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Which DACs bypass digital filtering?

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He is apparently aware of the noise issue and has addressed this. What do you think of the solution? I have only read a claim of 24 bit range. 26 bit is being inferred by the reader?

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1 minute ago, bilboda said:

He is apparently aware of the noise issue and has addressed this. What do you think of the solution? I have only read a claim of 24 bit range. 26 bit is being inferred by the reader?

 

There is no 24 bit range. That's the internal mathematics of the digital operations within the device, essentially how many decimal places it uses for its calculations. I've read about studio equipment that uses 80 bit internal mathematics for some DSP operations.

 

The true dynamic range or signal to noise can be given in decibels or bits, 6 dB per bit. So just divide the published -155dB "noise floor" by 6 and you get nearly 26 bits.


One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> wi-fi to router -> EtherREGEN -> microRendu -> USPCB -> ISO Regen (powered by LPS-1) -> USPCB -> Pro-Ject Pre Box S2 DAC -> Spectral DMC-12 & DMA-150 -> Vandersteen 3A Signature.

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143? 150? not very different and I suspect the spec was measured not calculated. You can speculate all you want but until you know how it was measured and duplicate it, (or correct it) you can't know. So if you do want to know, you should ask.

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2 hours ago, bilboda said:

Well, I view your statement as unsupported, likely submitted for controversy only and thus false,until proven otherwise.🤨

The burden of proof would fall to the company making the claim, especially in a case where the claim is it for far better resolution than is understood by to be possible with currently available parts.


ROON: DSD 256-Sonore opticalModule-Signature Rendu optical--Buffalo PRO or DSC-2--Ncore 400 Stereo-Focus Audio FS888-JL E-112 sub-Nordost Tyr USB, DIY AC cables, Iconoclast XLR, Iconoclast speaker, cables, Synergistic Orange & Hi Fi Tuning Supreme Cu Fuses, Dark Matter system clarifiers.    Design/Build Consultant with Sonore

 

                                                       

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50 minutes ago, bilboda said:

143? 150? not very different and I suspect the spec was measured not calculated. You can speculate all you want but until you know how it was measured and duplicate it, (or correct it) you can't know. So if you do want to know, you should ask.

 

As you'll see from @mansr's graph, the question is not whether the -155dB was measured or calculated, but whether the measurement was taken in standard fashion or in a way that was mistakenly or deliberately misleading. Actually that isn't really a question. We know the measurement was not done in standard fashion because the result is not possible under those conditions.


One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> wi-fi to router -> EtherREGEN -> microRendu -> USPCB -> ISO Regen (powered by LPS-1) -> USPCB -> Pro-Ject Pre Box S2 DAC -> Spectral DMC-12 & DMA-150 -> Vandersteen 3A Signature.

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I guess speculation is the order of the day then as no one really wants to know, I have to turn to the right and get back to work, y'all have a great Valentine's/Friday.

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21 minutes ago, bilboda said:

143? 150? not very different and I suspect the spec was measured not calculated. You can speculate all you want but until you know how it was measured and duplicate it, (or correct it) you can't know. So if you do want to know, you should ask.

It is impossible to have a noise level lower than -144 dB with 24-bit samples. The residual noise when playing digital silence or a carefully chosen ideal test signal could in theory be lower, but that's hardly interesting. For arbitrary signals, the -144 dB figure is a hard mathematical limit. If a measurement suggests otherwise, that measurement is flawed.

 

If the -155 dB figure is actually the noise spectral density, it corresponds to an effective resolution of 16.5­–18.5 bits depending on sample rate. At least the lower end of this range is realistic for this type of DAC.

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41 minutes ago, Jud said:

Second, Sonnet talks about a "noise floor" of -155dB, but as we can see from the reference in my previous post, the "noise floor" is not a reflection just of the signal to noise ratio, but of an arbitrarily large processing gain depending on the number of points in the FFT used for the measurement. Thus Sonnet substitutes for a true SNR figure a similar-sounding "noise floor" measurement that is not at all the same.

The correct way to use an FFT is to divide the raw values by the bin width. That way the values give the actual spectral density regardless of the number of bins, and the level of the "floor" doesn't change. If they didn't even do this when producing the -155 dB figure, that number is quite meaningless. Properly scaled, noise density is a useful metric often found in datasheets. Of course, they label it as such and don't try to pass it off as something else.

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11 minutes ago, bobflood said:

Now if we only had a room quiet enough and a recording good enough to take advantage of even standard 16 bit tech.

 

I have a quiet listening room in an exurban setting (about 3 miles from the nearest town of 5000) in a very well insulated house (we lost power and thus heat for 24 hours in a winter windstorm with 50-60mph winds and temperatures below freezing; indoor temperatures dropped from their setpoints of 69-70 degrees F to 67-68 degrees). The background level is about 30dB.


One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> wi-fi to router -> EtherREGEN -> microRendu -> USPCB -> ISO Regen (powered by LPS-1) -> USPCB -> Pro-Ject Pre Box S2 DAC -> Spectral DMC-12 & DMA-150 -> Vandersteen 3A Signature.

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When the environment is really quiet, it becomes really disturbing because you start hearing your own body organs. Your own breathing begins to sound loud, etc.

 


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Pulse & Fidelity - Software Defined Amplifiers

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21 minutes ago, Jud said:

 

I have a quiet listening room in an exurban setting (about 3 miles from the nearest town of 5000) in a very well insulated house (we lost power and thus heat for 24 hours in a winter windstorm with 50-60mph winds and temperatures below freezing; indoor temperatures dropped from their setpoints of 69-70 degrees F to 67-68 degrees). The background level is about 30dB.

