DIATONE 2S-305

Commentary

This speaker system was created after 3 years of improvement from the 2S 660 announced in 1955.
It was developed in collaboration with NHK Technical Research Institute.

For many decades, the 2S 305 has been designated as the R305 for sound quality monitoring specified in BTS 6131. It has been used for standard playback by domestic and overseas broadcasters as well as by sound manufacturers and sound research institutes.
In addition, in order to complete each part as a system made with high technical accuracy, all the process from the manufacture of the enclosure to the assembly and mounting of the parts was done by hand by skilled craftsmen.

A 20 cm cone woofer, PW 125, is installed in the lower range.
The vibration system of the PW 125 is a mechanical filter that attenuates the high-frequency range at a crossover frequency of 1500 Hz or more, so there is no unnecessary high-frequency radiation even without using a network.

The TW-25, a 5 cm cone type tweeter, is installed in the high range.
The diaphragm of this unit has an effective vibration radius of 2 cm, and the magnetic circuit is made of iron-cobalt alloy, which is considered to have a higher saturation magnetic flux than other magnetic materials, to achieve higher efficiency.

The enclosure uses a bass reflex method. In addition, thin plates of hippopotamus and lauan are bonded one by one to make the exterior angle round, preventing the influence of the diffracted phenomenon on the middle and high frequency range and increasing the mechanical strength.

Measured data in an anechoic room was attached to each unit.

There were also 2S-305C (gray) for hanging on the wall and 600 Ω matching transformer.

There was a special caster as an option sold separately.

Model Rating

Method	2-Way, 2-Speaker, Bass Reflex System, Floor Type
Configuration such as unit	For Low Band : 30 cm Cone Type (PW-125) For High Range : 5 cm Cone Type (TW-25) Network : HP-170
Playback frequency band	50 Hz to 15 kHz 40 Hz to 16 kHz ± 5 dB
Input impedance	8 Ω
Crossover frequency	1.5kHz
Rated input	20W
Max Input	60W
Output sound pressure level	96dB/W 102dB/VA
Network	High frequency : 12dB/oct
External dimensions	Width 650x Height 880x Depth 445 mm
Weight	45 kg (listed in the catalog after 1975) 50 kg (listed in the catalog from 1969 to 71)
Sold Separately	Dedicated Casters MC-1380A (¥ 30,000)