are we to the real thing ?

Fas42, assuming the goal for all equipment is as much accuracy as possible, I do lay the entire blame on speakers. Solid state electronics can be designed to be, for home audio purposes, perfectly neutral, in that their noise and distortions are inaudible, and their frequency responses are flat regardless of load.

Speakers, on the other hand, are usually "voiced" Sometimes this is because the designer wants to achieve a certain "sound", but they are also voiced to apply judgment of how much high frequency roll-off the designer wants to apply to make the speaker sound natural in a room with certain absorption assumptions. I suppose you could argue voicing in the bass might also be necessary, because of room variations.

The latest speakers, designed with the latest driver technology and sophisticated crossovers designed with the latest software, can produce awesomely flat frequency responses these days. The latest speaker designs seem to have frequency responses that remind me of curves we used to see for amps in the 1960's. (Distortion levels too.) But lots of speakers are still "voiced" to sound a certain way according to a designer's biases, and the best drivers and crossovers (and cabinets too) are actually very expensive, so a lot of high end speakers still have response curves that look like saddles (too much bass and too much treble), and compromised crossovers that produce anomalies at the crossover points.

The differences in solid state electronics are far smaller. With tube electronics, one can design them to be as neutral as SS types (VTL comes to mind), but things like SET amps will have nearly unpredictable interactions with a particular speaker.