Audio Technica ART9 sounds awful

My money is on Almarg's hypothesis that the two channels are 180 degrees out of phase with each other.  Even if you cannot prove that by visual inspection, you might try switching leads on one channel just for the heck of it.

I am no authority on the ART9, but I found on the AT website the following: Compliance = 18 @ 100Hz; Static compliance = 35.  Wally Malewicz's web page says that the compliance at 10 Hz (which is the value to use in the resonant frequency equation) is related to the compliance at 100Hz by a factor of 1.5-2.  So one would predict a compliance of 27 to 36 at 10Hz, not out of the range of the above quoted number.  However, Wally also says that the static compliance is related to the compliance at 10Hz by a factor of 0.5, which would lead us to think that the compliance at 10Hz is about 17-18.
This topic is quite messy.  As a person who likes to boil things down, I note that the resonant frequency is inversely proportional to the square root of the product of M X C, which actually leads to the finding that there is quite a lot of tolerance in the relationships that allow one to end up with a tolerable resonant frequency. (Try plugging in a range of real world values for M and C and take the square root of the product, to see what I mean.)

+1 on almarg's idea. I don't think break-in is the issue here. the cart should sound great from the get-go, and get better.  

In my post above about the plasticity of the relationship between effective mass and compliance, I might better have written that one should make the calculation of Fr for a variety of values of M and C, in order to see that you can get away with some fairly unlikely combinations and still be within an "acceptable" range.  In part, this depends also upon what one considers acceptable.

Anyway, I still think Almarg nailed this particular problem. Which has nothing to do with M and C.

" I don't think break-in is the issue here. the cart should sound great from the get-go, and get better."

Did you ever have a brand new cart? If you get one that sounds good out of the box, its probably not new. Or, if you had a dealer install it for you, they usually let it play for a while to get through those huge changes that occur when new.

Thank you all for your suggestions and ideas...well, maybe not lewm, what!?  I'll check the out of phase connections with speakers and with the cartridge.  Checked it once already, but worth the extra work.

sfall:  the Phono stage is set up right.  Also, I've had several new cartridges and each had sounded fine right out of the box but improved over time.

Thanks again.  I'll report back with the results.