SONY SS-7660 ULM66
¥ 68,000 (1 unit, around 1972)
Commentary
A speaker system that employs an Ultra Linear Magnetic Path (ULM) magnetic circuit that improves distortion caused by the magnetic circuit.
In ULM speakers, a notch is formed in the center of the center pole and thick copper plating or copper cap is added to the notch to eliminate the nonlinear distortion of the magnetic material.
We have also studied heat resistance and mechanical strength, adopted a newly developed special alloy resin adhesive, and used a metal bobbin for the woofer to raise the allowable input.
It is equipped with a 30 cm cone woofer in the low range and a 12 cm cone scoker in the middle range.
The cone paper greatly expands the piston vibration range due to its high rigidity using our unique paper manufacturing technology, and further reduces internal loss to suppress split vibration.
In addition, we discovered that abnormal noise of an extremely large level is radiated in a band two to three times the upper limit frequency due to abnormal vibration of vibration of the voice coil bobbin, voice coil bobbin and cone joint, etc., and we adopted a dust-proof cap with a large sound insulation effect to prevent the radiation of abnormal noise.
A horn type tweeter is installed in the high frequency range.
The network section has a large air-core coil that has little DC resistance and does not distort even under large input.
In addition, it is equipped with a change-over switch that can remove the LC network so that the woofer, squaker, and tweeter can be directly driven.
Level control is provided for the middle and high frequencies.
In addition, the ULM66 is equipped with a base controller, which can change the characteristics of 100 Hz or less in three stages : the closed type, the bass reflex type, and the intermediate type.
24 mm lauan plywood is used for the enclosure.
The decorative edge is also designed to avoid harmful reflection and interference.
Model Rating
| Method | 3-way, 3-speaker, bass reflex / closed variable system, floor type |
| Unit | For low band : 30 cm cone type For Medium Range : 10 cm Cone Type For High Frequency : Horn Type |
| Playback frequency band | 30 Hz to 20000 Hz |
| Output sound pressure level | 89dB/W/m (New JIS) |
| Impedance | 6 Ω |
| Maximum allowable input | 100W(weighted pink noise) |
| Crossover frequency | 600 Hz, 3 kHz |
| External dimensions | Width 499x Height 750x Depth 421 mm |
| Weight | Approximately 40 kg |