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Digital file noise and distortion

JeremyFife

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Worth noting that a digital recording of an analogue source (voices, miked instruments, tape hiss) will capture all that noise too. The noise will be there on the digital file, it's just not created by the digital chain. Some recordings will be cleaner, although not always better.
 
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freemansteve

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Sure, things need to be measured. I can't think of anything where you can't "identify the cause when a file doesn't sound right", as the OP was saying, with let's say, 'modern' kit. Although some people to claim to hear all sorts of things not apparent in measurement!

The OP also wrote "Let's assume the analog signal is not the problem i.e. the preamp out are fine. What in the digital section could cause the song to change? What changes the bits and bytes (1s and 0s) to alter the music?"

Since DAC units use op amps, I'm just suggesting that all analogue signals are subject to 'changes' at every point. May not be audible with decent gear, but measurable.

Also, as aside, many people may well be hearing their audio files played through systems where the "bits and bytes" do get changed before you get to a DAC - i.e. the OP may have heard kit that did lossy compression or SRC on his files that led to his post maybe?
 
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Rjharle

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Sure, things need to be measured. I can't think of anything where you can't "identify the cause when a file doesn't sound right", as the OP was saying, with let's say, 'modern' kit. Although some people to claim to hear all sorts of things not apparent in measurement!

The OP also wrote "Let's assume the analog signal is not the problem i.e. the preamp out are fine. What in the digital section could cause the song to change? What changes the bits and bytes (1s and 0s) to alter the music?"

Since DAC units use op amps, I'm just suggesting that all analogue signals are subject to 'changes' at every point. May not be audible with decent gear, but measurable.

Also, as aside, many people may well be hearing their audio files played through systems where the "bits and bytes" do get changed before you get to a DAC - i.e. the OP may have heard kit that did lossy compression or SRC on his files that led to his post maybe?
I think there is a level of confession caused by my original post. Let me try to be more clear. I don't think the problem is noise per se but more a change in the way the music sounds.

Take a FLAC file if I use the Nvidia Shield's internal DAC the music sounds thin with no body, If I bypass the Nvidia's DAC "pass through" and use the Anthem's DAC the music sounds slightly muddled; less definition. The setup is the same with all Anthem's processing turn off; ARC, Bass Management, Dolby, etc. just a flat signal in and out. Sometimes the same file will have frequencies (notes) with a longer or a sharper cutoff; especially on the voice. Wave and FLAC files sound different.

Also, if I try to use a program called WavePad to Automatic Gain Control (AGC) level a bunch of FLAC files in addition to the files sounding the same volume they sound like the middle frequencies have been suppressed.
 

BDWoody

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Take a FLAC file if I use the Nvidia Shield's internal DAC the music sounds thin with no body, If I bypass the Nvidia's DAC "pass through" and use the Anthem's DAC the music sounds slightly muddled; less definition.

I don't believe the shield has a DAC built in. You have to either connect through HDMI to whatever will be doing the decoding, or through a USB connected DAC.

What pass-through setting are you referring to? I want to try to be sure I understand.
 
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Rjharle

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I don't believe the shield has a DAC built in. You have to either connect through HDMI to whatever will be doing the decoding, or through a USB connected DAC.

What pass-through setting are you referring to? I want to try to be sure I understand.
In the Nvidia Shield using Kodi where audio can be Pass Through.

There is a third condition where the sound changes. If I go with an HDMI audio extraction and SPDIF out into the Matrix Audio Element or I use the MA app and play the files directly from the Matrix. I just never hear the same the music the same across all the DACs.

P.S The Matrix uses the analog input port on the Anthem. Shield uses the HDMI port on the Anthem with all processing turned off.
 
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dadregga

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Since I'm limited in my understanding of digital processing please, if possible, keep the answers simple.

Take a FLAC file if I use the Nvidia Shield's internal DAC the music sounds thin with no body, If I bypass the Nvidia's DAC "pass through" and use the Anthem's DAC the music sounds slightly muddled; less definition. The setup is the same with all Anthem's processing turn off; ARC, Bass Management, Dolby, etc. just a flat signal in and out. Sometimes the same file will have frequencies (notes) with a longer or a sharper cutoff; especially on the voice. Wave and FLAC files sound different.

If they do, it has absolutely nothing to do with the bytes in the files themselves - that's easy to prove. Binary data is extremely easy to compare via hashes to other binary data, and if even a single bit is off, you can prove it.

If you're hearing a difference, it has nothing to do with the digital part of the chain, or the actual contents of the WAV/FLAC file in terms of the bits. It has to do with analog output stages, DSP, forced resampling (Android especially is prone to this) or similar.
 
