The content of frequencies we don't hear...

[iomegaman]

Just read Dan Lavrys paper on optimal sampling rates...decent information...(http://www.lavryengineering.com/pdfs/lavry-white-paper-the_optimal_sample_rate_for_quality_audio.pdf)...but it got me to wondering...

There are a lot of things that music and sound do for us that are beyond the scope of our ability to decipher (at this stage in human development), things that lean into the spiritual, the mystical, aesthetic content that affects us all in different ways...I know that here on a forum populated primarily with guys that lean into science and quantifiable results that this discussion might be off the rails a bit, but thats why its here in the brewery...

I was wondering, if we follow Dans advice and never record above frequencies that capture human range audible signals, if we are not eliminating things we have not yet learned to appreciate simply by cutting out stuff beyond our cognitive abilities?

Maybe it accounts for the difference between a live setting and a recording because in a live setting there are things happening that are beyond the scope of our frequency interpreting mechanisms but not beyond our ability to experience...

Of course there is the issue of adding unwanted stuff regardless of our capacity to decipher it, that makes sense, but I wonder if there's a trade-off at this stage in the game because of our limited understanding of what is happening beyond the human ear?

What are your thoughts on this?

And down that road...in dc current on short trace circuits would there be an advantage to using higher frequency current rather than the typical 50/60hz we have defaulted to? Would capacitors charge up faster and transformers operate differently in ways that would be beneficial or is the trade-off to great?

 

[JohnRoberts]

Evolution is relatively slow in human lifespan terms. They just did a cat scan on a egyptian mummy and found clogged arteries so not much change in a few millennia.

There is learning involved with human audition. Our brain spends most of it's effort on ignoring superfluous input data. 

That said I have participated in some nonsense arguments about significance of above band musical instrument signals.  :

Dan is a solid citizen so I would support his conclusions without re-reading them recently.

My design philosophy about sounds humans can not hear is to pass them cleanly or remove, so they don't create audible in-band artifacts that we can hear.

JR

 

[Kingston]

I was wondering, if we follow Dans advice and never record above frequencies that capture human range audible signals, if we are not eliminating things we have not yet learned to appreciate simply by cutting out stuff beyond our cognitive abilities?

Cognitive? That's skipping the most important step. It's physically impossible for a human to hear a sound above maybe 20-22khz. That's the way ear (cochlea to be more exact) is set up down to cellular level (sensory hair cells). The information above it never enters the brain and no cognitive function ever has a chance to process or later interpret it.

There are several sane reasons to record at higher resolution, such as moving the decimation filters far above cochlear capability to eliminate any possible phase effects from less than optimal analog or digital filters, or sound design where you can pitch down the recording to make use of the information above the threshold of hearing. or dolphin communication etc. bat ultrasonic radar research.



If you are interested in differences between live versus recording settings, perhaps you should be looking at the psychological effects rather than the much lower level physical phenomena. Unless again you were interested in feline or canine interpretations of the ultrasonic frequencies of musical instruments. Or bats.

 

[MagnetoSound]

Just read Dan Lavrys paper on optimal sampling rates...decent information...(http://www.lavryengineering.com/pdfs/lavry-white-paper-the_optimal_sample_rate_for_quality_audio.pdf)...but it got me to wondering...

Uh oh ... 

There are a lot of things that music and sound do for us that are beyond the scope of our ability to decipher (at this stage in human development), things that lean into the spiritual, the mystical, aesthetic content that affects us all in different ways...

Agreed.

I was wondering, if we follow Dans advice and never record above frequencies that capture human range audible signals, if we are not eliminating things we have not yet learned to appreciate simply by cutting out stuff beyond our cognitive abilities?

Maybe it accounts for the difference between a live setting and a recording because in a live setting there are things happening that are beyond the scope of our frequency interpreting mechanisms but not beyond our ability to experience...

...

What are your thoughts on this?

My over-riding thought is this: the only thing we can record using sound recording equipment, whether in the studio or in a live setting, is the sound. 

We cannot record the smells, air currents, eye contact, empathy, telepathy, alpha waves or any other resulting human emotions that one may experience in real life events, using sound recording equipment - and therefore, if we hope that any of this may translate into a recording, said recording will be found lacking in this regard.

