The D28 is the tweeter that accompanies our bookshelf speaker and soundbar lines. Its 28 mm silk dome gives a flat response above 3 kHz without the resonance peak near 15 kHz that metal domes often show, so long listening sessions stay comfortable. Ferrofluid cooling lets it work continuously at higher power, and with rear-chamber damping the resonant frequency can be pushed below 800 Hz, which simplifies crossover design.