B-I-C T-4M (1979) | 2-Speed 3-Head

The B-I-C T-4M was no ordinary cassette deck. With two tape speeds, full metal-tape capability, and B-I-C's exclusive Broadband Electronics, it pushed the compact cassette format remarkably close to open-reel performance.

B-I-C T-4M Main Specifications

Tape speeds: 4.75 cm/s and 9.50 cm/s

Frequency response at 4.75 cm/s: 20 Hz–21 kHz ±3 dB

Frequency response at 9.50 cm/s: 20 Hz–23 kHz ±3 dB

Wow and flutter at 4.75 cm/s: 0.05% WRMS / 0.09% DIN

Wow and flutter at 9.50 cm/s: 0.03% WRMS / 0.07% DIN

Total harmonic distortion: 1.3% at 4.75 cm/s

Fast-forward/rewind: approximately 48 seconds with a C-60 cassette

Level meters: Peak-indicating LED bar graph, –36 to +9 dB

Drive system: Two-speed tachometer-feedback DC servo motor

Transport: Dual-capstan design

Spooling: DC spooling motor

Dimensions (W/H/D): 440x164x257mm

Weight: 8,4kg

Broadband Electronics was the heart of the T-4M's design. B-I-C developed this circuitry to take advantage of the increased performance available from higher tape speed while maintaining an unusually wide response at the standard 4.75 cm/s cassette speed. At 4.75 cm/s, the T-4M was specified to reach 20 Hz to 21 kHz ±3 dB. Increase the tape speed to 9.50 cm/s and the specification extended to 20 Hz to 23 kHz ±3 dB. That second speed was the real attraction. Running cassette tape at 9.50 cm/s offered substantially more bandwidth and lower wow and flutter, allowing B-I-C to position the T-4M as a cassette deck capable of challenging open-reel machines. Metal tape capability added another advantage. Combined with the higher tape speed and Broadband Electronics, it gave the T-4M the technical foundation for its unusually ambitious performance claims. The transport was equally important. A dual-capstan mechanism and tachometer-feedback DC servo motor were employed to maintain precise tape movement, while a separate DC spooling motor handled fast winding operations. Dolby NR and Signal-to-Noise Performance. Noise reduction was an important part of the T-4M's specification. At 4.75 cm/s, the quoted signal-to-noise ratio was 57 dB, increasing to 65 dB with Dolby NR. At 9.50 cm/s, the figure rose to 61 dB, while B-I-C specified 68 dB with Dolby NR and metal tape. For a cassette deck of its era, these figures demonstrate just how seriously B-I-C approached high-performance recording. The 9.50 cm/s Advantage. Why the higher speed mattered? Tape speed has a direct influence on cassette performance. Increasing the speed from 4.75 cm/s to 9.50 cm/s allowed the T-4M to achieve its widest specified frequency response while also reducing measured wow and flutter. At 9.50 cm/s, wow and flutter was rated at just 0.03% WRMS, compared with 0.05% at the standard speed. The same time you might ask yourself about compatibility with other devices. B-I-C solved this problem by adding a 2-speed car audio cassette deck for all your double speed recordings.

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