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Serious Question: How can DAC's have a SOUND SIGNATURE if they measure as transparent? Are that many confused?

Thorsten Loesch

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Yes. And it has the problems I surmised (see Thor's post above) when we auditioned it.

If it is the Lamm SE Amp, then it looks like this:

LAMml21FIG01.jpg


The line at -1dB would be the correct load impedance, 80kHz -3dB.

Lamml21fig05.jpg

10kHz squarewave.

And here THD vs. frequency at 0dBW:

LAMml21FIG09.jpg


We see ~ 0.35% THD 100Hz - 10kHz rising to 0.45% @ 20Hz and 0.4% @ 20kHz.

But atma spoke of "high power levels" which this SE Amplifier does not provide.

Vladimir build a fairly large number of different amplifiers. I rather liked his Hybrids.

Thor
 

moosso

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Personally I don't believe there are audible difference between DAC with proper design.
But I keep sawing people talk about transient performance in the other community, that most measurement we had about DAC/Amp only tested the steady state characteristics (output fixed voltage or only change it slowly).
A simple example is if you "measure" a Toyota Prius and Nissan GT-R by asking the driver accelerate from 0 to 60 mph in exactly 10 seconds, they probably give you same response, then you put them in a race they will have much different performance.
So, is there any test about extremely fast transient?
 

SIY

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But I keep sawing people talk about transient performance in the other community, that most measurement we had about DAC/Amp only tested the steady state characteristics (output fixed voltage or only change it slowly).
That would be a place to avoid and people to ignore. It's both untrue and entirely ignorant about how sampling works.

There's a video that's been linked here a million times and will be easy to find. It is an excellent primer on how digital audio works. Search "Monty Montgomery."

Edit: Here it is.
 
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levimax

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Personally I don't believe there are audible difference between DAC with proper design.
But I keep sawing people talk about transient performance in the other community, that most measurement we had about DAC/Amp only tested the steady state characteristics (output fixed voltage or only change it slowly).
A simple example is if you "measure" a Toyota Prius and Nissan GT-R by asking the driver accelerate from 0 to 60 mph in exactly 10 seconds, they probably give you same response, then you put them in a race they will have much different performance.
So, is there any test about extremely fast transient?
Don't listen to the transient FUD. The car analogy is completley unrelated. The measure of the "speed" of an amp is how high a frequency it can reproduce. Any amp or DAC that shows well on @amirm tests is not going to have any problems with musical transients.
 

Mr. Widget

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This thread needs to be split into DACs sound different (or not) and Amplifiers sounding different (or not).

It's getting derailed (@Thorsten Loesch )
It appears that group A will never be satisfied with what is being measured (both DACs and amps) and group B is absolutely satisfied by what is measured (both DACs and amps). These two groups are at an impasse. There is no point continuing to flog the rotting corpse of that dead horse.

The only solution I see is some form of properly controlled listening test to see if the uncontrolled listening impressions of both groups can be verified.

Agreeing on the parameters of that controlled listening test should be the start of a new thread and hammered on for a bit.
 

Killingbeans

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But I keep sawing people talk about transient performance in the other community, that most measurement we had about DAC/Amp only tested the steady state characteristics (output fixed voltage or only change it slowly).

Those people fail to understand that a transient response is a representation of the bandwidth of the device. In other words, it gives you the exact same information as the frequency response does. You can simply apply math to go from one to the other. It doesn't reveal anything previously unknown.
 

pma

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Those people fail to understand that a transient response is a representation of the bandwidth of the device. In other words, it gives you the exact same information as the frequency response does. You can simply apply math to go from one to the other. It doesn't reveal anything previously unknown.
Yes but is a bit academic reasoning. In case that the amp oscillates, like power amps sometimes do at MHz order and preamps at 10 MHz order, you can see it immediately from time response on the scope screen, however measuring frequency response limited to 100kHz or 300kHz would not tell. Practicing people do know, theoreticians often do not realize.
 
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Killingbeans

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Yes but is a bit academic reasoning. In case that the amp oscillates, like power amps sometimes do at MHz order and preamps at 10 MHz order, you can see it immediately from time response on the scope screen, however measuring frequency response limited to 100kHz or 300kHz would not tell. Practicing people do know, theoreticians often do not realize.

True. I was mostly thinking about DACs.

Frequency + phase response, to be more specific.

Yes! Brainfart on my part :D

But still no revelation to be found in transient responses.
 

solderdude

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Personally I don't believe there are audible difference between DAC with proper design.
But I keep sawing people talk about transient performance in the other community, that most measurement we had about DAC/Amp only tested the steady state characteristics (output fixed voltage or only change it slowly).
A simple example is if you "measure" a Toyota Prius and Nissan GT-R by asking the driver accelerate from 0 to 60 mph in exactly 10 seconds, they probably give you same response, then you put them in a race they will have much different performance.
So, is there any test about extremely fast transient?

The problem is that in a recording the max. frequency determines the max impulse response speed. That is when a proper reconstruction (steep) is used.
Also one should realize that the 'speed' in music (drum) hits, picking etc. is mostly a 'presence' in the 3kHz to 8kHz range which is no problem for any DAC.
The people claiming this show the response of a filterless or poorly (slow) filtered step/needle/squarewave response showing a steeper than 1/2 fs (sample frequency) risetime than can possibly be in a recording. They 'link' that to what they hear.
 

Blumlein 88

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Yes I have posted a few times high sample rate recordings of several cymbals on drum kits. The highest are around 8 to 10 khz. Plus they are not steep impulses like they sound. When struck sound energy travels across the metal disc and reflects several times building up the level by a resonance. So it starts off low and over a few cycles builds to a peak and then decays. It is no super steep transient.
 