Maybe we should be looking at ways to record and reproduce other things than audio, to be 'played back' along with the music, so as to heighten the 'listening' experience?

But then, are we not just trying to substitute some kind of vicarious quasi-life experience for the real thing? Where will it end? Is not the music enough any more?  8)

And down that road...in dc current on short trace circuits would there be an advantage to using higher frequency current rather than the typical 50/60hz we have defaulted to?

What does this even mean?   ;D

 

[iomegaman]

I was wondering, if we follow Dans advice and never record above frequencies that capture human range audible signals, if we are not eliminating things we have not yet learned to appreciate simply by cutting out stuff beyond our cognitive abilities?

Cognitive? That's skipping the most important step. It's physically impossible for a human to hear a sound above maybe 20-22khz. That's the way ear (cochlea to be more exact) is set up down to cellular level (sensory hair cells). The information above it never enters the brain and no cognitive function ever has a chance to process or later interpret it.

There are several sane reasons to record at higher resolution, such as moving the decimation filters far above cochlear capability to eliminate any possible phase effects from less than optimal analog or digital filters, or sound design where you can pitch down the recording to make use of the information above the threshold of hearing. or dolphin communication etc. bat ultrasonic radar research.



If you are interested in differences between live versus recording settings, perhaps you should be looking at the psychological effects rather than the much lower level physical phenomena. Unless again you were interested in feline or canine interpretations of the ultrasonic frequencies of musical instruments. Or bats.

Well that's kind of my point, cognitive for us at this point seems to be limited to only what we hear, but what if the frequencies are doing things for us that are not heard...there are plenty of phenomena where humans have perception that defy the limited range of the five senses...a mothers intuition comes to mind...I am not suggesting these things operate beyond the bounds of science, simply that "known" science might not have discovered the benefits/compromises yet...(http://oto2.wustl.edu/cochlea/romesalt.pdf)

 

[JohnRoberts]

We cannot record the smells, air currents, eye contact, empathy, telepathy, alpha waves or any other resulting human emotions that one may experience in real life events, using sound recording equipment - and therefore, if we hope that any of this may translate into a recording, said recording will be found lacking in this regard.

Not exactly a new theme, and smell-o-vision came and went decades ago.

Maybe we should be looking at ways to record and reproduce other things than audio, to be 'played back' along with the music, so as to heighten the 'listening' experience?

I have long argued that conventional sound reproduction is dimensionally challenged. i.e. sound exists in a 3 dimensional sound field but recording media generally records only 2 dimensions.  Stereo is remarkably richer than mono for creating the illusion of a real sound field but still critically flawed. (IMO)

This too has been well inspected and pursued with varying results for decades.

But then, are we not just trying to substitute some kind of vicarious quasi-life experience for the real thing? Where will it end? Is not the music enough any more? 

In fact we could make a passible imitation of a musician playing an acoustic instrument in the room with us. Squeezing a full orchestra into a 10x10, not so easy.

And down that road...in dc current on short trace circuits would there be an advantage to using higher frequency current rather than the typical 50/60hz we have defaulted to?

What does this even mean?  ??? ;D

nada..

JR

PS: Perception pathways other than our ears are not a practical concern for audio design with the possible exception of butt-shakers for drummers (or high end theaters). .

 

[iomegaman]

And down that road...in dc current on short trace circuits would there be an advantage to using higher frequency current rather than the typical 50/60hz we have defaulted to?

By this I am wondering about using high frequency current has potential in audio, I guess the trade off immediately is high induction fields probably melt transformer parts...this youtube thing has been stuck in my mind for a while now:  http://www.youtube.com/watch?v=aLwaPP9cxT4

 

[MagnetoSound]

John, as you well know, my point was that the additional options of smell-o-vision, the feelies, even Soundfield recording and Ambisonics, in no way impinge on sampling theorem, nor render it inadequate. 8)

I am still open to learning about high frequency DC current, though.

 

[Kingston]

I am not suggesting these things operate beyond the bounds of science, simply that "known" science might not have discovered the benefits/compromises yet...(http://oto2.wustl.edu/cochlea/romesalt.pdf)

Infra-sound and ultrasound are not interchangeable. We are perfectly able to record most if not all infra-sound information down to maybe 5-10hz already (mics permitting) and no high sample rates are needed for it.

