What Are The Most Important Specifications of a Cassette Tape Deck?

Whether a fist time buyer or a seasoned cassette tape archivist – what are the most important specifications of a cassette tape deck?

By: Ringo Bones

Given that the “lowly” cassette was the only egalitarian music medium for the budding audiophile back in the mid 1980s, it is easy to say that most of us have his or her own view when it comes to what specifications make a great cassette tape deck. But if you ask me, what I will rank from the most to least important goes as: (1) frequency response, (2) wow and flutter, (3) signal-to-noise ratio, (4) speed accuracy and (5) distortion – although some audiophiles may rank distortion higher as the most important specification.

Frequency response that’s flat- i.e. within ±3dB - and extends from 30-Hz to 18,000-Hz – could be considered impressive. But you should pay attention on how flat the response is, a frequency response specification of ±6dB is not impressive. However, if the specifications were ±3dB and applied to a range of 30-Hz to 16,000-Hz would be considered acceptable. Better still would be a much flatter range of ±2dB over such a frequency range. A high frequency range that extends to 19,000-Hz instead of just 16,000-Hz will not make an important difference to most listeners – especially “older” audiophiles. 

The wow and flutter should measure no higher than 0.05% peak. Although, people who are more sensitive than others when it comes to wow and flutter might require a tape deck with better specification in this department– i.e. 0.025% or lower.

The signal-to-noise ratio should be at least 75dB or better when using Dolby C noise reduction. And the deck should offer better S/N ratio results when a more advanced noise reduction system is used – like Dolby S.

Speed accuracy that that will deviate no more than 0.5% from correct speed. While some engineers consider such deviation in pitch is inaudible to most people, vinyl LPs are mastered on a device whose pitch deviation is under 0.2%.

Low distortion is of vital importance, especially if you exclusively play recorded acoustic instruments because it is much easier to hear distortion creeping in with a violin recording – than with a Gibson Les Paul played through an overdriven Marshall stack.

Why Cassette Tapes Aren’t Magnetically Shielded?

Given their propensity to go dull whenever they are accidentally placed near magnetic objects – even magnetic screwdrivers - why aren’t cassette tapes provided with inherent magnetic shielding?

By: Ringo Bones

Unlike your Barclay-Crocker prerecorded Open Reel tapes that came in mu-metal cans as standard, prerecorded cassette tapes back in the 1980s and even well into the 21^st Century doesn’t come with protection against erasure when accidentally placed against a strong magnet like refrigerator magnets and electric guitar pickups and electric bass guitar pickups. And if you Google search cassette tapes that are magnetically shielded, you are directed into Google’s lists of invented patents stating that the tiny nickel plated piece of steel behind the pressure pad functions as a “magnetic shield” for the cassette tape. Given that this concern was largely ignored by the leading cassette tape manufacturers during the format’s lifetime, is it even possible to magnetically shield cassette tapes against erasure and loss of high frequencies when accidentally placed closed to magnetic screwdrivers, fridge magnets, and electric guitar and electric bass guitar pickups?

Back in 1979, the world’s leading cassette tape manufacturer TDK released their MA-R series of cassettes and they were the top of the line of the company’s Type –IV metal particle cassettes. The tape formulation used is based on TDK’s patented Finavix particle. It’s very heavy and its metal shell construction – later revealed to be an aluminum-zinc alloy – has the potential to be made with an actual mu-metal alloy capable of actually provide magnetic shielding for the cassette housing instead of just a vibration reduction measure. Sadly, given that these were top of the line in the TDK’s range of cassettes, they were also very expensive. From the 1980s through to the 1990s, TDK’s MA-R series of metal particle cassette often carry a retail price of around a dollar and a half to two dollars less than a price of a compact disc - which for all intents and purposes just too high a price to pay for a blank cassette tape. This largely explains why I totally abandoned prerecorded cassette tapes in the mid 1990s when the “relatively affordable” Marantz CD-63 Ken Ishiwata Signature model entered the market. 

Avilyn Magnetic Particles: The Greatest advancement In Cassette Tape Development?

Though now largely forgotten, did the Avilyn magnetic particles represent the absolute zenith of cassette tape advancement?

By: Ringo Bones

This substance has now virtually become an “alien technology” for those born way after the heyday of the cassette tape. But back then, this represented the value-for-money in cassette tape technology terms when it comes to sound quality. Besides the more expensive metal particle tapes, cassette tapes that use Avilyn magnetic particles are probably the closest yet to sounding like professional open-reel tapes. Stranger still, Avilyn magnetic particle technology has its origins way before cassette tapes become a runaway commercial success in the 1980s.

Developed as a high coercive magnetic particle developed for sound and video recording back in 1974, Avilyn is an acicular magnetic iron oxide on whose surface certain cobalt compounds have been adsorbed. The coercive force of the particles is determined by the amount of cobalt and other preparing conditions, and is controllable between 450 and 800 Oe (Oersteds). The particles display much improved thermal stability with respect to remanence and coercive force. The new video tape having a coercive force of 550 Oe is compatible with chromium dioxide video tape in recording characteristic according to measurements on a conventional video tape recorder. The head wear rate of the new Avilyn tape is about one-fifth that of chromium dioxide tape and is almost the same as for conventional iron oxide tape. Tape demagnetization is not as serious as is in the case of cobalt-doped gamma ferric oxide tapes.

