We could talk about what comes after the S/H -- the A/D converter that turns that voltage into some number of bits, but that's just a question of how much signal to noise ratio you require. If 144 dB is enough for you, let's go with 24 perfect bits. If you think you can hear more, we can add more bits.
But that's a separate issue from the sampling. Now that we've sampled our audio at the insanely high rate of 10 GHz, so that for all practical purposes it's a continuous analog signal, we have to ask ourselves if such a high sampling rate is really necessary.
Mr. Nyquist proved that no, it's not. In fact, we only need to sample at twice the highest frequency of our input signal in order to EXACTLY reproduce it. Exactly means both amplitude and phase.
To determine how fast we must sample, we only need to know the highest frequency of our input signal, and we must intentionally attenuate (by a very large amount) anything above that frequency, to avoid aliasing.
I will grant you that there may be frequencies well above 20 kHz that matter to us, even if we can't explicitly hear them. We can define the audio band any way you like -- 20 kHz, 40 kHz, 60 kHz or whatever. But once we do that, and our sampler meets the Nyquist criteria, we then know with certainty that we can precisely reproduce the original analog signal -- both in amplitude AND in phase.
I have to disagree here.
The sound being picked up by the mic, amplified and then sampled is, in your example, two waveforms of equal frequency but differing phase. As you mentioned, that phase difference is what provides spatial cue information.
But an ideal sampler (sample & hold) does not average anything -- it simply takes a snapshot of the voltage at its input at a precise instant in time, at each active edge of the sampling clock. That sampling clock can be as fast as you want it to be, within the limits of technology or your budget.
At this point, we haven't digitized anything yet -- we've simply captured the analog signal (voltage) at discrete points in time, and held it at a constant value until the next sampling time. If that -- holding the value constant -- is troublesome to you, then lets increase the sampling rate so those sampling times are closer together. The faster we sample, the more closely the voltage held on that capacitor in the S/H resembles an unsampled continuous analog waveform. If I still haven't convinced you this is true, then let's increase the sampling rate some more. Nevermind 192 kHz or whatever, let's go for 100 MHz, or maybe 10 GHz. Now do you believe the voltage on that capacitor is for all practical purposes indistinguishable from a continuous analog waveform? Remember, this is audio, so the high end of its frequency spectrum is far lower than 10 GHz -- much closer to 20-something kHz in fact.
I’m 60. In my childhood I listened to 78s, 33-1/3s and 45s. I do not miss vinyl. I do not miss the snap-crackle-pop in soft passages, scratches that cause skips, the loss of high end, shorter sides sounding louder than longer sides which are softer, space consumption, wasted cardboard, the large display of mostly crappy graphics, dust collecting, moving a weighty vinyl collection up to a friend’s third floor apartment, warping and washing off beverage stains from last night’s party.
With the advancement in higher sampling rates and greater bit depths the sonic quality is greatly improved. Since I couldn’t find the old vinyl in my collection, I recently purchased a CD of “The Kingston Trio Live at the Hungry I” (circa 1959). I wasn’t sure what to expect. The re-mastering blew me away. The room tone was there. The frequencies, especially a sweet sweet bottom end. No loss of high end. No plastic nails scratching glass; a well-rounded sound. Except for clinking cocktail glasses, there was no noise; a thoroughly enjoyable listening experience.
This romance with retro stuff is nonsense. We are supposed to be moving forward with technology, not going backward. Vinyl was a stepping stone. Let it go. Anyway this fad with vinyl seems to have the marks of someone heavily invested in recycled vinyl (which is not as flexible as virgin vinyl) and related tools, and has created a need so they can unload and get rich.
I have a home studio with nice monitors connected directly to a computer using a studio oriented sound card (with very wide dynamic range). This setup is notable for price performance and because it creates an opportunity for digital room correction, which nowadays you can do with miniature computers.
The RME fireface is as close as anything to an industry standard. Echo Audiofires are notable for amazing value. These are products that are virtually indistinguishable from stuff that costs a lot more. Anything equal to or better than them will be fine.
The best audio recording I have ever listened to is a CD, "The Nightfly" by Donald Fagan of Steely Dan fame. This CD was in DDD format, which I assume meant that it was recorded digitally rather than converted from an analog recording. The sound is wonderful, at any volume, and far surpasses any vinyl recording I have ever heard. Gives me goosebumps!
Steve jobs is dead because he ate herbs instead of having surgery. He was never an engineer or a scientist. He never let facts get in the way of his feelings.
Analog 'warmth' is nice, but once you get used to high quality digital there's no going back. Its sad, but vinyl just sounds muffled now :(
"Finally, I have to chuckle a bit when I read "...I record my vinyl to digital format and it sounds better than retail CDs..."
Sound is subjective. So your chuckling really just goes to show how narrow minded you are.
Someone tells you something SHOULD sound better... and like a sheep you believe it.
The most obvious difference between vinyl and CD is the ability to reproduce frequencies above 20khz. Just because we can't hear those frequencies on their own doesn't mean they don't effect the frequencies we can hear. Those overtones may be the difference between the ear fatigue that CD listening causes and the smooth high end that a high quality analog playback system provides.
NASA's Orion Flight Software Production Systems Manager Darrel G. Raines joins Planet Analog Editor Steve Taranovich and Embedded.com Editor Max Maxfield to talk about embedded flight software used in Orion Spacecraft, part of NASA's Mars mission. Live radio show and live chat. Get your questions ready.
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