TRIO LS-707
¥ 89,000 (1 unit, around 1977)
Commentary
This 3-way floor type speaker system is based on the concept of "linear response" in which the output sound pressure deviation is suppressed to ± 2 db over the band from 55 hz to 16 khz.
A 33 cm cone woofer is installed in the low range. This unit uses a needle yoke and an alnico cast magnet in the magnetic circuit to obtain a uniform magnetic field.
In addition, in order to prevent the air in the air chamber surrounded by the damper, frame and top plate from being compressed by the movement of the cone paper and deteriorating the linearity, a ventilation hole is provided between the damper and frame to flatten the playback response and suppress the third harmonic distortion.
In consideration of the effect of the material of the cone on the reproduction response, the CF cone is coated with titanium oxide to enhance the reproduction response. In addition, an S-shaped, asymmetric cross-section, ester urethane foam edge with low anti-resonance is used for the edge.
Equipped with 12 cm cone type skoker in the middle area.
It uses an Alnico cast magnet and an acupressure type yoke that can obtain a strong uniform magnetic field like a woofer.
A horn type tweeter is installed in the high frequency range.
The diaphragm uses a V-shaped ring diaphragm molded with super duralumin. Because the distance between the driving surface and the edge of the ring diaphragm is short, the frequency at which split vibration occurs becomes higher and high-frequency resonance is less likely to occur. In addition, a small V-shaped edge is provided around the V-shaped diaphragm to further improve linearity.
This ring-shaped diaphragm is combined with a diffraction horn utilizing the diffraction effect of sound waves.
The magnetic circuit uses an 80 φ 20 mm ferrite magnet with a magnetic flux density of 15,000 gauss. The air chamber between the pole piece and magnet is filled with micron glass wool to prevent sound reflection and improve damping characteristics.
A step-down attenuator using Litz wire is used for level control to suppress the degradation of the damping factor and improve the transient response characteristics.
The baffle faces have an angle of 3.25 degrees, and the woofer is kept as far away from the floor as possible to prevent reflection and absorption of sound when installed on the floor. Tapered ducts with a gradually increasing cross-sectional area are used for the ducts.
The back cavity of the Skoker is made of a resin concrete material with a specific gravity of 2.3 mixed with wood chips, and special synthetic resin with moderate internal loss is used to suppress harmful vibrations.
Model Rating
| Method | 3-Way, 3-Speaker, Bass Reflex System, Floor Type | ||
| Unit | For Low Band : 33 cm Cone Type (LC-0068) For Middle Range : 12 cm Cone Type (ML-0061) For High Range : Horn Type (HH-0056) |
||
| Frequency characteristic | 25 Hz to 20 kHz | ||
| Output sound pressure deviation | 55 Hz to 16 kHz ± 2 db | ||
| Max Input | 100W | ||
| Rated input | 60W | ||
| Impedance | 8 Ω | ||
| Output sound pressure level | 93dB/W/m | ||
| Crossover frequency | 1.3 kHz, 6.5 kHz | ||
| Acoustic Level Control | Mid-range : ± 2 dB, 3 steps High frequency : ± 3 db, 3 steps |
||
| External dimensions | Width 440x Height 910x Depth 404 mm | ||
| Weight | 43kg | ||
| Unit Characteristics | |||
| Model number | LC-0068 | ML-0061 | HH-0056 |
| Type | 33 cm cone type | 12 cm cone mold | Ring diaphragm horn type |
| Playback band | Fo ~ 2.7 kHz | 400 Hz to 10 kHz | 3 kHz to 20 kHz |
| Output sound pressure level | 93dB/W/m | 97dB/W/m | 104dB/W/m |
| Impedance | 8 Ω | 8 Ω | 8 Ω |
| Magnetic flux density | 10,000gauss | 13,500gauss | 15,000gauss |
| Total flux | 145,000maxwell | 48,900maxwell | 28,400maxwell |