Understanding Sample Rate

[crenca]

7 minutes ago, beerandmusic said:

 

You hear a continually changing composite, with the gaps between samples averaged based on probability of samples, to keep the waveform continuous, but not based on factual samples between times?

 

A waveform has no "gaps", it is a rate of change - not a point like "here, then here, then here".  A waveform is not a stepping on individual stones (say in a river you are crossing), it is like the water flowing in the river.  Your confusing sample rate with rate of change.  Because human hearing (and sound itself through all mediums) is band limited, its rate of change can only be so much.  Thus, you only have to sample so much - you are thinking that the sampling is sampling the sound itself which you imagine to be particle like movement - it is not, it is sampling a waveform that just happens to exist in the particle based medium, which is like the flowing river and thus you do not need to sample every molecule of river water to measure the rate of flow.

[crenca]

5 minutes ago, beerandmusic said:

going to dinner and watch tv with wife....i must admit, it has me "thinking"....not sure if my conclusions are different, but more confused now than when i started (grin).

 

My wife and kids are at birthday parties and shopping, so I am just sitting here with my beer and music engaging you in this somewhat tedious imagining exercise  

[crenca]

2 minutes ago, beerandmusic said:

 

I have only considered frequencies within normal hearing ranges...i believe higher resolution provides more accuracy within the hearing range.  (e.g. i am, and only have been, concerned with what is within the audible frequency range).

 

As far as waveform accuracy they don't, except secondarily in that filtering distortion comes into play - higher sampling rates can be used with filters that do less damage during the reconstruction of the waveform.  In the human hearing range, to fully (with no "gaps") calculate a waveform (you think a waveform is "sampled", and put together back together again like humpty dumpty, or a puzzle, or a mosaic - it is not, it is fully calculated).

[crenca]

3 minutes ago, beerandmusic said:

 

what i meant by gaps is that at t1 you have freq x and t2 you have freq y, and you must connect the dots, so the detail between the dots is the gaps that is estimated, calculated, averaged, or whatever terminology you use....and that is where the details and accuracy are lost....between the samples.

 

Nope, because a waveform is calculated, not "sampled".  It is continuous...

[crenca]

24 minutes ago, GUTB said:

 

You do realize that we don’t listen to waveforms, right?

 

What we listen to are compressed air waves that are three-dimensional physical phenomenon that have a width, height, velocity and intensity. The electrical impulses that come out of a microphone are only a loose, linear approximation of that phenomena.

 

Yep, I have been simplifying, bending, and mangling for didactic purposes.

 

On the other hand, the "compressed air waves that are three-dimensional physical phenomenon that have a width, height, velocity and intensity" that come out of our dynamic/planar drivers based on this recorded waveform are strangely true to "the real thing".  Perhaps it's the linear, pistonic sensory apparatus we all have...

[crenca]

18 minutes ago, beerandmusic said:

compare 10 samples per second to 1000 samples per second, and the accuracy of the reconstruction would be more obvious, especially on a very complex waveform compared to a simple sine wave of one frequency.

 

I'mmm baaaccckkkk

 

No, because of the nature of sound, more samples does not mean more accuracy.  Once you reach a certain point, any further samples add nothing, zero, nada, to the sound's accuracy.  This truth has been measured and can be described - like other physical phenomena like the speed of light, or energy of a hydrogen atom, etc.

 

Beerandmusic, your still thinking of sound as a quanta, a series of "infinite" events in "infinite" time.  You are thinking of sampling as a real sample of the music - like the sample is a "capture" of the sound itself just like when a person goes out into their front yard and collects a "sample" of the grass.  You also think that these samples are put back together again in a series, like a puzzle, so that the more pieces you have the better or "more accurate" the picture is.   None of this is true.

 

(tangent:  You see folks, is it not unfortunate that the term "sampling" has been used - laypersons have a completely different understanding of what this term means)

 

Question beerandmusic:  I am 6'1 in height.  If I "sample" my height once a year, or once a day, or once a second, does the "accuracy" of my measurement change?  If I set my cruise control in my car at 60 miles per hour (and it is reasonably accurate - it always keeps my car within 2 miles per hour of 60 miles per hour), if I "sample" my speed 100 times a second, would me speed be more "accurate" then if I sample my speed about once a second...or once a minute...or just a few times between point Albuquerque and San Diego?

