Stirring Up Trouble


Part I

Stirring up trouble. Not usually a hard thing to do on this site. But my last attempt fell flat, probably because it was tucked into the end of a post about interconnects. So I’m going to try again and do so more explicitly.

Audio is fun, in part, because of the “discussions” it gives rise to. Is Nap Eyes “inspired” by the Velvet Underground or is just stealing from them? (Lots of talk about transparency and imaging on this forum. I would argue that nothing does that better than the Velvets first record. From the first notes, I’m taken back to the Factory in the mid-60s. There’s Andy in the corner, I see everything through lava lamp lighting, and Edie and all her gorgeous acolytes are dancing are dancing on risers with those great haircuts, the white boots, and all of the great eye make-up. Only downside: if I found myself in that scene, I’m sure that I’d shoot heroin. Maybe not such a downside, after all.


This should also probably be parenthetical but the evidence is awfully strong that Dylan wrote “Rolling Stone” about Edie Sedgwick. Fact: She was an uptown girl, family had a lot of money, she went to the best school but she only got juiced in it. Fact: Warhol spurned in a terrible way. One minute she was glamour girl #1, the next she was out on the street. Her family had tired of her and weren’t interested in sending her to some spa/rehab for the 43rd time. Not yet fact but the evidence is awfully damning: Bob and Edie had a little thing, a short affair while Bob was married to Sarah. Listen to the song in that light and a few things click into place.


But back to audio. The battles that rage here are legion. I just found a new one when I considered getting sorbothane pads for my electronics. Not knowing the first thing about the subject, I was surprised that trench warfare was well underway and that feelings had hardened on both sides. Can you hear hi-res? Do Ethernet sound different? The 100 Years War over cables. Sure, it’s fun to argue about trivia, even very expensive trivia. But the language used and the grudges held don’t seem like fun.


At heart, all of the combatants in these battles share one assumption: An objective sound exists. Somewhere, at some time, a source is emitting sound waves. And because this sound is objective, we are all supposed to experience the sound in the same way. One either gets it or he doesn’t. Either the angels sing to you or they don’t. What, you’re showing me another chart that shows that what goes in to one end of the cable comes out at the other end in exactly the same way whether it’s lamp cord or Nordost. Been there, heard the story, seen the chart. But I trust my ears and my ears tell me that the sound is different.


And so we come to a stand-off. From these positions, there cannot be any worthwhile discussion, we can’t find a new way forward. Luckily for us all, science doesn’t work that way.


The first thing science would do is look at the assumption that underlies the whole issue: that objectively exists in the world of acoustics and Observer #1 (Tom) hears the same thing as Observer #2 (Bill).


The scientist, strangely wearing a shirt covered with vertical black and white stripes and a black baseball cap runs into the listening room or cafe or lab, blows a whistle and throws a yellow handkerchief at the two listeners. “Penalty! Unlawful assumption.” (The handkerchief contains a heavy rubber weight and strikes Bill in the eye. Bill is able to continue but the next day he learns that he has a torn cornea.) The scientist runs outside to an unknown destination, leaving a lot of dazed onlookers.


But with just those few words, much of what we understand about acoustics tumbles to the ground. Tom and Bill both got their hearing checked recently. They are the same age, about the same size, and neither has any history of hearing problems. They are standing right next to each other in front of a pair of Wilson Alexandria’s supported by electronics of the same excellence and the Nordost cables that were recently swapped in. But Tom and Bill don’t agree on what they are hearing. “Listen carefully,” says Tom, who has long argued that cables make a difference. “The difference is subtle. But don’t you hear a little more definition in the bass? A sense of more air, more space in the midrange?” Bill, always a cable skeptic, looks at Tom like he’s from Mars. “You’re crazy,” he says.


So who’s right? Perhaps more importantly, what would the current state of acoustic science and brain science say is right?


Happily, they both are. The explanation has been a part of both fields for decades. Two observers simply do not experience sound in the same way. (Pretty much everything I’m going to say from this point on can be found in the references below. But those aren’t particularly special articles. It’s more that they came up high on the Google list. Please, bring more literature into the debate.


