Objectivist or Subjectivist? Give Me a Break

[Ethan Winer]

Well, the first thing I'd like to see is a study design, perhaps using a passive preamp, comparing 3' and 30' lengths of the same cable where there is a measurable difference between the two in the audio range (where it should be detected). Since I haven't even read about that, I'm unwilling to speculate yet about what would be nice after that demonstration.

I agree this should yield a measurable difference that is also audible. The key being audible and measurable. But that's a pretty specific and non-typical case, coupling a passive volume control with 30 feet of wire. I think a more common arrangement is a competent preamp driving about 6 feet of wire.

--Ethan

 

[Ethan Winer]

Of course it would be dandy if someone actually defined the parameters of "competent" first.

Competent to me is a response deviation of 0.1 dB or less throughout the audible range. This is not difficult to achieve with either electronic gear or wires.

--Ethan

 

[Groucho]

Many papers have been published on this subject of of "harmonic splatter", the most interesting ones in the in the 50's, when power was limited and people were debating triodes versus pentodes. I read them mainly by curiosity, not professionally, in the british magazine Wireless World, as I did not have access to the US audio electronics literature of that period. Unfortunately it was all paper, and looking for them again is not now a fast job. IMHO the level of debate was much deeper than in Stereophile or any similar magazine.

The discussion about 'euphonic distortion' seems to centre on old fashioned amplifiers. Can't we just use a modern amplifier that has ample power and doesn't clip? Not sure whether people are justifying 'euphonic distortion' because it lets their tube amp off the hook, or whether they are saying it would actually be preferable to a (hypothetical if you insist) zero distortion amplifier.

 

[Groucho]

Non-harmonic intermodulations are processed by the ear as tonality, typically brightness. Intermodulations can occur in a variety of manners, essentially anything that is non-linear in the system can cause intermodulations (transformers, transistors, pentodes, poor layout, poor topology choices, etc.)- I have seen a dirty switch make a big difference. One inharmonic intermodulation point occurs at the feedback node of any amplifier (Crowhurst), which is one reason I avoid using loop feedback.

The earlier discussion pointed out that all distortion is inharmonic when there is more than one note playing in the music.

But if feedback is a problem, I presume you can measure it or simulate it..? And draw a conclusion in listening tests as to how audible/objectionable it is..?

There's an audio designer called Bruno Putzeys who seems quite highly regarded in audio circles. He has a quite interesting presentation online. One page stood out for me:

Practical open-loop errors are too large for guaranteed transparency.
•Feedback is the most effective tool for reducing errors
•Moderate loop gain does more harm than good in realistic circuits.
•Improved open-loop linearity reduces NFB-related products by a greater extent. Don’t Be a Wimp. Use NFB and use tons of it.

http://www.hypex.nl/component/weblinks/?task=weblink.go&id=62

 

[Groucho]

And FWIW, although I run vinyl and valves and my system is very full-range (although you may be referring to single-driver loudspeakers), I rarely listen to girl-and-guitar. That sounds like some sort of grossly inaccurate stereotype to me. IMO this comment can best be regarded as specious. I know a lot of audiophiles that play tubes and vinyl and they have very diverse tastes as one might expect.

OK, I withdraw my slightly tongue-in-cheek generalisation. It was loosely based on my experience at audio shows.

 

[rbbert]

I agree this should yield a measurable difference that is also audible. The key being audible and measurable. But that's a pretty specific and non-typical case, coupling a passive volume control with 30 feet of wire. I think a more common arrangement is a competent preamp driving about 6 feet of wire.

--Ethan

My point was that a test or study has to have sensitivity and specificity to differentiate these two cables (that are really two lengths of the same cable)

 

[microstrip]

The discussion about 'euphonic distortion' seems to centre on old fashioned amplifiers. Can't we just use a modern amplifier that has ample power and doesn't clip? Not sure whether people are justifying 'euphonic distortion' because it lets their tube amp off the hook, or whether they are saying it would actually be preferable to a (hypothetical if you insist) zero distortion amplifier.

