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Topic: Impulse ringing embedded on cd (Read 11897 times) previous topic - next topic
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Impulse ringing embedded on cd

Hi. I just want to know something. A slow roll off filter of a cd player might improve the the impulse response but not eliminate the embedded ringing on the cd itself caused by the sample rate converter (e.g 96 khz to 44.1 khz) using steep brick wall filtering, Right? Does the method of pioneer's legato link converter eliminate or make the ringing frequency higher by adding extended frequency signals?  Sorry if this has been discussed before. Thank you very much.

Impulse ringing embedded on cd

Reply #1
The fear of ringing is spread by marketing and audiophile mass histeria. Let us know when you can demonstrate a problem with a normal filter implementation in line with our TOS.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Impulse ringing embedded on cd

Reply #2
No sorry I didn't mean that ringing was audible, I just wanted to know if this was possible and is what this type of filter was accomplishing.

Impulse ringing embedded on cd

Reply #3
A slow roll off filter of a cd player might improve the the impulse response but not eliminate the embedded ringing on the cd itself caused by the sample rate converter (e.g 96 khz to 44.1 khz) using steep brick wall filtering, Right?

Wait a moment. Could you describe in some more detail what you are trying? There's no sample rate converter inherent in a CD-player's function. So what is the arrangement of devices you are working from? What kind of "impulse" are you talking about? The CD, or any digital audio system, can't represent an impulse (in the strict sense) due to its bandwidth limitation. Perhaps you are starting with erroneous assumptions, so please elaborate.

Impulse ringing embedded on cd

Reply #4
A slow roll off filter of a cd player might improve the the impulse response but not eliminate the embedded ringing on the cd itself caused by the sample rate converter (e.g 96 khz to 44.1 khz) using steep brick wall filtering, Right?

Wait a moment. Could you describe in some more detail what you are trying? There's no sample rate converter inherent in a CD-player's function. So what is the arrangement of devices you are working from? What kind of "impulse" are you talking about? The CD, or any digital audio system, can't represent an impulse (in the strict sense) due to its bandwidth limitation. Perhaps you are starting with erroneous assumptions, so please elaborate.


Sorry if my wording was not clear. By "sample rate converter" I mean the src software on computer before burning to a cd.

Impulse ringing embedded on cd

Reply #5
So what are you trying to do? Where do you get the signal from that you are feeding into the software SRC? Is it an artificially generated signal? What does it look like?

Impulse ringing embedded on cd

Reply #6
I guess he simply did read how bad ringing is and there must be done something against it.
Like some hf damping, early rolling off, alias producing, phase penetrating wonder filter
There are most likely more audible factors created with preventing this terrific ringing as the ringing itself can ever create. Extreme ringing may be a problem but a normal DAC should not have to much of it.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Impulse ringing embedded on cd

Reply #7
I suspect that the misconception is at the very start, in the impulse that people tend to use for this sort of experiment. People usually construct the impulse by handcrafting the numbers that they store as sample values. Either they use a series of samples with value zero, followed by a series of samples of value one (or any other fixed positive value), or they choose a single non-zero sample in a sea of silence. And then they promptly forget what the meaning of this is in a bandwidth limited system. The time-domain consequences of this artificial starting point will almost inevitably produce erroneous ideas and conclusions in the unwary audience.

Impulse ringing embedded on cd

Reply #8
C'mon guys, get with the program. The word du jour is "smearing". "Ringing" is so passe.
Elixirs like Hi-Re$/MQA et al, will "unsmear" the timing smudge of the painting. Or some such.

cheers,

AJ
Loudspeaker manufacturer


Impulse ringing embedded on cd

Reply #10
Hi. I just want to know something. A slow roll off filter of a cd player might improve the the impulse response but not eliminate the embedded ringing on the cd itself caused by the sample rate converter (e.g 96 khz to 44.1 khz) using steep brick wall filtering, Right? Does the method of pioneer's legato link converter eliminate or make the ringing frequency higher by adding extended frequency signals?  Sorry if this has been discussed before. Thank you very much.


CD players generally don't have what I would call slow roll off filters.  They are usually built into the DAC chip. Their corner frequencies, roll-off slope and phase characteristics are in this day, pretty whatever someone is willing the investing the resources in producing. 

Digital filter design is not a black art. It has been reduced to an algorithm and packaged up into freeware such as Octave.

The characteristics of a given DAC are documented in the publicly-available spec sheets for DAC chips that litter the web like cigarette butts, and are obviously something that one should study before publicly prognosticating upon them.