Thorsten Loesch

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The people claiming this show the response of a filterless or poorly (slow) filtered step/needle/squarewave response showing a steeper than 1/2 fs (sample frequency) risetime than can possibly be in a recording. They 'link' that to what they hear.

Many of my DAC's allow a filter less option together with different filters.

Essentially the use of a reconstruction filter is the direct consequence of the difference between the theoretical ideal of "Nyquist" and the real world. An ideal filter would have an infinite number of taps.

Now here a fun fact, a digital filter and a digital reverb unit operate on the same hardware principles (which can of course also be expressed in DSP).

So let's see what a "1Million Tap" filter does? The filter shape will be near ideal, if a symmetrical FIR filter is used.

In addition a delay/reverb chain is generated that is 1 million samples long, 500,000 samples will create a pre echo, the others a post echo. And this is 11.3 seconds of pre and post echo each. And no, we do not need an impulse to get this echo and reverb, it applies to everything. The transient or square wave response is simply an illustration of the time domain behaviour.

Now, if we add seconds worth of reverb, will this be potentially audible? And if it is audible, how do people normally describe the addition of reverb to music? What does it do to location accuracy of phantom images in the stereo soundstage?

What is the most distinct quality reviews of the 1million tap filter DAC mention, compared to others?

And does such an additional reverb qualify as fidelity impairment or "distortion"?

A higher sampling rate would resolve this, if we sample at (say) 176.4kHz and use a cascaded set of analogue filters to achieve (say) -90dB @ 88.2 kHz the whole problems disappears in a puff of logic.

But there are a few, shall we call them effects from dispensing with the digital filter that are interesting. Naturally, extra reverb is cancelled. But what else happens?

1) Ultrasonic images are produced.

Due to a number of factors these images tend to be dominated by the signals high frequency content. Combined with a shallow slope analogue filter (which may also compensate for the HF droop) a spectrum of music tends to show a similar one to what would be present had the music's ultrasonic content be recorded.

Is ultrasonic content in music audible or percievable? AFAIK nobody has invalidated any of the experimental results of Oohashi et Al.

2) The ultrasonic images act in effect as signal level dependent "dither" analogous to noise like dither used by pro audio manufacturers, e.g. Apogee UV22.

Anyway, I suggest everyone listens for themselves and selects what they find preferable.

Thor
 
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pma

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Yes I have posted a few times high sample rate recordings of several cymbals on drum kits. The highest are around 8 to 10 khz. Plus they are not steep impulses like they sound.
This time, I would respectfully disagree, a bit. 44.1 kHz does not catch it. Sound sample attached in the zip.

clash.jpg


1675438202223.png
 

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  • attacks.zip
    1.6 MB · Views: 31

Blumlein 88

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This time, I would respectfully disagree, a bit. 44.1 kHz does not catch it. Sound sample attached in the zip.

View attachment 261981

View attachment 261993
What about it makes you think it didn't catch it? Looks like what I described, it builds up and begins decay. There are harmonics with cymbals that won't be caught, but the sound itself even if you sample at a high rate does not burst forth like a steep transient.
 

danadam

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Yes I have posted a few times high sample rate recordings of several cymbals on drum kits. The highest are around 8 to 10 khz. Plus they are not steep impulses like they sound. When struck sound energy travels across the metal disc and reflects several times building up the level by a resonance. So it starts off low and over a few cycles builds to a peak and then decays. It is no super steep transient.
Here's that "paiste-24-inch-rude-mega-power-ride-ping.flac" at 176.4 kHz compared to 44.1 kHz when resampled with simple:
Code:
sox input output rate 44100
(the continuous lines are both versions resampled to 705.6 kHz)
paiste-24-waveform.png


And the spectrogram of the original:
paiste-24-inch-rude-mega-power-ride-ping.png
 
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restorer-john

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This time, I would respectfully disagree, a bit. 44.1 kHz does not catch it. Sound sample attached in the zip.

View attachment 261981

View attachment 261993

44.1kHz captured on what exactly? A FIR oversampled ADC? How is that valid?

Maybe a successive approximation A/D made using a NOS DAC with an analog LPF up front- how would those 'samples' differ? Quite a lot I would expect. Bottom line- there is nothing before the stimulus.
 

pma

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44.1kHz captured on what exactly? A FIR oversampled ADC? How is that valid?

Maybe a successive approximation A/D made using a NOS DAC with an analog LPF up front- how would those 'samples' differ? Quite a lot I would expect. Bottom line- there is nothing before the stimulus.
We have 96/24 capture as well. It is only a selected part of much longer capture. Long story short - there is an information above 22kHz from some music instruments, without a smallest doubt. Audibility is questionable, however not excluded. You may make your own search through scientific papers, I am not the one to take part in circles of useless debates and arguing. Debates are not my goal.
 

Blumlein 88

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My point in posting cymbal captures done at I think it was 176 khz wasn't to show there is nothing above 20 khz (these posts were in another thread). It was to show that most energy is concentrated below 20 khz and that it was more of a Gaussian pulse than a Dirac pulse. It starts slow and builds to a resonance then fades out. It isn't a super steep sharp pulse. I also wherever it was posted included downsampling to 44 khz. And yes there are overtones above 20 khz though not at all that high a level and they too showed a ramping up and down rather than a short steep transient.

Maybe we need some jangling keys. 3 metal keys on a metal keyring jangled don't sound very loud at all. They are pretty impressively loud above 20 khz.

I believe Danadam's post above was from the cymbal files I am referring to here.
 
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