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Delta-sigma vs “Multibit”: what’s the big deal?

Veri

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@Veri
The first filter claimed natural is'the super slow filter and is actually non oversampling.
OK but what is the difference between "natural", "acoustic", "traditional", .... :p this kind of thing is obviously not decided by the engineering guys lol. And I really can't discern between these filters on my DX3 at all, whatsoever. I can hear the Super-Slow roll-off yes, but honestly it does not sound "NOS", it sounds a lot like the other 5 filters to me. Maybe I suck at this :p
 
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Blumlein 88

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Comments on filters. The traditional filter with pre and post ringing is fine. The ringing only occurs in the transition band. Audiophiles got bent out of shape about nothing seeing the graphs and not understanding them. The transition band is from 20 khz and the 22.05 khz cutoff for CD. So you'll not hear it.

This created a marketing opportunity to sell something as different and Superior. People created filters that ring only after the pulse. Or ring less time after the pulse. This usually would cause the upper octave response to droop some. And/or let aliasing artifacts thru. That might seem to beef up the detail with some music. Technically most of these filters are less correct than the traditional type.

As already mentioned the fashion is softer treble is more analog like. And some of these filters sound different which was pushed as being Superior.

Search for the xiph.org Digital show and tell video. It is very educational and easy to understand.
 

Frank Dernie

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A lot of popular pickup cartridges for LPs are very rolled off in the treble.
I think a lot of listeners prefer this.
I have noticed filters making a difference to the sound of a DAC though it is clear that the normal one is the most accurate, with the others either adding spurious tones, altering frequency response, or both.
 

Veri

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Also on expert photo camera you can take photo disabling the anti aliasing filter and they say it s sharper
https://www.lifepixel.com/photography-gear/anti-aliasing-low-pass-filter-removal
Has nothing to do with anti-aliasing audio though. In photography one must avoid formation of moire with huge resolutions and resizing.

Sharper images and more captured fine detail in those images. This may be a great feature for studio and landscape photographers who may not mind the occasional occurrence of moire in some images while getting more sharpness and detail in EVERY image.

So basically, photography broscience? :p
 

Frank Dernie

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You re brick wall filter fans here :)
Nothing to do with being fans simply the only filter where the output waveform is accurate over the whole of the defined bandwidth.
They don’t need to be “brick wall” as you call it, just to be in the stop band, fairly steep.
The half cycle of 22.05Hz which produces pre-ringing is a signal which could not exist in the analogue domain, so will never occur in music.
All the other filters used sound different and some may well like the effect, but don’t produce high fidelity reproduction.
 

Bluespower

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Hey
Let's talk about the ringing myth. On impulse response usually we see that the ringing level is pretty high like 10÷ of the impulse level and sometimes higher depending on the filter.
Also the rising time of the impulse vary between filters nos beeing the better.


1. Why don't we call the ringing of filter noise?
(And measures it it would be pretty high)
2. Does ringing of the filter mask some content in fast transient music as it's pretty high?
3. Can the fastness of nos raising time of impulse response explain natural tone perception? In case of fast transient complex music.
4. Does ringing occurs only in impulse response, or does it occurs also on real music on other conditions?
 
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Frank Dernie

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Hey
Let's talk about the ringing myth. On impulse response usually we see that the ringing level is pretty high like 10÷ of the impulse level and sometimes higher depending on the filter.
Also the rising time vary between filters.


1. Why don't we call the ringing of filter noise?
(And measures it it would be pretty high)
2. Does ringing of the filter mask some content in fast transient music as it's pretty high?
3. Can the fastness of nos raising time explain narural tone perception? In case of fast transient complex music.
If you read a book about how digital works you will be able to understand the importance of bandwidth limiting and hence anti-aliasing and reconstruction filters.
Since there is an anti-aliasing filter on the recorder there can never be a transient in the music fast enough to cause any ringing in the filter, if I understand it correctly, this is a crucial thing to understand then the normal reconstruction filter is the only one which is producing an accurate reproduction on playback, the others add and or take away musical information.
 

