Who here can hear above 22kHz......!!!!????...

[ericj23]

just to clarify - the nynquist theory requires an umlimited time frame - i.e. it is an infinite function -

I'll stop your right there.
The nyquist theory says no such thing, it assumes that functions are periodic. ie, you dont have to wait till infinity to say that a 50 Hz tone is 50Hz.

yet

from http://www.digital-recordings.com/publ/ ... ml#theorem

presented by a doctor in digital recording

"It is worth noting that information about the signal V = V(t) at any given moment in time t n TS is distributed among ALL discrete samples { V[n] } with appropriate weights. Realistically, we are never presented with an infinite discrete time sequence and are therefore forced to perform the summation over a finite range.

This is equivalent to a loss of information about the function V = V(t) not only before and after our time window (which is understandable), but also at the time points between the sampling points. "

im afriad that they seem to think that for the proven maths to be able to tell a 50hz wave it really does have to see ALL samples - which is clearly impossible

[The Chase]

Honestly, Besides 10 I heard 20 the best. 15 dropped out a bit on me though.

really? that doesnt make much sense. Are you sure nothing was distorting and you were hearing the distortion at 20? or maybe hearing something vibrate?

[birrbits]

presented by a doctor in digital recording

There are plenty of academic papers, such as this, that sadly don't demostrate much of anything.

Looking at the conclusions for this particular paper tells you that they need to do more research but theres little presented to show any benefit in doing this research.

I guess it comes with the territory, you get some sort of doctorate degree and you feel overwhelmingly inclined to publish stuff.

[rockstar_not]

Honestly, Besides 10 I heard 20 the best. 15 dropped out a bit on me though.

really? that doesnt make much sense. Are you sure nothing was distorting and you were hearing the distortion at 20? or maybe hearing something vibrate?

Sure it makes sense. Have a look at equal loudness contours. These curves represent average response by a group of people. The wiggly nature at the upper end of the curve shows that there is a definite turn arounds possible in the sensitivity curve. It's entirely possible that someone could be sensitive at 10kHz, and 20 kHz, with a 15 kHz 'hole'.

There is also the possibility that whatever playback device he was using, had a 'hole' at 15 kHz, and peaks at 10 and 20 kHz.

-Scott

[birrbits]

cool, i was wondering where the replay gain site moved to, thanks rockstar_not

[ericj23]

summation we can just say the sum was zero before the song started, and zero after it ended (we cheat).

sorry my take on this was that that a dac does not have a big enough time frame to know the whole song so i would have thought that the time frame is very likely to be decidedly non zero

the later part of the paper just define an equation for the real start and finish errors when there is a shortened time window - and all of this is true

as i stated in my first post I have no idea whether these are relevant - just that they are a mathematical possibility - ie a possibility that the nynquist theory is not as infallible as made out

my personal interest is not to rubbish peoples points tho - i don't have the knowledge to back that up - it is just to get an understanding of why sacd/dvd-a sound so much better than cd's on my set-up

is it the high frequency interactions ? bit depth ?

i would just like to know

[birrbits]

sorry my take on this was that that a dac does not have a big enough time frame to know the whole song so i would have thought that the time frame is very likely to be decidedly non zero

no, the ADC nor the DAC need to know the whole song, and any buffering they accomplish is not going to make a difference either way in whether Nyquist sampling theory holds water, it does.

as i stated in my first post I have no idea whether these are relevant - just that they are a mathematical possibility - ie a possibility that the nynquist theory is not as infallible as made out

you'll have to take my word on this, the paper isnt relevant to whether or not nyquists sampling theory
is infallible. The entire paper basically proves one simple concept, that if you remove apples from a basket, you are going to be missing some apples.

my personal interest is not to rubbish peoples points tho - i don't have the knowledge to back that up - it is just to get an understanding of why sacd/dvd-a sound so much better than cd's on my set-up

is it the high frequency interactions ? bit depth ?

i would just like to know

its a bit hard to say not knowing your setup and whether you or not you are playing the cds/sacds/dvds through exactly the same components or not.
bit depth for one makes a huge difference imho.

[meeks]

I was pushed against the stage with probably around ten lines of leather clad figures pushing behind.

[Hypertone]

I can't hear 20hz, but I can feel it. If I crank it up loud, It's this weird pressure, it's actually nauseating. I figured out that audacity can generate tones, so I generated a 22kz wave and I still know that it's there, that weird pressure, you could torture people with it.

[Timfonie]

When I had my first synth (a DX9) I decided one day to test the upper limits of my hearing. Using a pure sine wave I stopped hearing any sound at 19 kHz even at high volume. Then I lowered the pitch again ... and to my surprise I couldn't hear 18 kHz or even 17 kHz anymore! Help!!

Hmm, yes, I had blown up the tweeters.
Beter than blowing up my ears though

[duncanparsons]

I was pushed against the stage with probably around ten lines of leather clad figures pushing behind.

I did think about the possible response to that when I typed it, but couldn't think of a better wording; so yes, it was there for the taking..

oops, I did it again..



DSP

[birrbits]

Hmm, yes, I had blown up the tweeters.
Beter than blowing up my ears though

on more than one occassion I have thought my ears were ringing after a long mixing session and then realized that it was just the air conditioner running again.