The 24-Bit Delusion

The 24-Bit Delusion

UPDATED: 11.3.17

INCLUDING INFORMATION ON MQA


Introduction

In the past decade, more and more music has become available in “high-definition” (HD) digital formats, such as 24-bit 192KHz downloads, 24-bit 192KHz MQA streaming, and DSD. Now I hear talk about developing a new 32-bit 384KHz standard for HD music. Interestingly enough, not everyone agrees that greater bit depth and higher sampling rates are good things.

This blog will explain the math and physics of digital recording and musical reproduction in layman’s terms so that you can decide for yourself if this is progress or simply marketing madness. Continue…

 

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3 thoughts on “The 24-Bit Delusion

  1. I understand about the higher sampling frequency not being a big factor on sound improvement (heck, I probably can’t hear beyond 16 kHz anyway!), but I must admit that I’m confused about the bit rate. I was under the impression (as were/are thousands of others) that with a higher bit rate you got more data. A smoother approximation of the analog signal, if you will. Using a photography analogy, I assumed that 24-bit files were more like, say, a 15 Mp camera, whereas 16-bit files were akin to, say, a 2 Mp camera. The larger, 15 Mp image is just smoother – a much closer approximation of the real thing. Apparently this is not a fair comparison, though? Perhaps you can explain more so this mechanical engineer can understand? (And also offer your explanation why higher-resolution files do indeed frequently sound better. I’ve done some A/B testing with the same tracks in 16 vs. 24 and have definitely noticed an improvement. Or so I think. Maybe it’s just wishful thinking?)

    • Your comparison to a digital photo is correct in many ways. Just like with music, the original source of the photo is more significant than the resolution. If the lens was dirty or the photo was taken out of focus more resolution will only better identify these flaws.

      Similarly, bit depth is comparable between audio and photo if you were to substitute the dynamic range of audio with the physical size of the photo being printed out. The 144db dynamic range of 24-bit audio would be comparable to the resolution of photo you would need to print a bill board. Similarly, both would require professional vs. home equipment to output and both could only be appreciated from a considerable distance.

      Just like most home audiophile systems can’t play accurately much above 110db, the resolution required to view photos on your 60″ flat screen HDTV is no where near the resolution required to view the same photo on a larger banner or bill board. The higher resolution native audio and photo formats are important in editing, but not necessary once they audio or photo are output. Resolution is always restricted to the resolution of the output device and only relative to the person’s perspective who is viewing or listening to the output. Just like I wouldn’t want to share photos printed out on bill boards with people visiting my home, I wouldn’t have an audio system engineered to fill an concert hall playing in my listening room.

      If you are hearing an improvement between a 16/44.1 and a 24/192 music file is is because of one or both of these factors: higher sampling frequency and/or better digital mastering. I would be willing to bet that less than 1% of the digital audio recordings available have greater than 12-bit dynamic range despite whatever the label is on the file. Limiting actual bit depth and dynamic range on recordings is engineered into the files because the industry realizes that few systems are capable of playing back more dynamic files.

      Once again, it comes down to the resolution of the output device being he limiting factor as opposed to the software, and that higher resolution than is attainable by output devices is necessary for undetectable editing.

  2. To further extend the photograph analogy, it seems that what can be done with HDR in photography corresponds to the “sane dynamic compression” that you refer to for audio. Done well, it can bring out details in a photo lost to under/over-exposed regions, by shifting the tones in these regions back towards the gray “center” of the dynamic range from ultra-black to blinding-white, thus compressing the true dynamic range of the original scene into something that can be reproduced by the monitor or printer you are using, not to mention what can be seen by your eyes.

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