There are aome stuff I'm curious about. When were the first 1 bit D/A converters introduced? Why almost all converters ended up being 1 bit (or low bit like Matsushita's MASH) designs? Wasn't 1 bit technology a bit overkill at the time of its introduction? Did they really sound better than multibit designs of the time. The 1 bit converters we have today use the same technology of those produced around 25 yesrs ago? Did 1 bit converters led to DSD? I know, too many questions...
Well, DSD is essentially saving the output of one of those single-bit converters. And yeah, the 1-bit converters did pretty much replace the oversampling converters, although there are those who feel a good oversampling converter sounds better (the 1-bit converters do have ultrasonic issues - like DSD - although in practice I doubt that has much impact on the audible signal).
Back in the late 80s, some audiophiles got the idea that drawing a ring around the outer circumference of a CD with a green marker improved the sound. Something about reducing the deflection of the laser or some BS like that. Out of that grew a product of green plastic rings that you would place around your CD to reduce vibration as it spun.
The DAC typically uses a different resistor for each bit. A 4-bit DAC needs 4 resistors working in parallel to provide a steady analog signal. When you get to the 16-bit or even 32-bit level found in CDs and DVDs, the number of gradations required per resistor makes it very difficult to precisely match values. For example, a typical 16-bit DAC would have 16 resistors requiring a total of 65,536 gradations. What a 1-bit Dual D/A converter does is allow the digital-to-analog conversion to happen without the need for all those extra resistors. Essentially, this type of DAC does not use a bank of resistors operating in parallel. Instead, it creates a carefully modulated signal from the digital. The converter relies on noise shaping, a phenomenon that takes advantage of the human ear's inability to notice noise when it occurs in higher frequencies. Basically, the human ear is most sensitive to noise at 5 KHz, and is almost unable to detect it at 20 KHz. A key part of the converter is a circuit called a delta-sigma modulator, which takes the binary signal (1s and 0s) from the CD and changes them to a steady pulse, called a pulse train. The pulse train contains an average of the change in the amount of energy represented in the sample. A low-pass filter removes all time-domain information and recovers only the average energy of the pulse train that feeds it. The key here is to understand that the pulse-train waveform is clocked at a very high frequency compared to the 44.1 KHz sample rate. The pulse train is sent through the DAC and changed into an analog signal.
At the very least the music seemed louder!! But logically, digital is either correct or not. I knew all that and I still used it on about 400 cds!
I wouldn't Phil. As with that DS, that thing is on there permanently. I'm afraid of cracking the hub...
I had asked because my learning about the topic is that it is very hard to reliably tell the difference as judged by a good sampling of qualified listeners. I do not have the most sophisticate day stem and haven't been able to perform reliable testing myself. I found this reporting convincing: 24/192 Music Downloads are Very Silly Indeed "Empirical evidence from listening tests backs up the assertion that 44.1kHz/16 bit provides highest-possible fidelity playback. There are numerous controlled tests confirming this, but I'll plug a recent paper, Audibility of a CD-Standard A/D/A Loop Inserted into High-Resolution Audio Playback, done by local folks here at theBoston Audio Society. Unfortunately, downloading the full paper requires an AES membership. However it's been discussed widely in articles and on forums, with the authors joining in. Here's a few links: The Emperor's New Sampling Rate Hydrogen Audio forum discussion thread Supplemental information page at the Boston Audio Society, including the equipment and sample lists This paper presented listeners with a choice between high-rate DVD-A/SACD content, chosen by high-definition audio advocates to show off high-def's superiority, and that same content resampled on the spot down to 16-bit / 44.1kHz Compact Disc rate. The listeners were challenged to identify any difference whatsoever between the two using an ABX methodology. BAS conducted the test using high-end professional equipment in noise-isolated studio listening environments with both amateur and trained professional listeners. In 554 trials, listeners chose correctly 49.8% of the time. In other words, they were guessing. Not one listener throughout the entire test was able to identify which was 16/44.1 and which was high rate [15], and the 16-bit signal wasn't even dithered! Another recent study [16] investigated the possibility that ultrasonics were audible, as earlier studies had suggested. The test was constructed to maximize the possibility of detection by placing the intermodulation products where they'd be most audible. It found that the ultrasonic tones were not audible... but the intermodulation distortion products introduced by the loudspeakers could be. This paper inspired a great deal of further research, much of it with mixed results. Some of the ambiguity is explained by finding that ultrasonics can induce more intermodulation distortion than expected in power amplifiers as well. For example, David Griesinger reproduced this experiment [17] and found that his loudspeaker setup did not introduce audible intermodulation distortion from ultrasonics, but his stereo amplifier did."
