SP-31
ABSOLUTELY AS NEW. THE THING WORKS LIKE THEY SAY. THE FILTERS REALLY DO WHAT THEY SAY THEY DO.
MORE ABOUT IT:

The Kenwood SP-31 is a high quality external speaker with audio filtration. It is 8 ohms, can handle up to 2 watts and has a normal frequency response of 160 Hz to 7 kHz. This speaker may be used with virtually any communications receiver or transceiver. The SP-31 features a 4 inch (10 cm) speaker in a metal enclosure. The switch in the upper the right corner can select from two audio input sources. The three switches on the lower right activate two high (HIGH 1, HIGH 2) cut and one low (LOW) cut audio filters. This allows you to tailor the frequency response of the speaker system. Click here to see diagram.

• With both HIGH 1 and LOW filters the passband width is from 400 to 3000 Hz
• With both HIGH 2 and LOW filters the passband width is from 400 to 1200 Hz
• With both HIGH 1, HIGH 2 and LOW filters the passband width is from 400 to 900 Hz

By narrowing the bandwidth of the audio stage, the noise component of the signal can be reduced.

This speaker also has a standard 1/4 inch headphone jack on the front panel of the speaker and a Line Output Jack on the back panel (to feed a recorder, RTTY unit, etc.). These convenient output jacks are post filtration. The input posts are spring-loaded terminals. An audio cable (bare wire to 3.5 mm mini plug) is provided. This speaker filter is 7.2 x 4.7 x 12.3 inches 4.4 lbs. (180x120x310mm 2 kg). The front panel may elevated by the extending the front feet.

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