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Since 1978, the Ob-303 subscriber loudspeaker has been producing the Novosibirsk low-voltage equipment plant. Loudspeaker "Ob-303" is intended for reproduction of low-frequency channel transmissions of a local wire broadcasting network. The voltage in the transmission line is 30 (or 15) V. The nominal frequency range of the sound is 160 ... 6300 Hz. Frequency response is about 15 dB. The average sound pressure is 0.23 Pa. The price is 5 rubles.