 

[zebra50]

...additional options of smell-o-vision...

Johnny Marr played the brown note at least three times last tuesday. You can't capture that on DAT!

Everyone was very excited, like seeing the Smiths but without Mozzer, which i think we can agree is a good thing.

??? Sorry, been reading too many of CJ's transformer posts...

 

[iomegaman]

I am not suggesting these things operate beyond the bounds of science, simply that "known" science might not have discovered the benefits/compromises yet...(http://oto2.wustl.edu/cochlea/romesalt.pdf)

Infra-sound and ultrasound are not interchangeable. We are perfectly able to record most if not all infra-sound information down to maybe 5-10hz already (mics permitting) and no high sample rates are needed for it.

Ok thanks for being patient and not making me feel more uneducted than I really am, but maybe I am not discribing what is in my head properly.

A full bridge rectifier takes the "unused" wave and puts it back into the signal, on a scope this has the effect of "smoothing" things out a little...so here in the states we go from 60hz and take part of the signal, flip it and now we have essentially 120 hz (give or take everything you need here)...which becomes somewhat more usuable even though there is still ripple...obviously when trying to get a clean power source you want to eliminate the ripple and straighten out the signal on the scope...so what iff we could increase the cycles per second?

Is this simply a limitation of how our AC power comes to us and there's no real way to increase the cycles? Is it a standardized sort of issue that all of our components have adhered to regardless of science or is it a physical limitation?

As I get it a capacitor can charge and s=discharge quite easily in this cycle range...what happens if we sped up the cycles, do we also speed up all the bad stuff as well or can we filter it better...or is this essentially what the filter caps are doing? Simply operating at a much faster cycle rate?

I know this is outside the box and probably way off target tot he actual engineering, but its how my mind works...sorry.

This is what I mean by a higher frequency rate...not necessarily in the signal path but maybe before in the psu design...if we could fill up and empty the capacitors faster would it clean up even more or is there a trade off somewhere?

 

[Kingston]

http://en.wikipedia.org/wiki/War_of_Currents

should break down those questions nicely. Very different topic than all these audibility and psychology ponderings.

 

[Andy Peters]

A full bridge rectifier takes the "unused" wave and puts it back into the signal, on a scope this has the effect of "smoothing" things out a little...so here in the states we go from 60hz and take part of the signal, flip it and now we have essentially 120 hz (give or take everything you need here)...which becomes somewhat more usuable even though there is still ripple...obviously when trying to get a clean power source you want to eliminate the ripple and straighten out the signal on the scope...so what iff we could increase the cycles per second?

Well, you could use a switch-mode power supply and arbitrarily run it up in the megahertz range.

Which is done every day with little fanfare.

-a

 

[Andy Peters]

And down that road...in dc current on short trace circuits would there be an advantage to using higher frequency current rather than the typical 50/60hz we have defaulted to?

I think you mean "advantage to using a higher frequency for AC mains distribution."

As others are trying to tell you, there is no frequency content to DC.

-a

 

[ruffrecords]

Maybe it accounts for the difference between a live setting and a recording because in a live setting there are things happening that are beyond the scope of our frequency interpreting mechanisms but not beyond our ability to experience...y in ways that would be beneficial or is the trade-off to great?

The main difference between live and a recording is that our ears have evolved to generate 3D spacial information from delays and frequency response differences caused by the shape of our ears. My professor at Nottingham University in the 70s was working on ultrasonic aids for the blind. Part of that work was trying to understand how the ear provides us with 3D information. Binaural recording was quite popular at this time and they did a lot of experiments based on it. One thing that puzzled them was that simple artificial heads were unable to provide height information. Then they had a brain wave. The placed the head on a pair of artificial shoulders and voila! they had height.

So, my point is that recording are so different from the live event, not because of any frequency response differences but because most of the spacial information is lost.

Cheers

Ian

 

[ricardo]

I was wondering, if we follow Dans advice and never record above frequencies that capture human range audible signals, if we are not eliminating things we have not yet learned to appreciate simply by cutting out stuff beyond our cognitive abilities?

Dr. Olson investigated this in the last millenium.

