Tuesday, February 18, 2014

Woodles: The Bane of Cassette Tape Bass?

A “technical term” used to describe the lumpy low frequency response of cassette tape decks, can “woodles” be engineered out or reduced to nonexistence? 

By: Ringo Bones 

The term woodles was first coined by Steve Holding, a hi-fi audio equipment reviewer in Australian Hi-Fi magazine in which the term was used in the March 1998 issue. In this context, woodles means the irregular response in the bass or low frequency section of the audio frequency graph of a cassette tape deck under test. More popularly known in America as the “head contour effect” and is primarily caused by the bending of the tape as it travels around the record / replay head. 

A competently engineered cassette tape deck usually has woodles that deviates no more than plus or minus 2.5 dB below 50 Hz and plus and minus 1 dB above 50 Hz or better. A typical competently engineered modern cassette tape deck manufactured around 1990 onwards has a head contour effect that are usually below plus or minus 2.5 dB below 50 Hz due to modern record / replay head profiles and advances in record / replay head design. 

Historically, the Nakamichi DR series of cassette tape decks were known for having virtually nonexistent woodles or head contour problems since they’ve began making them by the start of the 1980s. It wasn’t until years later – as in the early 1990s – that other cassette tape deck manufacturers began making tape decks that can compete gamely with Nakamichi when it comes to engineering out the “woodle problem”. Like the Teac V-7010 cassette tape deck with a well set up head geometry virtually gave it a woddle free performance. And by the mid 1990s, Technics RS-AZ6 and Technics RS-AZ7 thin film head technology not only engineered out the head contour effect while pricing their cassette tape decks half that of a typical Nakamichi DR series cassette tape decks, but also gave the Technics series of thin film head technology equipped cassette tape decks CD-like bass and midrange without the use of proprietary Dolby S technology. 

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