In our no-nonsense journey with the world of audio innovation we’ve so far have looked at digital audio as well as the vinyl disk recording. What’s missing? Magnetic tape, the once-ubiquitous recording medium that very first revolutionised the broadcast as well as recording markets in the mid-20th-century, as well as went on to be a mainstay of house audio before spawning the entire field of personal audio. Unless you’re an enthusiast or collector, it’s likely you won’t have a tape deck in your audio configuration right here in 2021 as well as you’ll most likely be packing your 8-bit games from SD card rather than cassette, however surprisingly there are still lots of audio cassettes released as novelties or ephemeral collectables.

The gadget That Made The noise Of The latter half Of The 20th Century

“Like a travelling razor blade”, a Blattnerphone steel-strip tape recorder at the BBC in 1937. Douglas Hallam, Jr., Public domain.
The very first magnetic recordings were made directly on metal wires, however metal fatigues as it bends. By covering a versatile plastic tape in ferrous particles, the exact same basic method of laying down an audio signal as variations in the magnetic field might be made smaller, lighter, as well as a lot more robust. however the crucial to the format’s runaway success is the technical improvements that differentiate those 1950s machines from their cable recorder ancestors.

Whether it is a humble cassette recorder or a top-end studio multitrack, all tape recorders are extremely similar. There are two reels that hold the tape: the playback reel that homes the recording, as well as the take-up reel that stores the tape as it plays in the machine. The take-up reel is lightly driven to run quicker than the tape speed, as well as the playback reel has a minor braking force to keep the tape under tension in any way times.

The pinch roller as well as tape head of a Sony cassette mechanism. Raimond Spekking, CC BY-SA 4.0.
If the tape is just pulled past the head by the force on the take-up reel, it will run at a variable speed dictated by the power on the reel as well as the radius of the tape spooled upon it. It’s crucial that the tape speed be kept constant, as well as this is accomplished by clamping it between a constant-speed turning metal roller as well as a rubber one. This pinch roller regulates the speed, with tape tension maintained on both sides of it by the reel drives. before the tape passes with the pinch roller, it passes by two or three magnetic checked out as well as compose heads. very first get in touch with is with an erase head, complied with by the record as well as playback heads. In some machines the record as well as playback are done by the exact same head. The heads have adjustable azimuth, which is set such that the space between the head’s poles is perpendicular to the edge of the tape.

Many tape recorders such as this Sanyo cassette deck had considerable switches to repurpose parts of their circuit between play as well as record. tony_duell, CC BY 2.0.
The recording as well as playback heads are both linked to audio amplifiers. In some affordable machines these two amplifiers are the exact same physical circuit reversed by indicates of the record/playback switch, however in high high quality recorders they will be separate. The erase head is driven by a high-frequency AC signal when recording, with the intent of eliminating as well as overwriting any type of previous recordings.

Magnetic tape is not a linear medium, indicating that the degree to which it can be magnetised is not linearly proportional to the magnetic field applied. however it does have a variety where it’s around linear, leading engineers to seek methods to keep the audio recording into the linear region as well as vastly lower the distortion. originally they utilized a DC bias with a fixed DC present streaming with the recording head, however later styles utilized an AC bias in which a high-frequency AC signal a number of tens of kHz higher than the audio signal is recorded together with it, the AC being inaudible on playback however having the impact of supplying a constant recording level to keep within the linear region of the tape’s magnetic properties. The AC bias is originated from an oscillator that likewise supplies the drive for the tape erase head, as well as whose frequency as well as level are set to different values depending upon the type of tape medium in use. different magnetic materials have been utilized in tape media including iron oxide, chromium dioxide, as well as finely split iron particles, as well as each of those has different magnetic properties as well as needs a different bias.

