About the [Pre-Sale] Douk Audio S4 Dual 4-Inch 2-Way Passive Bookshelf Speakers
From the product page on doukaudio.com.
Dual 4-Inch Sound with Real Body: Built for listeners who want richer, more grounded sound from a passive bookshelf speaker, each S4 uses dual 4-inch mid-bass drivers to handle lower mids and bass with more ease. Vocals gain warmer presence, drums hit with cleaner impact, and audio feels fuller and more complete without loose boom.
Three Drivers for Layered Texture: A coated 25mm silk dome tweeter with a neodymium motor keeps highs smooth and clear. Nomex composite mid-bass drivers, long-excursion design, and shorting rings support steadier cone control and lower distortion. The result is richer texture and cleaner separation, making complex music easier to follow.
Acoustic Tuning for Balanced Playback: A 3kHz crossover with selected MKP capacitors and air-core inductors refines the handoff between the silk tweeter and dual mid-bass drivers. The tuned bass-reflex cabinet reinforces low-end body through controlled airflow, giving S4 a more cohesive, well-balanced playback character.