Tool to verify bit depth and sample rate?

[Sebastian_Alvarez]

I wonder if Wavelab Pro 12 comes with any tools to verify that an audio file is really what the vendor says it is. With the impending death of the CD, and many current albums being only available on a few outlets in lossless format, I have purchased tons of albums as files for the past three years. Some of them are up to 24 bits 192 Khz, some 24/96, etc. I just want to check at least a few to make sure that I paid for what they say, since I read quite a few complaints about vendors upsampling CD quality and charging more for that version.

[ASM]

Q: Is it possible to determine whether an audio file with a low sampling frequency (e.g. 44.1 kHz) has been upconverted to a high sampling frequency (e.g. 192 kHz) without improving the audio quality?

A: It is almost always possible to determine if an audio file has been upconverted (or upsampled) from a lower sample rate (e.g., 44.1 kHz) to a higher one (e.g., 192 kHz) without any genuine quality improvement.

This process does not add new audio information; it just places the existing data into a larger “container.” Here are the primary methods for detecting this:

1. Spectral Analysis (The Most Common Method)

This involves looking at a spectrogram or frequency spectrum of the audio file.

• The “Brick Wall” Cut-off: A genuine 44.1 kHz recording has a theoretical maximum frequency of 22.05 kHz (the Nyquist frequency). Anti-aliasing filters in the ADC (Analog-to-Digital Converter) typically create a sharp roll-off just below this point.

  • An upconverted file will show this exact same sharp cut-off around 22 kHz, but with completely empty or noisy content above it, all the way up to 96 kHz (the Nyquist frequency for 192 kHz).

• Empty Ultrasonic Band: A true, high-resolution 192 kHz recording captured by capable hardware will contain genuine, albeit often inaudible, ultrasonic information and noise that can extend up to 80-90 kHz.

  • An upconverted file will have a “dead” or “flat-lined” spectrum above the original cut-off. Instead of complex waveforms, you’ll often see just the noise floor of the original recording or artifacts from the conversion process.

Visual Difference:

• Genuine 192 kHz file: The spectrogram shows a gradual, natural decay of frequencies, with content and noise extending well above 30 kHz.

• Upconverted 44.1 → 192 kHz file: The spectrogram shows a hard, vertical “wall” at ~22 kHz, with nothing but emptiness or a different noise pattern above it.

2. Analyzing the High-Frequency Content

• Dithering and Noise Patterns: The shaped dither noise from the original 44.1 kHz master will be visible only in the lower frequency band. The ultrasonic range (e.g., 30-96 kHz) will have a different, often lower and flatter, noise profile, which is a clear sign of upsampling.

• Lack of Intermodulation Distortion: In true high-sample-rate recordings, ultrasonic content (even if inaudible) can create intermodulation distortion products that fall back into the audible range. The absence of such artifacts can be a clue, though this is a more subtle analysis.

Tools You Can Use

• Audio Editors: WaveLab, Adobe Audition, Audacity, iZotope RX (all have advanced spectral analysis tools).

• Freeware: Spek or Sonic Visualiser are excellent free tools for this purpose.

• Dedicated Analysis Software: Tools like Tau Analyzer and auCDtect are specifically designed to detect sample rate conversion and CD audio transcode.

Important Caveats

• Modern Converters are Good: High-quality sample-rate conversion (SRC) algorithms can sometimes make the “brick wall” slightly less obvious, but the fundamental lack of ultrasonic information remains the tell-tale sign.

• It Doesn’t Mean “Bad”: An upconverted file is not inherently worse than the original 44.1 kHz file. It is sonically identical. The issue is one of misrepresentation—being sold a “high-res” file that contains no more information than a standard CD.

In summary, by examining the ultrasonic frequency content with a spectrogram, you can almost always spot the signature of an upconverted file: a sharp frequency cut-off at the original Nyquist limit and a complete lack of genuine information above it.

(Courtesy of DeepSeek)

[Marker]

Fakin’ The Funk? - Detect the true quality of your audio files in one batch.

Was reading reviews on this, some say it is not very accurate, but may still work. May be PG can add a feature similar to this for Batch.

[Paul_Rat_Blakey]

Hi

I am not really sure if this is what you are after, but if it is just basic

File Proerties, this is displayed when you drag or open a file in an edit window (as opposed to a montage).

Apologies if I have misunderstood what you are looking for.

[S-EHansson]

MediaInfo

together with WaveLab e.t.c

regards S-EH

[Thomas_W_Bethel]

@ASM

A: It is almost always possible to determine if an audio file has been upconverted (or upsampled) from a lower sample rate (e.g., 44.1 kHz) to a higher one (e.g., 192 kHz) without any genuine quality improvement.

This process does not add new audio information; it just places the existing data into a larger “container.” Here are the primary methods for detecting this:

1. Spectral Analysis (The Most Common Method)

This involves looking at a spectrogram or frequency spectrum of the audio file.

• The “Brick Wall” Cut-off: A genuine 44.1 kHz recording has a theoretical maximum frequency of 22.05 kHz (the Nyquist frequency). Anti-aliasing filters in the ADC (Analog-to-Digital Converter) typically create a sharp roll-off just below this point.
  • An upconverted file will show this exact same sharp cut-off around 22 kHz, but with completely empty or noisy content above it, all the way up to 96 kHz (the Nyquist frequency for 192 kHz).
• Empty Ultrasonic Band: A true, high-resolution 192 kHz recording captured by capable hardware will contain genuine, albeit often inaudible, ultrasonic information and noise that can extend up to 80-90 kHz.
  • An upconverted file will have a “dead” or “flat-lined” spectrum above the original cut-off. Instead of complex waveforms, you’ll often see just the noise floor of the original recording or artifacts from the conversion process.

Visual Difference:

• Genuine 192 kHz file: The spectrogram shows a gradual, natural decay of frequencies, with content and noise extending well above 30 kHz.
• Upconverted 44.1 → 192 kHz file: The spectrogram shows a hard, vertical “wall” at ~22 kHz, with nothing but emptiness or a different noise pattern above it.

2. Analyzing the High-Frequency Content

• Dithering and Noise Patterns: The shaped dither noise from the original 44.1 kHz master will be visible only in the lower frequency band. The ultrasonic range (e.g., 30-96 kHz) will have a different, often lower and flatter, noise profile, which is a clear sign of upsampling.
• Lack of Intermodulation Distortion: In true high-sample-rate recordings, ultrasonic content (even if inaudible) can create intermodulation distortion products that fall back into the audible range. The absence of such artifacts can be a clue, though this is a more subtle analysis.

Tools You Can Use

• Audio Editors: WaveLab, Adobe Audition, Audacity, iZotope RX (all have advanced spectral analysis tools).
• Freeware: Spek or Sonic Visualiser are excellent free tools for this purpose.
• Dedicated Analysis Software: Tools like Tau Analyzer and auCDtect are specifically designed to detect sample rate conversion and CD audio transcode.

Important Caveats

• Modern Converters are Good: High-quality sample-rate conversion (SRC) algorithms can sometimes make the “brick wall” slightly less obvious, but the fundamental lack of ultrasonic information remains the tell-tale sign.
• It Doesn’t Mean “Bad”: An upconverted file is not inherently worse than the original 44.1 kHz file. It is sonically identical. The issue is one of misrepresentation—being sold a “high-res” file that contains no more information than a standard CD.

In summary, by examining the ultrasonic frequency content with a spectrogram, you can almost always spot the signature of an upconverted file: a sharp frequency cut-off at the original Nyquist limit and a complete lack of genuine information above it.

Thanks for the info…much appreciated.