GNFB and distortion

[Wavebourn]

Originally posted by phase_accurate
The distortion mechanisms of speakers and amps are quite different.
And they are perceived different. So the higher speaker THD is still less objectionable than the amp's nonlinear distortion.

Earl Gedds has a nice paper on that.

Does somebody need any paper to understand that we are surrounded by so called "mechanical distortions" the whole our life; we sing, cry, communicate using them, we play music using mechanical oscillating system that generate such "distortions", but we don't perceive them as distortions. We perceive them as sounds and when level of such "distortions" change we perceive as changed loudness

[phase_accurate]

I boldly claim that it isn't the origin as such (i.e. mechanical or electrical) that causes the differences in perception.

It is how the nonlinearities behave. If a "mechanical distortion" is made to behave like amplifier crossover distortion for instance it will be perceived the same way I claim.

Regards

Charles

[Wavebourn]

Originally posted by phase_accurate
I boldly claim that it isn't the origin as such (i.e. mechanical or electrical) that causes the differences in perception.

It is how the nonlinearities behave. If a "mechanical distortion" is made to behave like amplifier crossover distortion for instance it will be perceived the same way I claim.

Hmmm... Can you describe a model of such a mechanical device?

[traderbam]

Originally posted by myhrrhleine
Given otherwise identical zero-GNFB amps, I prefer the lower distortion amp.
I strive to reduce distortions with other means than GNFB because I really don't want the distortion.

How about you?.

Me too. Any distortion is undesirable in principle. But it depends on the type of distortion. Our brains are very choosy about the specific mix not just the total. It is a bit like judging the impact of noise pollution based on total amplitude rather than specific noises. For this reason, amongst others, THD+N is not an effective parameter to compare sound quality between amps or speakers.

Also, when two amps have the same total distortion, any two people might have different preferences of the mix. When modest distortion is present there may be disagreement about which amp plays music better. Only when all audible distortion is eliminated will there be a good chance of agreement.

[phase_accurate]

Hmmm... Can you describe a model of such a mechanical device?

Not at the moment but maybe I will stumble upon one.

The difference in perception is not coming from the fact that one is natural and the other isn't IMO.

HOW they influence a signal is what matters IMO. Just imagine that a nonlinearity around the zero crossing will influence almost any signal and the weakest even the most.
Whereas 2nd and 2rd order distortion from a speaker is almost absent for really weak signals and is rising with level. It is influencing signals of high amplitude (where the ear is also far from linear) but leaves weak signals (and fine details) almost untouched.

Regards

Charles

[jacco vermeulen]

Originally posted by myhrrhleine
How about you ?

I like New York in June.
How about you?
I like a Gershwin tune.
How about you?

I like a fireside when a storm is due.
How about you?
I like potato chips, moonlight, and motor trips.

How about you?

[myhrrhleine]

Originally posted by lineup:

No, actually, no
For Pavel Macura maybe
But not for one listener.

I explain:
- Tube amplifiers are know to distotion producers.
- Loudspeakers are REALLY distortion producers. Does not matter what power amplifier you use.
Valve power or Solid State power or MOSFET power.
No big difference for our loudspeaker part.
It will produce considerably more distortion than any modern amplifier.


von Schweikert are expensive High End audiophile speakers
no doubt about this
Still von Schweikert has a level of 0.5% THD at 1-2 Watt RMS.
1 meter away from speaker on axis.

PMA talks about the -90 dB level. He is in his dreams
Because when listen with loudspeaker
and consider the Listening Room effects
( floor and ceiling and walls indirect sounds )
we are close to 1 % THD at 1 Watt.

===============================
1% = -40dB
0.0032 % = -90dB
What will dominate what we hear?
the Op-Amp THD or the Speaker THD.
===============================

I do not know what you think is correct answer.
But fortunately still I have some intact logics in my brains.

===============================

I attach the THD test curve of von Schweikert very expensive speakers.
They are NOT low or ordinary quality as of yours and mine speaker systems.
And they try to avoid Room influencis when measure
by putting Test Microphone 1 meter on Axis in front of speakers baffle.

so, you *like* distortion?
Personally, I do not.

My original post said

Do you truly like 2nd harmonic or third harmonic distortion?
Not me.
Given otherwise identical zero-GNFB amps, I prefer the lower distortion amp.