Re: Re: Re: Re: Re: Re: Here we go again
Granted, but what worried me is the realization we are talking of errors (no matter whether amplifier induced, coil induced, cable induced, crossover induced etc.) whose magnitude fall squarely within the range of others much more widely accepted as detrimental.
I tend to believe like you there is only a slim chance this really matters, but makes me uneasy.
(which of course makes for much more fun)
Rodolfo
Bob Cordell said:
Granted, but what worried me is the realization we are talking of errors (no matter whether amplifier induced, coil induced, cable induced, crossover induced etc.) whose magnitude fall squarely within the range of others much more widely accepted as detrimental.
I tend to believe like you there is only a slim chance this really matters, but makes me uneasy.
(which of course makes for much more fun)
Rodolfo
As a standard, I assume measurement both step response and FFT at the speaker binding posts, i.e. the whole chain. I can see no special "transmission line behaviour" for audio amplifiers and speaker cables. If, then only for RFI (not the signal through amp). This can be effectively damped by placing a resistor of some 50 - 300 ohms directly at speaker binding posts.
Talking about transmission line remind me of something.
Inductive peaking (T coil) was used in oscilloscope to drive capacitive load of the deflection plate, and not only 1 coil, but many.
At that frequency the tube/transistor is operating with the output lagging significantly from the input, but that doesn't seem to cause any nonlinear distortion.
Inductive peaking (T coil) was used in oscilloscope to drive capacitive load of the deflection plate, and not only 1 coil, but many.
At that frequency the tube/transistor is operating with the output lagging significantly from the input, but that doesn't seem to cause any nonlinear distortion.
Re: Re: Re: Re: Re: Re: Re: Here we go again
I think maybe I disagree. I don't think that we can equate a linear frequency response error that is in some respect 60 dB down to the error of a nonlinearity that is 60 dB down.
When we have a nonlinearity generating an error, it is creating new spectral components, typically both harmonic and intermodulation in nature. That is a source if dissonance.
A linear frequency response error of 0.01 dB, which would correspond roughly to 60 dB down, is only going to be perceived as the very slightest coloration, far, far smaller than that produced by the loudspeakers, for example.
Bob
ingrast said:
I think maybe I disagree. I don't think that we can equate a linear frequency response error that is in some respect 60 dB down to the error of a nonlinearity that is 60 dB down.
When we have a nonlinearity generating an error, it is creating new spectral components, typically both harmonic and intermodulation in nature. That is a source if dissonance.
A linear frequency response error of 0.01 dB, which would correspond roughly to 60 dB down, is only going to be perceived as the very slightest coloration, far, far smaller than that produced by the loudspeakers, for example.
Bob
Re: Re: Re: Re: Re: Re: Re: Re: Here we go again
Yes, I was aware of that implication, which fits with the fact some (relatively) high harmonic distortion amplifiers are welcome to some listeners, as long as IM products are not out of control, something that depends on the shape of the transfer characteristic.
Rodolfo
Bob Cordell said:
Yes, I was aware of that implication, which fits with the fact some (relatively) high harmonic distortion amplifiers are welcome to some listeners, as long as IM products are not out of control, something that depends on the shape of the transfer characteristic.
Rodolfo
andy_c said:
Hi Andy,
I have noticed the same thing on several reviews. The Stereophile quote of output impedance at 20 kHz seems to under-estimate the output inductance inferred from it.
I think it is dicey at best to try to infer output inductance from the Stereophile reviews, but the way that I try to do it is as follows: I look at the difference in the amount of high-frequency attenuation in the small-signal frequency response between an 8 ohm load and a 2 ohm load.
This is still probably subject to a number of caveats, but it seems to render a larger, more realistic value of effective output inductance. Note that this will estimate total effective output inductance, not necessarily limited to just the R-L coil itself, and may yield an effective output inductance even for amplifiers that use no coil.
Perhaps another approach to use the same data would be to spice a bandlimited voltage source with an output R-L combination into both 8 ohm and 2 ohm loads, and adjust the R-L combination to get a best fit to the data.
Bob
PMA said:
I'm only suggesting transmission line behavior in the sense of what kind of impedance the amplifier sees at high frequencies where it may be destabilized. I'm certainly not suggesting that there needs to be some matching situation, as, for example, trying to make speaker cables with an 8 ohm characteristic impedance.
However, a speaker cable will exhibit some of the characteristics of a mis-terminated transmission line at high frequencies in the MHz range.
Cheers,
Bob
Conrad Hoffman said:The problem as I see it, is two-fold. Most claimed sonic differences disappear when the many pitfalls of comparison are addressed. People with great knowledge and experience seem just as vulnerable to those pitfalls as anybody else. I do it myself, almost as if there were a Jekyll and Hyde nature to audiophiles. Cold and rational one minute, then all excited about some capacitor change when things sound really good. The second problem is that when differences really do exist, people tend to blame/attribute them to the wrong things. They change A and hear something, then assume it was A that's the fundamental cause, when A really triggered B and C and whatever else. Since the pitfalls are mostly well known, yes, I place the burden of disclosure on those who hear differences that conventional engineering suggests are unhearable. Without disclosure, there isn't much to discuss, which is why we're all here.
Seemingly going w-a-y back (although less than 2 days), I would like to quote this as a very sober and meaningful piece of analysis.
Yes, Conrad, I have also given up on keeping up, and very sadly, as someone else remarked much later than this, we have politics and personal emotions smothering much that one would like to ponder. Would have been handy to have time to condense stuff out. Maybe sometime in future (after my time) a "relevance filter" software will be introduced.
andy_c said:Just to put some numbers to this, I'm reposting a chart from an article reviewing speaker cables, where they measured the R, L and C of the cables. These numbers are per foot. The article was at audioholics.com
If the amps used were monoblocks and placed right behind the speakers using a very short length of the Goertz wire and no output coil, it seems like one could get some pretty low series inductance values between the amp output and the speaker. Would the improvement be audible? Dunno.
Oh, forget about all this nonsense. If you want the ultimate speaker cables, go to your local auto parts supplier and pick up a couple of sets of those really cheap, made in China, jumper leads.
Cheers,
Glen
mikelm said:
Mike,
I believe you have left one group out, perhaps a sub of group 1, but indeed very different: Those who have not tried the idea because it is so contrary to established science that it will be a waste of time.
E.g. a ridiculous example: That a 1pF capacitor across the mains leads will cause an audible effect. But some "beliefs" are just that.
G.Kleinschmidt said:Oh, forget about all this nonsense. If you want the ultimate speaker cables, go to your local auto parts supplier and pick up a couple of sets of those really cheap, made in China, jumper leads.
Yeah, and those clamps are way cooler than those chicken**** banana plugs too
.PMA said:Yes, here we go again
Could anybody explain me destroying sound effect of 1uH//1ohm coil and no problem with at least 2 - 4 uH of a speaker wire?? I am just one ear
Why ask? take a few minutes, build a coil, use a switch or relay (I don't buy into the ABX nonsense) wire it into your system and listen. It's called manual, non-electronic simulation.
Do you hear it, or not? If you do, what do you hear? Try a wide range of music. Pretend you're a reviewer and keep detailed notes. Most importantly enjoy listening to music while your at it.
Report back,
Group discusses.
If results are not what was anticipated,
hammer the messenger,
insult their mother,
roll out a couple of simulations to refute the heathen,
continue on with business as usual.
Just a thought. I posted my observations on inserting a standard coil/resistor 20-30 or so pages back.
Most importantly, enjoy the ride! It's all entertainment.
Mike.
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