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Rjharle

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If they do, it has absolutely nothing to do with the bytes in the files themselves - that's easy to prove. Binary data is extremely easy to compare via hashes to other binary data, and if even a single bit is off, you can prove it.

If you're hearing a difference, it has nothing to do with the digital part of the chain, or the actual contents of the WAV/FLAC file in terms of the bits. It has to do with analog output stages, DSP, forced resampling (Android especially is prone to this) or similar.
Now I'm confused. I was told and read posts that all amps/preamps sound the same since they only increase the signal's volume. If the file is resampled from 24/192 to 16/44 I wouldn't hear the difference. :confused:
 

dadregga

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Now I'm confused. I was told and read posts that all amps/preamps sound the same since they only increase the signal's volume. If the file is resampled from 24/192 to 16/44 I wouldn't hear the difference. :confused:

Unless it's unusually bad resampling you wouldn't.

What I'm saying is that bits are bits - and that's a mathematical fact. A WAV and that same WAV compressed to FLAC cannot sound different because they have exactly the same contents, in the same way that both 2 and 4 cannot help but be divisible by 2. It's how math works.

Once those bits become analog signals, things become much more variable - all the audible differences you describe, if they exist at all, are very likely created in the analog stages.

Good amps don't color the sound - not all amps are good, not all amps or preamps output at the same levels, etc.

You can test this all - if you hear a difference, and it's not psychoacoustic, then you can isolate and measure it.

When you do that, you will find the difference doesn't lie in the bits, it will lie somewhere in your analog stage, if it exists at all - unless something very unusual is happening in software and we're no longer getting bit-perfect output to the DAC.
 
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Rjharle

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Unless it's unusually bad resampling you wouldn't.

What I'm saying is that bits are bits - and that's a mathematical fact. A WAV and that same WAV compressed to FLAC cannot sound different because they have exactly the same contents, in the same way that both 2 and 4 cannot help but be divisible by 2. It's how math works.

Once those bits become analog signals, things become much more variable - all the audible differences you describe, if they exist at all, are very likely created in the analog stages.

*Good* amps don't color the sound - not all amps are good, not all amps or preamps output at the same levels, etc.

You can test this all - if you hear a difference, and it's not psychoacoustic, then you can isolate and measure it.

When you do that, you will find the difference doesn't lie in the bits.
The conditions I'm hearing are not from the file because I'm using the same one for comparison. I only have one AVR and that is the Anthem MRX 720. The or thing that is changing in the DAC. If I feed the file from the Shield > HDMI > Anthem (DAC) the file sounds muddled with less definition. The shield audio extractor > SPDIF out > Matrix Element I (DAC) > Anthem Analog inputs the sound is the notes (voices) sharp cutoff. The Matrix Element (DAC) > Anthem analog inputs sound clear but bright. The Anthem setting was not changed and set as flat as I can make them.
 

dadregga

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The conditions I'm hearing are not from the file because I'm using the same one for comparison. I only have one AVR and that is the Anthem MRX 720. The or thing that is changing in the DAC. If I feed the file from the Shield > HDMI > Anthem (DAC) the file sounds muddled with less definition. The shield audio extractor > Matrix Element I > Anthem Analog inputs the sound is the notes (voices) sharp cutoff. The Matrix Element > Anthem analog inputs sound clear but bright. The Anthem setting was not changed and set as flat as I can make them.


1. Is this a blind test? Can you tell a difference if you don't know what you're listening to? "Muddled with less definition" and "clear and bright" are vague terms that would be more quantifiable with measurements.

2. Matrix element has digital volume control. Is that a factor?

3. Try with another device that does SPDIF to the Matrix and see if you can hear a difference between SPDIF ->Matrix->Anthem and Matrix->Anthem. If you can, it's something to do with the Matrix. If not, it's something on the Shield side, probably a software misconfig.
 

SIY

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The conditions I'm hearing are not from the file because I'm using the same one for comparison. I only have one AVR and that is the Anthem MRX 720. The or thing that is changing in the DAC. If I feed the file from the Shield > HDMI > Anthem (DAC) the file sounds muddled with less definition. The shield audio extractor > SPDIF out > Matrix Element I (DAC) > Anthem Analog inputs the sound is the notes (voices) sharp cutoff. The Matrix Element (DAC) > Anthem analog inputs sound clear but bright. The Anthem setting was not changed and set as flat as I can make them.
Try level matching (electrically to 0.1 dB) and comparing double blind.
 
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