Why are objective assessments important...

[jabbr]

7 hours ago, Archimago said:

 

When it comes to audible distortions, using multiple blinded listening tests to identify and verify audible anomalies then use objective testing to measure the problem probably is the best way to effectively weed out issues, and keep findings relevant (eg. audible TIM back in the day might be an example). These days, the "golden ears" who claim to hear differences but never bother to run a blind test to prove to themselves and others that the impression is anything more than a mirage would not be helpful in this endeavor.

Yes with a caveat. 
 

Measurements have multiple purposes. If you are really looking at something like TIM, you need careful testing. TIM is a nonlinearity so you can’t simply plop the sound into an AP frequency analyzer and expect a result. You need to know what you are looking for and do the measurement accordingly. That means knowing a lot about electronics theory. 
 

Similarly the relationship between power supply noise and clock phase error is a nonlinearity. 
 

Blinded listening tests can be hard to do for the engineer testing a prototype circuit on the bench. Blinded tests are needed when there is an identified subjective difference, specifically when “golden ears” hear differences that no reasonable electronics theory predicts. 

[jabbr]

6 hours ago, Audiophile Neuroscience said:

What I think most subjectivists sceptically reject is the notion that excellent device specs translates into sonic transparency and the corollary, that an excellent set of specs means that the device will sound like any other device with the same specs.

Don’t assume that the provided measurements are “specs” for an electronic circuit, We know that, for example, THD does not entirely denote “SQ”

[jabbr]

55 minutes ago, Audiophile Neuroscience said:

Hi Jonathan,

not sure I completely follow what you mean when you say don't assume that the provided measurements are specs for an electronic circuit. At any rate my intention was to use the word specs or specifications in a broader sense, pertaining to materials, design and performance et cetera - the things that define what a product is and does.

Cheers

David

 

Davd, 

 

Well yes, a complete specification would be the electronic circuit, firmware, drivers etc, but aside from a FirstWatt amplifier, that is never available. Even then, a SPICE simulation of the circuit is not the same...

 

A measurement is not a spec in that sense. Some of these specs are more akin to marketing. Of course you may need a certain wattage amp with certain speakers, and a DSD or PCM DAC input etc.

 

Some measurements like spectra may give an idea about how the product sounds. 
 

Tell me though, do you find that “performance specs” give you an idea about how the products sounds? If so, which specs? I’d say that some common specs give a very general idea but not at the level of detail I’m interested in — I think that some of the nonlinear behaviors give a better idea of the unique product sound but these aren’t commonly measured nor published.

[jabbr]

1 hour ago, Audiophile Neuroscience said:

I would much prefer to be informed by objective data even at the end of the day if I reject it and still make my own subjective choice. At least I would have an option, a choice.🤔

Yes absolutely. I believe in a combination of understanding the electronic circuit, measuring the circuit to ensure that it is behaving as intended, as well as listening!

 

This is the crux of the question: which measurements predict great sound?

 

Hard to say but if a product claims low jitter, then let’s see the measurements. If a power cord or supply supposedly improves a DAC then let’s see the measurement! If a product claims to block leakage current then let’s see the effect n a DAC!

[jabbr]

11 minutes ago, Archimago said:

Again, we are just fortunate to be living in a time when our reproduction gear is good enough to keep measurable distortions low enough that for the most part, people lose sight of how important the objective side is. When devices often measured poorly say in the 40's to the early 80's, surely the focus on objective performance can be understood.

It is true that the commonly measured parameters such as THD and frequency response are almost universally excellent. Yet products sound different. What is needed is a focus on measurements that highlight the differences between equipment, rather than measurements which are almost universally good. 
 

Let’s me highlight (again) the FirstWatt series of amplifiers because:

1) same quality/case/power supply/price

2) published schematics

3) each has unique sound

 

So which measurements best explain the unique sound of each amp?

[jabbr]

Ok how about these measurements — as some examples, there are others:

 

1) isolation from common mode noise (CMRR) — common mode noise, whether through the power supply or inputs, leads to leakage currents, hum etc

2) input rise time sensitivity

3) impedance mismatch sensitivity 

4) power supply noise sensitivity

 

(I’ve heard very audible issues with several components which otherwise measure very well)

 

*** this list has nothing to do with the series of FirstWatt amps!

[jabbr]

7 hours ago, Archimago said:

 

Hey @jabbr

I dunno. Let me get back to you when I have a FirstWatt to measure on the bench... 🙂

 

 

You could build one! I picked this series as an example because the circuits are published and there is a forum on DIYAudio devoted essentially to building them. 

Archi, you do a great thoughtful job on your blog. I’m writing this to answer the question, not necessarily for you, but for the “subjectivist” who doesn’t find THD and frequency response helpful.

 

Rather than trying to “prove” to people why they aren’t hearing what they are hearing, we all could do a better job using objective data to demonstrate why people are hearing what they are hearing. 
 

Nelson Pass, for example, allows people to play around with 2nd harmonic. Tube vs transistor. Note that jFets were selected because similar behavior to tiroides etc. 

 

So think of this from a scientific POV, rather than prove an observation isn’t meaningful, scientists do much better explaining an observation in a new light. 
 

As an example consider a paper:

”Differential transmission of common mode noise in a series of USB cables as a function of a series of USB transmission devices”

 

7 hours ago, Archimago said:

If we are to compare objective performance, we cannot speak in generalizations but must specify devices and examples so everyone's on the same page. What THD and frequency response are you referring to specifically?

 

Exactly, yet these seem to be the universal “specs” that are published... 

7 hours ago, Archimago said:

 

Of course devices sound different including the FirstWatt amps, but notice that they do measure quite differently as well.

 

Yes, if you do the proper measurements! THD and FR not so dissimilar.

7 hours ago, Archimago said:

Are there 2 FirstWatt amps that measure almost identically in detailed testing (not just FR, but also stuff like output impedance / damping factor across the audible frequency, relative amounts of odd/even and higher order harmonics...), and specified which speaker they're connected to? Remember, unless we can confirm load invariance with the amp, all bets are off.

 

Exactly. My point is that if you look at the circuit, the specific testing becomes more apparent.

7 hours ago, Archimago said:

 

Furthermore, Pass makes no bones about appreciating that varying amounts of harmonic distortion might be preferable (and makes devices like the H2 Harmonic Generator to play with this). It's objectively demonstrable and yes, audible...

I firmly believe that everything audible is measurable if and only if the right measurements are done. Not all that is audible is measurable by an AP analyzer, or demonstrated solely by an FFT. 

[jabbr]

13 hours ago, Archimago said:

Coming back to the thread title, we must still contend with the fact that the vast majority of that "nourishment" is a result of the art itself (ie. music), and not confuse that with the devices we're using to convey the sound. The machines we use to reproduce the music are conduits for the art and IMO the job is to transmit the signals that encode the art. And objective analysis is the primary way of determining that these devices are performing to expectations

Yes! From a pragmatic perspective, objective assessments are important if they increase our enjoyment of this hobby.

 

That could be ...

... improving the sound of our systems in a predictable way without needing to listen to a gazillion different components and combination of components

... allowing us to have the best sound for our individual budgets

... Improving the convenience of listening

... Allowing us to understand how components of our hobby work

 

Not everyone will value each element, or any of the above, and most people simply want to hit a button and listen!