Thank you enfield. As I understanding from your post and other I've read on other websites what 1 bit converters do is accelerate the data from the CD (th DSDat's the difficult part of the process) and then use the resulting 1bit digital signal to define audio waves both on the amplitude and time domain. The more 1's, the higher amplitud, that makes filtering easier. As the only one resistor has to open and close at an extremely fast speed, that creates noise but noiseshaping comes to the rescue. That is the basis of SACD's DSD, but I honestly don't know how DSD achieves a higher Signal to noise ratio, higher dinamic range and an extended frequency response, all I know is that I like how DSD sounds and as many have said and I agree with them DSD is the most analog sounding of all digital systems.
This thread makes me want to make a recording of the CD played in analog from my HDCD capable CD/DVD player to my Emu 1212m computer sound card that I use for needle drops and a 16 bit rip from the CD.
My first CD player was a Pioneer, bought in 1987 and it was only okay. I didn't try the green pen but I did use another "technique" which was popular at the time - namely placing a second CD on top of the one playing. It was supposed to improve bass and smooth out harsh treble. I did notice an improvement, I must admit, but I soon got rid of the Pioneer and bought a better player.
Ever hear of confirmation bias? Well, it works both ways. If you believe something, you will seek out information that confirms your beliefs.
@Grant, yes, I am familiar with confirmation bias. In this case, 24/192 Music Downloads are Very Silly Indeed , I thought that a decent argument was made. Of course, more samples in different environments may yield contrary results. I'm sure that you hear a difference and as I wrote, I don't have the equipment, HIREZ files, nor experience to discriminate a difference.
Please tell me you're joking. It's silly when analog people try to treat digital media like it's analog. Nothing you do to a CD will make it sound better.
This point has been made for many years, but I never understood the logic. Assuming intermodulations (basically beat frequencies) between ultrasonics and audible sound are a thing, it still doesn't mean an audio system has to relay ultrasonics. Because if these intermodulations do exist, they must also occur in the microphone membrane making the recording, and will thus be faithfully recorded by a system limited to 20 kHz.
Well, this was back in 1987 and I had been using vinyl since 1963 so the concept of digital information was new to us all. I know now that bytes are bytes but "piggy-backing" (as we called the placing of a second CD in the tray) did produce a different sound. Even though it was 30 years ago, I can remember that clearly and several friends agreed with me at the time. I can't explain it either. Maybe we were all silly.
You see, I don't agree with the articles you pulled up. They don't reflect my experience, either. And, if you don't have equipment, or know what to listen for, how do you know 24/96 downloads are silly? As I hinted: you want to believe hi-rez is silly, so you've sought out things that just confirm your beliefs.
I did not the write the article/webpage and don't endorse it's entitlement. I did not call HIREZ silly. I don't think that I have a bias either way, except that I do believe in the scientific method (if that is my bias) I am not disagreeing with you and was honestly asking for your insight As the topic is something that different people do not agree upon, I have searched out information upon the topic and the URL which I have linked to, appears to be very informative. You suggest that it was written with an agenda and I see that it does, but that hadn't dismissed the facts that I read in it. I am willing to agree that it is not conclusive about HIREZ being unfounded as better sounding. It would suggest that their specific testing did yield any reasonable difference. I did offer it up as a counterpoint to your statement, not necessarily as a challenge. I do not currently have the money for the equipment necessary to play HIREZ files. Therefore, I may be starting a GOFUNDME, so that before I engage in any further debate upon the topic, I will find out for myself. Because honestly, I think that it will be expensive to A/B accurately. Eliminating differences in mastering, loudness, and ensuring it is double blind seems like a bit of money. And I haven't had my hearing tested in a long time, so that might obscurely results.
