The QI65CST single stereo ceiling speaker from Q Acoustics runs off of both the left and right channels of an amplifier to produce the complete sound of your favourite songs with immersive stereo sound performance from a single unit. This in ceiling speaker features a 6.5" bass driver and two coaxially aligned 0.75" swivel tweeters, ensuring flawless reproduction of a full frequency range with stereo output. For a fine-tuned high-frequency level, there is a HF switch to adjust the output by + or - 3dB.