The JBL CSM 14 has four inputs — plenty for connecting background music sources and a microphone. You can manually adjust the volume threshold for voice-activated ducking, so music drops out temporarily when the microphone is on.

Music sources can be connected via balanced three-pin Euroblock connectors, or unbalanced RCA inputs that sum to mono. An RJ-45 connector on the back panel lets you add a convenient  in-wall volume control.

Product highlights:

• 4-input, 1-output commercial mixer
• four individual input level control knobs
• single master output volume control
• independent bass and treble tone controls
• "vox" adjustment sets input threshold for voice-activated ducking during announcements
• frequency response: 20-20,000 Hz
• switchable 70Hz high-pass filter for eliminating low-frequency microphone rumble
• switchable 27V phantom power for microphones
• rack mounting kit included

Connections:

• 3 three-pin Euroblock mic/line inputs
• 1 five-pin Euroblock mic/line input with priority muting for announcements
• 3 stereo analog RCA mono sum inputs
• three pin Euroblock line level output
• RJ-45 connector for  in-wall volume control