[Phil Allison[_3_]]

"patrick-turner"
Phil mentioned...

- show quoted text -

** The AR9 was first sold in 1978 and used two 12 inch woofers, same ones
used in the AR11 released in 1977.
** AR constantly refer to the above woofers as being 12 inch.
But they are closer to 11 inch, in reality.
I remember now there was something odd about the woofers in a friend's
AR11s.
The impedance curve of the AR11 was so wild I drew it out and kept a copy -
here is a listing:

DC = 4.2 ohms
10Hz = 5 ohms
32Hz = 30 ohms
100Hz = 4 ohms
500Hz = 10 ohms
1kHz = 4 ohms
2kHz = 2.5 ohms
5kHz = 2 ohms
10kHz = 2 ohms
12kHz = 2 ohms
20kHz = 3 ohms
50kHz = 8 ohms

BTW:
The low figures above 2kHz are because the 4ohm dome mid and 4ohm dome
tweeter are operating in parallel.
The owner was originally using twin wire he got from Tandy / Radio Shack (
14x0.14 stuff ) - so each run was about 1.5 ohms resistance, plus about 2.5
ohms of inductance at 15kHz.
So I made him up some leads using "Tocord" ( aka Mogami cable) with near
zero inductance and about 0.2 ohms resistance.
His mouth dropped open when he heard the difference.
..
Before completely re-forming the pair of AR9 I was given to fix, I did
manage to get one working as it may have worked when new by swapping out
working mid/HF drivers so that enough working drivers were in the same box.
I found the acoustic response response using the middle position of mid-HF
level switches was anything but flat and extremely poor by my standards. I
don't recall any HF dips to 2 ohms as you state exists above 2kHz,



** Please, read my post more carefully - it's the *AR1 * that has absurdly
low impedance above 2 kHz.

But your post said AR11,

** Yeah - NOT the AR bloody 9 !!!!!!!!!!!!!!!

( AR1 is an obvious typo)


IMHO, it is very easy to make a better pair of speakers than the AR9.


** The various AR speakers I have seen and tested were riddled with unholy
compromises and evil Yankee dodges - plus built as cheaply as possible.

Their Aussie built models were even worse, with plastic veneer - yuck.

But still better than Bose by a mile.

-------------------------------------

I'd certainly agree with you on that.

Ah, the un-glorious 1970s, full of Krapp from all directions. Hardly anyone
knew what hi-fi was about, and hardly anyone attended concerts with
unamplified music to calibrate their ears. Mostly ppl experienced music when
boozed up, smoking and talking with ppl mostly liking highly processed pop
music.

I cringe when I listen to some old records I have.


** OTOH I was enjoying digitally recorded Bartok piano via half speed
mastered LPs from Denon, as early as 1976, played through my Quad ESL57s.

For low processed pop - early Beatles or some live recordings of Jimi
Hendrix were excellent.

Jazz recordings were always pretty natural sounding too.



.... Phil