We can make music and be pretty confident in what we’re doing. We can make a machine that produces a steady 200 Hertz note. Might not sell too well but doing that is well within the range of our technology. Beethoven’s Fifth has many more variables but we know how to reproduce it.


The same is not true at the other end of the equation. We can be almost certain that Tom and Bill will not hear the same thing as each other. Possibly the single note but almost certainly not the symphony. Those sounds are not objective. Different observers will heat those sounds differently. It’s possible that their will be a different observation made by every individual on earth.


As I make my attempt at an explanation, here’s where you need someone smarter than me. Here’s where I urge you to read the cited material.


We all hear different things because we are all so different in so many ways. The shape of our ears are different from each other, as are the internal mechanism of hearing: aural canal, ear drum, cochlea, all that other stuff you learned about in sixth grade bio. Some sound reaches us as vibrations through our skulls, and all of our skulls are thicker or thinner at different parts of our head. Oy gevalt, and the brain hasn’t even gotten involved yet.


As with most functions of the brain, an auditory signal is processed in many different parts of our brain. There is no “hearing center” that lights up when the 1,375,492 second of the ninth symphony is played. A new constellation of lights—a very short lived one—is created with each sound.


Sounds like a lotta work? The brain agrees. So it tries to make its job easier. One thing it does is try to spot patterns. Once it has kind of a code a new constellation isn’t created with each sound. Even more importantly, this code lets the brain make predictions. Instead of inventing the wheel with every note, the code takes care of much of what has already happened and is likely to happen plus it can predict what new touches will be added. That means that if the brain has its way, we will, to quote the title to one of the cited works, “We Hear What We Expect To Hear.”


This tendency is pushed aside when a major new sound enters the scene. We may expect to hear the left turn signal make its usual clicking noise if we indicate a turn but if the result is a blaring noise and tires squealing, the brain will ignore it’s preference for patterns. The difference between speaker cables, if any, is many multiples less loud and dramatic. If Bill is a cable skeptic who expects all the cables to sound the same, that’s what he gets. The same way that Tom, who is expecting not just different but better, gets just what he’s expecting. Neither is right, neither is wrong. Both are human.


The bottom line is that something that we would call sound or music doesn’t exist until a sound wave travels through out physically different aural systems, our neurons with their biases and ways of working, rides neurotransmitters across the synapses. Only when this is done does the brain produce something that we can recognize as music. Our brains are very good at appreciating music and making sure that, at any given moment, our collection of eardrums, skull vibrations, neurons, and chemicals produce a sound that we perceive as awful close to the note that was played and intended by the musicians to sound a certain way. But there’s just so much stuff, so many steps, that inevitably each of us puts our own special stamp on it. That’s how Tom and Bill can both be right. They expected to hear something different and, voila, so they did.


https://www.sciencedaily.com/releases/2021/01/210108120110.htm

https://en.m.wikipedia.org/wiki/Neuroscience_of_music

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5819010/

https://www.cognifit.com/science/cognitive-skills/auditory-perception

https://plato.stanford.edu/entries/perception-auditory/

paul6001
Did anyone notice that this diatribe is labeled "Part l"?
Looking forward to Part ll: The Empire Strikes Back 

Excellent discussion. Should end a lot of highly contentious arguments. Some people like the smell of gasoline!

MC's video almost had me hypnotized. I thought they were going to ask me to join a cult at the end.

My only comment is there are SOME universal truths about audio equipment and music that are not debatable. That is what I like to find out about here on AG.
a little long........however a very well written, articulate, researched article.   Well done !!!!

Just for fun, you might want to know how you "hear" that sax or guitar.  Just think how much fun you would have reciting this to someone admiring your gear.  However do take a look at the 3rd paragraph up from the bottom.

Taken from an article by Davies and Surgano

The auditory pathway conveys the special sense of hearing.

Information travels from the receptors in the organ of Corti of the inner ear (cochlear hair cells) to the central nervous system, carried by the vestibulocochlear nerve (CN VIII).

This pathway ultimately reaches the primary auditory cortex for conscious perception. In addition, unconscious processing of auditory information occurs in parallel.

