DENON SC-307

Commentary

This speaker system achieves follow-up and responsiveness by incorporating a twin drive system as the center axis and dramatically improving the dynamic range.
The unit is jointly developed by DENON and Peerless Co. of Denmark.

A twin drive system using two 25 cm cone type woofers is adopted for the low range, and the vibration area equivalent to that of a 35 cm diameter woofer is obtained.
The diaphragm is made of non-pressed cone paper made of Scandinavian pulp. The surface is coated with a damping agent to control split resonance in the high frequency range, prevent air leakage, and prevent interference with reflected sound of different phases from the inside of the enclosure.
In addition, the voice coil has improved resolution by suppressing diametral deflection, and the aluminum bobbin with excellent heat radiation effect is treated with high heat-resistant adhesive to realize high input resistance.

The mid-range is equipped with a 10 cm cone type squaker.
The back cavity and frame of this unit are made of light alloy die-cast to prevent acoustic interference due to air pressure and vibration from the woofer. In addition, the cavity is filled with ring-shaped glass wool to control the low-frequency characteristics of the squaker.
In addition, the vibration system is composed of non-press cone paper coated with a damping agent on the back side, a voice coil with an improved allowable input by using a high heat-resistant insulating material on an aluminum bobbin with a good heat radiation effect, and a foamed polyurethane roll edge coated with a damping agent for low distortion and high input resistance.

Two 5 cm cone type tweeters are installed in the high range, and a twin drive system is adopted in which they are arranged vertically so as not to give directivity in the horizontal direction.
A damping agent is applied to the unit to suppress the split resonance. Since the effective radius is approximately 1.8 cm, it has excellent directional characteristics. Moreover, in order to improve the high frequency characteristics, the center cap is made of material molded with ultra-thin aluminum foil to reduce the moving mass.

All capacitors in the circuit are connected in parallel to minimize losses in the network and ensure clear sound quality.
Capacitors that have a significant influence on sound quality include aluminum and plain foil electrolytic capacitors, high-pressure metalized polyester film capacitors, and large-capacity metalized film capacitors.
In addition, a large ferrite bobbin type coil with sufficient consideration for power loss is used for the coil for the woofer, and an air-core coil is used for the coil for the squaker and the tweeter, with a low strain design.

The tweeters and woofers are mounted using a sandwich support system with aluminum die-cast rings and plates that firmly attach the entire circumference of the unit to the baffle board.
This reduces vibration of the unit itself and cabinet.

The enclosure has been determined to have an internal volume of 65.5L by repeated listening and measurement in increments of 0.5L.
In addition to ordinary glass wool, three types of materials, such as micron wool made of ultra-fine glass fibers, are packed into two or three layers for sound absorption material, and a dense sound absorption process is applied.
The material is a hard particle board. In order to suppress and disperse only harmful vibration frequency components, aluminum foil laminated butyl rubber is pasted inside the back plate by laser holography measurement and audition, and natural sound is obtained.

Model Rating

Method	3-Way, 5-Speaker, Airtight Type, Bookshelf Type
Units Used	For low band : 25 cm cone x2 For Medium Range : 10 cm Cone Type For High Pass : 5 cm cone x2
Maximum allowable input	120W (program source)
Playback frequency band	35 Hz to 20 kHz
Crossover frequency	500 Hz, 4000 Hz
Impedance	8 Ω
Average output sound pressure level	92dB/W/m
Total harmonic distortion factor	1.5% or Less (50 Hz or More, 5W)
Level control	Medium and high frequency continuously variable
External dimensions	Width 392x Height 700x Depth 355 mm
Weight	22 kg (25 kg when packed)