I have few questions on CD recording format/quality and CD player capability.
Supposing that I have 4 CDs and each is recorded in different format, as follows: CD-A - Recorded at 24-bit/192kHz with HDCD encoded CD-B - Recorded at 24-bit/192kHz without labeled HDCD encoded CD-C - Labeled HDCD encoded CD-D V Standard one, without any special recording format labeled
And I also have 2 different CD Players, as below: Player-A - With 24-bit/192kHz DAC and HDCD decorder built-in Player-B - With 24-bit/192kHz DAC
Will each CD play on different Players sound differently with significance or hardly identified? I have heard that the HDCD encoded CD is recorded at 20-bit. Does it mean that a CD recorded at 24-bit is generally better than a HDCD encoded CD?
A CD can't be recorded at 24-bit. CDs are 16-bit. When a CD says it was taken from a 20 or 24-bit digital master it is still sampled down to 16-bits. The advantage is, the previous recording used to make the CD might not have been great quality before it was sampled to CD, so sometimes they re-master, and/or sometimes they just want people to think exactly what you are thinking now.
HDCD means there are 4 more bits encoded into the regular bit stream by adding random noise which the HDCD decoding chip will recognize as more than just random noise, and thus start to decode the extra 4 bits to add to the analog end product, which improves the detail in the final analog signal. These 4 additional bits are mixed into the regular 16 bits via the random noise.
A HDCD will not necessarily sound better on a CD player with HDCD decoding, but it will reveal information that a non-HDCD player cannot decode. There are companies like Wadia, which use proprietary algorithms to "spline fit" (add extra data) to upsampled space with great effect, but it can't recreate exactly what was there in the original analog signal (though it is arguable that you could hear the difference with this technology). HDCD gives you 20 bits, which is 4 bits more of what "was" there instead of using algorithms to guess. Most CD players on the other hand just upsample and leave space, or use more simplified algorithms to connect the dots. Purists tend to prefer the latter, while technically inclined people who understand how spline-fitting works probably don't mind.
You have two CD players there that should allow you to listen for yourself and see if there is a difference. If someone used a 16 bit digital master to make a HDCD, obviously the 4 extra bits will have no new information. I don't know if there are discs out there like that.
As far as a 24-bit being better, or even 20-bit being better than 16-bit requires an understanding of Nyquist's Theorem. Nyquist paraphrased: the minimum sampling rate of an analog signal should be at least twice the range of human hearing. This prevents high frequency noise from being transposed down into human hearing ranges when being converted back to analog (aliasing). The human hearing range is generally considered 20Hz to 20KHz, meaning we must sample at least 40KHz (16 bit samples are 44KHz). Nyquist's Theorem is only concerned with aliasing, not authentic reproduction of analog music from digital sources. Thus the CD format was designed without taking into account the need for authentic recreation of higher frequencies in music, which is what these newer formats were created to solve. Unfortunately, the majority of people in the world don't care if they listen to a CD or, even worse, an MP3. Most people can't distinguish quality of music, or rather; they just don't care enough about it to try to distinguish the difference. Thus CD now, and likely MP3 eventually, is still the main media format for music.
Until recently I had a Meridian G08 and now I have a Wadia 302 for my redbook CDs. I use a Denon DVD-5910 for movies, DVD-A, SACD, and HDCD playing.
Even with HDCD at 20 bits CD can not solve the problem of low sampling rate speed, since the CD is still sampled at the regular CD rate of 44KHz no matter the resolution value in bits. So the extra bits added in HDCD only add to the dynamic range and does not actually add any extra sound material to the recording between the regular CD sampling rate. All it does is add to the resolution of each sample.
I was incorrect in my original comparison between the Wadia and HDCD decoding, because HDCD does not actually add samples, it just improves the dynamic range (as stated in the last post above).
So the definitive answer is, HDCD makes no difference unless you plan on turning your stereo up extremely loud without having distortion occur while playing CDs (loud enough to hurt yourself permanently most likely, lol). So it is better to go with a similarly priced CD player without HDCD than one with it, since extra money went into playing CDs themselves instead of wasting money adding and designing for the extra HDCD decoder chip. Any great sound difference would be better found by investing in a SACD or DVD-A player.
The best way to visualize the two is to imagine a time-sound domain graph. Where the time axis represents the frequency resolution (sampling) and the sound axis represents the bit resolution. So as you take a sample your bit resolution allows you to have more definition between the floor (0th bit) and the ceiling (19th bit).
The reason HDCD makes no difference is because the CD needs to be backwards compatible so the original 16-bits cover the normal range of the music at 16-bit resolution. They can't add it to any area where the actual music is located without distorting the sound.
So it is better to go with a similarly priced CD player without HDCD than one with it, since extra money went into playing CDs themselves instead of wasting money adding and designing for the extra HDCD decoder chip.
Well, I see your point, but who really knows what they did with the extra money. Could be into a better face-plate, more marketing, or simply a bigger markup for all we know.
The old saying "you get what you pay for" also includes brand name, marketing and profits in the "you pay for" category, but you don't always get the benefits of them even if you do pay for them.
This is also a possibility. I would add that it is generally the case that you are getting more R&D invested in the rest of the system rather than wasting the time and money on designing the system to incorporate the HDCD decoding chip (this way your idea is still a possibility - sorry for the extreme language in the earlier post).
It really depends. Some companies make their own chips, like Levinson, where I heard they licensed HDCD to build their own solution. Obviously in cases like this, a lot of R&D went into that portion of the machine. Some people find the HDCD filtering to have a pleasant effect on the sound of the music. What is considered the reference redbook DAC on the market, the dCS unit, doesn't have HDCD. Ultimately, what matters most is if you like how it sounds in your system. I personally don't see how HDCD really benefits anyone very much. A better means of filling in the space when using over/up-sampling seems like a better use of R&D to me.
Your player will have to have a digital filter chip, almost all designs do. The HDCD chip is/was an excellent digital filter for 16 bit and HDCD encoded discs. I don't think you have to play at high volumes to reap the benefits of HDCD...you do need a HDCD encoded source, though. If anything, I would say that an upsampling board would cause more lost r&d especially when you are dealing with a 16 bit source. Unfortunately, thanks to the popularity of DVD, there probably aren't a whole lot of 16-20 bit DAC chips around. Just like there are not a lot of transports optimized for CD players.