In today’s digital world, recording any sound you want is a piece of cake right? Well, why wouldn’t it be? The whole process can be done with just a click of a button. However, sound recording technology used to be way more cumbersome that it is now. Curious to find out more? Then you need to know what is analog recording all about!
The overwhelming majority of home recording enthusiasts and producers of this digital age, might not want to concern themselves with today’s subject. But if you truly have a passion for audio engineering, then I think it is important to understand the basics of early recording methods, and its limitations. Let us dive right into in!
Analog Recording – The Beginning
The technique that is used to record analog audio signals is known as analog recording. At the same time, it also allows recorded analog audio and video signals to be played back. The unique aspect of analog recording methods is that it actually stores signals as a “continuous signal” in or on the media.
Continuous analog audio signals that have been recorded may be stored as either a physical texture on a phonograph record, or a fluctuation in the field strength of a magnetic recording. This is the exact opposite of digital signal processing where analog audio signals are being sampled and then represented as discrete numbers.
Let us now go through the development of analog recording since the beginning:
- The Phonograph
- The Magnetophon
- Fidelity improvement
The first ever machine that is capable of capturing analog sound was invented in 1877, by the famous inventor Thomas Edison. Various elements that had been incorporated into his Phonograph would later become fundamental aspects of modern recording devices even to this day.
There are three main steps in a Phonograph’s sound recording process. The sound first enters a cone-shaped component called the microphone diaphragm. That sound will then cause the microphone diaphragm, together with a small metal needle that is connected to it, to vibrate. This causes the needle to etch a distinctive groove into a cylinder that is made out of tinfoil.
Sound playback is achieved by spinning the cylinder, causing the needle to follow the etched groove. This causes the needle, and the attached diaphragm, to vibrate. The vibrating diaphragm then creates a disturbance in the air, thus producing sound, much like the bell on any wind instrument. The final outcome of this process is an audible reproduction of the originally recorded sound.
The major drawback of the Phonograph was the physical contact between the small metal needle and the tinfoil diaphragm. The groove on the tinfoil would eventually wear down since the needle had to make continuous contact with it every time a recording was played back. This meant that the more often a recording was played back, the closer it is to being lost forever.
In 1935, inventor Fritz Pfleumer used the method of “electromagnetic recording” and further improved on it. Pfleumer had discovered that normal strips of paper can be coated with tiny particles of iron. These iron particles would allow the paper to be magnetized, in the same way as a steel wire, but without most of its limitations and problems.
When a coated paper strip passes under a recording head, varying patterns of magnetic polarity are created within the paper, which can later be played back. In order to achieve playback, the recording process had to be reversed. The pre-magnetized paper (which is eventually known as “tape”), passes over a coil, creating changes in magnetic flux.
These changes are then translated into an electric current, which can then be amplified, thus reproducing the originally recorded sound. The magnetophone records sounds using a process called electromagnetism, which is vastly different from earlier inventions such as the gramophone or the phonograph, where sound is recorded using a completely mechanical process.
The invention of the magnetophone eventually led to the development of “multitracking“, which occurs when multiple takes of a performance, recorded at separate times, are brought together to be played simultaneously. This is a recording method that all recording studios use to this day, in order to record various parts of a song, and get the best possible takes from all of the performers.
A reel of tape could also store up to thirty minutes of sound recording. This is a major improvement as compared to a Berliner’s disc, which could only hold a few minutes of recording, meaning that each disc typically contains a single song, or multiple short recordings. This development eventually gave birth to the concept of a music “album”, or collection of multiple songs.
All of the analog recording devices suffered from low fidelity sound. Inventors had been using a type of current called “DC” in electromagnetic recording devices, and they had not considered “AC” current. It just so happens that AC current contains higher frequencies than its DC counterpart, and those higher frequencies were the key in improving the fidelity of electromagnetic sound recordings.
Those high frequencies “shake-up” the magnetic particles on the tape in a desirable way, which led to the production of the first high fidelity sound recordings. Interestingly enough, this process known as “AC Bias” was actually discovered in 1940 by two inventors who lived in different parts of the world, and they were both unaware of each other’s discovery.
Well, that just about does it for today’s article. I hope you had some fun learning about the recording methods in the past!
Let me know your thoughts down below, and do share this with your buddies!