Oh boy, this test is going to ruffle some feathers. However, the choice of audio clip ensures that you can't tell the difference easily.
It's known that the only difference between well-prepared files of different bit depths is the noise floor. Basically, in any PCM audio file, you can expect noise of about 1 ULP. So in a 16-bit file you get a noise floor of -90 dB, and in an 8-bit file it's at -42 dB. This is the ONLY DIFFERENCE.
People who are here listening for distortion artifacts aren't going to find any, and they're going to be surprised. That's because you can always choose to introduce noise instead of distortion artifacts when you do the conversion. The noise is actually added on purpose, it's "dithering noise", and it's not there to mask the distortion, but to entirely replace it.
The math works like this. Take a high-resolution input, say, 16-bit. You're converting it to 8-bit. If you just convert, you'll introduce a distortion signal of about 1ULP. However, if you introduce 1ULP of uncorrelated rectangular noise, the distortion signal is now also uncorrelated noise, which is less objectionable than correlated noise. It's also harder to hear.
Then, how do you tell the difference between 16-bit and 8-bit audio files? You can only do it if there's a quiet part somewhere in there. As soon as there's a quiet part, you can hear a "hissing" sound in the 8-bit file at -42 dB. If you're listening to the middle of a rock song like this, the hissing sound is going to be buried in the mix. Heck, a typical guitar amp will already be putting out uncorrelated noise.
Note also that many people (me, for example, and most folks over 40 in general) can't hear a -42dB white noise layered on top of an audible signal at all. The pipes just don't pick it up over the general noise in the receiver "circuit".
Oh thanks for that. I can now pass the test with 10/10 correctness. There's a noticeably louder noise floor in the 8bit sample that is really clear between the samples.
10/10, but I had to listen closely. Sennheiser 650s & external DAC/amp, quiet room, hearing is still good to ~16khz.
The primary place I picked out to hear this not the quiet parts, but rather a hiss above 10khz, which was audible even at the beginning - and particularly at the beginning. It's almost mistakable for brighter cymbals, if you're not listening closely. It also changes in perceptibility over the duration of the sample.
I tested myself using that same trace: I got 10/10 with the sound of the cymbals, then confirming with the fadeout at the end.
This is with HD-598's with 16 feet of cheapo headphone extension cords, loud old refrigerator running in tiled studio apartment, and motherboard built-in sound output.
10/10 using HD215s plugged into whatever cheapo onboard DAC this laptop has. But like you I did know what to listen for, having done a signals engineering course in the deep dark past.
The fade out at the end makes it possible to identify it. I couldn’t do it perfectly (also played over my laptop speakers because I’m lazy), but I still got 8/10.
It's known that the only difference between well-prepared files of different bit depths is the noise floor. Basically, in any PCM audio file, you can expect noise of about 1 ULP. So in a 16-bit file you get a noise floor of -90 dB, and in an 8-bit file it's at -42 dB. This is the ONLY DIFFERENCE.
People who are here listening for distortion artifacts aren't going to find any, and they're going to be surprised. That's because you can always choose to introduce noise instead of distortion artifacts when you do the conversion. The noise is actually added on purpose, it's "dithering noise", and it's not there to mask the distortion, but to entirely replace it.
The math works like this. Take a high-resolution input, say, 16-bit. You're converting it to 8-bit. If you just convert, you'll introduce a distortion signal of about 1ULP. However, if you introduce 1ULP of uncorrelated rectangular noise, the distortion signal is now also uncorrelated noise, which is less objectionable than correlated noise. It's also harder to hear.
Then, how do you tell the difference between 16-bit and 8-bit audio files? You can only do it if there's a quiet part somewhere in there. As soon as there's a quiet part, you can hear a "hissing" sound in the 8-bit file at -42 dB. If you're listening to the middle of a rock song like this, the hissing sound is going to be buried in the mix. Heck, a typical guitar amp will already be putting out uncorrelated noise.