Merely? other factors like conductor material, shielding, contacts also come into play. My experience tells me that capacitance does play a role in the audible results especially with some sources and at certain lengths. Which is why using a Y-adapter fails. Instead of comparing the 74 pF cable to a 510 pF cable in my linked example, you end up comparing a combined 626 pF to the very same 626 pF.
I think that is a pretty big difference!
If when attempting to prove that all ICs sound the same, you assume that C is irrelevant - and your methodology includes that assumption, they all you're exhibiting is circular reasoning.
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nice, the discussion focusses on pf's and other minor tech details.
It's clearly drifting far away from the initial question: "Is distortion really a problem for music reproduction?"
imho distortion is of no consequence as long as it does not influence the musical experience in a negative way. Relative large amounts of higher harmonics in the distortion's spectrum, for instance.
It's clearly drifting far away from the initial question: "Is distortion really a problem for music reproduction?"
imho distortion is of no consequence as long as it does not influence the musical experience in a negative way. Relative large amounts of higher harmonics in the distortion's spectrum, for instance.
An audiophile buzz word, "microdetail", is a marker as to where control of distortion behaviour is so crucial - this word hypes up a simple concept, which is just low level information in the sound presentation, which often contrasts strongly with the obvious, musical notes and harmonics content. A simple example is hearing a pianist's fingernails striking the keys, strongly contrasting with the musical piece being played - in real life it is easy to hear these "microdetails", in almost everything heard there are contrasting, unrelated sounds riding along, which the brain separates out, and can clearly focus on if it chooses to do so.
In recordings, there is always this "microdetail", the subtle little sounds are picked up by the microphones, and will be reproduced in some fashion by the playback system. If the distortion gods are agin you,
, this information is badly overlaid with, masked, modulated by distortion artifacts generated in the reproduction chain - the recording subjectively is very "dirty", "murky", "grungy", "non-transparent", etc, etc, etc. The aim of the motivated listener, , should be as much as possible to prevent this taking place, by "cleaning up" the playback - the "microdetails" are then more clearly heard, understood for what they are, at often an unconscious level, and discarded if irrelevant; or, taken on board as part of the musical message if that's what they truly are - this is when playback starts to become "magical", the reproduction begins to become convincing ...
So, it's not so much "distortion"; at a crude level of expressing it, it's "macro-distortion" vs. "micro-distortion" - everyone knows what macro-distortion is, it's micro-distortion that leaves most people floundering - they know the sound's not right, but they find it hard to express exactly what's going on - they know the sound can, and should be better ...
In recordings, there is always this "microdetail", the subtle little sounds are picked up by the microphones, and will be reproduced in some fashion by the playback system. If the distortion gods are agin you,
, this information is badly overlaid with, masked, modulated by distortion artifacts generated in the reproduction chain - the recording subjectively is very "dirty", "murky", "grungy", "non-transparent", etc, etc, etc. The aim of the motivated listener, , should be as much as possible to prevent this taking place, by "cleaning up" the playback - the "microdetails" are then more clearly heard, understood for what they are, at often an unconscious level, and discarded if irrelevant; or, taken on board as part of the musical message if that's what they truly are - this is when playback starts to become "magical", the reproduction begins to become convincing ...So, it's not so much "distortion"; at a crude level of expressing it, it's "macro-distortion" vs. "micro-distortion" - everyone knows what macro-distortion is, it's micro-distortion that leaves most people floundering - they know the sound's not right, but they find it hard to express exactly what's going on - they know the sound can, and should be better ...
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Conductor material and contacts are still being tested when two cables are in parallel at the source end. I accept that shielding effectiveness is not, but that is well into the realm of proper cable engineering!Estat said:
My theory tells me that capacitance plays by far the major role, but that this will be irrelevant for reasonable lengths driven from a sufficiently low source impedance.
Far from it - I assume it is about the only thing which matters. It is cable fans who claim that other issues are in play too, but most of these issues would still be in play with two cables paralleled at the source end. Hence such a test shows that these matters are not relevant, but leaves the capacitance untested. That does not matter, as engineers know that capacitance matters - we can calculate its effects! The test has the advantage that small frequency response changes caused by capacitance are removed, so any other cable properties which are relevant can be concentrated upon.
So a null result from such a test is good evidence that capacitance is the thing whuch matters. Of course, this involves an assumption that audio equipment and its connections are subject to the normal laws of circuit theory. If you want new physics, then audio ICs may not be the best place to look first.
Here's the specific claim from the article:
"But interestingly, all well designed interconnects sound identical."
That is quite different from your highly qualified version. And quite laughable at face value.
In the real world, there are most certainly occasions where you need longer IC runs (room structure, use of active monitors, etc.) and your source has relatively high output impedance (tube outputs). High cap ICs do not work well with some systems. Not to mention the effects of poor EMI/RFI shielding.
Hi and yes you are right.
I can only say that i have declared my personal war to distortion
Having read that speakers distortion is orders of magnitudo higher than amps distortion i have decided to go for speakers with very low distortion
This is quite a change for me obsessed with electronics
To be clear i have decided to go with HE speakers .. and after that to move up the chain ...
