DIATONE 4S-4002
Unreleased (released in 1976)
Commentary
Large 4-way monitor speaker.
The 4S 4002 was developed to cope with the improvement of program source performance by adoption of direct cutting and PCM deck.
The main targets are wide-band wide-band playback from 20 Hz to 30 kHz and low distortion of -50dB or less. In addition, improvements in phase characteristics, which have a significant effect on sound quality, and input resistance, which is required as the basic performance of professional speakers, are also being sought.
Based on this speaker, the 4S-4002P was developed and sold since 1977.
A high-rigidity diaphragm using a honeycomb sandwich cone is adopted for the diaphragm in the middle and low frequency range, and reproduction characteristics which uniformly extend to 20 Hz in 2 π space are obtained.
In addition, the magnetic circuit is made of permalloy to reduce current distortion, thereby realizing a lower distortion than ever before. In addition, the voice coil is made of newly developed heat-resistant epoxy imide adhesive to improve input resistance.
40 cm cone type woofer and 40 cm cone type passive radiator are mounted for low range.
The mid-range is equipped with 18 cm cone mid-range.
A 5 cm cone type tweeter is installed in the high range, and a 2.3 cm dome type super tweeter is installed in the ultra high range.
These units are equipped with a protective circuit to protect against excessive input and contribute to improved input resistance.
In order to improve the phase characteristics in the network section, a phase correction circuit is installed in the units above the mid-range.
The network configuration is designed to allow switching between multi-amplifier mode and full-range mode.
At the top of the rear of the enclosure there was space for the driver amplifier.
Model Rating
| Method | 4-way, 4-speaker, passive radiator system, floor type |
| Unit configuration | For low band : 40 cm cone type For Medium Range : 18 cm cone type For high-pass : 5 cm cone type For Super High Range : 2.3 cm Dome Type Passive radiator : 40 cm cone type |
| Playback frequency band | 20 Hz to 30 kHz |
| Input impedance | 8 Ω |
| Maximum allowable input | 300W |
| Crossover frequency | 400 Hz, 2 kHz, 7 kHz |
| Output sound pressure level | 93dB/W/m |
| Harmonic distortion factor | -50dB or less (input 1W, 30 Hz or more) |
| External dimensions | Width 660x Height 1,365x Depth 545 mm |
| Weight | - |