It’s all compression and rarefaction of air and its conversion by transducers. It’s the brain that decodes the music.
Question about how analog audio recording works
Hello!
My wife and I are high and having a discussion about how sound is recorded on records. I have an, I think, more than average understand of how sound and recording/playback works so I was trying to explain how grooves on the record represent sound waves.
What we don't understand is how polyphony is physically represented. So I can see how a single sine can easily be represented on a record. But when you're talking several sounds at once, some on the same pitch some now, dozens of timbres happening all at once, how do we differentiate those sounds on a physical medium like vinyl, or how do we represent it digitally? Is it literally nothing more than 1s and 0s? That'd be sick
Anyway, I hope this makes sense. Thanks!
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- 26 posts total
@mahgister , WELCOME BACK! I won't ask where you have been, curiosity can be fatal. This is not a problem of math. Math is a way of describing the problem. I believe it is a problem of conception not a problem in and of itself. It is reality and the proper use of electrons, physics and acoustics by people who can conceive of these issues. The beautiful thing about humans is we all have different talents. My understanding of math is very limited, but I can design in my head what people think is beautiful furnisher. Enjoy the Music and forget about the questions. Curiosity is fatal. |
Thanks for your kindness mijostyn , I was sometimes rude when we discussed in the past... I am too much passionnate and not so wise ...i am happy to be welcome by you... And i am happy to discuss with you even if we will differ of opinion in the future...but very opposite perspective are helpful to us and to all .. I was sad and very busy selling my house then loosing my acoustic room depressed ... This impacted my health...I sell the house by force not by my own free will... My new house is smaller... No acoustic dedicated room... 😥 Then i decided to go back to headphone not so happily because my room was spectacular...and none of my headphones ( 9 ) ever pleased me except the last one i never optimized because of my room spectacular acoustic.. but i stumbled on this headphone not easy to figure out and i take 6 months of daily listenings experiments to modify and optimize it ( 6 modifications) ...Surprizingly , it goes under 30 hertz and then the soundfield i reach rival my speakers which stayed at 45 hertz or 50 at most...The AKG K340 is the top headphone of 1978 and is always top today ( modulo optimization) It is not an headphone i will advise to everybody bec ause you must be ready to open it and to created a DEDICATED system only fot it ... I lost my "mechanized equalizer" 😁 but i used an electronic equalizer as you do yourself to optimize once for all the k340 my hybrid headphone...This k340 is the most difficult headphone and the most picky ever to drive and i even read the Dr. Gorike patent to figure it out how to optimize it ... Then my house sold, my health coming back , my new audio system ready, i missed all people here and decided to go back... I wish you with my heart the best possible for you and your family...
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@maynovent - Your question is a difficult one to visualize and, I think, the seed for a lot of misunderstanding and even pseudoscience in the audiophile world. I’m far from an expert, but have spent quite a bit of time trying to make sense of things. I think "visualizing" the analog process is the easiest way to understand it. Sound waves cause a microphones diaphragm to move in and out which creates an electrical signal that is a series of +/- voltages that will eventually cause the speaker drivers to replicate the in and out pattern of the original sound wave. A - negative voltage at the speaker makes it move one direction and a + voltage makes it move the opposite direction. Lower notes have longer wave forms so the speaker driver has to move farther in each direction to replicate it. Where it get’s harder to think about is when there’s more than one frequency because it’s hard to imagine a single driver replicating more than one frequency. In reality, the drivers can replicate high frequencies (think a vibration) at the same time as a deep bass note (think about when you an actually see a bass driver moving). In the end, the audio signal is really a series of positive and negative voltages that in super simple terms could be visualized as you taking one step forward and then one step back (representing a higher frequency) while standing on a moving belt that was simultaneously moving you forward 5 feet and then back 5 feet (representing a lower frequency). In the end, your absolute position (representing the driver) is what creates the combined sound wave. I’ve seen a great YouTube video that showed what multiple sounds looks like on an oscilloscope, but I can’t seem to find it today. I think a lot of audiophiles believe that cables are literally carrying a lot of music signals in parallel when it’s really just one signal. Something like a tuning fork will result in a nearly perfect sine wave while a full symphony will have a very complex wave form that is still just a more intricate series of positive and negative voltages. Without getting into the cable controversy, it’s important to recognize that music is not flowing through cables and it’s instead just a series of alternating positive and negative voltages of varying amplitudes. When it is thought about in this way, it’s easy to understand how maintaining the timing and amplitude of the pulses in the electrical signal are critical. The concept of "bandwidth" is, I believe, often mistakenly thought of as being able to pass more signals through in parallel and you’ll see a lot of the advertising capitalizing on this misunderstanding.
Think of an ideal audio system acting a rigid connection between the microphone diaphragm and the speaker driver. Every movement in the diaphragm should be perfectly translated to the speaker driver. |
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