On the Trinity DAC thread (Forum: Digital) we had a brief discussion about the question if the 16/44 CD format is even theoretically sufficient, apart from the technical problems that have been tough to solve but now have resulted in implementations which, three decades after the introduction of CD, show that CD is really a true high-resolution medium indeed.
On the Trinity DAC thread (p. 47 ff.) some people including me have argued that, yes, the 16/44 CD format is at least theoretically sufficient, but others have argued that the 16 bit dynamic range and high frequency issues, quite apart from practical filtering problems, indeed pose theoretical problems. I had contended that the dynamic range is more than sufficient, since you can't get below something like 25 dB background noise (very quiet living room, or basically empty concert hall except musicians) and an orchestra only on very rare occasions reaches 110 dB (which is screamingly loud). This would make for a maximal dynamic range for orchestral music of about 85 dB (at 110 dB - 25 dB). A similar dynamic range for orchestra (around 70-80 dB) has been cited on several websites, including on the Wikipedia page on dynamic range with a book citation on this. For recording that dynamic range, the dynamic range of 96 dB of 16/44 CD is more than sufficient.
Yet even so, trying orchestra at maximum live levels at home in everyday listening situations is not recommended, since 110 dB is close to ear-damaging levels even for just short amounts of time (I never go beyond 95-97 dB for short orchestral climaxes at home, which is really really loud, and usually I keep max levels somewhat below that -- after 2 minutes of the final brass chorale of Bruckner's Fifth Symphony at 95-97 dB, reproduced without appreciable distortion, I already feel pressure in my ears). So I would say that makes even an 85 dB dynamic range unnecessary in home listening situations. Your noise floor in your listening room is a minimum of 25 dB -- at least it is around 25 dB in mine, in a very quiet neighborhood, with sound-suppressing windows and no electrical gear except the stereo system, thus under really optimal circumstances. So for practical listening situations that would make for around a 95 dB - 25 dB = 70 dB effectively needed dynamic range.
Those thoughts about dynamic range are basically mirrored and expanded upon in the following article:
http://kenrockwell.com/audio/why-cds-sound-great.htm
Quote from the article:
16 Bits: More than enough
While professional editing, mixing, processing, equalizing and level shifting usually use more data bits for computation (24 bits linear, 32-bit floating point or now 48-bit linear), 16 bits is more than enough for unlimited fidelity as a release format.
The reason we use more bits in production is so we can create and preserve a true 16 bits through the whole process after all the truncation and rounding and nastier stuff that goes on between the microphone and your CD.
16 bits is more than enough, and with popular music today, even 8 bits is more than enough.
How is this?
16 bits have a signal to noise ratio of 98 dB (theoretical SNR = (bits x 6.0206) + 1.72 dB). That doesn't sound like much compared to 24 bits theoretical 146 dB, but realize that a library's background noise is about 35 dB SPL. Your house probably isn't any quieter. A full symphony orchestra giving it all it's got (ƒƒƒƒ) peaks at about 104 dB SPL. Let's give the orchestra 105 dB, and 105 dB - 35 dB = only 70 dB real dynamic range if you brought the orchestra into your home.
Supposing we recorded on the moon in a pressurized tent with no background noise? Well, the self-noise of most recording studio microphones is about 16 dB SPL equivalent input noise, or in other words, microphones aren't any quieter than about 16 dB SPL anyway.
Even though some people can hear to 0 dB SPL, we're always hearing background noise if we shut up and listen. It takes a lot of money to build an NC 25 or NC 15 studio, in other words, a recording studio with about a 15 dB or 25 dB SPL background noise. Even in an NC 15 studio, 105 - 15 = 90 dB SPL, well within the range of real 16-bit systems, if you record it well.
16 bits was chosen because it has more than enough range to hold all music. I know; I was doing 16-bit recording back in 1981 before the CD came out, and my recordings would have their levels carefully set so the loudest peak of the entire concert hit about -3 dB FS, and leaving it running after the audience left and the hall was empty, you can still bring up the playback gain and hear a perfectly silent recording of the air conditioning noise in the hall. The world just doesn't get quiet or loud enough to need more than 16 bits as a release format, if it's recorded well.
