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Understanding Analog & Digital In Terms Of Audio

Neither is "better" or "best" -- an uncolored look at the underlying simple truths of both formats...

By Bruce Jackson & Steve Harvey June 26, 2018

Zeroes & Ones

Simply, the numerical representation of a slice of audio frozen in time could be either above or below a threshold. There are just two choices: on or off. The resulting one-bit audio would sound like a nasty guitar fuzz box.

Greater precision in measurement leads to more faithful reproduction of the sound we wish to preserve. We could choose to record sound as a stream of numbers using our familiar decimal system, based on our 10 fingers.

But digital electronic circuits are much more comfortable with the binary system of counting, where instead of 10 different levels there are only two, represented by zero and one.

The string of numbers flip by like the frames of a cartoon to create the illusion of a continuously variable analog of the original sound. The faster the pictures flip by every second and the better the picture quality the more realistic the illusion of movement in the cartoon, and so it is in audio, where a higher sampling rate and longer word length results in better quality digital audio.

When we put up a microphone and create an audio signal chain between the natural sound and what comes out the other end, we are putting our faith in the equipment manufacturers.

Just as we have a palette of choices in creating that signal chain, manufacturers have a broad palette of components to choose from when creating the piece of equipment that we choose to run our sound through.

While the equipment designer is picking just the right resistor, capacitor, or digital signal processor, he has to keep in mind a slew of constraints placed on him, such as reliability, end cost to the customer, support, appearance, and so on.

Regardless of using resistors (analog) or chips (digital), the designer still has a slew of constraints of which to be aware.

So a lot of the talent a designer brings to a product is the ability to make the right balance of compromises to deliver a cost-effective solution for the customer. And this is what makes one product or technology a better choice than another. So where do they go right and what are the traps?

Playing The Numbers

More is better, right? In our society, we tend to be impressed by bigger numbers. If 16-bit audio sounds better than 8-bit audio, then 24-bit audio must sound even better.

Manufacturers wow us with science. They tell us that their analog to digital converters have 24-bit performance.

A simple engineering rule of thumb says that we get about 6 dB of signal-to-noise improvement with every bit we add. This means that 24-bit audio has a dynamic range of six times 24, or 144 dB.

Yet when we read the specs, we’re lucky to see 118 dB out of a so-called 24-bit converter. So the difference between the claim of 24 and the reality of not even 20 is called “marketing bits.” They are in there to make you and I believe we are getting something more.

Dynamic range is just one measure of performance. Other measurements, such as distortion, similarly fall short of the claimed number of bits.

So our 24-bit converters are really 20-bit converters. But 20 bits is still impressively good when you consider dynamic range—the difference between the loudest sound and the noise floor.

But these are just measurements. Unfortunately, measurements aren’t always a true indicator of how something is going to sound.

Often we find that a piece of gear sounds great even though its specs leave something to be desired. The key is clean conversion in and out, and numeric precision once inside the box. Once digital equipment designers have transferred the analogue audio into their digital world, they use math to manipulate the sound.

Functions such as EQ involve repetitive processing of numbers. If the digital circuits don’t maintain enough precision, noise and distortion can creep into the pristine digital audio.

It’s like balancing your checkbook. If you only paid attention to the dollars and ignored the cents, your balance would be off by more and more each month. The rounding-off to the nearest dollar causes a bigger and bigger problem the more you do it.

Whether it’s the digital signal processor in your digital console or the hardware in your laptop, care has to be taken not to allow the small rounding errors to creep up on you and cause noise and nasty distortion.

And here’s where we encounter a fundamental difference between analog and digital audio: There’s good distortion and there’s bad distortion.

Good & Bad

What sounds “good” depends upon whom you ask. That is, it’s a subjective matter to a great extent. Those firmly in the analog audio camp point to an indefinable emotional impact inherent in non-digital sound.

The common observation: vinyl is “warm” and CD is “cold.” But is this accurate?

Audiophiles and purists still prefer the open and natural sound of recordings on vinyl, for example, when compared to what they consider the harsh, cold, or unemotional sound on compact discs.

But what is the accepted norm also plays into the equation.

