What is Analog Sound?
It’s impossible to understand the difference completely without understanding what distinguishes analog audio from digital audio. Here’s a brief explanation of what these two words mean, and the differences between them.
Analog
Analog recording, of course, predates tape — with everything from wax cylinders to wire being used to capture a performance. But when American audio engineer Jack Mullin discovered a pair of German Magnetophon machines during World War II, he knew right away he was on to something big. The format offered two major advantages over the acetate disks of the day: a recording time of more than 30 minutes, and the ability for recordings to be edited. It was the first time audio could be manipulated.
Mullin brought the two Magnetophons back home after the war and demonstrated them for Bing Crosby at MGM Studios in 1947. Crosby immediately saw the potential for prerecording his radio shows, and invested a small fortune of $50,000 in a local electronics company called Ampex to develop a production model.
Ampex and Mullen soon followed with commercial grade recorders. One of the first Ampex Model 200 recorders was given to guitarist Les Paul, who took the concept of audio manipulation to a higher level. Paul had already been experimenting with overdubbed recording on disks and, quickly realizing the potential for adding more channels and additional recording and playback heads, came to Ampex with the idea for the first multi-track tape recorders.
The format evolved from two tracks to three and four, and although Ampex built some of the first eight-track machines in in the late 1950s, most commercially available machines were limited to four tracks until 1966, when Abbey Road recording engineers Geoff Emerick and Ken Townshend began experimenting with multiple machines during the recording of Sgt. Pepper's Lonely Hearts Club Band.
Pioneers in these advanced analog techniques include Les Paul (credited with inventing multi-track recording and sound on sound techniques), The Beatles and the Beach Boys. At the time, four tracks were the maximum available-but creative audio engineers were able to use this to great advantage.
Sound on sound, or overdubbing, allowed for a previously recorded track to be played back while an additional instrument or vocal was added to the track. As recording machines added tracks, it became possible for these additions to be recorded on a separate track, eliminating the possibility of a bad sound on sound take ruining the master recording.
The Beatles and the Beach Boys were masters of bouncing, or dubbing down—a technique where three of the recorded tracks would be mixed down to one track, thus freeing up three tracks to record additional parts of the song. A variation on this technique used two four track recorders, the first would play back the four tracks to one track on the other machine allowing for three additional tracks to be recorded as accompaniment.
Punch in editing allowed for the musician or vocalist to ‘repair’ a bad section of a track. The tape would be played back and the engineer would punch the recording button, on the fly, at the beginning of the section to be recorded and punch out at the end of the section. The musician or singer would hear the old track in their headset up until the punch in point, at which time they would hear themselves live as they recorded the replacement section.
By the late 1960s, eight track tape machines were showing up in recording studios, allowing for additional complexity.
Even as analog recording evolved, it still had limits. The equipment was big and expensive. The number of tracks was limited. In theory, overdubbing and bouncing could allow for as many tracks as needed, in reality there were definite limits as each dub down or bounce degraded the audio signal. Additionally, if you wanted to create duplicates of your final mix for distribution on albums or cassettes they had to be done in real time. In other words, if you wanted to copy a three minute song it would take three minutes.
Perhaps the biggest advantage of the analog recording process was a byproduct of its limits. You really had to have your shit together before you started recording. You had to map out your tracks and plan accordingly.
Here’s a plan for a simple four track recording session.
1. Live on tape record the kick drum on track one, the rest of the drum kit on track two and the bass on track three.
2. Bounce these three tracks to track four. Now tracks one, two and three are freed up.
3. Playback track four while recording backup vocals on tracks one and two.
4. Bounce track two background vocal mixed with recording rhythm guitar onto track three. Now track two is freed up.
5. Bounce track one backup vocal mixed with recording lead guitar onto track two. Now track one is freed up.
6. Record lead vocal on track one.
7. Mix down the four track: track one lead vocal, track two lead guitar and backup vocals, track three rhythm guitar and backup vocal, track four bass and drums. Lead vocal, bass and drums (tracks one and four) panned to center; guitars and backup vocals (tracks two and three) panned to the sides—one to the left, one to the right.
With the prevalence of home and project studios and digital technology in the late 1980s and 1990s, a number of other tape formats emerged, including various multitrack on-reel and cassette configurations as well as multiple digital tape formats. But for the sake of this article, we'll focus mainly on multitrack analog tape, the most sonically revered recording medium of all time.
Digital
Then along came digital audio with unlimited tracks and built in effects. Compression, EQ and echo/reverb and other modern day “plug ins” were developed for analog audio recording. They were stand-alone cumbersome and somewhat limited “black boxes”, or in the case of an echo chamber they were a physical room with acoustics designed to create delay. Today, they are almost always included in any DAW and extremely versatile in their capabilities. This allowed musicians and singers to have the luxury of unlimited overdubbing with precise punch in and punch out points, processed effects at their fingertips, and a wide range of electronically produced sounds and beats. Whether this lifting of analog’s technical limits has led to better music is another story.
Can you see the difference?
Analog refers to a continuously changing representation of a continuously variable quantity. Digital, however, refers to representing these variable quantities in terms of actual numbers, or digits. The last two sentences seem a bit complex, but let’s try to simplify them with an example. If you consider the numbers 1 and 2 on a number line, there are actually an infinite number of points between 1 and 2. This is what analog represents—the infinite number of possibilities between 1 and 2. Digital, on the other hand, only looks at certain number of fixed points along the line between 1 and 2 (for example, 1 ¼, 1 ½, 1 ¾, and 2).
Digital takes a few “snapshots” of the number line, while analog takes the whole line into account.
As another example, think of analog vs. digital as the difference between seeing something in real life and watching it on film. When we see something happen in real life, there are no “spaces” between what we see, so we’re watching it happen in analog. Film, however, is actually a series of still photographs that are taken in rapid-fire intervals, and when we see them in succession, it tricks our minds into thinking we’re seeing a continuous flow of movement. So in a manner of speaking, when we watch the event happen on film, we’re watching it digitally, because we’re watching increments of the event, rather than the whole thing in fluid motion. (Not to be confused with digital video vs. film, which is another discussion completely!)
A purely analog recording would be something that was recorded on tape and produced using manual equipment to mix, master and press into a vinyl LP. A purely digital recording would be recorded on a computer program such as Pro Tools, mixed, mastered and produced digitally, and eventually burned onto a CD as an MP3 or audio file.
Fidelity sound
The most ironic aspect of the debate about digital vs. analog recording is that nowadays a lot of music is a combination of the two.
For example, you might record a song onto analog tape, but mix and master it digitally, or release it on the Internet as an MP3.
So what’s the difference in quality between analog and digital? The idea between digital recording is that our ears and brains technically can’t determine the spaces between the digital values, just like our brains interpret film as continuous motion. However, to many people, analog sound tends to be warmer, has more texture and is thought to capture a truer representation of the actual sound. Digital is felt to be somewhat cold, technical and perhaps lacking in analog’s nuance.
Cost:
Digital is much cheaper. Recording an album with analog technology can require a whole studio full of equipment, but with digital recording technology, it’s possible to record a whole album in a bedroom on a laptop.
Whereas analog technology can wear out or be damaged, digital media can last for an indefinite length of time.
Today many recording artists, both major and independent, record using a mixture of digital and analog techniques. While analog audio does give warmth and a truer sound quality, digital is cheaper to work with and offers more control over the finished product. It’s amazing that artists could and still do so much with so little.