The assumption that they are the consequence of some sample rate converter looks like blind acceptance of golden ear dogma that all recordings are made at high sample rates and downsampled. In fact a lot of recordings are still made at 44.1 KHz sample rates.

The idea that this ringing is an audible problem is more golden ear dogma that has a lengthy track record of failing to be apparent at all when put to a reliable test. 

It's a very easy test to do, given that so much high sample rate music is now available for reasonable prices and that downsampling software can be as good as it gets and much of it is freeware.

Impulse ringing embedded on cd

Reply #11
You are right Arnold.  I just wanted to know what a filter or processor is capable of, not that ringing is a (or the) problem. Anyway Thanks to everybody for all the replies.

Impulse ringing embedded on cd

Reply #12
IMO - If it's embedded on the CD it's part of the production and it's NOT the job of the CD player to correct production flaws.  The job of the CD player is to reproduce the sound with high fidelity (faithful to the source).  If you want to use EQ, reverb, a compressor or expander, noisegate, or some magic filter, that's OK, but it's not the job of the CD player to correct or enhance the audio.

Not that I accept the premise...

Impulse ringing embedded on cd

Reply #13
You are right Arnold.  I just wanted to know what a filter or processor is capable of, not that ringing is a (or the) problem. Anyway Thanks to everybody for all the replies.

I'm still curious what the motivation was behind your question. I don't yet see the sense of it. I still suspect that you harbor a misconception about how this sampling stuff actually works. The way you write about impulse responses leads me to believe that you probably interpret them wrongly. But alas, you are unkeen to provide enough context for us to help you understand.

Impulse ringing embedded on cd

Reply #14
I just wanted to know what a filter or processor is capable of, not that ringing is a (or the) problem.


Linear filters can adjust the magnitude and phase response of a system.

Impulse ringing embedded on cd

Reply #15
I just wanted to know what a filter or processor is capable of, not that ringing is a (or the) problem.


Linear filters can adjust the magnitude and phase response of a system.



Agreed.

Products like Apodising Filters provide that as a measurablebenefit.

Thing is most audiophiles are trained to believe that if it is measurable, then it must be audible, and the connection with reality becomes increasingly tenuous after that.

I can still remember when I flunked an ABX test with about a thousand degrees of phase shift @ about 1 KHz. But if one listens to recordings of bullwhips cracking in anechoic chambers, you can do a lot better.

Impulse ringing embedded on cd

Reply #16
Wombat. Thanks for telling me that there are most likely more audible factors created with preventing this terrific ringing as the ringing itself can ever create, I did not consider this. And I,m not saying this sarcastically. Every day I learn something (or at least try to)  . Thanks again.

Impulse ringing embedded on cd

Reply #17
Hi again. I know that CD is transparent,  I was wondering if someone could tell me if Pioneer legato link conversion strategically calculates the added ultrasonic frequencies
or is it simply allowing ultrasonic images through. Again I think CD is transparent but I just want to know how this works.
Sorry If I am unclear.

Impulse ringing embedded on cd

Reply #18
Hi. I just want to know something. A slow roll off filter of a cd player might improve the the impulse response but not eliminate the embedded ringing on the cd itself caused by the sample rate converter (e.g 96 khz to 44.1 khz) using steep brick wall filtering, Right?
The ringing is at a specific frequency = the cut off frequency of the low pass filter that caused it. In your context, it will usually be somewhere around Nyquist (~22kHz), maybe a little lower. Such ringing is most visible where the original signal had a sharp burst of energy across a wide range of frequencies, including energy at the cut off frequency itself. If there is no energy in the original signal at the cut off frequency, the filter won't ring.

If a subsequent filter (e.g. a filter used during playback, in or before the DAC) removes (or reduces) content at that frequency, then it will remove (or reduce) the ringing. If it lets that frequency through, it will leave the ringing intact. It really is that sample. It doesn't matter what else it is doing. All the "complexity" (if you can call it that) is in filtering something out without introducing yet more ringing. If the filter is gentle rather than sharp, it will ring less. If the filter has interesting phase properties, it might seem to ring a little less but importantly it will ring less before and more after, which many people believe is a good trade-off, because (in the audible range) the ear is less sensitive to ringing after a signal, and more sensitive to ringing before a signal. Note: Remember these filters are rarely acting within the audible range.

