15 x 22 cm Waveguide of high-quality plastic for 25 mm tweeters. The exponential enlargement provides a high sound pressure level gain in the lower high frequency range, which discharges the tweeter. In addition, the focus and the coupling to a woofer are improved, because the sound generation planes move closer together. This Waveguide was adjusted in width and length to 15 cm and 22 cm loudspeakers. For the connection of the tweeter 4 pieces M4 screws (length approx. 10 mm) are added.