DonH56

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Hey
Let's talk about the ringing myth. On impulse response usually we see that the ringing level is pretty high like 10÷ of the impulse level and sometimes higher depending on the filter.
Also the rising time of the impulse vary between filters nos beeing the better.


1. Why don't we call the ringing of filter noise?
(And measures it it would be pretty high)
2. Does ringing of the filter mask some content in fast transient music as it's pretty high?
3. Can the fastness of nos raising time of impulse response explain natural tone perception? In case of fast transient complex music.
4. Does ringing occurs only in impulse response, or does it occurs also on real music on other conditions?
I keep thinking this guy is just playing us and happy to waste our time but I'll take a shot...

It is not a myth, it is a real output of a real filter hit with a real (albeit unrealistic) signal. Like many, many things it has been morphed into a distinguishing factor among products to differentiate among them even if the effect is irrelevant. Sort of like the bandwidth wars of years ago; "My amp is better than your amp because mine has 1 MHz of bandwidth and you only have 100 kHz!" The extra bandwidth usually did more harm than good, in both cases...

1. Because it is not noise. It is correlated to the filter response and not a random thing like noise. It could be considered distortion though is not nonlinear distortion people typically consider distortion. Ringing is usually considered separately from noise and classical distortion. And BTW, NOS DACs have anti-image filters at their outputs that exhibit the same sort of ringing (albeit different mechanisms cause it), and in fact the analog filter ringing is usually worse because without oversampling the transition band (filter bandwidth from passing signals to rejecting signals) is much narrower due to the lower sampling frequency.

2. People think of things like drum strikes, piano hammers, plucked strings and the like as "fast transients" even though they tend to be fairly low in bandwidth. Really fast transients require high frequency content, typically above what we can hear, and thus ringing in filters at frequencies beyond (above) audibility will not in any way affect "fast transient music". As has been said, the recording chain will eliminate those frequencies anyway. And of course oversampled converters have wider bandwidth to begin with (see below), sort of blasting the NOS being "faster" argument. Non Over Sampled = lower bandwidth.

3. An oversampled data converter has greater bandwidth and thus faster transient response than a NOS design. Not sure where you are going with this... Handling "transient complex music" requires reasonable bandwidth with high linearity (low distortion) and high resolution (wide dynamic range). Delta-sigma converters have repeatedly exhibited greater dynamic range and better linearity and thus should be more suited for complex musical passages. The issues they had with tones and limit cycles was solved twenty, thirty years ago and NOS DACs have plenty of their own issues. I tend to doubt (being from Missouri) you could tell them apart in a blind test unless one or the other had some sort of measurable issue (show me).

4. Frequency response and impulse response are frequency-domain and time-domain representations of the same transfer function. One can be converted to provide the other. If the "real music" has significant energy up in the filter's transition band, be it a NOS or delta-sigma output filter, then it will excite the filter and lead to ringing. In the real world such energy is small (very low in amplitude/volume) and filtered by the recording and production (mixing, mastering) process so I believe it is a non-issue. But I am not a mastering engineer nor speaker nor audio component designer blessed with ears to hear such things (and that of course is the usual audiophile's recourse; "you just aren't good enough to hear or measure it" -- balderdash.)
 
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Bluespower

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Thank for explaining.
Then if some natural instrument contains natural aliasing
1. does it means that digitally we cannot render it accurately and that the natural aliasing will be removed?
2.Does natural aliasing exists?
3. Does old instruments like analog synth that generates triangular or square waves cannot be rendered digitaly?
 

solderdude

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Thank for explaining.
Then if some natural instrument contains natural aliasing
1. does it means that digitally we cannot render it accurately and that the natural aliasing will be removed?
2.Does natural aliasing exists?
3. Does old instruments like analog synth that generates triangular or square waves cannot be rendered digitaly?
If you knew enough about this stuff you wouldn't have to ask so much silly questions.
 

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