arcam r25R25 Bookshelf Loudspeaker The R25 is the largest and most capable bookshelf speaker in ARCAMs Radia series, designed as a serious alternative to floorstanding speakers in compact high end systems. With a 6. 5 (165 mm) Micro Ceramic Composite woofer, a 1 DCC aluminum dome tweeter integrated into an Acoustic Lens waveguide, and a precision optimized crossover at 1. 7 kHz, the R25 delivers extended low frequency response down to 43 Hz and linear