(A sharp filter lets everything through below the cut off frequency, and removes everything above the cut off frequency, with little or no "transition band" where it changes from one behaviour to the other. Such filters "ring". A gentle filter changes from "letting everything through" to "removing everything" over a wide range of frequencies, and has a wide transition band where it's progressively letting less and less through, but isn't removing it all. Such filters ring far far less.)

As an example, imagine for some reason you had a recording which, when mastered, had a sharp low filter applied at 20kHz. Assuming there was content up there originally, you would see ringing at 20kHz. To remove it, you would have to filter out everything at 20kHz. You could do this with a 19kHz low pass filter. However, letting everything below 19kHz through while removing everything above, say, 19.9kHz, is in fact quite a sharp filter and it would ring a bit. Make the filter too gentle, and it'll start cutting too low down (IMO), well within the audible range of younger listeners. If you keep it reasonably sharp, the cut off frequency (say 19.5kHz) is now where you may find ringing. You might design the filter cleverly so there was less ringing, but you've moved it to a lower frequency.

Is the ringing at 20kHz audible? Is less ringing at 19.5kHz less audible because there's less of it, or more audible because it's at a lower frequency? What about original ringing at 22kHz replaced by less ringing at 18kHz? What are the trade offs?

You need carefully controlled listening tests to find out. And the few listening tests that have delivered statistically significant results suggest that absolutely chronic ringing at about 22kHz is sometimes audible, but only just, on certain content, with certain speakers. How many CDs have chronic ringing at 22kHz? On how many CDs is the ringing the worst problem?

Cheers,
David.

Impulse ringing embedded on cd

Reply #19
Hi again. I know that CD is transparent,  I was wondering if someone could tell me if Pioneer legato link conversion strategically calculates the added ultrasonic frequencies
or is it simply allowing ultrasonic images through. Again I think CD is transparent but I just want to know how this works.
Sorry If I am unclear.


Ah. I did a quick lookup of "Legato Link" and it appears to be 1990's bitstream DAC technology and still used on some Pioneer products today. Think it's basically a sort of oversampling, and the real aim is to allow for cheaper/simpler analog filters. If properly implemented, it shouldn't allow anything beyond ~22 kHz through. Not aware of any product which can reconstruct data that doesn't exist on the recording.

Impulse ringing embedded on cd

Reply #20
I was wondering if someone could tell me if Pioneer legato link conversion strategically calculates the added ultrasonic frequencies
or is it simply allowing ultrasonic images through.


I don't know/care what that is, but if you're asking if it can calculate some imaginary thing that doesn't exist, I'm guessing the answer is no. 

Impulse ringing embedded on cd

Reply #21
You need carefully controlled listening tests to find out. And the few listening tests that have delivered statistically significant results suggest that absolutely chronic ringing at about 22kHz is sometimes audible, but only just, on certain content, with certain speakers. How many CDs have chronic ringing at 22kHz? On how many CDs is the ringing the worst problem?

Cheers,
David.

Do you have a link for publication of the results of these listening tests David?

Impulse ringing embedded on cd

Reply #22
Yes. We discussed it to death in a nightmare of a thread here...
https://www.hydrogenaud.io/forums/index.php?showtopic=107124
Someone with more patience than me might be able to find a suitable summary post within the 1000. The link to the paper is at the top though.
Cheers,
David.

Impulse ringing embedded on cd

Reply #23
on certain content, with certain speakers

...and with a very specific filter which may or may not exist in the wild.

Impulse ringing embedded on cd

Reply #24
I try to summarize the thread David linked to.
If filters are steep and survive the DAC playback their ringing may be audible. The long thread started about a filter with a small transition band of 500Hz that was positively abxed in a AES paper. The playback chain and the way the abxed samples were created have several questionmarks. The samples were downsampled with mathlab and upsampled afterwards again to 192kHz for playback. Worst case may be alone for that addititional fillter ringing was added.
If the files would be played with a typical DAC at their downsampled rate the ringing would mostly depend on the DAC. These samples had the ringing completely preserved.
Even with that the result was at 56% positive.
Looking thru datasheets i guess a transition band of 1000-1500Hz is more realistic for 44.1kHz playback.

Then comes the question i am still lost with is how to prepare 44.1kHz files from higher sample rates.
Some try to filter as steep as possible at 22kHz because the strong ringing will be cut by the DAC filter. I heard theories that the created ringing already does harm the way the DAC works internal no matter how it filters.
I for example filter from 20kHz when creating 44.1 files so the DAC has not so much influence anymore.
Biggest problem is i am unable to do conclusive abx here.
Hope that helped.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!