During the 1980s, Avilyn was mostly used in TDK’s high-bias Type-II cassette tapes and VHS video tapes. TDK also produces Avilyn open-reel tapes for professional studio recording use at the time when 16-bit digital audio recording technology was still in its infancy. Sadly, during the early part of the 21sr Century as the prices of recordable compact discs and associated equipment came tumbling down and availability increased, everyone’s love affair with the cassette tape slowly waned.

GoldStar Blanks Cassette Tapes: The Best Value for Money Blank Cassette Tapes of the 1990s?

Even though the company has since renamed itself did GoldStar managed to manufacture the best value-for-money blank cassette tapes back in the 1990s?

By: Ringo Bones  

Now known as LG, the South Korea based GoldStar managed to build one of the best value-for-money consumer electronic and data storage media products back in the 1990s. Even my 14-inch GoldStar color TV model CN-14A146 with serial number 60514212 that was bought back in July 1995 still works to this very day. And did you also know that GoldStar managed to manufacture value-for-money blank cassette tapes whose performance were comparable to that of up-market TDK and Maxell blank cassette tapes during the 1990s? 

Even though TDK Type-I ferric blank cassette tapes were the most widely available here in South East Asia during the 1990s, many audiophiles preferred GoldStar’s series of blank cassette tapes because they are on average cost one-fifth as much as equivalent TDKs. TDK’s D series of Type-I normal ferric cassette tapes normally sell for around 1 US dollars each back in the 1990s, GoldStar’s HR series of Type-I normal ferric cassette tapes on average sell for around 20 US cents each – only voices grade cassette tapes destined for phone answering machines were cheaper – but Goldstar’s HR series of cassette tapes like their GoldStar HR60 (60-minute) and GoldStar HR90 (90-minute) cassettes managed performance that’s comparable to TDK’s higher spec normal Type-I ferric tapes like their TDK AD and AR series of  Type-I cassette tapes. 

And during the mid 1990s, GoldStar blank tapes managed to make your cassette tape equipped car stereo and Walkmans sound like the famed Marantz CD 63 SE Ken Ishiwata signature model if you placed a GoldStar HR series of normal blank cassette tapes on an audiophile quality cassette tape deck – these start at around 150 US dollars each brand new back in the mid 1990s – and record from a good value for money CD player like the famed Marantz CD 63 SE KI Signature. And GoldStar also manufactured value-for-money Type-IV metal particle cassette tape like their GoldStar MTX60 and MTX90 series of cassette tapes during the 1990s and they too cost one-fifth as much as comparable TDK metal tapes.      

Tips For Recording A Loud Hair Metal / Heavy Metal Bands Onto Cassette Tape?

Given that cassette tape, as a recording medium, has inherent limitations in the low and high frequency extremes, would you still be able to record good loud hair metal tunes on it?

By: Ringo Bones 

Whether from a live band or from a “realistic sounding” open-reel analog master tape, the lowly compact cassette really has inherent limitations when recording very low and very high frequencies at very loud levels. And yet during the heyday of hair metal – between 1980 to 1992 – recording studio mavens managed to make a significant number of recordings that managed to sound very good on the lowly cassette tape which during the time, was still the dominant recording medium and it wasn’t until the mid 1990s that CD players that can be described as both affordable and good sounding entered the market. Maybe it’s just for nostalgia, but here are a few tips on how to record a loud hair metal band onto cassette tape and make them sound relatively pristine. 

Of all the cassette tape recording tips, the one that’s frequently overlooked is that audio cassette tapes can have a hard time handling very high and very low frequencies. In the low end, the lowest bass notes like the open E-string form a bass guitar – at around 40 Hz – can cause distortion if the level is too high. In the high frequencies, sibilance or “sss-sounds” can cause tape distortion via high frequency saturation so using a de-esser helps keep things under control during mastering onto cassette especially if the open reel master tape was recorded at 30 inches per second with gobs of very loud and pristine high frequencies. If you are already saturating cassette tapes from excessive high frequencies, boosting your high frequencies to create a ” brilliant timbre” cassette recording will only cause more trouble. 

One tricked employed by 1980s era heavy metal bands in recording onto cassettes that resulted in a “brilliant” sound without resulting in distorted high frequencies is by mixing in more presence in the upper midrange / lower high-frequency range – from 2,000 Hz to 6,000 Hz – to mask the tape hiss of low-cost Type-I ferric cassettes. Giving more space between the microphone and acoustic guitars and cymbals will definitely help – especially back in 1989 where acoustic electric Ovation guitars with built in equalizers that were then in vogue when hair metal era heavy metal bands record power ballads often produce enough high frequencies to saturate Type-I ferric cassette tapes with ease.  

