High Output Internal Horn Sounder. SO812/C is a Horn Sounder, Sound is Output is 122 dB(A). A range of horn sounders with different sound outputs and current consumption, suitable for use in internal and external applications. Specification: Voltage: 6 - 15 vdc, Current: 650mA, Sound output at 1m: 122 dB(A), Frequency range: 0.8 - 1.7 kHz, Material: ABS, Weight: 440gm, Size mm: 83 x 96 Horn 83.