I am interested in this last bit. I find it fascinating and look forward to more breakthroughs done on this in my lifetime.
I have tons of curious questions.
For instance
How does the brain sync the auditory information up with our visual field and how does it make it happen so fast without much delay? How does the brain translate a complex set of tones in to a particular distinct sound that we perceive.
I think this part has had good research done already: how does the brain use very fast variations between the left and right ear to form a mental shape of the sound.
What mechanism does the brain use to create height information from just two ears?
Are all these perceptual things completely hardwired in to us from birth or do we learn it as we age/practice?
Fascinating stuff.
Hi,
I know you moved this debate with me here but I am in England, so most of yesterday here there was nothing for me to look at at all and this morning I wake to a large number of posts which take a long time to digest!
My point is this. Whatever the mental or ear brain response is like may be fascinating but in this context it is not relevant, apart from any expectation bias or placebo effect.
This is why:
Before it gets to the speakers all the sound is is an electrical wiggle.
It is produced first at the microphone, of course, but that is usually manipulated by recording and mixing engineers to produce the LP, CD, file we buy.
Next we play it back at home. We, or at least I
, am fully conversant with all the many ways in which different record players can and do produce different electrical wiggles from the same LP, so lets ignore LPs for now.
In the case of a DAC the "end result" isn't whether it is a ladder dac has different filters or analogue sections it is "what is the electrical wiggle coming out of the analogue outputs, and how close is it to what it should be?"
This is also the case for the preamp and power amp. They can be treated as a black box with a transfer function.
If the transfer function of the "black box" is exactly as it should be, then there is no mechanism by which it could possibly actually sound any different to any other with the same transfer function, is there?
The electrical wiggle is unchanged so the air pressure wiggle from the speakers created by it is unchanged too, so how our brain may intereact with it can only percieve a difference by expectation bias or the placebo effect.
There is, of course a caveat. This is interaction between power amps and speakers. What I wrote above is the case for properly engineered DACs an preamps. Power amps have interaction with speakers which means that changing the power amp into the same speaker may well change the air pressure wiggle. This can be measured too though and show the changes/deviations from how it should be.
It is debateable exactly where distortion and signal to noise starts being audible, so I quite agree that the level at which deviation from perfect transfer function becomes audible is an unknown, so here it is just a case of preferring less deviation to more as a matter of principle IMO.
In the case of speaker/power amp interaction there is clipping and other sorts of overload into the actual speaker rather than an 8 ohm resistor that is obviously relevant to whether a system sounds different or not, but also the effect of a high output impedance of an amp on the complex impedance of actual speakers. This obviously is both amp and speaker dependant but since we know that changes in level of 1dB are definitely detectable, and very possibly much less by practiced listeners, it is probable, even likely, that an amp with a sufficiently high output impedance into speakers with a sufficiently complex impedance will result in sound level and frequency response
changes which are audible, in that even though the speaker/room FR won't be flat the change created in it should be audible.
I know the ear has a very high dynamic range, but as a person who has made many recordings over the last 55 years it has never been necessary for me to record all of it at the same time, so having a level control on my recorder to get the recording into the "good bit" of a restricted dynamic range has always been possible (though more difficult on a reel-to-reel tape since it is quite marginal for classical music in a quiet environment).
Personally I agree with you that with music dynamic range and masking may well make most distortion inaudible, but it might not
and the point is, why, since accurate stuff is available at modest prices, take the risk?
So, in summary, there is no mechanism by which the sound coming out of the speaker can be changed in any way that may be sensed by some little understood brain/ear phenomenon if there is demonstrably no way in which the electrical wiggle generating the pressure wiggle we sense has been changed - that is the nub of my point and the measurements we can do today
do show whether that has been achieved or not.