Maximum SQ from a CD? 44.1/16? or ???

[monsterjazzlick]

Re: Maximum SQ from a CD? 44.1/16? or ???

Here's a quote from Wikipedia [Hearing Range] (emphasis mine):

Mike,

Thanks for the link.

Ha ha, a ferret can hear lower freq. than an elephant!

Paul

[mville]

Re: Maximum SQ from a CD? 44.1/16? or ???

None the less, the specifications of Red Book CD's still exceed the hearing capabilities of human beings. The engineers at Sony and Phillips did a great job designing a spec that wasn't just "good enough". It's better than required as basically no one can hear beyond those limits.

Try telling that to sound engineers and professional digital recording studios around the world, that now use 192kHz/32-bit to record. If Sony/Philips were to design a mass media format for optical disc today, it would not be limited to 44.1kHz/16-bit, IMO.

Without getting technical, your statement considers only one aspect of digital sampling, when there is more to sampling an analog waveform than simply capturing frequencies, some of which exceed the hearing capabilities of human beings.

[Dat Ei]

Re: Maximum SQ from a CD? 44.1/16? or ???

Hey Mike,

44.1 kHz is the absolut minimal sampling rate to record a frequency of 22.05 kHz (see Nyquist or Shannon theorem). That doesn't mean that you have a good recording or reproduction. The bit depth is very important for the fine dynamics and dynamic range. So from my point of view 44.1 kHz and 16 bit isn't the limit...


Dat Ei

[mville]

Re: Maximum SQ from a CD? 44.1/16? or ???

44.1 kHz is the absolut minimal sampling rate to record a frequency of 22.05 kHz (see Nyquist or Shannon theorem). That doesn't mean that you have a good recording or reproduction. The bit depth is very important for the fine dynamics and dynamic range. So from my point of view 44.1 kHz and 16 bit isn't the limit...

Correct. Some of the statements made here in this thread don't tell the whole story, such as you have stated above e.g. the relationship between resolution, amplitude and dynamic range.

It does worry me that other users may be mislead about the technologies involved and who/what to believe, when some important details are ignored or omitted.

[Dat Ei]

Re: Maximum SQ from a CD? 44.1/16? or ???

It is important to understand signal digitisation to realise the problems, limits and quality of that process. It's no surprise that there are more people talking about sound quality than there are people who have an idea of signal digitisation and it's influence to the sound quality. Nowadays we have a confusing mixture of mp3 users, mobile phone speaker users, bad recordings (with low dynamic range), multi room multi channel sound correction amplifiers, and dealers, who pretend to sell hi res music.


Dat Ei

[Michael Sargent]

Re: Maximum SQ from a CD? 44.1/16? or ???

Try telling that to sound engineers and professional digital recording studios around the world, that now use 192kHz/32-bit to record. If Sony/Philips were to design a mass media format for optical disc today, it would not be limited to 44.1kHz/16-bit, IMO.

Without getting technical, your statement considers only one aspect of digital sampling, when there is more to sampling an analog waveform than simply capturing frequencies, some of which exceed the hearing capabilities of human beings.

Of course sound engineers need more headroom, but that's irrelevant to the discussion on listening.

This thread, like almost every thread where this comes up, devolved into people thinking that they can hear beyond the limits of 44.1/16. But have you ever tested yourself? Too many people assuming they have "golden ears" (which don't exist, BTW). I strongly recommend you do the simple test to find out what you can actually hear. It's easy. It's free. And it's a bit humbling.

I found out that even on my best system (Denon 4520 driving PSB Stratus Gold speakers), I can't hear anywhere near the quality that a normal CD can reproduce. Without driving my system to unrealistically high volume levels, I topped out around 14 kHz and about 50 dB of dynamic range (versus 22 kHz and 96 dB which CD's can easily deliver.) There is no reason to test with the dial up to 11, because there is no way I will ever listen to music at an average volume of over 100 dB (and if you do, you won't for long).

If you haven't tested yourself, don't assume you can hear Hi-Res and go out and spend a fortune on sounds that you can never hear (and probably no one else can either).

Mike

[Dat Ei]

Re: Maximum SQ from a CD? 44.1/16? or ???

Hey Mike,

do you know the Nyquist / Shannon theorem? Do you know how signal digitisation works?

If you digitize a 22.05 kHz signal with a sample rate of 44.1 kHz you just generate 2 digital values for one period. So imagine what the original sinus wave looks like and how the digitizes wave can look like if you just have two values.