What do you call old fashioned amplifiers? I am addressing the best of tubes, such as cj LP275m, ARC ref 150 , ref 610t or Atmasphere MA2 mk3. My system is calibrated in power and I know that problems of voltage clipping are not an issue in my system - although clipping due to current limitation is more difficult to prevent or diagnose.
BTW, I find this picture very interesting (from http://www.nutshellhifi.com/library/tinyamps.html . We can see that even SS amplifers distortion trends split.

 

[Groucho]

I know that problems of voltage clipping are not an issue in my system - although clipping due to current limitation is more difficult to prevent or diagnose.

If you're driving a real load and the voltage doesn't distort, you're presumably not having a problem with current, though..?

BTW, I find this picture very interesting (from http://www.nutshellhifi.com/library/tinyamps.html . We can see that even SS amplifers distortion trends split.

Funny that I am, in fact, using one of the exotic Quads as part of my active speaker setup - which brings me onto that topic. Yes, an amplifier has a very hard job to do, and so the active speaker simply sidesteps the issue and splits the load into easily-managed frequency bands, and as a bonus gets rid of the power-sapping passive crossover, and as a further bonus the load of each driver becomes much more benign on its amplifier. This is one of those 'paradigm shifts' where it is easy to imagine a very modest setup trumping a super-high end system. Like a Ford Focus driving better than a top-of-the-line Bentley three wheeler.

Are objectivism and subjectivism purely 'passive' philosophies in hi fi? i.e. taking existing equipment and measuring it or listening to it?

Or does it feed into design as well? Is the example of a designer discarding passive speakers and going active an example of objectivism or subjectivism?

 

[Orb]

Competent to me is a response deviation of 0.1 dB or less throughout the audible range. This is not difficult to achieve with either electronic gear or wires.

--Ethan

The problem I see Ethan is as I briefly touched in asking JJ; no-one has been able to create the satisfactory test of 0.1db being audible with music in the more traditional objective position of DBT ABX test -this is critical because nearly all this recent discussion is about perception and testing with music on real world systems (which is different to the actual testing to confirm 0.1db audibility as JJ mentioned in #1740 that has some very special caveats).

And yes I am one of those who does wonder what the effects are on sound quality perception once it drops below a listener's cognitive ability to hear the change as loudness (JJ may not remember but touched on this with him ages ago either here or on Stereophile before site-forum changed) and which was touched upon briefly a bit before post #1740 but that deserves its own thread if one wanted to discuss it in detail.
Again another one that is of interest is that of decay and possible 1ms to 4ms (only for speakers I would hope at 4ms) difference between products.

I remember a more recent scientific study (after 2010) where they noticed part of the perception of loudness for a piano note related to the very 1st ms of the attack of the sound generated by the actual key press rather than the actual full sounded note (removing that very initial key press attack reduced cognitive ability in differentiating between two different loudnesses of same key pressed at different strengths).

Cheers
Orb

 

[Ethan Winer]

The problem I see ... no-one has been able to create the satisfactory test of 0.1db being audible with music

But that's my point. If two wires both measure flat enough that nobody can hear a change in response, then anecdotal reports of the wires sounding different are incorrect and due to faulty perception.

--Ethan

 

[rbbert]

But that's my point. If two wires both measure flat enough that nobody can hear a change in response, then anecdotal reports of the wires sounding different are incorrect and due to faulty perception.

--Ethan

No, Ethan, that is a tautology. It may be true, but the logic isn't, nor is the data ("nobody"? Really??)

And it fails to address the question at hand, which is why measurable differences in frequency response in the audio band are not necessarily detected in listening tests. The two most obvious possibilities are that the difference is too small to be detected or that the test is not designed to be sensitive enough to detect the differences.

And this also ignores the possibility that frequencies outside the "audio band" (20-20kHz) may still affect our perceptions of music.

 

[j_j]

Are you suggesting that amplifier clipping enhances a system's apparent dynamic range, because "harmonic splatter" fools us into thinking that our Fletcher Munsons are being stimulated?

It's very simple, increase (within 20-20k) the bandwidth of a signal for the same overall energy, and the loudness will increase.

Your arguments about harmonicity fail completely for non-periodic sounds like percussion hits, and even for complex music, where the error spectrum will be correlated in energy (nonlinearily) with the input signal, but will be near-white or near-pink (signal depending) and not have a lot of prominent lines.

