Normal / Type I lineup
Normal Position is both the starting point and the endpoint of cassette tape history. TDK was no exception: SYNCHRO CASSETTE, released in 1966, began its cassette story, which lasted almost forty years. AD, introduced in 1977, then began conquering the cassette market…
AD
A long-running success that began with penetrating high-frequency clarity
ACOUSTIC DYNAMIC
Third generation: 1983
C46: 450 yen.
The third AD generation appeared in 1981 under the name MUSIC REFERENCE. Mid- and high-frequency performance was improved for balanced sound. Its SP mechanism matched MA’s. The shell changed from the earlier mechanical gray to black.
AD: explanatory notes
The first AD was released in 1977 as the successor to SD, considered the world’s first cassette for music, and as the central model in TDK’s Dynamic Series.
AD stands for Acoustic Dynamic. Its debut slogan was Penetrating high-frequency clarity. This Normal cassette greatly improved high-frequency performance, previously a weakness because of the cassette’s low tape speed.
Chrome tapes and High Position cassettes such as SA had already appeared to improve high frequencies, but they were all expensive. AD cost about the same as ordinary LH cassettes and the previous SD. Its appeal went beyond high tape performance: the same high-precision Precision cassette half shell sections used for SA had a grid pattern that gave a premium appearance. It was thus also good value for money.
Jazz trumpeter Miles Davis was invited to advertise the first generation. Having a famous overseas artist in a Japanese cassette advertisement was itself an innovation.
AD was subsequently refined over many years, remained in demand and gradually became a standard Normal music cassette.
As generations changed, cassette decks improved too, reducing the need for the tape itself to emphasize high frequencies. From the original penetrating high-frequency clarity with slightly forward treble, AD gradually moved toward the flat response and balanced sound of a good Normal tape. Toward its final generations, however, tuning again emphasized AD’s characteristic high-frequency definition.
AD had ten generations, the last released in 1993. When the High Position AD Type2 (AD2) appeared in 1995, AD was renamed AD Type1 (AD1).
Incidentally, third-generation AD attracted attention even before release and almost immediately became scarce. It was so popular that TDK had to place newspaper apologies.
First generation: 1977
AD accounted for more than half of TDK’s cassette sales in Japan during 1977-1982, approximately 130 million units.
C45: 450 yen.
The first generation went on sale in March 1977. It used newly developed Linear Ferric magnetic material with high coercivity and high remanent flux density. MOL and high-frequency sensitivity were greatly improved. The shell used the same high-precision sections as SA. Blue, inherited from SD, also suited its sonic image.
Launch-period advertisement: Music must keep moving forward. Penetrating high-frequency clarity. AD.
Second generation: 1979
C45: 450 yen.
The second generation was released in 1979. Improvements to the magnetic material and binder system, the coating material, reduced bias noise by 1.5% while increasing high-frequency sensitivity and MOL. It used micron-precision shell sections, double tape-clamp reels and a DB sheet.
Fourth generation: 1984
C46: 470 yen.
The fourth generation, Musictracer, arrived in 1984. Densely packed new Fine Linear Ferric magnetic material increased maximum remanent flux density. Sensitivity and MOL rose, noise fell and frequency range widened further. The shell used the exceptionally precise, rigid SP-X mechanism.
Fifth generation: 1986
C46: 470 yen.
The fifth generation appeared in 1986. The new SPR mechanism, with multifaceted shell joints and a striking, exceptionally wide H-shaped window, provided low resonance and high rigidity. Ultrafine Super Linear Ferric particles were precisely oriented and densely packed for further improvements. Large-hub reels were introduced for C46.
Sixth generation: 1988
C46: 400 yen.
The sixth generation appeared in 1988 with the theme SUPER VOCAL. Highly oriented, densely packed new Pure Linear Ferrics material improved the middle and high frequencies for vocal recording and provided exceptionally low noise for a Normal cassette. The shell used the low-resonance SPR mechanism and an H-shaped window.
Seventh generation: 1989
C46: 390 yen.
The seventh generation appeared in 1989. Flash Surface Form flattened the shell surfaces and rounded their edges to make the cassette easier to hold. Packaging also changed substantially, gaining a lighter, predominantly white appearance.
Eighth generation: 1990
C46: 390 yen.
The eighth generation was released in 1990. Noise was reduced further to one of the best levels among Normal tapes. Reinforced polyester tape, with elongation variation no greater than 0.01%, remained reliable through repeated use. Streamlined shell sections and a rounded Fit Case were used.
Ninth generation: 1992
C46: 430 yen.
The ninth generation arrived in 1992. Its theme, Clear high frequencies, newly defined sound, recalled the original AD. It felt like a return to the first generation, whose chief attraction was expressive treble. The shell used the SPR mechanism with streamlined Aeroline sections.
Tenth generation: 1993
C46: 430 yen.
The tenth generation arrived in 1993 under the slogan High frequencies sound clear. High-frequency MOL was increased. It used a short leader and a slim, rounded case 14 mm thick. A C150 joined the range. This was the last AD generation without an additional suffix, passing the baton to AD Type1.