1990-1991 Model

Meaning: AR: Acoustic Response Bias: Normal (Type I) Description/History:   The AR was in some ways a replacement to thet AD-X of the 80's. AR was a higher end cassette that pretty much matched AD in performance. It is said that AR was better adaptable to CD than AD was, but AD always sounded better. AD always sounded clearer. I guess that's why AR was, in my opinion, the Pro version of AD, it would take the highs with such a kick. Great for Electronica and Trance, as well as Classical music styles.   The main reasons why it ranked so low was because of availabilty and cost. First off, I never found AR anywhere, and the cost if you did was quite a pretty penny. You're better of with SA. Compare to: Denon DX1; TDK AD; Maxell UDI BTG All-Time rank: 29

2004 Model

Meaning: D: Dynamic Bias: Normal (Type I) Description/History:   The original. That's the only way to describe the best selling Normal Bias tape of all-time. TDK first introduced D as their first cassette in 1978. Later adding the SD and ED cassettes as what was known as the "D line." The D line contunued till 1980, then the array changed at least every other year. But D never changed at all. In 1984, the formulation changed a bit by also making the tape itself lighter. What TDK had was their best formulation to date, and would not change till 1993. In 1996, D changed completely, packaging and all. The color of the tape was darker, the sturdiness was weaker, but the quality remained. Most recently, 1999 saw the most recent change, the 60 minute version of the tape was the same thickness of 90 minute tape, not to make one tape better than the other I guess, and the package was changed for maybe one last time. More about the TDK D Compare to: Maxell UR; Maxell UDI; Fuji DRI; JVC GI BTG All-Time rank: 12