- Audio & Video
What is Digital Recording?
What is the Definition of Digital
Digital is the process by which music, video, or spoken word is recorded using computers and software which in turns captures the sound and images by the process of sampling or capturing a portion of the audio spectrum over a given period of time. Digital recording is also referred to as digital audio and digital video which is recorded directly to a storage device or media in the form of discrete numbers, 1's and 0's which represent a binary code representing changes in air pressure i.e. sound and in the case of video chroma and luminance values over time. The result is an abstraction template of the original sound or moving image.
While analog audio i.e. sound is composed of a continuous wave shape or frequency it must be converted into a binary stream of discrete numbers, that represent the changes in air pressure values over time in air pressure for audio, and chroma and luminance values for video. The SPARS code was developed in the 1980's to describe the processes of analog and digital used in the recording, mixing and mastering of music. SPARS is an acronym for the Society of Professional Audio Recording Services. The SPARS code is a three-letter code that appears on Compact Disc recordings telling whether analog (A) or digital (D) equipment was used to produce the recording.
- An analog signal is transmitted from a input device to an analog-to-digital converter (ADC).
- The ADC converts the signal by repeatedly measuring the momentary level of the analog (audio) wave and then assigning a binary number with a given quantity of bits (word length) to each measuring point.
- The frequency at which the ADC measures the level of the analog wave is called the sample rate or sampling rate.
- A digital audio sample with a given word length represents the audio level at any one given moment.
- The longer the word length the more exact the representation of the original audio wave levelwise.
- The higher the sampling rate the higher the upper cutoff frequency of the digitized audio signal.
- The ADC outputs a sequence of samples that make up a continuous stream of 1s and 0s.
- These numbers are stored onto recording media such as magnetic tape, hard disk drive, optical disk drive, or solid state memory.
- The sequence of numbers is transmitted from storage into a digital-to analog converter (DAC), which converts the numbers back to an analog signal by connecting together the level information stored in each digital sample, and rebuilding the original analog wave form.
- The signal is amplified and transmitted to the loudspeakers or video screen.
The hard part of recording the Bits
After getting the signal converted to bits, it is still difficult to record: the hardest part is finding a scheme that can record the bits fast enough to keep up with the signal. For example, to record two channels of audio at 44.1kHz sample rate with a 16 bit word size, the recording software has to handle 1,411,200 bits per second.
Tom Dowds Opinion of Digital and Analog
One of the greatest engineers of all time Tom Dowd said in his documentary "the language of music: Tom Dowd" that he still tracked on 24 analog, but then he would transfer everything once done over to digital. He praised the new technology because it allowed for greater flexibility in editing, mixing, and mastering after the fact, and he said that he really loved the automation and instant recall features of digital. In the old days you would have pull out the charts and redo all of the original settings and patch work if you wanted to return to a previous mix of a song. This process could take quite a lot of time to set up, and studio time is both precious and expensive. In digital you just push a button and your mix, patches, and setting are all instantly recalled voila!
Analog and Digital the Differences
Analog allows you to push the envelope an go for the much treasured tape saturation, and digital is totally unforgiving about anything pass 0db and there are no exceptions to this rule. Digital recording has gotten better over the years due to greater oversampling and higher frequency e.g. 16 bit became 24, 32, 48. but these higher bit rates also meant that files sizes were increasing exponentially also. Now as digital bit rate sampling got closer to 96khz and 192khz respectively the sound got a lot closer to analog, and of course came along the plug-ins that emulated tape saturation and the analog sound using algorithmic code, but thats a whole other conversation in itself. Both platforms offer advantages and disadvantages, but to the human ear and soul nothing beats the sound of analog. In the end its all about the technique and experience on the part of the recording engineer to capture the sound to the best of his ability so that the highest quality sonic experience can be expressed.
The Comb Effect
The average user is not likely to have a super high end 192khz recording system to achieve that analog like sound in their digital recordings, and last time I looked CD's still were recorded at 16bit, which leads us to another phenomenon in digital recording called the comb effect. Simply put you are going to lose a lot of the sound you recorded once you start going backward in bit rate, much like a comb going through your hair has a lot of you hair on it after your done combing.
And until consumers stereo systems become affordable enough to raise the bit rate bar from 16bit to a bit rate that would be more analog sounding, analog will always rule as the better sound. Digital is clean and perhaps to clean for some purist, and analog is warm and fuzzy, or perhaps I should say cozy.
There is the HD band wagon that everyone seems to be jumping on which in fact does offer a whole lot more quality in the digital domain, but how many records are reproduced in that format and where are the consumer products to playback such recordings, never mind the cost of buying such a finished product to the average consumer. Yes digital has made it possible for more people to get in on the recording scene without spend obscene amounts of money in the process, and it may seem to a newer generation that analog has seen its heyday.
But if you have never tasted analog, the matrix will tell your mind that your digital recording is both tasty and delicious and that ignorance is bliss. Me personally
I will always have a warm place in my heart and soul for analog, may it live long and prosper.
If you are editing digital beats a razor blade and tape any day of the week. although using a razor was and is an art in of itself. But digital as far as recording goes has limitations it can never overcome, and it will always only be as good as what you put in it in the first place. Experience and technique are the keys to a really great digital recording. The real benefits of digital is that you can rewind endlessly without worrying about wearing out the magnetic particles associated with tape, although I still have cassette tapes from nearly 40 years ago that I can still play today, and the quality hasn't diminished one bit, but that comes from good equipment being used and cared for over time.
If you are mixing, editing, or even mastering for the today sound or even for the golden age of analog recorded music. Digital is the way to go and I think that no one disputes this fact, I mean digital is where were headed technologically as innovators without a doubt. But when it comes down to tracking music analog will always be king.
The Myth of Digital
The biggest myth of digital really concerns speaker and monitor systems. The fact is that digital works on a system of 1's and 0's and there is no way around this, but the human ear doesn't hear 1's and 0's. And speakers don't create sound by 1's and 0's either. Both the human ear and speakers create and hear sound by moving AIR, which in turn translates that in to frequencies that can be interpreted as sound. The speaker cone creates air pressure, the air pressure moves the ear drum, the ear drum translates that air pressure into sound waves and frequencies that represent sound.
So no matter how much you want to digital will always have to defer to the mechanics of sound as we know it. And the real reason why most people prefer analog to digital is because we as humans, have the ability to realize that in digital something seems to be missing. In other words a lot of the sound picture has been comb out by the bit rate of the oversampling algorithmic process.
A Lost Art and the Best of Both Worlds
The other reason why many people feel like digital sounds good to them is the fact that much of music today is recorded using digital instrumentation and virtual instruments that emulate analog gear and instruments. Very few recordings in modern music are the result of a band or orchestra playing live in a studio. This not true of all music but for the most part it is, an the act of recording live players is almost a lost art except in certain genres of music where live musicians are actually playing instruments in a room, or on a stage. And yes there are things that can be done by digital that could never have been done using analog alone.
So its about using the best of both worlds to get the best possible quality in the end. Analog and digital can walk hand in hand into the sunset.
Scenes from The Language of Music
- Tom Dowd and the Language of Music - Home
Tom Dowd was a musician, engineer, producer, physicist, mathematician, and everyday genius. Along with Eric Clapton he discusses how the album Layla and Other Assorted Love Songs came together with Clapton, Duane Allman, and Derick and the Dominos.