For a 11.025 kHz signal, which is clearly a hearable tone, you generate only 4 digital values. And you don't know at which point / time you measure the analog signal.

Increasing the sample rate increases the quality of recording / measuring the original signal and reproducing the digitized signal.


Dat Ei

[mville]

Re: Maximum SQ from a CD? 44.1/16? or ???

Of course sound engineers need more headroom, but that's irrelevant to the discussion on listening.

I wasn't discussing headroom, you were. I was taking about detail and dynamic range, which is very relevant in this discussion.

I guess we will have to agree to disagree, as I don't want to turn these forums into in-depth technical discussions on sampling. There are many other forums on the internet for that.

[Michael Sargent]

Re: Maximum SQ from a CD? 44.1/16? or ???

I guess we will have to agree to disagree, as I don't want to turn these forums into in-depth technical discussions on sampling.

Might as well give up on this. All I have been trying to do is get people to test to see what they can actually hear before wasting money on high-res audio. Sampling theory is irrelevant to that discussion.

If you can't hear it, don't pay for it. Test yourself. Know what you can and can not hear.

Mike

[Dat Ei]

Re: Maximum SQ from a CD? 44.1/16? or ???

Hey Mike,

All I have been trying to do is get people to test to see what they can actually hear before wasting money on high-res audio.

although I second this, I have to contradict this statement in so far that you've said this before:

None the less, the specifications of Red Book CD's still exceed the hearing capabilities of human beings. The engineers at Sony and Phillips did a great job designing a spec that wasn't just "good enough". It's better than required as basically no one can hear beyond those limits.

And this statement is basically not right. There are a lot of "no ones" out there, who can hear beyond those limits. Maybe they use even better equipment than a Denon 4520 or have a more trained and skilled hearing to tell the differences.


Dat Ei

[mville]

Re: Maximum SQ from a CD? 44.1/16? or ???

All I have been trying to do is get people to test to see what they can actually hear before wasting money on high-res audio. Sampling theory is irrelevant to that discussion.

No-one is disputing the idea of individuals testing whether they can hear the difference between hi-res audio and red book CD audio. In fact, it is a very good idea.

However, what is in dispute is this kind of statement that you make, which IMO, is simply untrue:

None the less, the specifications of Red Book CD's still exceed the hearing capabilities of human beings. The engineers at Sony and Phillips did a great job designing a spec that wasn't just "good enough". It's better than required as basically no one can hear beyond those limits.

[d2b]

Re: Maximum SQ from a CD? 44.1/16? or ???

It seems that some of you, perhaps all, do not really understand the premise upon which the Nyquist sample theorem is based. This is the case for anyone that states that a sample rate of 44.1ksps taken alone is sufficient to perfectly reproduce a 22.05kHz signal. Quoting theorems without understanding their origins and hence the premise upon which they are built is careless and foolhardy. Unfortunately, far too many enthusiasts believe the common misinterpretations passed between them, taking the claim that it applies to dynamic sound sampling in an exact manner.

The Nyquist theorem is a mathematical theorem based on *binary* samples of the amplitude of band-limited signals. A perfectly band-limited signal has to have existed for all time. Otherwise, it would have been amplitude-modulated at some time in the history of its existence. It is true, according to the sample rate theorem, that if you sample a purely band-limited signal at any rate just at or above twice the "Nyquist" sample frequency, you can perfectly deduce the original signal. But to do so requires a perfectly band-limited signal and an infinite number of samples to reach a mathematically exact result.

In the practical world, where one is considering the reproduction of an continuously-varying audible sound stream, there are many factors that suggest that a much higher sample rate with greater resolution will result in a more accurate result. For one, there is no such thing as a perfect brick-wall filter. Both analog and digital filters add amplitude and phase distortion, even with *perfect* sample rate clocks. Then of course is the inherent *less than perfect* analog-to-digital and digital-to-analog signal converters and how they affect a system's ability to generate an exact representation of an original musical experience.

Tests of one's ability to hear high-frequency sounds generally were conducted with steady-state sounds derived from a low distortion sinusoidal signal generator. Tests that "prove" that one cannot hear the differences in an additive mix of two tones, one of which has a unrelated time relationship with the other, are also based on continuous signals. Neither of these tests accurately reflect the circumstances one experiences when listening to dynamically changing music prior to reproduction.

Making bold claims about sampling and music reproduction without actually understanding the basis for the theory, as well as the practical limitations of all of the components in the recording, processing and reproduction phases, is not wise.

Dennis, aka "d2b"