Audio Database
SCM50A
Commentary

A speaker system with built-in electronic crossover and 3-channel power amplifier, similar to the SCM100A.

A 24 cm cone type woofer, SB75-234 is mounted in the low range.
75 mm diameter aluminum bobbin and voice coil of edgecopper ribbon is adopted on a 75 mm diameter aluminum bobbin, and it is designed to be placed in a uniform magnetic flux even for high power input, so that uniform linearity and braking force are obtained.

The mid-range is equipped with SM75-150 which is 7.5 cm soft dome type mid-range.
This unit contains a magnetic circuit with a gap length of 5 mm, similar to an ordinary woofer, and an edge-wise copper ribbon voice coil with a winding width of 3.5 mm. The coil diameter is 75 mm, the same as the dome diameter. Coupled with a double suspension mechanism, this unit can withstand at least 10 times the power of a typical mid-range radio and has an extremely wide and smooth directivity.

The SH25-100, a 2 cm soft dome type tweeter, is installed in the high range.

Built-in electronic crossover and dedicated power amplifiers for the woofer, mid-range and tweeter.
MOS FET elements with high linearity and low crossover distortion are used for power devices, and the output that matches each unit is supplied.
In addition, in order to improve safety against excessive input, we use ATC's own high-speed response gain reduction circuit and thermal protection limiter in the high frequency section. These circuits act only as sensors to prevent interference with signal transmission.

The crossover is an active type of 12dB/oct and has a phase compensation function so that the frequency response at the crossover point can be adjusted according to the listening environment.
It also features mid-range and high-level controls and a balanced input terminal.

The enclosure is a bass reflex type with an internal volume of 50L using MDF material.
The surfaces are finished with natural wood plywoods and waxed after sealing with satin lacquers.
The front baffle can be attached and removed for professional maintenance.

The final adjustment before shipment is done strictly with the stereo pair.

There were 4 types of exterior finish.
The size of the heat sink of the amplifier part was different depending on the catalog. There may be some variations.

Model Rating
Method Built-in Amplifier / 3-Way / 3-Speaker / Bass Reflex System / Bookshelf Type
Units Used For Low Band : 24 cm Cone Type (SB75-234)
For Middle Area : 7.5 cm Dome Type (SM75-150)
For High Range : 2 cm Dome Type (SH25-100)
Frequency characteristic 40 hz to 20 khz -6dB
Max Input 200W continuous
300W (peak)
Output sound pressure level 85dB/W/m
Crossover frequency 380 Hz, 3.8 kHz
Input terminal 3 pin XLR (male, 1G, 2 -, 3 +)
Input Sensitivity / Impedance 1V/10k Ω or More
Built-in amplifier output Bass:200W
Mid:100W
High:50W
Level control Mid/High : ± 3 dB
External dimensions Width 304x Height 716x Depth 397 mm
Weight 58kg