It will take me a little time to assemble everything
It will be DIY of course ... but well worth i think
It will be a learning process
Thanks again and kind regards, gino
A cable could cause high frequency distortion if all three of the following are true:
1. the cable is unusually long (for a domestic interconnect) and hence (or otherwise) has unusually high capacitance,
2. the cable insulator is a particularly nonlinear dielectric,
3. the source has unusually high output impedance (such as badly designed valve circuits or idiosyncratically designed SS circuits).
However, long before distortion was noticed a significant HF rolloff would be heard. The distortion would likely be 3rd-order, unless the cable carried a standing DC voltage in which case a higher level of 2nd-order distortion might occur.
1. the cable is unusually long (for a domestic interconnect) and hence (or otherwise) has unusually high capacitance,
2. the cable insulator is a particularly nonlinear dielectric,
3. the source has unusually high output impedance (such as badly designed valve circuits or idiosyncratically designed SS circuits).
However, long before distortion was noticed a significant HF rolloff would be heard. The distortion would likely be 3rd-order, unless the cable carried a standing DC voltage in which case a higher level of 2nd-order distortion might occur.
One has to be careful about this approach, IMO, gino - it's extremely easy to derive, measure seemingly horrendous levels of distortion from speakers, by picking a frequency low enough, and a level of output high enough. But is this particularly relevant? So, one gets, say, 20% distortion at 50Hz from a speaker driver - well, the last time I looked around extremely highly rated valve amplifiers can easily do the same thing if one pushes the volume a little bit higher than normal - a curiousity, for me, is that I have never seen what the distortion figures are for speakers when driven at the SPLs that 95% of time the material will listened to; where are the numbers that show what the misbehaviour is during normal listening?
The other thing is the type of the distortion: is it benign, or extremely disturbing - a nail being dragged a saucepan can be obnoxious to hear, but the sounds levels are miniscule - it's the nature of the distortion that does the damage, subjectively. And that's something that's very rarely talked about.
Personally, the 'quality' of the distortion from electronics not quite right is far, far more disturbing than the vast majority of speaker "issues" - a cheaper speaker can go from being bliss to listen to, to excrutiatingly unpleasant, merely by upsetting, through simple means, a few aspects of the electronics behaviour of the system.
Hi and thanks and i see.
A driver should be use in its best range
This will lead me in the end to active amplification because the precision in the cut that active xovers can provide is unmatched by passive ones.
This unfortunately will complicate the audio chain ...
But for instance the power requirements between the bass and the mid-high sections are hugely different
Brute force in the bass and delicacy in the mid-high
It is extremely difficult to find an amp good at both i guess
I agree and if one thing is sure i will never ever use tubes on bass
If i will go for a single amp it will be solid state ... and very low in distortion
at all powers
I have no answer of course ... but i think that with some music even at what could be normal listening level the peaks can go higher ... maybe reaching 100 dB ?
Well ... many commercial speakers at 100 db can have 2 figures distortion ... i am sure of that
I think that a distortion above 10% is detrimental for sound ... maybe i am wrong
Of course for quiet music at low level distortion should be also low ...
I like an optical comparison ... distortion is like an object out of focus
Lke a window not perfectly clean ... sometimes you see glass wall so clean that you hit them ... it is happened to me ... i hit one with the head
So the style of my messages can be better understood keeping this in mind
Seriously ... you know what i mean. I think we all strive for cleaness in sound ... transparency ... realism
Distortion ruins everything ... every
Yes but ... what if a more musical amp is less detailed that a not musical amp ? I am becoming a low distortion addict.
The only thing that holds me a little is that maybe all the forms of distortion are not completely understood. Not easily measured.
But the most gifted designers of the best sounding audio equipment they know what to look for. I am sure of that.
And maybe they have developed specific tests able to give evidence of all negative issues with equipment.
Thanks a lot and kind regards, gino
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Ninety years later.
Well, as far as I can tell this discussion started somewhere before 1938 (according to Rupert Neve at AES 1999 who quotes Masa as saying): "The total harmonic distortion (THD) is not a measure of the degree of distastefullness to the listener and it is recommended that its use should be discontinued"
About twenty years later Crowhurst revisited this issue in "Some defects in Amplifier Performance not covered by standard specifications" (AES vol 5 number 4 1957) with the observation "amplifier designers have been faced with an anomaly: the need to design an amplifier which works well and also gives a good specification"
Moving forward another two decades and Otala "discovered" TIM in '70 (IEEE Trans. Audio Electroacoust., vol. AU-18,
pp. 234-239, Sept. 1970.) While a "new" problem this is still a number that can be "gamed" and remains as marginally relevant as THD.
Belcher (40s), Shorter (50s), Wigan (60s) and most recently Lee & Geddes (2002) have been trying to come up with a more useful measure of amplifier performance than 'THD +N' (Howard Hi-Fi News 2005 provides a nice summary of this history).
Most of those efforts attempted to use what was then known about human hearing and perception.
