second paragraphe du lien
After considerable development time the “S-SPEC’ tweeter completes the rollout of proprietary drivers across every ATC loudspeaker system. Six years in the making, the new SH25-76S design is a significant technical advance for ATC and a proud achievement for Managing Director Billy Woodman and R&D Manager Richard Newman. The Woodman/Newman collaboration has ensured that both the standard SH25-76 (as fitted to the Company’s SCM7/11/19/40/40A models) and ‘S-Spec’ SH25-76S tweeters exceed the exceptionally high levels of performance and consistency expected of an ATC driver.
20 version Tower Hifi : Frequency Response (±2dB): 80Hz–17kHz
20 version Pro : Amplitude linearity : 80Hz – 20kHz (+/-2dB)
La pro va plus haut.
Par contre, la version hifi me parait beaucoup plus cher (10000 € le tower contre environ 6500 € pour la version Pro). Cela fait cher le prix du bois si cela ne tient qu'à ça (pourtant la version S n'est présente que sur la gamme Pro)
Un test de la 20Pro (moins aisé à trouver que la gamme hifi) : http://www.audiotechnology.com.au/wp/in ... -monitors/