DIATONE DS-505

Commentary

This 4-way speaker system is designed to be a bookshelf that exceeds the bookshelf type and is compatible with digital audio.

The DS 505 has a 4-way configuration with a mid-bus unit, and the mid-bus unit is equipped with fundamental bandwidth to achieve both high resolution in the mid-range and high quality in the low frequency range, which was difficult to achieve with the conventional 3-way system.

A 32 cm cone type woofer is installed in the low range.
The diaphragm uses a newly developed aramid honeycomb cone. Aramid fiber is an aromatic polyamide fiber that combines high strength and high elasticity with low density and moderate internal loss. Diatone uses a special blend of flexible resin reinforced with aramid fiber to create a honeycomb diaphragm with a large internal loss in the resin itself. This skin and aluminum honeycomb core bonded together.
The voice coil uses a polyimide film with three times the Young's modulus of conventional aromatic polyamide film and excellent heat and cold resistance. It is designed to dramatically improve input resistance and to transmit the driving force generated by the voice coil to the diaphragm without loss.
The magnetic circuit is equipped with a low-distortion magnetic circuit. In this method, a nickel-based magnetic alloy material with excellent linearity of magnetization characteristics is developed and installed in the vicinity of the magnetic pole gap using a metallurgical engineering approach to reduce non-linear strain. Furthermore, regarding strain based on non-uniformity of magnetic flux density distribution in the magnetic gap, the effects of shapes, dimensions, materials, etc. of the pole piece and plate are analyzed by a computer to realize a structure with uniform magnetic flux density distribution and less strain.

A 16 cm cone type midbus unit is installed in the middle and low range.
This unit uses voice coil and low distortion magnetic circuit using aramid honeycomb cone and polyimide film as well as woofer.

A 4 cm dome type mid-high unit is installed in the middle and high area.
This unit uses a sandwiched boronized diaphragm made of titanium treated with high-temperature boronization. Moreover, this diaphragm has a DUD structure unique to Diatone, which integrates the voice coil bobbin and diaphragm. This diaphragm prevents a decrease in rigidity caused by bonding the diaphragm and voice coil bobbin and eliminates high resonance frequencies out of the audible band. In addition, by eliminating energy loss at the bonded part, the driving force generated in the voice coil can be transmitted to the diaphragm without loss, reducing attenuation in the high frequency range. Moreover, since the heat generated in the voice coil is directly conducted to the diaphragm, the increase in conductor resistance of the voice coil itself due to temperature rise is prevented, and linearity and input resistance to input signals are improved.
A large strontium magnet is used for the magnetic circuit, and the distortion of the drive system caused by the magnetic circuit is eliminated by operating the magnetic circuit in the saturation region.

A 2.3 cm dome-shaped tweeter is installed in the high range.
Similar to the mid-high unit, this unit uses a boronized diaphragm and a large strontium magnet.

In order to reduce distortion in network circuits, we have been studying constituent parts and elements.
The coil for the network is designed to take advantage of both the good damping of the core and the low distortion of the air core. Therefore, the shape of the coil is thoroughly pursued and the winding diameter is increased to 1.4 mm to reduce DC resistance and distortion. In addition, careful attention is paid to the production of the element such as using a bonded iron core made by heat-pressing silicon steel plate with a special adhesive in order to suppress harmful core noise.
We have adopted a polyester film capacitor with excellent high-frequency characteristics. This capacitor is also designed with double vibration isolation structure in consideration of its own vibration. We have also adopted a low-distortion type electrolytic capacitor with extremely low leakage current and dielectric loss.
We also pay attention to the layout of network components and wiring methods, and reduce distortion to minimize interference between components.

Oxygen-free copper wires are used mainly for network circuit wiring.
Compared with general tough pitch copper wires, oxygen-free copper wires have superior characteristics such as high conductivity, no hydrogen embrittlement, excellent workability, and low content of impurities such as dissimilar metals.
In addition, we have eliminated the need for soldering and adopted a crimping connection using a oxygen-free copper sleeve.

The enclosure uses a joint structure and material determined by modal analysis and repeated thorough hearing to bring out the performance of the unit. Also, the mounting position of the unit was determined by modal analysis and repeated listening of various prototype model systems. By this method, the midbus unit is placed on the upper part and intermodulation distortion is suppressed.

Model Rating

Method	4-way / 4-speaker / bookshelf type ・ Acoustic air suspension system
Units Used	For low band : 32 cm cone type For middle and low band : 16 cm cone type For Middle and High Areas : 4 cm Dome Type For high-pass : 2.3 cm dome type
Rated impedance	6 Ω
Playback frequency band	28 Hz to 40 kHz
Lowest resonance frequency	35Hz
Output sound pressure level	90dB/W/m
Crossover frequency	350 Hz, 1.5 kHz, 5 kHz
Level control	Mid-range : 4 positions (1.5 kHz to 5 kHz) High Frequency : 4 positions (5 kHz to 40 kHz)
Maximum allowable input	100W(EIAJ)
Rated input	30W
External dimensions	Width 422x Height 720x Depth 425 mm
Weight	42kg