I have seen several attempts to either beg the question or avoid the simple psychoacoustic facts, but yes, distortion of the right kind does increase the sensation of dynamic range.

Fletcher-Munson has very little to do with it, however.

I would suggest you check out the loudness tutorial at www.aes.org/sections/pnw/ppt.htm for starters.

 

[j_j]

J_J,

IMHO your statement is too imprecise and vague to be analyzed. Unless it is qualified, electrical performance can mean many different things in audio and we can have good and erroneous blind tests.

Your opinion has no effect on either physics or psychoacoustics. By the way, who were you really quoting there, anyhow, and in what context? Would you prefer to be a bit more careful in your quoting in the future, say so as to not avoid context?

 

[j_j]

The discussion about 'euphonic distortion' seems to centre on old fashioned amplifiers. Can't we just use a modern amplifier that has ample power and doesn't clip? Not sure whether people are justifying 'euphonic distortion' because it lets their tube amp off the hook, or whether they are saying it would actually be preferable to a (hypothetical if you insist) zero distortion amplifier.

I was talking about vinyl. You?

 

[j_j]

My point was that a test or study has to have sensitivity and specificity to differentiate these two cables (that are really two lengths of the same cable)

Have you learned about positive and negative controls in a test yet?

 

[rbbert]

Have you learned about positive and negative controls in a test yet?

Isn't that to what I was (indirectly) referring? I'm fairly conversant with testing methodologies; thus my skepticism about the validity of conclusions that are often drawn from poorly designed studies.

 

[j_j]

Isn't that to what I was (indirectly) referring? I'm quite conversant with testing methodologies; thus my skepticism about the validity of conclusions that are often drawn from poorly designed studies.

There are certainly some poorly designed tests bandied about.

Tests without controls are one of my pet peeves.

 

[Robh3606]

or that the test is not designed to be sensitive enough to detect the differences.

Hello rbbert

Not sensitive enough?? I can see a couple of decimal places past .1dB with relative ease. Looking at the posted response curves do you really expect to hear any differences and again just for fun here is a photo of the two cables. The difference in level is because I added 1dB to one of the test files to make them easier to compare.

Take a close look at the posted measurement. There are red and green dashed lines, if you look at the legends you can see the measured dB reading for each one and the Delta between the two in dB and Frequency. Each minor division is a tenth of a dB. Measurement Sensitivity is not the issue.

Rob

 

[Groucho]

It's very simple, increase (within 20-20k) the bandwidth of a signal for the same overall energy, and the loudness will increase.

...I have seen several attempts to either beg the question or avoid the simple psychoacoustic facts, but yes, distortion of the right kind does increase the sensation of dynamic range.

I'm well aware of the trick of introducing a bit of clipping in order to convey a sense of loudness - any kid with a tape recorder knows that! But is it hi fi?

It sounds as though you are coming from the angle that distortion should be introduced deliberately to enhance the apparent dynamic range. And this distortion just happens to be the kind produced by vinyl and tubes. Wouldn't it be more controllable to use a zero distortion amplifier (or as close as we can achieve) and apply DSP to the signal - if we really must?

I can see that if we have no choice but to use sources and amplifiers with limited power and/or inherent distortion, then we might want to tailor that distortion to give us this loudness effect. They do it with tablet and mobile phone speakers to make them seem more dynamic. But my experience with low distortion systems, big speakers and the right recordings (of course) is that clean playback can be breathtaking. It would be a shame to mess it up with added scuzz.

 

[Phelonious Ponk]

Hello rbbert

Not sensitive enough?? I can see a couple of decimal places past .1dB with relative ease. Looking at the posted response curves do you really expect to hear any differences and again just for fun here is a photo of the two cables. The difference in level is because I added 1dB to one of the test files to make them easier to compare.

Take a close look at the posted measurement. There are red and green dashed lines, if you look at the legends you can see the measured dB reading for each one and the Delta between the two in dB and Frequency. Each minor division is a tenth of a dB. Measurement Sensitivity is not the issue.

Rob

The blue one sounds better. Anyone can see that.

Tim