There is no such thing as a real 24-bit audio DAC or ADC. Look at the specs, and you'll never see a 144 dB SNR spec; all audio 24-bit converters do have 24 bits wiggling, but the least few LSBs are just noise. There is plenty of 24-bit and higher DSP, which is good to keep the 16-bits we need clean, but you're never getting 24 real bits of analog audio in or out of the system. It's a good thing you can't; 140 dB SPL is the threshold of instant deafness, and if you lift the gain enough to hear a real 24-bit noise floor at say 20 dB SPL in a very quiet studio, maximum output would be 20 + 144 = 164 dB SPL, or 4 dB over the threshold of death. Yes, 160 dB SPL kills.
But wait, there's more. 98 dB is the theoretical SNR. With dither, we still can hear pure undistorted signals down into the noise for at least another 10 or 20 dB. While a typical real-world 16-bit system's SNR might be 92 dB, we can hear tones down to -100 dB FS easily. That's over 100 dB of dynamic range in real 16-bit systems.
There's even more than that! By the 1990s, people learned how to "noise shape" the dither to push it up mostly to 15 kHz and above, so it became much less audible, but just as effective as regular dither. These systems made the noise much less audible. These systems are also called Super Bit Mapping (SBM) by Sony and UV22 byApogee; they claimed 22-bit effective SNRs with 16-bit systems. They didn't really work that well, but they did make our 16-bit system even better than it was. These clever sorts of dither are still used today for 16-bit releases.
That's right: done right, 16 bits is way, way more than enough for any sort of music. Once you've heard it done right, you'll realize any noise you here out of a CD is due to sloppy recordings (usually sloppy level settings someplace in the chain), not the CD medium itself.
(End Quote.)
The article also has interesting things to say about SACD and loudness wars.
***
I think the first two paragraphs quoted from the article are important for those worrying about data loss in 16/44:
While professional editing, mixing, processing, equalizing and level shifting usually use more data bits for computation (24 bits linear, 32-bit floating point or now 48-bit linear), 16 bits is more than enough for unlimited fidelity as a release format.
The reason we use more bits in production is so we can create and preserve a true 16 bits through the whole process after all the truncation and rounding and nastier stuff that goes on between the microphone and your CD.
So what do you think, is 16 bit enough or not?
On the Trinity DAC thread (p. 47 ff.) some people including me have argued that, yes, the 16/44 CD format is at least theoretically sufficient, but others have argued that the 16 bit dynamic range and high frequency issues, quite apart from practical filtering problems, indeed pose theoretical problems. I had contended that the dynamic range is more than sufficient, since you can't get below something like 25 dB background noise (very quiet living room, or basically empty concert hall except musicians) and an orchestra only on very rare occasions reaches 110 dB (which is screamingly loud). This would make for a maximal dynamic range for orchestral music of about 85 dB (at 110 dB - 25 dB). A similar dynamic range for orchestra (around 70-80 dB) has been cited on several websites, including on the Wikipedia page on dynamic range with a book citation on this. For recording that dynamic range, the dynamic range of 96 dB of 16/44 CD is more than sufficient.
Yet even so, trying orchestra at maximum live levels at home in everyday listening situations is not recommended, since 110 dB is close to ear-damaging levels even for just short amounts of time (I never go beyond 95-97 dB for short orchestral climaxes at home, which is really really loud, and usually I keep max levels somewhat below that -- after 2 minutes of the final brass chorale of Bruckner's Fifth Symphony at 95-97 dB, reproduced without appreciable distortion, I already feel pressure in my ears). So I would say that makes even an 85 dB dynamic range unnecessary in home listening situations. Your noise floor in your listening room is a minimum of 25 dB -- at least it is around 25 dB in mine, in a very quiet neighborhood, with sound-suppressing windows and no electrical gear except the stereo system, thus under really optimal circumstances. So for practical listening situations that would make for around a 95 dB - 25 dB = 70 dB effectively needed dynamic range.
Those thoughts about dynamic range are basically mirrored and expanded upon in the following article:
http://kenrockwell.com/audio/why-cds-sound-great.htm
Quote from the article:
16 Bits: More than enough
While professional editing, mixing, processing, equalizing and level shifting usually use more data bits for computation (24 bits linear, 32-bit floating point or now 48-bit linear), 16 bits is more than enough for unlimited fidelity as a release format.