When recording your master tape onto cassette, use a multi-band peak limiter with a built-in pre-emphasis before limiting, like the Behringer Combinator or Aphex Dominator or a high frequency limiter. The resulting cassette will be more open-sounding without sounding unduly dull in comparison to its open-reel master tape. Using a good high-pass filter to roll off very low frequencies definitely helps because cassette tapes tend to compress when recording signals below 50 Hz or so. Even up-market Nakamichi cassette tape decks produce “horrendous” harmonic distortion readings below 50 Hz. 

Use a device that adds brilliance only to low-level signals. That is what Dolby B does in its encoding stage. The higher the input level, the less high-frequency boost Dolby B gives. The widely used cassette tape recording “plug-in” called the Aphex Aural Exciter with its “Big Bottom” mode and similar devices work similarly by adding low levels of high-frequency harmonic distortion. This is tricky because you generally want to push the cassette tape as loud as possible just to the cusp of distortion and saturation, but if you already have distortion in your mix – especially in the open-reel master tape – there may be a compounding effect. And if you want to avoid your drum-kit – especially the kick drum – from sounding like a 1980s era synth-samples, practice restraint when it comes to boosting low frequency signals below 50 Hz.  

High Bias Type II Cassette Tapes: The Most Cost Effective Upgrade form Normal Cassette Tapes?

Costing on average twice that of Normal Type I cassette tapes are High Bias Type II cassette tapes the most cost effective upgrade for the budget conscious audiophile?

By: Ringo Bones 

During the 1980s – and in fact well into the 1990s and the first decade of the year 2000 – audiophiles who still use cassette tapes in compiling their own “mix tapes” for personal listening via Walkman or car stereo will probably gravitate towards TDK’s Super Avilyn cobalt-doped series of high bias Type II cassette tapes despite that on average these costs twice as much as Normal or Type I cassette tapes. But is the improvement in sound quality really worth the cost? 

In my actual experience on the matter, CD players were still a relative rarity in the 1990s and no CD potable – then and now – even approaches the sound quality capability of the famed Marantz CD 63 SE Ken Ishiwata Signature. But inexplicably, if you are lucky enough to own or have access to a good sounding CD player and an excellent audiophile tape deck, like a Marantz CD 63 SE connected to those Technics “Thin Film Tape Head” series of cassette decks, recording your CDs onto a TDK Super Avilyn blank cassette even without resorting to speed doubling could make your still functional 1980s era Sony Walkman sounds as good as a Marantz CD 63 CD player. 

To me at least, my primary raison d’être for using high bias tapes over normal tapes is that not only that high bias tapes like TDK SA can record better high frequencies in comparison to normal cassette tapes but also of their low noise or tape hiss. Walkmans and car stereos are usually equipped with Type II High Bias 70 μ second / Type I 120 μ second switch. Switching the setting to Type II 70 μ second usually results in a noise reduction that’s better than Dolby B without the dulling effect of low cost cassette playback equipment with a not optimally set Dolby B noise reduction system . And I bet others' preference of other high bias tapes than the TDK SA over normal Type I tapes may be largely due to tape hiss issues.

Commonly Available Test Cassette Tapes, Anyone?

Even though Mobile Fidelity Sound Labs’ Geo Tape is the one often mentioned, are there more widely available test cassette tapes out there?

By: Ringo Bones 

Believe it or not, even well into the 1990s – and probably even until this day – there’s still no agreed for the level at which the 0VU peak record level is set on high fidelity cassette tape decks. During the 1990s, the 200nWb (nano Weber) Dolby flux was most commonly used for quality budget decks, but lower down the price scale on budget designs with inferior tape heads that would overload at a much lower level, 0VU is set -3dB below Dolby. Some top line models, like Nakamichi, have their 0VU set high up at IEC 0dB flux of 250nWb which many audiophiles and engineers, then and now, think is most sensible. But is there a reliable way to “calibrate” the cassette tape decks you currently own regardless of quality even if you don’t have access to a sophisticated signal generator and an oscilloscope? 

The British made Harrison Test Cassette available from Canford Audio which retailed for around £20 back in the mid 1990s is one of the most widely available and often turns up in garage sales and weekend swap meets. This has Dolby level plus other tests that are useful in aligning cassette tape decks. While the “Cadillac” of test cassette tapes are those BASF IEC test tapes, especially those that are IEC Primary Reference Standard which back in the mid 1990s costs £69.20 each. But it is a very reliable way to establish IEC 0dB using the “Level Control 315Hz Code-XB” track and given that it is a premium quality cassette test tape, it can establish IEC reference level to a degree of certainty manufacturers cannot question. 

After having reliably establish IEC 0dB, you can now record to around +4dB above it on musical peaks on metal tape and around +2dB on ferrics and chromes. And don’t forget to add 2dB to these figures if you set the 0dB of your cassette tape deck at 200nWb Dolby flux. But the most effective test you can perform after aligning your cassette tape deck is on how effectively it can record music tracks.