On 5/05/2016 4:44 PM, Eiron wrote:
On 05/05/2016 07:17, Don Pearce wrote:
On Thu, 5 May 2016 15:12:49 +1000, Trevor Wilson
wrote:


http://me-au.com/me850data2.jpg

It will even survive the crowbar protection system (until that
protection system is destroyed).

Why would anyone design that amplifier and say it is for music? One of
the most pointless specs I've ever read. You're just ****ing your
money away if you buy that.

Because of the Australian fashion for designing speakers with impedances
that drop to zero at the crossover frequencies.


**As PA has indicated, that type of speaker is commonly manufactured by
Americans, not Australians. Here are the impedance plots of two old
American speakers:

Infinity Kappa 9:

http://www.rageaudio.com.au/modules/...656_kappa9.jpg

Acoustat (I can't recall the model - Spectra something-or-other):

http://www.rageaudio.com.au/modules/...05452_accu.jpg

I ran the impedance curve of the infamous Infinity 4.5 many years ago,
but it was long before computerised test equipment and the curve
(primitive that it was) has long since vanished. The impedance fell to
around 0.75 Ohms in the bass region. I'll dig out the crossover
schematic provide a link. Be very careful when you examine it. Make
certain you are sitting down with a nice cool beverage (alcoholic). It
is a truly scary stuff.


--
Trevor Wilson
www.rageaudio.com.au

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In article , Trevor Wilson
wrote:
I ran the impedance curve of the infamous Infinity 4.5 many years ago,
but it was long before computerised test equipment and the curve
(primitive that it was) has long since vanished. The impedance fell to
around 0.75 Ohms in the bass region. I'll dig out the crossover
schematic provide a link. Be very careful when you examine it. Make
certain you are sitting down with a nice cool beverage (alcoholic). It
is a truly scary stuff.

This was the kind of dilemma faced by amp designers of the period. A
variety of highly regarded ( or at least highly hyped! ;- ) 'super
speakers' appeared. Some needed a hell of an amplifier to drive them
because they were inefficient had awful impedance behaviour. Yet others
could be toasted by an amp designed to drive the awkward squad. Limiting
the amp then limited its use.

Jim

--
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