The noise reductions chips with the Dolby logo in a Yamaha cassette deck. Retired electrician, CC0.
Magnetic tape is an inherently noisy medium, to the degree that the whooshing noise of background noise is clearly audible in a tape recording. If you’re familiar with Dolby Laboratories it may be with their surround-sound encoding for motion picture theatres as well as house cinema systems, however it was in analogue recording noise reduction systems that they started. The original Dolby system was a set of filters applying companders (amplifiers with a logarithmic action meant to boost the dynamic range) to different frequency bands, which when reversed had the impact of minimizing the high frequency noise element of the resulting signal. The consumer version of this was called Dolby B, as well as it was a basic function of tape recording devices from the early 1970s onwards.

Which Tape Is The One For You?

A reel to reel tape recorder was seen as important sufficient to be created into the capsule apartments of Tokyo’s popular Nakagin tower. Dick Thomas Johnson, (CC BY 2.0)
For the collector, ther have been a multitude of esoteric tape cartridges as well as cassettes over the decades, however for the functions of a Hi-Fi system it’s likely that only two styles will be of interest. The reel-to-reel was the original tape recorder, having as its name suggests a pair of open reels of tape. consumer as well as lower-end expert reel-to-reel machines utilized 1/4 inch large tape running at a range of speeds, from 15 inches per second for broadcast high quality to 7.5 inches per second as a typical workaday recording medium, as well as 3.25 inches per second for speech recording. Its extreme simplicity of editing with a razor blade to cut the tape before splicing with special sticky tape made it a transformation in the broadcast world, as well as a few of us were still doing this in the 1990s.

Perhaps you’ll be a lot more familiar with the cassette tape, a style established at Philips in the 1960s as a dictation medium however which because of its popularity was established into a Hi-Fi medium as well as then with the success of Sony’s Walkman, to the genesis of portable music players. This style takes the two reels, miniaturises them, as well as encases them in a plastic cassette, with a 0.15 inch large tape consisting of four tracks in two stereo pairs moving at 1 7/8 inches per second. That the style might be established to the point at which such a low tape speed might supply what ultimately ended up being a high high quality system is a tribute to the work of the lots of engineers at the contending audio business of the age who pushed it to its limit.

A 30 or 40-year-old cassette deck will still noise good, as well as expense you far less than you’d think. waterborough, Public domain.
If you hadn’t looked at a tape recorder much a lot more than as a novelty had by an older relative, then we hope you’ve discovered something of interest. maybe you’d like one for your own stack, as well as surprisingly it’s still possible to get brand new cassette recorders in 2020. however while cassette player mechanisms were when produced to a extremely high basic by high-end makers for their own products, now there seems to be only a extremely little number of different mechanisms produced that appear in all new cassette players on the market. There’s a top-loading system that appears in all AliExpress Walkman clones, in addition to a slot-loading one that can be discovered in whatever vehicle cassette players stay available. The Web will tell you that they are clones of mechanisms made by a Japanese business called Tanashin, makers of budget plan mechanisms up until 2009, as well as the general consensus is that they are of a extremely low quality. We would suggest trawling the auction sites as well as goodwill stores for a great high quality Hi-Fi deck from the late 1980s or early 1990s, getting a replacement belt kit, as well as discover exactly how to set up its tape head azimuth.

Tape recording is obsolete as well as perhaps even irrelevant for audio in 2021; why on earth would you discover it of interest? Its cultural impact. It’s fair to state that tape defined the noise of prominent musical production considering that the 1950s. music moved from set pieces that might be done live, to studio production masterpieces that depended on months of work to create a noise unachievable with instruments on their own, as well as this is since of tape. before the (tape) Walkman, listening to recorded music was a sit-down-in-the-living-room affair, as well as now we take portable music for granted. maybe a a lot more easily accessible tradition lies in a a lot more human plane, exactly how lots of of you have set up a mixtape? send your cherished a hand-crafted tape of your present musical choices, with a hand-drawn sleeve for the cassette case, as well as if you get one in return play it to death. “I set up a Spotify playlist for you” just doesn’t have the exact same sound to it.

After this sojourn into obsolete analogue audio we’ll be back on track with our next installment, as well as this time around it’s getting ideal to the heart of afew of the audio world’s a lot more doubtful claims. We’re going to look at cables.