Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion HiFi & HT Chat Can sound quality be measured?

Firstly, define "Sound Quality".
What does that mean in itself ?

If you are talking about Fidelity, then yes, that can be measured, but it also requires qualification : do you consider Fidelity to be the difference between - the sound that comes out of the instruments (in the performance environment), or that's experienced @ the place you were standing in the Concert Hall (or wherever), or that the Mixing Engineer created / the Band signed-off on (MQA !), or that the waveform that's embedded on the LP represents, or that the bitstream that's embedded in the CD / Hard-drive represents, etc etc etc - to that which arrives at your ears ?

Oh, also don't forget that a signal that arrives at your ears (externally) will be different by the time it's starting to be processed by your brain than it would if you "used my head" instead ! Our ears are different - we're unique - and our brains are different too.

You can quantify the data that's on a CD and you can measure the stream that's eventually passed to the speakers.
You can measure audible (and inaudible) frequencies with incredible accuracy : a near-field measurement of the speaker's analogue output, or even a measurement in an anechoic chamber, would be a simple option.
But bear in mind that as soon as you introduce "an environment" then the output from a transducer - the speaker - is affected.

Also remember that cables DO NOT HAVE A SOUND - that's completely absurd. They pass electrical signals - they don't have a "sonic signature".
We can measure with extraordinary accuracy what goes into a cable & what comes out the other end, far beyond the frequencies that have an influence on Audio equipment. There is absolutely no doubt that if the signal is altered during its journey, we can find it - and if the signal is altered then the cable is either poorly manufactured, or deliberately designed to cause an alteration (which requires actual processing), or it's in an extreme / unsuitable environment.

Digital signals are digital and cables cannot change the data - they can only corrupt it - and you will hear this as a "glitch" / white noise / click - which I'm sure everyone has heard from time-to-time.
If there is a genuine & true difference in sound noticed when using different digital cables, then it's the source / receiver at fault - in other words your DAC is sh*t. Poor endpoint design. Simple as that.

Once again, some of us work in Industries where high-speed digital & analogue signals are critical : Motor-vehicle engine-control units (and the in-car networks), Aircraft control-systems, Spacecraft control-systems, Weapon control-systems etc.
There can be a mixture of extreme levels of Electro-Magnetic-Radiation, analogue signals & digital signals.
Fundamentally, the wires & transmission / receiving nodes aren't much different from those you will find in a domestic environment, but in these usage profiles there is absolutely no place for corrupt data - and there's a lot more information transmitted at higher speed & bandwidths in much harsher environments than in a domestic audio system. Transference of signals is an extremely well-understood branch of science !
Digital data is not changed by cables unless they are faulty / not fit for purpose - and then the failures are obvious.

Expectation-bias is incredibly powerful, especially when coupled with a new, shiny, VERY expensive purchase.
Opening a window or door in your room, or even adjacent room, can have an effect on the acoustic response of the room you're in.
The weather - air temperature / humidity - does have an effect on acoustics.
Your physical condition - drunk / dehydrated / tiredness / starting to suffer from the effects of an illness of which you're not yet aware / stress / joy / etc etc etc - has an effect on the processing that goes on between your ears.
MOVING YOUR HEAD 5cm IN ANY DIRECTION CHANGES THE PRESSURE WAVES THAT YOUR EAR EXPERIENCES....
As you relax into your seat, with a couple of glasses of your favourite tipple, during an evening of enjoyable listening, then you're both physically & physiologically changing the input to your brain and it's processing parameters simultaneously.

So, in summary, yes, we really can measure the differences that pervade the audio chain, but what specific difference is it that you wish to understand ?
And if you were in the business of selling equipment, at a high mark-up, would you shroud your palette of products in impenetrable mumbo-jumbo which sound enticing / credible to the lay-man, or would you publish detailed / verifiable / RELEVANT measurement data ?