Understanding Sample Rate

[mansr]

1 hour ago, beerandmusic said:

In audio production, a sample rate (or "sampling rate") defines how many times per second a sound is sampled. Technically speaking, it is the frequency of samples used in a digital recording.

This is correct.

 

1 hour ago, beerandmusic said:

However, because digital audio recordings are estimations of analog audio, a smoother sound can be gained by increasing the sample rate above 44.1 KHz.

This is incorrect.

 

 

[mansr]

1 hour ago, beerandmusic said:

Back to my suggestion of 9 million singers singing at the same time, and every quanta (smallest time slice possible below pico seconds) one of the 9 million singers changes their tone. 

You have a fundamentally flawed understanding of the concept of frequency.

[mansr]

1 minute ago, beerandmusic said:

Well you stated that this is incorrect?

In audio production, a sample rate (or "sampling rate") defines how many times per second a sound is sampled.

No, I said that part is correct.

[mansr]

7 minutes ago, beerandmusic said:

My biggest problem is that in my thinking is that a higher sample rate doesn't just allow you to sample higher frequencies....it also allows you to capture more data in very complex signals having nothing to do with the audible frequency range.

Those complexities are higher frequencies.

[mansr]

1 minute ago, jabbr said:

the stuff Einstein got a Nobel prize for

I don't see the photoelectric effect being of particular relevance here.

[mansr]

1 minute ago, crenca said:

Also, for those engineers - beerandmusic's understanding of frequency and sound is very common.  It is a laypersons perspective and reveals the distance between your education and theirs...not to give your already inflated egos a boost or anything

There's a reason it takes years of study to get an engineering degree.

[mansr]

13 minutes ago, beerandmusic said:

are you suggesting that an infinite amount of frequencies don't exist?

Frequencies are continuous, just like real numbers, so in that sense they are infinitely many. In the real world, they are, however, not unbounded. It is physically impossible for air to carry a sound wave with a frequency above a few GHz, and even at 1 MHz it is attenuated to oblivion withing a couple of inches. For the purposed of recording music, there can be no frequencies above 250 kHz or so. In practice, the highest frequencies encountered by a microphone are less than 100 kHz.

 

The sampling theorem allows for any number of frequencies within a limited range (bandwidth), so with a sufficiently high sample rate, nothing is lost.

[mansr]

1 minute ago, beerandmusic said:

Let me ask this....

is it possible to have an infinite amount of frequencies between 600hz and 700hz?

e.g. is it not possible to have 600hz 600.001, 600.002, 600.003, etc...

whether it is discernible to hear the difference from one person's voice to another, not being the question.

I believe I just answered that question.

[mansr]

4 minutes ago, beerandmusic said:

that is the part the confuses me...every time where it is suggested that is above our hearing (e.g. higher than 40Khz)?

I am talking about an infinite number of frequencies WITHIN the boundaries of 20-20khz

There's no problem with that. The sampling theorem has it covered.

[mansr]

5 minutes ago, jabbr said:

The point being that our fundamental understanding of the universe is quantized, and hence an infinite number of frequencies do not physically exist.

The quantisation is small enough that for practical purposes it doesn't exist. More importantly, the sampling theorem is fine with a true continuum of frequencies whether or not they can all physically exist.

[mansr]

As usual, pay no attention to GUTB.

[mansr]

4 minutes ago, jabbr said:

That's a common misconception:

 

https://arxiv.org/pdf/1108.3135.pdf

https://arxiv.org/pdf/0802.1348.pdf

 

(you may need to read the references in these papers to understand)

I don't recall the sampling theorem relying on a quantised frequency. Clearly, a time-limited signal has limited frequency resolution. That limitation is unrelated to sampling. The relevant point here is that all frequencies that can meaningfully be said to exist in a given signal are accurately captured by sampling at a rate greater than twice the highest frequency.

[mansr]

5 minutes ago, beerandmusic said:

I don't think physics can prove God either (wink).

God is by definition that which cannot be shown to either exist or not. God is thus irrelevant.

[mansr]

10 minutes ago, Ralf11 said:

physics & biology have shown the limits of action by any diety

And then you get crazy studies like Effects of remote, retroactive intercessory prayer on outcomes in patients with bloodstream infection: randomised controlled trial.

[mansr]

5 minutes ago, Ralf11 said:

in fact witchcraft is known to be just as efficacious as psychotherapy

Is there a difference?

[mansr]

7 minutes ago, jabbr said:

Of course the sampling theorem works. Quantised frequency is where the fourier transform becomes the discrete fourier transform, and yes it also works. The uncertainty theorem determines the frequency resolution limits. 

Seems like we're in agreement.

[mansr]

8 minutes ago, beerandmusic said:

I read what mansr, jabbr, crenca and many others write, but I typically don't read what you write (wink)...you fall in a different category...but i see you still read and reply to me....prefer you didn't.

Not cool.

[mansr]

9 hours 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.

A frequency doesn't exist a single point in time, only over an interval. The longer the interval, the more well-defined the frequency becomes. I this might be the root of your misunderstanding.

[mansr]

Just now, beerandmusic said:

Sounds a bit biased and not sure I would even want to watch it unless it is approved by an authority I trust.

You can trust Monty on this. Or you can follow the derivation of the maths all the way from basic arithmetic if you prefer. This is generally called "getting an engineering degree," and typically takes a few years of full-time study.

[mansr]

1 minute ago, beerandmusic said:

Yea, i am definitely not interested in that (grin).  I only want to know why an SACD sounds better than a CD and why so many people are reluctant to accept that....i don't think i am willing to spend more than an hour or two, so I will likely be considered "remained lost" by those that don't believe an SACD can sound better than a CD.

If you're not willing to put in the time yourself, you're going to have to trust those of us who have.

[mansr]

32 minutes ago, Don Hills said:

Of course it uses sampling. At each sample interval, it samples the input analogue signal and decides if it's a higher or lower value than the previous sample it took. It outputs one bit for each sample, a 1 or a 0.

That's a gross over-simplification but more accurate than the previously offered "explanation."

[mansr]

Just drop the topic of DSD for now. You can't possibly begin to understand it before you understand basic sampling (PCM).

[mansr]

26 minutes ago, beerandmusic said:

ok, so i watched it...it doesn't really touch on my confusion about a more complex signal...i am sure the suggestion would be the same applies...but he really doesn't go into complex waveforms.

Let's ask Monty if he has a version of the video with a higher frame rate. Perhaps that would be more accurate.

[mansr]

1 minute ago, adamdea said:

If (with very few exceptions) you think you don't need to read this, you really really need to read this.

I've read other books that probably cover most of the same topics. Is that a good enough excuse?

[mansr]

19 minutes ago, kumakuma said:

waveforms do not have an infinite number of frequencies, they have one frequency at any arbitrary point in time

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