Which brings us to the ironic point that the "lossy compression" and "Home Theatre" people have had the money to work on the problem from this direction.
And thus work out what we can and cannot hear - so are using "human simulation" to compare CODECs - for a summary (OK 333 pages of summary) of the SOTA read Robinson's 2002 PhD thesis (Uni Essex)
So, some 90 years after Masa, why is anyone talking about a single THD number as if it matters?
Cluelessness or conspiracy?
Well, as far as I can tell this discussion started somewhere before 1938 (according to Rupert Neve at AES 1999 who quotes Masa as saying): "The total harmonic distortion (THD) is not a measure of the degree of distastefullness to the listener and it is recommended that its use should be discontinued"
About twenty years later Crowhurst revisited this issue in "Some defects in Amplifier Performance not covered by standard specifications" (AES vol 5 number 4 1957) with the observation "amplifier designers have been faced with an anomaly: the need to design an amplifier which works well and also gives a good specification"
Moving forward another two decades and Otala "discovered" TIM in '70 (IEEE Trans. Audio Electroacoust., vol. AU-18,
pp. 234-239, Sept. 1970.) While a "new" problem this is still a number that can be "gamed" and remains as marginally relevant as THD.
Belcher (40s), Shorter (50s), Wigan (60s) and most recently Lee & Geddes (2002) have been trying to come up with a more useful measure of amplifier performance than 'THD +N' (Howard Hi-Fi News 2005 provides a nice summary of this history).
Most of those efforts attempted to use what was then known about human hearing and perception.
Which brings us to the ironic point that the "lossy compression" and "Home Theatre" people have had the money to work on the problem from this direction.
And thus work out what we can and cannot hear - so are using "human simulation" to compare CODECs - for a summary (OK 333 pages of summary) of the SOTA read Robinson's 2002 PhD thesis (Uni Essex)
So, some 90 years after Masa, why is anyone talking about a single THD number as if it matters?
Cluelessness or conspiracy?
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I think THD as a spec is here to stay. It very simple for a prospective buyer, who isn't interested in subtle differences or tech talk, to compare two numbers and decide which one is the better. A fact of life, and we as a designer community can not change that.
Compare it to the car industry. There's much more to the quality of a car than mere horsepower, but the attractiveness of a horse power spec is again: a simple number, and in this case, the bigger the better. It's much more difficult to attach a single number to, say, the road handling quality. Just as it is very difficult to attach a simple number to, say, and amplifier's sound stage rendition.
Jan
Compare it to the car industry. There's much more to the quality of a car than mere horsepower, but the attractiveness of a horse power spec is again: a simple number, and in this case, the bigger the better. It's much more difficult to attach a single number to, say, the road handling quality. Just as it is very difficult to attach a simple number to, say, and amplifier's sound stage rendition.
Jan
Bateman capacitor articles
For those of you interested in 'Capacitor Sound' or lack thereof, I have posted Cyril Bateman's landmark article series on my personal website.
Thanks to Cyril and the Editor at Electronics World for making this possible!
Enjoy!
Jan
For those of you interested in 'Capacitor Sound' or lack thereof, I have posted Cyril Bateman's landmark article series on my personal website.
Thanks to Cyril and the Editor at Electronics World for making this possible!
Enjoy!
Jan
Fortunately,
, it is possible to get the best of all worlds: a system, rather than just an amplifier, can reproduce high levels of detail and be musical - the two aspects are not mutually exclusive, even though many systems seemingly do one, or the other, .Unfortunately,
, getting this is not easy - it requires the builder of the system to be fastidious, cutting no corners, taking every care, and being prepared to spend a great deal of time and effort in refining every aspect of the system and its environment.The best test I have found is using the ears, they tell me every time whether the sound is "good enough", irrespective of spec's or conventional measurements.
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what engineer ever looks at a single THD number? - look in any chip amp datasheet - THD is given in graphs vs level, frequency, load - many thousands of "single THD values"
and standards for IMD are pretty old too - longer than most engineers working lifetimes
from the Cabot review article: AES E-Library Comparison of Nonlinear Distortion Measurement Methods
Cabot and Hofer book chapter: http://www.eselab.si/doc/Chapter13_3.pdf
B&K has another good paper: http://www.bksv.com/doc/bo0385.pdf
Czerwinski Multitone testing paper's bibliography on distortion measurement goes back over a century http://www.aes.org/e-lib/browse.cfm?elib=10174
the recycling of old memes continues here - a post of mine from a decade ago:
and standards for IMD are pretty old too - longer than most engineers working lifetimes
from the Cabot review article: AES E-Library Comparison of Nonlinear Distortion Measurement Methods
Cabot and Hofer book chapter: http://www.eselab.si/doc/Chapter13_3.pdf
B&K has another good paper: http://www.bksv.com/doc/bo0385.pdf
Czerwinski Multitone testing paper's bibliography on distortion measurement goes back over a century http://www.aes.org/e-lib/browse.cfm?elib=10174
the recycling of old memes continues here - a post of mine from a decade ago:
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