That sounds about right. I have measured mine as low as 30bB but most of the time it is in the low to mid 30 range. I don't think most appreciate that any sound that our brains can process (including music) must first emerge from that background din (noise). I read some interesting research that showed that our brains don't do well in a really quiet environment. They put people in an anechoic chamber and if memory serves they started having hallucinations after a while. Link below:

https://www.smithsonianmag.com/smart-news/earths-quietest-place-will-drive-you-crazy-in-45-minutes-180948160/

 

My point being that an extreme dynamic range is not really very useful and is rarely if ever used to its full capacity. The low end is lost and the high end would be dangerous. That said, most recordings especially "loudness wars" recordings are so compressed that they use only a fraction of what would be pleasing, safe and easily available. 

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36 minutes ago, bobflood said:

. I don't think most appreciate that any sound that our brains can process (including music) must first emerge from that background din (noise)

Actually, I do not think this is correct at all?  Humans can hear sounds below the noise floor (the in room noise floor), as the brain can sort these sounds from noise, right?  Think about LP playback, one can certainly hear sounds at levels well below that of the surface noise: this process is usually helped if the sound in question is well known by the brain already (not necessarily the same sound, but a "like" sound, such as the sound of a bell).

Also consider dither, I am sure @mansr has a good explanation of this.


ROON: DSD 256-Sonore opticalModule-Signature Rendu optical--Buffalo PRO or DSC-2--Ncore 400 Stereo-Focus Audio FS888-JL E-112 sub-Nordost Tyr USB, DIY AC cables, Iconoclast XLR, Iconoclast speaker, cables, Synergistic Orange & Hi Fi Tuning Supreme Cu Fuses, Dark Matter system clarifiers.    Design/Build Consultant with Sonore

 

                                                       

SONORE computer audio

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1 minute ago, barrows said:

Actually, I do not think this is correct at all?  Humans can hear sounds below the noise floor, as the brain can sort these sounds from noise, right?  Think about LP playback, one can certainly hear sounds at levels well below that of the surface noise: this process is usually helped if the sound in question is well known by the brain already (not necessarily the same sound, but a "like" sound, such as the sound of a bell).

This is another variant of the same confusion. The total noise power of TPDF dither at the 16-bit level is roughly -92 dB. The spectral density, however, is around -135 dB/Hz. If we create a 1 kHz tone at -100 dBFS and dither it to 16-bit precision, we get this spectrum:

image.thumb.png.92cdf4d065dce9e1e2e235055f7bc1e9.png

 

The tone is clearly visible above the noise. If we play this signal on a decent DAC with the volume turned up high, we can hear a distinct tone as well as some hiss. This is because the tone has much higher intensity than the noise in the immediately surrounding frequencies. The ear separates sounds by frequency much like an FFT, so it's no surprise it too can detect such signals.

 

When people talk about hearing below or into the noise, this is what they (perhaps unknowingly) mean. There is nothing special, mysterious, magical, or in any way remarkable about it.

 

1 minute ago, barrows said:

Also consider dither, I am sure @mansr has a good explanation of this.

Dither is just noise with a specific purpose. In the context of this discussion, it requires no special consideration.

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56 minutes ago, mansr said:

This is another variant of the same confusion. The total noise power of TPDF dither at the 16-bit level is roughly -92 dB. The spectral density, however, is around -135 dB/Hz. If we create a 1 kHz tone at -100 dBFS and dither it to 16-bit precision, we get this spectrum:

image.thumb.png.92cdf4d065dce9e1e2e235055f7bc1e9.png

 

The tone is clearly visible above the noise. If we play this signal on a decent DAC with the volume turned up high, we can hear a distinct tone as well as some hiss. This is because the tone has much higher intensity than the noise in the immediately surrounding frequencies. The ear separates sounds by frequency much like an FFT, so it's no surprise it too can detect such signals.

 

When people talk about hearing below or into the noise, this is what they (perhaps unknowingly) mean. There is nothing special, mysterious, magical, or in any way remarkable about it.

 

Dither is just noise with a specific purpose. In the context of this discussion, it requires no special consideration.

Thanks, I stand corrected. I guess I knew that one can hear below the ambient noise but I did not express what I was trying to get across clearly. I remember something I read years ago said that for something to reach the level of perception below the noise floor it had to be differentiated from the noise for the brain to register it otherwise it would be ignored as noise. This requires more brain processing than sound above the noise floor. This fits in with your explanation above.  Thanks again.

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10 hours ago, Miska said:

When the environment is really quiet, it becomes really disturbing because you start hearing your own body organs. Your own breathing begins to sound loud, etc.

 

 

Like with earplugs in.

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On 1/26/2020 at 7:42 AM, audiofool said:

I've emailed FiiO, is there any other way to determine if it operates in direct mode?   They have a block diagram on their site showing a second order low pass filter after the dac and before the volume control followed by OPA1642 and TPA6120.  https://fiio.com/k5pro

 

Hi, did they reply?

 

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On 2/14/2020 at 12:12 PM, bilboda said:

He is apparently aware of the noise issue and has addressed this. What do you think of the solution? I have only read a claim of 24 bit range. 26 bit is being inferred by the reader?

 

Fantasy.


"Science draws the wave, poetry fills it with water" Teixeira de Pascoaes

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