You and JC are just the same !
When you move to Berkley
the ritual will be complete !
Antonio,
it is captured by Spectraplus software. I have noticed these small time differences, and I am not able to explain their origin. Anyway, the spectral representation does not show any jitter.
Amplitude values may be expressed in %FS, Volts or digital values, I have chosen the %FS.
Regards,
it is captured by Spectraplus software. I have noticed these small time differences, and I am not able to explain their origin. Anyway, the spectral representation does not show any jitter.
Amplitude values may be expressed in %FS, Volts or digital values, I have chosen the %FS.
Regards,
I quoted from a book. Of course, 6dB/octave is very slow, AND at ultrasonic frequencies, perhaps the negative effect described by Slot, goes away, BUT then I did not select 44.1KHz either, neither did Ampex, Philips, or anybody else, BUT Sony. Most everyone else started with 50KHz, and hoped to go higher. This made the filters easier to make, and gave the ears a potential break.
Yes, and 60 kHz would have provided a nice response comparable to professional tape. We really should leave CD behind in the history books - in selecting that standard, so many compromises were made based on short-term cost limitations.
Now we shall think over why we cannot produce products in the same quality like 60 years ago, but we have a so much better technical capabilities (CAD / CAM etc.) ...
Sensibility of human craftmanship cannot be implemented into machines.
Are we talking about an anti-aliasing filter before the ADC or a reconstruction filter (to suppress images) after the DAC? A first-order anti-aliasing filter would be about as useful as a chocolate teaspoon. The NOS crowd will claim that a first-order reconstruction filter is overkill as their amp, speakers and ears do the job OK unassisted.rsradio said:
You talkin' to me?
You can't really see aliasing on the CD itself. Your description doesn't say whether you're analyzing the data on the disc or the analog output of your DAC.
What I described was my 48 kHz recordings of 44.1 kHz DACs being operated by musicians on a budget. It's impossible for 44.1 kHz data (CD) to contain information above Nyquist, but once the data is converted to analog by a particular DAC circuit you might easily find images. What I saw was completely different from one act to the next, even on the same sound system, because each artist brings different equipment. Most DAC gear, even some of the cheaper stuff, does fine when it comes to anti-aliasing the output, but a few times there are problems. This is probably most prevalent with those MP3 DJ softwares where a vinyl time code disk is used on a real turntable to alter the playback rate of the MP3, and the resulting digital resampling creates all sorts of mayhem, both in the data and in the converter hardware.
By the way, when looking at HD discs, i.e., media beyond CD, it's actually more common to see aliasing within the data itself. I've seen quite a few examples of 96 kHz "HD" audio where it was really nothing more than 44.1 kHz data plus aliased frequencies above 22.05 kHz. Disgusting and unforgivable!
The same filter is required both before ADC and after DAC. It doesn't really matter whether it's called an anti-alias filter or a reconstruction filter. At least for NOS they have to both be as sharp, because a DAC has aliased frequencies starting right at 22.05 kHz.
An oversampling DAC can certainly employ a low-order filter, but it would probably require many times oversampling to enable first-order to work (not to mention a steep digital filter before the DAC).
D'oh! (Homer headslap)You talkin' to me?
You can't really see aliasing on the CD itself. Your description doesn't say whether you're analyzing the data on the disc or the analog output of your DAC.
Of course this gets back to my earlier diagnosis- the big limitation in CD sound is the source material.
The name does matter, because the name identifies the function. One filter removes aliases, which are spurious components arising within the normal audio band from any signal components above 22.05kHz. These, if present, are likely to be audible and unpleasant. The other filter removes images, which are spurious components arising above the normal audio band which may or may not be audible and may or may not be unpleasant.rsradio said:
Both filters have to be sharp if the aim is to faithfully reproduce the band-limited version of the analogue signal. People differ on whether this should be the aim. It is clear that in some quarters, but hopefully not here, people are confused and blame the reconstruction filter for issues which are actually (and possibly unavoidably) caused by the anti-alasing filter. Maintaining the distinction between these two filters is thus a vital aid to clarity of thought and expression.
My aim is clarity, not pedantry. An anti-alias filter removes the source of aliases, which I accept is not quite what I said.
When I first began reading about digital audio I often became confused. Then I realised that part of the reason for this was that others were confused too. People often say 'alias' when they mean 'image', and mix up the two filters.
When I first began reading about digital audio I often became confused. Then I realised that part of the reason for this was that others were confused too. People often say 'alias' when they mean 'image', and mix up the two filters.
Be there Friday, though the realtors insist there are places I do NOT want to live.
Although in psychoacoustic it quite often seems to be a normal distribution and in the case of the graph from Zwicker/Fastl the authors explicitely mentioned the 5% - 95% range which is normally a good hint for the assumption of a underlying normal distribution.
But if you want to use data from a small sample to draw conclusions wrt to the whole population, you _have_ to assume an underlying distribution otherwise a conclusion isn´t possible.
That is the difference between descriptive and interference statistics.
Let us concentrate on the arguments. If these are correct there is little room left.
I totally agree, but of course other people might percept it different (due to interindividual differences).
And that it is not "unlistenable" should not prevent us from doing better if possible .
If am not totally mistaken, Kunchur does not work with IATDs .
Your underlined sentence is exactly the essence of his studies, that with diotic signals the temporal resolution is higher than the upper frequency bound would predict.
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I meant IATD as an additional example of "unexpectedly" small time resolution numbers that people naively want to use to imply 100-200 kHz "hearing"
Kunchur's models don't require modifying "conventional" psychoacoustic understanding of high frequency sensitivity - he is ascribing the increased time resolution to the result of a convolution like process from phase locking of frequency content totally within conventional < 20 kHz human hearing limits
His explanation of filtered 7 kHz square wave results do appeal to possible 21 k
Hz nonlinear mixing, 14 kHz in band IMD – but not to direct sensitivity of hearing the 21 kHz fundamental
On the Slot ref – “sharpness” in psychoacoustics is correlated with increased high frequency content – rising sensitivity with frequency above ~ 3 kHz
So sharpness sensitivity to filter order for corner frequencies below our upper frequency hearing limit is “conventional” psychoacoustics – care to post what filter corner frequencies he was citing?
Kunchur's models don't require modifying "conventional" psychoacoustic understanding of high frequency sensitivity - he is ascribing the increased time resolution to the result of a convolution like process from phase locking of frequency content totally within conventional < 20 kHz human hearing limits
His explanation of filtered 7 kHz square wave results do appeal to possible 21 k
Hz nonlinear mixing, 14 kHz in band IMD – but not to direct sensitivity of hearing the 21 kHz fundamental
On the Slot ref – “sharpness” in psychoacoustics is correlated with increased high frequency content – rising sensitivity with frequency above ~ 3 kHz
So sharpness sensitivity to filter order for corner frequencies below our upper frequency hearing limit is “conventional” psychoacoustics – care to post what filter corner frequencies he was citing?
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