However, AT THE PRESENT STATE OF THE ART, with recorded & reproduced music, ALL serious studies of the audible effect of Band Limiting have shown a clear cut PREFERENCE for the BAND-LIMITED SIGNAL.

ie it sounds BETTER if you "cut stuff out beyond our cognitive abilities".  I've conducted my own Blind Listening Tests on this and was pleased that stuff this millenium only confirm my results.

..would there be an advantage to using higher frequency current rather than the typical 50/60hz we have defaulted to? Would capacitors charge up faster and transformers operate differently in ways that would be beneficial or is the trade-off to great?

Yes.  Its called a switched mode power supply.

But it needs to be designed & built properly so it exhibits only the benefits and none of the trade offs.  Today, the knowledge, bits & tools to do this are much better known and available.

 

[alexc]

Maybe we should be looking at ways to record and reproduce other things than audio, to be 'played back' along with the music, so as to heighten the 'listening' experience?

I think that's been explored .. with horticulture. Or maybe, pheromones.
.
.

But then, are we not just trying to substitute some kind of vicarious quasi-life experience for the real thing? Where will it end? Is not the music enough any more?  8)

Yep. That's exactly it.

It will end in a discrete time life simulation with quantized resolution equal to the first significant digit of the 'tuned' cosmological constant. With only the occasional blue screen of death.

 

[pucho812]

How many times have you tweeked an eq for a few minutes to get the perfect sound and then noticed it wasn't even inserted?

If you want to heighten the musical experience, check out Scriabin the composer, he started to get into the idea of using the other senses like sight and smell into his musical works. He did things like use a color organ and have perfume sprayed into the performance hall while his music was playing.

(for example)
http://en.wikipedia.org/wiki/File:Scriabin_keyboard.png

 

[CJ]

i think that your "musical software" is way more important than specs on audio reproduction equipment,

that is, your ability to enjoy music as granted to you by He.

this can be witnessed at any concert you go to,

fans will range from "i can't wait til this is over" to "play all night!".

music hits people very differently. i once took a nice Asian lady to a rock show and she just did not get it.  plugged her ears the whole time while everybody else was dancing in the isles, maybe a DNA thing caused by cultural differences due to geographical location,

this explains why MP3's thru ear buds can be considered acceptable to some folks,

in other words, the medium is Not the message.

there is a lady in the Ken Burns masterpiece "Jazz". she say Louis Armstrong is better than booze and sex, that's what i am talkin about,

Armstrong was my first musical influence at age 5 on the Mark Twain steamer at Disneyland, they had a film of him running inside the boat, still remember it, Pops was smiling "were gonna rock this ol Mark Twain, all the way to New Orleans", then I wandered over to see Joe Tex perform live over in Fantasyland and i was hooked for life."show me a man who's got a good woman", big ol band tearin it up, them Mom found me and it was time for the hotel swimming pool. you could turn your kids loose back then and not worry about it.  :-\

then it was The Music Man, wanted a trombone after that, 

thank God the Beach Boys came along and got me out of that funky jam.

Round Round I get Around, still sends shivers up my spine, first Album was Surfer Girl, then Desraili Gears, talk about shiftin gears, sheesh,

i bet seeing Benny Goodman live would kick ass on anything out there, too bad i missed that, Kruppa tearin up Stompin at the Savoy or One O'clock Jump. holy crap, no sh*tty sound systems and echo halls back then, just pure music.


The content of frequencies we don't hear?

No.

The content of Talent we don't hear.

right now i am suffering thru a guy trying to play piano in the next room, can't even spell the word Meter.  :'(
could not cop a groove if his life depended on it, poor Tarzan,  ;D

http://www.youtube.com/watch?v=nk93tJoyh74

 

[Rossi]

There are two ways to look at frequency content above the audible range:

a) why worry, I can't hear it anyway?
b) OMG I might miss something!


Some facts:

Not many instruments produce and few microphones are able to pick up content above 20k.

Not many loudspeaker systems can reproduce frequencies above 20k.

Quite a few high quality monitor systems (Genelec 80xx series and many more) show strong resonance peaks above 20k. If you excite those resonances, you'll get IM distortion in the audible range.

So, all thing considered, how much is there to gain by higher sampling rates?

Do an experiment: Listen to a sine wave at 17 kHz. If you can hear it (you may not), you'll find it's actually not such a pretty sound. So it's not like there is an aural paradise waiting for you "on the other side".