I first met Dr (amir) Bose in 1968 at his factory in Framingham, MA...I purchased a series I pair of 901s...They were great for some music...rock, broadway, choral...not so much for opera and chamber music BUT they throw a HUGE image when properly set up and , yes, needed ALOT of power...I upgraded to Series II a few years later...somewhat more efficient..since then I've owned ARs, KLH, B&W, Magnum Opus, JBL, Legacy..and many others I've forgotten but I still have a deep fondness for those 901s....put on some DEAD, AIRPLANE, STONES, big Verdi choruses, Act 1 finale to Turandot, etc, etc...sit back and enjoy the sound wrapping around you...they made listening to music FUN