AudiogoN Forums: Why dosome high pwr amps fail to drive some spkrs?

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.

Ulf (System | Threads | Answers | This Thread)

07-20-05

Responses (1-13 of 13)

Click title to read one, or click date to read all below it.

07-20-05 Do those amps really drive a two or three ohm load? some am ... Nrchy

07-20-05: Joeabrams
The problem may not be what you think it is. For example, if your preamp had high output impedance, like 500 ohms, and you were running long interconnect from that to the amp or to the AA's crossover box, that might be the cause. Why?
Because the Rowland and the Halcro both have _low_ input impedance, but the Classe' and the Krell both have input impedance over 47 K ohm.
In other words, the impedence mismatch -- if that were the case -- would be enough to make the difference in apparent (lack of) bass drive in the Rowland and Halcro.
Just a theory ...
Joeabrams (Threads | Answers | This Thread)

07-20-05 Why have such a hard speaker to drive in the first place? Philefreak

07-20-05 Both rowland and halcro was used with rowland synergy pre an ... Ulf

07-20-05 "may 17, 2004 as i'm in europe, i will be pleased if y ... Ulf

07-21-05 Hi ulf,- it remains a fact that not all amps will drive all ... Atmasphere

07-22-05 Ironic but the rowland model 6 is the first amp i have had t ... Snook2

07-22-05 Interesting discussion. ulf, what exactly do you mean when ... Onhwy61

07-23-05 At the 1997 ces audio artistry displayed the beethovens with ... Onhwy61

07-24-05 Ulf : the halcro are a bit thin... never heard the avalon. Ndeslions

07-24-05 An important variable to consider is the frequency response ... Justin_time

07-26-05 With drive i mean the ability to drive my 2 10`in each main ... Ulf

07-27-05 Ulf -- you've got outstanding speakers, you lucky .....:)! a ... Gregm