 

A true sampling story that occured on the internet one day:

 

beerandmusic, what is your name?

 

Crenca, my name is "beerandmusic"

 

But beerandmusic music, I only know you "digitally", not in the real world, so I need to be more accurate  - what is your name?

 

Crenca, I already told you, my name is "beerandmusic"

 

Yes, but this is digital sampling, so for accuracy I will need to ask  you several times a second - what is your name?

 

Crenca, obviously you don't understand, your initial sample is an accurate sample of my name, and doing more samples does not give you a more accurate understanding/measurement of my name.

 

Why?  Because some engineers told you?  Logic dictates that because we know each other digitally, the more samples I get from you the more accurate I can hear you, see you, and know you - a sample is just a sample after all, and the more the better because I only captured a few instances of your name, I must need more for accuracy - what is your name?

 

But Crenca, names don't work that way, you have a fundamental misunderstanding of the nature of names

 

beerandmusic, I have already told you how sampling works...more is better because it leads to more accuracy - what is your name?

 

....

 

 

[crenca]

10 minutes ago, beerandmusic said:

 

when you sample the same thing, the accuracy doesn't change, but if i changed my name the sampling matters for accuracy.

i will ponder the rest.

 

 

Very good!  NOW we are getting somewhere.  Tell me, are you a god or a man?  If you are a god, then you have the ability to change your name at an infinite rate (if you so choose) and since I am a man I could not sample your name fast enough to accurately reproduce your name.  However, if you are a man, then you are limited by the laws of the universe - you are a creature, and you are not infinite.  Thus, there is a limit as to how fast you can change your name. Tell me, what is this limit?  

 

How fast can you change your name???  

 

I ask because I can then tell you (even better, I can prove it too you) how fast I need to sample, to accurately, fully, without any errors or "gaps", reproduce your name...

[crenca]

5 minutes ago, beerandmusic said:

 

i only changed my name for the moment that you did not sample....i changed it back the next moment you did not sample....you have the correct current name but you have no knowledge of the moment i changed my name....you are missing the details....but it doesn't matter now, because it is in the past.

 

Ah, you are a god then.  You can change your name at an infinte rate.  I am but a man, and I live in the world which you created - this orderly world where men can only change their names up to a certain frequency.  True, bats and other animals can change their names at a greater frequency, but even they have their limits.  Man, being a creative and intelligent creature (made in your image of course) through his art can make machines that can change their name even faster (much faster) than creatures, but alas, even these machines have  their limits.

 

What is it like to be a god, such that you can not be sampled accurately?  Tell me please, I am but a lowly man...

[crenca]

1 minute ago, beerandmusic said:

 

even man can create sound at an infinite rate...the pluck of a guitar string for instance.

the complex waveform has an infinite number of frequencies within it's own frequency range that man just is not able to record.

 

Man?  no.  Demigod?  Perhaps.  Do you speak of the winged Cupid, plucking on his strings?  These strings produce frequencies of an infinite rate?!?!  Oh, to be a god and hear the infinite sounds of the heavens!!  Tell me noble beerandmusic, your highness, what is it like to hear the infinite sounds of the gods and their heavens!!??  Please tell me, for I am but a man, and when men pluck on our crude and limited strings, only finite frequencies come forth from them....OH, MY SOUL my soul,  I lament at my mortality, my finiteness, my limitations.  PLEASE, please noble and great beerandmusic, tell me what do the sounds of the gods sound like??

[crenca]

2 minutes ago, beerandmusic said:

"infinite rate" was taken in your context.

 

But i have heard "things" that you would never believe in the material world you know....but i won't go into because it is off topic (lol)...only sharing because you asked.

 

 

 

 

I hear you noble beerandmusic!  I too believe in the gods!!  I have seen their shadows on the walls, seen the shapes out of the corners of my eyes.  But, alas, I am but a man and have also seen that a stone is just a stone as well.  When I walk home, after a weary day, the distance is always the same.  The gods, yes yes they are infinite, but the world that they created for us is not arbitrary.  They are also not facetious or cruel - they help us lowly men by creating order and limits.  Our names and the notes that our instruments create, alas, they are finite as well, and can only be manipulated so fast.  Thank the gods!  This means that they can be measured!!  If men were infinite, then men would have no names, and music would have no frequency, just as you point out noble beerandmusic!!!

