Why dosome high pwr amps fail to drive some spkrs?


I have Audio Artistry Beethoven speakers. They are dipoles with main panel, active xover and separate unpowered subs. In the main panel ther are 2 10´ woofers covers the range 100-200 Hz. This speaker A A Beethoven was Speaker of the year by Stereophile 1998. According to S. test the speaker has a sharp drope in impedance in than region 100-200 hz to about 3 ohm. The problem is that some amps fail to move this 2 10´woofers. A Rowland 8TiHC (high current) of 400 w and lots of current fails to drive the woofers resulting in a lack of midbass (otherwise the Rowland was very good). Also "the worlds best amp (Stereophile cover)" Halcro DM 68 at mega bucks also fails to drive the woofers. Halcro says that this amps has no problems down to 2 ohms. BUT a 10 year old Classe 300 (300W) at budget price drove the woofers with no problem.I finaly settle with big Krell monos and they have absolute no problems in this area.
I was told by a well know audiophile on Audio Asylum that he had the same problem with the even bigger Rowland model 9 that fails to deliver midbass to Big Avalon speakers.
Can someone explain this to me or has anyone similare experince?
I can also say that the speakers are truly world class now with the Krells!! I use a Krell KSA 300 to power the dipole subs with exellent result and 20Hz wall shattering bass.
128x128ulf

Showing 1 response by snook2

Ironic but the Rowland Model 6 is the first amp I have had that gives me the bass and midbass control. Major slam and can also sound delicate. I have not heard the 8ti so I am not sure while it would fail. I also use the Manley steehead preamp which is an excellent match.