How close to the real thing?

"If you have two widely differing systems that don't distort then they must sound identical".
So, when 2 different cone materials sound different on speakers, one is more distorted or when you roll tubes for a completely different sound, one is distorted, or when a designer changes from bipolar to mosfet or vise versa, they sound different because one has distortion or when we add spikes to a speaker and the sound cleans up a bit, we have lowered distortion or 2 identically spec'd phono cartridges sound completely different, its because of distortion????? Does Silver copper or gold in wire carry more distortion??? They all sound different. I can go on and on.... Your comments do not hold merit. I'm glad that you have a Holodeck, distortion matters overall, no argument, but it is not the one thing catch all.
Sorry Frank, I can't agree on this one.... I've been convinced of a few things on here...Thanks Atmosphere & Almarg, but you've got a long way to go to change my mind on this one. Good Listening, Tim

Its true that by definition a reproduced signal that is not exactly identical to the original source (ie exactly the same as the real thing) is distorted and that the reason no two systems deliver the exact same sound is because each distorts the input signal differently.

So not all distortion is necessarily unpleasant. In fact some may be enticingly pleasant! Others will induce different responses, both positive and negative.

FWIW, low ordered distortion is pleasant, but it does obscure detail, and the ear tends to hear it as a fatness or warmth in the sound. Lower orders are the 2nd, 3rd and 4th.

Transistor amps have almost none of these distortions, but they are common with SET amplifiers. P-P tube amps on the other hand tend towards the 3rd and 5th.

Now it is the higher odd orders that our ears use as loudness cues. Anytime they are distorted, the amp will sound louder than it really is. This is why SETs will sound very 'dynamic' for their power, as normally they don't make much distortion, but if you push them (which is what transients do) then the loudness cues appear **but only on the transients**.

Transistor amps 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.

This, BTW, is why two amps can seem to have such different tonal characteristics even though they both measure flat frequency response on the bench. The addition of global negative feedback to any amplifier will increase the odd-ordered distortion slightly, which is why any amp with GNF will tend to sound brighter even though frequency response is unaltered.

(The trick, IMO, is to build an amplifier that does not use feedback, and use other means to eliminate distortion.)

The bottom line here is that distortion is always audible and to nearly anyone. Its just that it does not *sound* like distortion to us, often it sounds like a tonal aberration ('bright' in the case of many transistor amps, 'caramel' in the case of many tube amps).

Mapman,

taken in that context, all hi-fi is distortion and I'm sure we can all agree that when the reproduced signal is different from the original the effect is distortion.

What Frank has stated is that we hear differences in the sound due to an increase or decrease in "distortion" and if there is no distortion change then both systems will sound the same

What we are trying to determine "which distortion" , tim, thd, phase, slew, VCID, maybe Frank is describing the changes in the RLC makeup when switching out wire for eg. changing the original "distortion".

Regards,

Good explanation Atmasphere. Agreed
To you and Weseixias also