[crenca]

1 minute ago, beerandmusic said:

 

P.S. Thanks for spending so much time patiently with me.  Where it may not be apparent that I have gained anything, i believe I have.

 

 

No worries.  I know upstream you mention your education.  Have you considered reading Plato?  The dialogues of Socrates you would find very very interesting.  Rather than trying to teach you Fourier math, these dialogues can teach a man to think, such that you can under-stand ALL ideas including Fourier math. (think about that term, it means to "stand under" some thing or idea  - you uphold it, it does not "inform" you)

 

https://www.penguinrandomhouse.com/books/131793/the-dialogues-of-plato-by-plato/9780553213713/

[crenca]

14 minutes ago, mansr said:

Wrong. Frequencies don't exist at points in time. Waveforms have a set of frequencies (possibly only one) over an interval of time.

 

A dirac pulse is (or does it merely approach?) a state of energy at a "point in time" (or is this incorrect?), but by definition a frequency assumes a period of time...

[crenca]

10 minutes ago, mansr said:

A Dirac pulse is a signal whose value is non-zero at one single instant and zero for infinite duration before and after. It contains all frequencies from zero to infinity throughout the infinitely long interval.

 

Ah, a pulse of the gods then...

[crenca]

3 hours ago, jabbr said:

 

 

But year upconverting to DSD works absolutely great for DACs that prefer DSD (lots and lots).

 

That is my position as well.  It is not that DSD is "more accurate", it's just that the iFi Micro (or do I have the IDac2?) "likes" DSD a wee bit better than PCM - it "implements" it slightly better...

[crenca]

9 hours ago, yamamoto2002 said:

 

If bit depth is infinite, it is possible.

 

I calculate real world example about 44.1kHz 16bit PCM data of 1/100th of second (441 samples).

It can store the difference of

1000.0000000 Hz from 1000.0000010 Hz but

1000.0000001 Hz signal is rounded to 1000.0000000 Hz.

By increasing bit depth to 24bit, frequency precision increases by 256 times.
 

 

I have a "wow" reaction to that!  Intuitively who would have thought that 16 bits would lead to such "accuracy", but then if a sample rate of >200Hz can lead to a perfectly reconstructed wave form, then it follows (within a certain amplitude if I am not mistaken)...

[crenca]

1 minute ago, mansr said:

DSD128, yes. DSD64 has some issues.

 

Makes sense.  I have not even tried upsampling to DSD64 for quite a while now - I just upsample to DSD256 since that is trivial for my system and the iFi seems to like it...

[crenca]

14 minutes ago, semente said:

 

I see we have a Trumpette here. Touchy too.

 

Make Audio Great Again!

[crenca]

18 minutes ago, beerandmusic said:

It came to me while i was laying in bed and hearing my wife moving around and cooking in the kitchen and outside background noise, and my ears as microphones able to distinguish location and details that i know that NO reproduction is capable of. 

 

Others are telling you you came to the wrong conclusion but you already know that

 

There are DSP programs in beta now that will be able to fool you into thinking you are hearing your wife in the kitchen when you are lying in your bed headphones on!  Also, someone could sneak into your house and add room treatments and those little directional cues you are picking up would be skewed and you would be thrown off - and yes all this can be reproduced but it is hard, expensive, etc. to do.  In other words those waveforms you are hearing are just that, and can be  perfectly reproduced digitally.

 

Not that any of this has anything to do with recording waveforms accurately...

[crenca]

1 minute ago, beerandmusic said:

 

even if everything in the world told me i was wrong, that wouldn't change my belief.  Belief is not something you can control....you can "choose" to believe without actually believing, but that just mean you gave up.

 

 

but how would the recorded data be able to tell you that street noise is to the south of me and kitchen noise to the north of me so that whoever applies the DSP would know how to properly program.

 

 

 

 

Your right - other people and even to a certain kinds of experience (when you are in "evaluative mode", etc.) can not change your belief.  Only certain kinds of experience, when coupled with certain states of mind can change a belief because beliefs are at the core of who you (and everybody else) are and nobody can allow any old thing to willy nilly come into the core of who you are - that is far far too dangerous.

 

Do you read literature? 

 

These kinds of directional cues and sounds are already being used in multi-channel recordings - do you have a surround sound system at your home?  