The audio world is transitioning to digital at a rapid pace. In post-production and music recording, two areas that were among the first to make the digital transition, the entire process, from ingestion of the source material to outputting the finished product, can take place entirely within the digital domain.

The television and radio broadcast industries have also been busy making the transition to fully digital operation over the last few years.

The last bastion of analog audio is live sound. But there, too, over the last few years, the tools have begun to emerge that have allowed engineers to set up systems that, except for the transducers at either end of the signal path, are wholly digital.

Arguably, beginning with the widespread availability of CDs during the 1980s, there has been a widespread acceptance of digitally delivered music as being perfectly satisfactory, even preferable to analog methods.

Yet analog in the 1960s, ‘70s, and ‘80s seemed somehow more pure, within the limits of the available technology.

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Kevin Chand says

Digidesign, now there's a name I know and love (and don't exist anymore). Good primer article. Please like my facebook page @thenexusllc :D

HalfSpeedMastering says

the laws of physics forbid reaching 0 or 100%, No power supply will ever be 100% efficient, today the best are 94%-96%, Science has never reach 0° temp, it can get close, but never 0°, also OFC copper cables: 99.9999997% 8N copper, but Never 100%., Gold Bars: 999.9 Never 100,0 Digital Nyquist degrades with frequency. at a SampleRate of 44.1Khz, a Square wave lower than 5.5KHz is very close to 100% emulation, the lower the closer, but over that frequency becomes less & less accurate, a 20KHz square wave, looks near 100% distortion or Near 0% emulation at 44.1KHz SR.
digital is an emulation, & plugins are an emulation inside an emulation. assuming the best plugin manufacturers have an emulation 95% perfect, in some cases that extra 5% will be 10x the price.. plugin vs. hardware.
is Not the same A/B: analog vs. digital, vs. analog digitized.
is it worth that 5% of digitized analog? depends on the listener, wax level on the ear, loudspeakers, DA, cables, power, etc... some people wont hear a 5% difference... others hear a night & day... depends on the day, the ear gets tired, like muscles, some days i hear night & day, some days i hear my pocket. LOL.
most plugins are designed to be transparent sounding, makes real analog sound Dated/old, but HW can be modified to sound transparent ...
HW cannot be bounced faster, must be realtime, for some jobs thats No Go.
EQ´s can be emulated very close, some analog noise floor without power cleaners is around 18-bits Dither Apogee, most AD&DA are 20-Bits noise floor, but HP&LP filters, Compressors, Tape & Tube equipment are Not as close, example: all 12ax7 brands sound a bit different, they change organically, like moving waves, most digital emulations are like a photograph of that moving sea of electrons breathing, CPU power vs. accuracy curve, 1% more accurate is usually 100% more CPU. HW is a lot more expensive, people buy plugins 1st, then make A/B test to compare, to find the sound they are looking for, its like pizza, the same pizza tastes different in different stores, but some brands are very similar.... some brands have a unique pizza, that is what most people "that hear a Night&Day difference" are looking for.
because HW is more expensive, makes more sense in Mastering...

HalfSpeedMastering says

also there is another problem, HW emulations are usually besed on different Hardwares, and HW have component tolerances, cheaper components have a high tolerance +/-20%, but precisión components have a 1% or less tolerance, the same resistor can be $1usd or $1000usd. each... age, different ac power, component tolerances can make the same HW sound very different, with some exceptions.. rare fairchild compressor are so rare that plugin developers usually rent the same unit, to make the emulation, but different ac power, different converters... Also there is the quote: using right tool for the right job, a single screwdriver cannot do it all... for rap & pop vocals a medium to high THD equipment is more desired tan ultra low THD equipment... more dynamic, or less dynamic, more transparent, or more colored/less transparent, selecting a swiss army knife or hand picking HW to make your own signature sound, that defines your brand/taste/personality, is not purchasing for purchasing, like John Deere vs McLaren/Lamborgini, one is slow, the other fast. LOL. having the right tool for the job is very important... for example MCI jh-426 mic-pre sound very unique, that sound is very interesting for some music styles, but dull for others... having all the tools in HW is very expensive, but in plugins is very easy, for mastering a signature sound or a transparent sound, some music styles sound alien with the wrong color/tool. running in high heles, or using lamborginis in the farm, is just wrong. LOL...

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