Who will survive? One last table til I die.

Dear TWL:****" Raul, anyone who thinks that the location and order of harmonic distortion is "not matters", has no clue of what harmonic distortion is, nor how it affects a musical presentation. Please bone up on it, and try again."***

The subject that the 2nd harmonics are a " gentle " one, it don't say that there is no distortion. Right?

***"The frequency response of my amp is totally unaffected by speaker reactance in my particular system."****

Do you already measuring?

***"The "very high output impedance" as you put it, has no bearing at all on anything, until you connect a speaker to it."*** Yes, everybody knows that.
****" If you actually knew anything about this parameter, then you would not make statements such as you do."***

Which ones?

***" By the way, we are all still waiting for you to reveal the contents of your "highly musical" solid state system that will be revealing of the "true music" that you think we all are lacking in our systems. "***.

You really think that some " names " can tell you that?, come on you are a wise people.

***"You seem to think that it is ok to ignore anyone else's points.."****

I never ignore anyone else's points: that's the problem.
BTW, till now ( like Chris ) you are not prove nothing on the subjects.

Tom, again, this is not a contest it is not important who is right the important issue is that all of us in this forum can learn about. Now maybe you can feel good if I tell you that you are right and that you are the winner one, Ok: you are the winner and I'm " seriously lacking in audio knowledge ."
Regards and enjoy the music.
Raul.

Here is a very recent article "cut and pasted" from the Audioholics website regarding this very matter.

Damping Factor: Effects On System Response
Monday, August 30 2004

Damping Factor: Effects On System Response

Analysis
Several things are apparent from this table. First and foremost, any notion of severe overhang or extended "time amplitude envelopes) resulting from low damping factors simple does not exist. We see, at most, a doubling of decay time (this doubling is true no matter what criteria is selected for decay time). The figure we see here of 70 milliseconds is well over an order of magnitude lower than that suggested by one person, and this represents what I think we all agree is an absolute worst-case scenario of a damping factor of 1.

Secondly, the effects of this loss of damping on system frequency response is non-existent in most cases, and minimal in all but the worst case scenario. Using the criteria that 0.1 dB is the smallest audible peak, the data in the table suggests that any damping factor over 10 is going to result in inaudible differences between that and one equal to infinity. It's highly doubtful that a response peak of 1/3 dB is going to be identifiable reliably, thus extending the limit another factor of two lower to a damping factor of 5.

All this is well and good, but the argument suggesting that these minute changes may be audible suffers from even more fatal flaws. The differences that we see in figures up to the point where the damping factor is less than 10 are far less than the variations seen in normal driver-to-driver parameters in single-lot productions. Even those manufacturers who deliberately sort and match drivers are not likely to match a figure to better than 5%, and those numbers will swamp any differences in damping factor greater than 20.

Further, the performance of drivers and systems is dependent upon temperature, humidity and barometric pressure, and those environmental variables will introduce performance changes on the order of those presented by damping factors of 20 or less. And we have completely ignored the effects presented by the crossover and lead resistances, which will be a constant in any of these figures, and further diminish the effects of non-zero source resistance.

Frequency-Dependent Attenuation
The analysis thus far deals with one very specific and narrow aspect of the effects of non-zero source resistance: damping or the dissipation and control of energy stored in the mechanical resonance of loudspeakers. This is not to suggest that there is no effect due to amplifier output resistance.

Another mechanism that most certainly can have measurable and audible effects are response errors due to the frequency dependent impedance load presented by the speaker. The higher the output resistance of the source, the greater the magnitude of the response deviations. The attenuation can be approximated given the source resistance and impedance vs. frequency:

where is the gain or loss due to attenuation, is the amplifier source resistance, and is the frequency dependent loudspeaker impedance.

As a means of comparison, let’s reexamine the effects of non-zero source resistance on a typical speaker whose impedance varies from a low of 6W to a high of 40W .

Damping
factor
RG
GdB(MIN)
GdB(MAX)
GdB(ERROR)

¥
0 W
0 dB
0 dB
0 dB

2000
0.004
-0.006
-0.001
±0.003

1000
0.008
-0.012
-0.002
±0.005

500
0.016
-0.023
-0.003
±0.01

200
0.04
-0.058
-0.009
±0.025

100
0.08
-0.115
-0.017
±0.049

50
0.16
-0.229
-0.035
±0.098

20
0.4
-0.561
-0.086
±0.23

10
0.8
-1.087
-0.172
±0.46

5
1.6
-2.053
-0.341
±0.86

2
4
-4.437
-0.828
±1.8

1
8
-7.360
-1.584
±2.9


As before, the first column shows the nominal 8W damping factor, the second shows the corresponding output resistance of the amplifier. The second and third columns show the minimum and maximum attenuation due to the amplifier’s source resistance, and the last column illustrates the resulting deviation in the frequency response caused by the output resistance.

What can be seen from this analysis is that the frequency dependent attenuation due to the amplifier’s output resistance is more significant than the effects on system damping. More importantly, these effects should not be confused with damping effects, as they represent two different mechanisms.

However, these data do not support the assertion often made for the advantages of extremely high damping factors. Even given, again, the very conservative argument that ±0.1 dB deviation in frequency response is audible, that still suggests that damping factors in excess of 50 will not lead to audible improvements, all else being equal. And, as before, these deviations must be considered in the context of normal response variations due to manufacturing tolerances and environmental changes.

Conclusions
There may be audible differences that are caused by non-zero source resistance. However, this analysis and any mode of measurement and listening demonstrates conclusively that it is not due to the changes in damping the motion of the cone at the point where it's at it's most uncontrolled: system resonances. Even considering the substantially larger response variations resulting from the non-flat impedance vs. frequency function of most loudspeakers, the magnitude of the problem simply is not what is claimed.
End

As you can see from these calclulations, a damping factor of 5(1.6ohms/8ohm spkr) provides 0.86db variation in frequency response as a maximum. This falls well within a +/-1db spec. It is inside the +/- tolerance of any loudspeaker, and certainly far inside the tolerances of any listening room. Other factors in the listening system/room will far outweigh this factor, thus making it insignificant in magnitude, even in a low damping case such as 5.

How anyone can make a case that tube amps are "equalizers" from this performance data, is beyond me. I certainly hope that this puts this matter to rest.

And my last post was premised on the damping data alone, and did not even take into account the other important factors that may play into this matter.

Raul- If you really wanted someone like me to learn, how 'bout trying to teach by example? As you say, this forum is about learning- help me learn by telling me of products that exemplify your points. Maybe even let me know what you have so that I have a clearer understanding of your own point of view. In that way, I can truly learn from you! (That is your stated goal, correct?)

Jim

Dear TWL: Just checked out your system. Was curious about the Rottweiller tweak. Does it work best between the speakers or on top of them?