[crenca]

8 minutes ago, beerandmusic said:

 

I am not denying that it is beyond my desire to spend the time to fully understand.

 

I do know i had a recorded genius iq at one time, and likely much lower, now, but I believe I am still very smart.

I believe there are many here that are much smarter than me, but anyone that suggests that I am not smart will not hurt my feelings....that would be the same as someone teasing me for my blonde hair, when i have brown hair.

 

I am able to accept that what others have posed that the nyquist theorem is not without reproach and gets "very close"

But, likewise, i will always believe that more samples means more accuracy to the point where engineering cannot compensate for errors in processing, for the simple fact that in real life there is infinite time slices and infinite frequencies and infinite complex waveforms and HUMAN ears.

 

Can we get close, sure....but isn't that what the continual effort to improve audio is all about?

Until a playback system can accurately reproduce what my ears are able to hear in live, there is room for improvement, and I am not willing to state it ends at 44.1Kpcm.

 

 

 

Are you a wrencher?  Do you work on cars/motorcycles, or study/collect them?

[crenca]

4 minutes ago, beerandmusic said:

 

I hate reading...I am ADD.  I have never read a novel in my life, only tech manuals, but i have bad eyes now...prefer videos.

I have multi-channel in family room for watching blu-rays but not for music...and rarely use it anymore...

I really have expended far more energy in this topic than i really care to...i am content with my current belief, and really my youthful science days are over.  I would rather watch big brother or blacklist (grin).

Although, I do like to debate even if i don't know what i am talking about...i find it challenging...if it was something i knew (like religion) it's not as fun....but this topic has wore me out...lol

 

Yea, your ADD comes through   I know your writing helps you focus.

 

What sort of tech manuals did you used to have to work through?

[crenca]

@beerandmusic, As you already know, your past experience makes you good at gadget tinkering and hacking - trying this with that, questioning this recommendation and trying something new, and the like.

 

Have your tried HQPlayer?  If not check it out - it is cheap and there are many combinations of filters, modulators, etc.  That way, you can see for yourself the differences between PCM & DSD, upsampling with this filter vs. that, etc.  There are lot's of options that are not meaningless in these sorts of areas and for which one thing works for one person, one set of equipment, and one room - and another combination works for somebody else. 

 

As far as sampling theory, your trying to tinker in one of the few areas where there is actually a substantial body of scientific, mathematical certainty and proof in audio.  The differences in sound you experience and rightly question, the cause is not because of sampling method (i.e. the math and digital construction of the waveform), but rather because of the implementation of the equipment, room, music, and person.  

 

Divert to these other areas for fruitful and interesting things!

[crenca]

20 minutes ago, Ralf11 said:

 

 

you can get more help if you avoid acting like an ass

 

Everyone else, especially those in education (ADD, ADHD) & medicine (the same, stroke, TBI, PTSD) think of your training...

[crenca]

1 hour ago, mansr said:

The sampling theorem assumes infinite sample precision. With a limited number of bits, we get quantisation error which is a non-linear distortion. This happens at any sample rate and has nothing to do with aliasing. With TPDF dither, the quantisation error is (mostly) turned into white noise at a level determined by the bit depth. If the sample rate is increased, the quantisation energy is spread over a wider frequency range, thus reducing the level of dither noise at any specific frequency. Doubling the sample rate gives the same improvement as extending the sample precision by one bit. In other words, not very efficient. A high sample rate does, however, bring another benefit in that it enables the use of noise shaping. Instead of the quantisation noise being spread evenly over the full spectrum, it can be concentrated at high frequencies where there is no signal of interest. This is very useful since a high-rate flash ADC with a small number of bits, say 8 or less, is much easier to construct than a slower ADC with high precision. Low-resolution noise-shaped sampling at a high rate, 10 MHz or more, followed by a digital low-pass filter can thus be functionally equivalent to high-resolution sampling at a lower rate. In fact, it can be better since there is no need for an analogue anti-aliasing filter, and the digital filter can be designed with just about any characteristics we desire.

 

This is the most concise summary of these realities I have ever read.  Really for the first time, I now understand why delta sigma DAC's are the norm in the market right now...thanks!!

[crenca]

1 minute ago, mansr said:

I was talking about ADCs, but the same concepts apply in reverse too.

 

Ah shucks, I thought I was on to something...I will have to re-think now