SONY SS-7300 ULM3

Commentary

This is a standard bookshelf speaker system developed by Sony based on fundamental research on speakers from scratch.
We have developed and adopted a new magnetic circuit that theoretically clarified the distortion caused by the magnetic circuit and eliminated the harmful effects.

In ULM speakers, the structure of the magnetic circuit is different from the conventional one.
In order to prevent the occurrence of non-linear distortion in the magnetic circuit of the speaker, two improvements have been made to eliminate the non-linear distortion of the magnetic material by creating a notch in the center of the center pole and adding a thick copper plating or copper cap to the notch.

The voice coil uses a newly developed special synthetic resin adhesive after careful consideration of heat resistance and mechanical strength, and the woofer uses a metal bobbin to raise the allowable input.

30 cm and 12 cm cone type units are used for the low and middle range, respectively.
We have thoroughly studied the types and processing methods of pulp, which is the material for corn paper, and used corn paper which is excellent in theoretically and audibly.
In addition, the edge is made by applying a special thin rubber to the cloth for airtight treatment and molding. Therefore, the valley which tends to occur around 400 hz is taken, and smooth characteristics are realized.
In addition, high-purity imported copper foil processed with special resin is used for the lead wire to prevent breakage, extending the life by more than 10 times.

A 2.5 cm dome type tweeter is used for the high range.
To improve the frequency response, we have developed a special equalizer (diffuser) to obtain smooth response.

The enclosure is a walnut finished bass-reflex structure.
The baffle on which the unit is mounted has no decorative edges, and the Saran frame has a streamlined shape with no brim to avoid harmful reflections and interferences.

It is equipped with level control so that it can be adjusted to the acoustic characteristics of the room.
Built-in continuously variable level control for + / - 3 dB control of tweeter and mid-range levels.

It has a multi-selector switch and a switch to disconnect the LC network so that you can drive the woofer, mid-range and tweeter directly.

Model Rating

Method	3-Way, 3-Speaker, Bass reflex system, Bookshelf Type
Unit	For low band : 30 cm cone type For Medium Range : 12 cm cone type For high-pass : 2.5 cm dome type
Playback frequency band	50 Hz to 20000 Hz
Output sound pressure level	90dB/W/m (New JIS) 96dB/W/0.5m (Old JIS)
Impedance	6 Ω
Maximum allowable input	100W (weighted pink noise 24-hour guarantee)
Crossover frequency	600 Hz, 4500 Hz
External dimensions	Width 390x Height 636x Depth 300 mm
Weight	Approximately 19 kg