In this article, we will discuss the anatomy of the auditory pathway – its components, anatomical course, and relevant anatomical landmarks

Components of the Auditory Pathway

The auditory pathway is complex in that divergence and convergence of information happens at different stages.

There are two main components of the auditory pathway:

  • Primary (lemniscal) pathway – this is the main pathway through which auditory information reaches the primary auditory cortex (A1).
  • Non-lemniscal pathway – mediating unconscious perception such as attention, emotional response, and auditory reflexes.
Primary Pathway Spiral Ganglion

The spiral ganglion houses the cell bodies of the first order neurons (ganglion refers to a collection of cell bodies outside the central nervous system). These neurones receive information from hair cells in the Organ of Corti and travel within the osseous spiral lamina. Their central axons form the main component of the cochlear nerve.

The vestibular nerve joins the cochlear nerve entering the internal acoustic meatus, and from this point onward they are collectively called vestibulocochlear nerve. This proximity is clinically relevant since lesions to this nerve will usually produce symptoms in both the auditory and vestibular components.

The nerve enters the cranium through the internal acoustic meatus and travels a short distance (around 1 cm) to enter the brainstem at the cerebellopontine angle. For more information on the vestibulocochlear nerve, its anatomical course and function please read this article.

The first order neurons synapse at the ipsilateral cochlear nuclei.

By OpenStax College [CC BY 3.0], via Wikimedia Commons

Fig 2 – The spiral ganglion houses the cell bodies of the first order neurones in the auditory pathway.

Cochlear Nuclei

Fibres from the cochlear nerve bifurcate and information is sent to the cochlear nuclei on each side of the brainstem:

  • Ventral (anterior) cochlear nucleus – located in the area where the nerve enters the brainstem.
  • Dorsal (posterior) cochlear nucleus – located posterior to the inferior cerebellar peduncle.
    • It forms a small bulge on the surface of the brainstem – known as the auditory tubercle.

From the dorsal cochlear nucleus, most fibres cross the midline and ascend in the contralateral lateral lemniscus. Other fibres ascend in the ipsilateral lateral lemniscus.

From the ventral cochlear nucleus, some fibres also ascend in the lateral lemniscus bilaterally. However, most fibres from the ventral cochlear nucleus decussate to the contralateral superior olivary nuclei in a region known as the trapezoid body. Although the ventral cochlear nuclei neurons decussate at the trapezoid body, some fibres synapse at the ipsilateral superior olivary nucleus. The superior olivary nucleus is located just next to the trapezoid body. It also projects upwards through the lateral lemniscus.

In summary, in both the dorsal and ventral nuclei, some fibres decussate while others do not. For that reason, information from both ears travels bilaterally in each lateral lemniscus. This is important because supranuclear lesions (i.e. above the level of the cochlear nucleus) will not lead to serious hearing impairment. Therefore, hearing problems can be conductive or sensorineural but are rarely central.

Adobe Stock, Licensed to TeachMeSeries Ltd

Fig 3 – Information from each cochlear nucleus is transmitted bilaterally.

Inferior Colliculus and Medial Geniculate Body

fibres ascending through the lateral lemniscus from both cochlear nuclei and from the superior olivary nuclei arrive at the inferior colliculus, where all these fibres carrying auditory information converge.

These fibres project to the ipsilateral medial geniculate body (MGB) in the thalamus (recall that vision is relayed on the lateral geniculate body).

The MGB does not act as a simple relay centre: it has reciprocal connections with the auditory cortex and mediates refinement of the incoming information. Projections from the medial geniculate body proceed then to the primary auditory cortex.

Note: A good way to remember what information passes through each geniculate body is that music goes to medial and light goes to lateral.

Primary Auditory Cortex

The primary auditory cortex (A1) is located in the superior temporal gyrus, right under the lateral fissure. The primary auditory cortex is organized tonotopically, although its organisation is complex, and the details are beyond the scope of this article.

Non-Lemniscal Pathways

These are pathways that do not lead to primary auditory cortex. They involve multisensory integration, reflexes, attention, and emotional responses.



Any two given people (take your pick) are as likely to hear something - anything - exactly the same as they are to have the same fingerprints.