The reason we use more bits in production is so we can create and preserve a true 16 bits through the whole process after all the truncation and rounding and nastier stuff that goes on between the microphone and your CD.
16 bits is more than enough, and with popular music today, even 8 bits is more than enough.
How is this?
16 bits have a signal to noise ratio of 98 dB (theoretical SNR = (bits x 6.0206) + 1.72 dB). That doesn't sound like much compared to 24 bits theoretical 146 dB, but realize that a library's background noise is about 35 dB SPL. Your house probably isn't any quieter. A full symphony orchestra giving it all it's got (ƒƒƒƒ) peaks at about 104 dB SPL. Let's give the orchestra 105 dB, and 105 dB - 35 dB = only 70 dB real dynamic range if you brought the orchestra into your home.
Supposing we recorded on the moon in a pressurized tent with no background noise? Well, the self-noise of most recording studio microphones is about 16 dB SPL equivalent input noise, or in other words, microphones aren't any quieter than about 16 dB SPL anyway.
Even though some people can hear to 0 dB SPL, we're always hearing background noise if we shut up and listen. It takes a lot of money to build an NC 25 or NC 15 studio, in other words, a recording studio with about a 15 dB or 25 dB SPL background noise. Even in an NC 15 studio, 105 - 15 = 90 dB SPL, well within the range of real 16-bit systems, if you record it well.
16 bits was chosen because it has more than enough range to hold all music. I know; I was doing 16-bit recording back in 1981 before the CD came out, and my recordings would have their levels carefully set so the loudest peak of the entire concert hit about -3 dB FS, and leaving it running after the audience left and the hall was empty, you can still bring up the playback gain and hear a perfectly silent recording of the air conditioning noise in the hall. The world just doesn't get quiet or loud enough to need more than 16 bits as a release format, if it's recorded well.
There is no such thing as a real 24-bit audio DAC or ADC. Look at the specs, and you'll never see a 144 dB SNR spec; all audio 24-bit converters do have 24 bits wiggling, but the least few LSBs are just noise. There is plenty of 24-bit and higher DSP, which is good to keep the 16-bits we need clean, but you're never getting 24 real bits of analog audio in or out of the system. It's a good thing you can't; 140 dB SPL is the threshold of instant deafness, and if you lift the gain enough to hear a real 24-bit noise floor at say 20 dB SPL in a very quiet studio, maximum output would be 20 + 144 = 164 dB SPL, or 4 dB over the threshold of death. Yes, 160 dB SPL kills.
But wait, there's more. 98 dB is the theoretical SNR. With dither, we still can hear pure undistorted signals down into the noise for at least another 10 or 20 dB. While a typical real-world 16-bit system's SNR might be 92 dB, we can hear tones down to -100 dB FS easily. That's over 100 dB of dynamic range in real 16-bit systems.
There's even more than that! By the 1990s, people learned how to "noise shape" the dither to push it up mostly to 15 kHz and above, so it became much less audible, but just as effective as regular dither. These systems made the noise much less audible. These systems are also called Super Bit Mapping (SBM) by Sony and UV22 byApogee; they claimed 22-bit effective SNRs with 16-bit systems. They didn't really work that well, but they did make our 16-bit system even better than it was. These clever sorts of dither are still used today for 16-bit releases.
That's right: done right, 16 bits is way, way more than enough for any sort of music. Once you've heard it done right, you'll realize any noise you here out of a CD is due to sloppy recordings (usually sloppy level settings someplace in the chain), not the CD medium itself.
(End Quote.)
The article also has interesting things to say about SACD and loudness wars.
***
I think the first two paragraphs quoted from the article are important for those worrying about data loss in 16/44:
While professional editing, mixing, processing, equalizing and level shifting usually use more data bits for computation (24 bits linear, 32-bit floating point or now 48-bit linear), 16 bits is more than enough for unlimited fidelity as a release format.
The reason we use more bits in production is so we can create and preserve a true 16 bits through the whole process after all the truncation and rounding and nastier stuff that goes on between the microphone and your CD.
So what do you think, is 16 bit enough or not?