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| What's special about expensive "audiophile" amp/DAC? |
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| NiHaoMike:
--- Quote from: blueskull on March 05, 2020, 06:20:19 am ---It increases your error margin. Unless you have ideal main input and ideal 0dB normalized and well compressed audio input and perfect bang-on amplifier gain setting, you need your DAC to provide you with error margin without degradation. --- End quote --- Audio engineers are always conservative with recording volume levels, since they rather lose a few dB of dynamic range than run the risk of clipping at a critical time. They're supposed to correct the volume during editing, but many don't bother and leave it up to the listener to adjust the volume on their end. (Is it correct that with lossy codecs like MP3, reducing the signal input a small amount does not necessarily reduce the dynamic range?) |
| schmitt trigger:
As Dave would say, the reason these audiophile components are so expensive, is because they are assembled by nude Swiss virgins in a cottage deep in a secluded forest, where birds chirping under a deep azure sky and a crystal-clear brook provide the unique harmonic content to align the electronic sources for the purest sound reproduction. Or something to the effect...... :P |
| tooki:
--- Quote from: NiHaoMike on March 05, 2020, 01:51:39 pm --- --- Quote from: blueskull on March 05, 2020, 06:20:19 am ---It increases your error margin. Unless you have ideal main input and ideal 0dB normalized and well compressed audio input and perfect bang-on amplifier gain setting, you need your DAC to provide you with error margin without degradation. --- End quote --- Audio engineers are always conservative with recording volume levels, since they rather lose a few dB of dynamic range than run the risk of clipping at a critical time. They're supposed to correct the volume during editing, but many don't bother and leave it up to the listener to adjust the volume on their end. (Is it correct that with lossy codecs like MP3, reducing the signal input a small amount does not necessarily reduce the dynamic range?) --- End quote --- Say what now?!? No, the exact opposite has been happening for years now: the loudness war. Tons of recordings are being released with absurdly high levels, often clipped. (And previously-good recordings are being re-released in such a fashion!) Digital audio, even "just" 16-bit/44.1KHz, already has plenty of headroom to allow for massive amplification without adding perceptible noise. (The dynamic range of CD audio already far, far, far exceeds what a human can perceive safely. The dynamic range is such that the smallest sound on CD, amplified to audible levels, would have a system whose peak volume would cause physical harm.) "Leaving it up to the listener to adjust the volume" is precisely what they should be doing, but aren't. "Turn Me Up" is literally the name of a campaign to get mastering engineers to stop succumbing to the loudness war: https://www.turnmeup.org |
| tszaboo:
--- Quote from: blueskull on March 05, 2020, 04:47:19 pm ---To utilize the full 100dB dynamic range of human ear plus waveform resolution of 40dB, 24 bit is what is needed to cover entire human ear's range. Adding some software volume control for lazy users, I can't see why 32 bit is ridiculous. --- End quote --- Hmm, no. http://www.cochlea.eu/en/sound/psychoacoustics Read the part about masking. |
| tooki:
--- Quote from: blueskull on March 05, 2020, 04:47:19 pm --- --- Quote from: tooki on March 05, 2020, 04:21:40 pm ---Digital audio, even "just" 16-bit/44.1KHz, already has plenty of headroom to allow for massive amplification without adding perceptible noise. --- End quote --- Are you kidding? 16 bit=98dB, say we allocate 8dB for mastering volume loss and DAC internal headroom, 20dB for volume control, then we only have 70dB of usable dynamic range. If you listen at 100dB, then your LSB is 30dB. Keep in mind that this 30dB is not the amplitude of a wave, but the minimum step of a signal (a singe step in that wave). That's way insufficient. Human ears can perceive 0dB, and that's the level, not the LSB making up the waveform. To utilize the full 100dB dynamic range of human ear plus waveform resolution of 40dB, 24 bit is what is needed to cover entire human ear's range. Adding some software volume control for lazy users, I can't see why 32 bit is ridiculous. --- End quote --- Except that you're, well, all wrong. Because of how sampling and dithering works, an LSB is not the smallest signal that can be represented. Consequently, the effective dynamic range of CD audio is not 96dB, but 120dB: https://people.xiph.org/~xiphmont/demo/neil-young.html --- Quote ---The dynamic range of 16 bits 16 bit linear PCM has a dynamic range of 96dB according to the most common definition, which calculates dynamic range as (6*bits)dB. Many believe that 16 bit audio cannot represent arbitrary sounds quieter than -96dB. This is incorrect. I have linked to two 16 bit audio files here; one contains a 1kHz tone at 0 dB (where 0dB is the loudest possible tone) and the other a 1kHz tone at -105dB. Sample 1: 1kHz tone at 0 dB (16 bit / 48kHz WAV) Sample 2: 1kHz tone at -105 dB (16 bit / 48kHz WAV) [image] Above: Spectral analysis of a -105dB tone encoded as 16 bit / 48kHz PCM. 16 bit PCM is clearly deeper than 96dB, else a -105dB tone could not be represented, nor would it be audible. How is it possible to encode this signal, encode it with no distortion, and encode it well above the noise floor, when its peak amplitude is one third of a bit? Part of this puzzle is solved by proper dither, which renders quantization noise independent of the input signal. By implication, this means that dithered quantization introduces no distortion, just uncorrelated noise. That in turn implies that we can encode signals of arbitrary depth, even those with peak amplitudes much smaller than one bit [12]. However, dither doesn't change the fact that once a signal sinks below the noise floor, it should effectively disappear. How is the -105dB tone still clearly audible above a -96dB noise floor? The answer: Our -96dB noise floor figure is effectively wrong; we're using an inappropriate definition of dynamic range. (6*bits)dB gives us the RMS noise of the entire broadband signal, but each hair cell in the ear is sensitive to only a narrow fraction of the total bandwidth. As each hair cell hears only a fraction of the total noise floor energy, the noise floor at that hair cell will be much lower than the broadband figure of -96dB. Thus, 16 bit audio can go considerably deeper than 96dB. With use of shaped dither, which moves quantization noise energy into frequencies where it's harder to hear, the effective dynamic range of 16 bit audio reaches 120dB in practice [13], more than fifteen times deeper than the 96dB claim. 120dB is greater than the difference between a mosquito somewhere in the same room and a jackhammer a foot away.... or the difference between a deserted 'soundproof' room and a sound loud enough to cause hearing damage in seconds. 16 bits is enough to store all we can hear, and will be enough forever. --- End quote --- |
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