Walrus like alarm sound

[Alex '94 325i]

I have the stock alarm system that has changed recently from a quiet honk, to a normal volume honk (sounds like a walrus) when I arm and disarm it. The dealer said it would be the siren (air horn?) and to replace it was something like $200!
Does anybody have any advice on how to get around this problem. I hate arming and disarming my car now because of this sound. It always makes people look and not the type of looks I want for my car.
Would it be possible to use an aftermarket siren, or would that effect my regular horn. Finally where could I buy a replacement horn, if that is what I have to replace.

Thanks,

[Bones774]

I don't know what car you have, but I doubt it is an air horn, I have a electric siren should be clearly visible when you open your hood, the sound has to be able to escape from under there. Take a look something may have gotten into siren horn(leaf, plastic, small animal) if not it is easily replaceable, just two wires, you can get it at BMW or aftermarket if the specs are the same or close.

[IMAGE&STYLE]

$200 to fix it?
i belive its the wires yo.....
also if its $200 to fix, i say get a aftermarket alarm system, fixing the stock is not worth it imo!

[Alex '94 325i]

(I&S) I checked all the wires and everything seemed to be making good contact. (Bones) you were absolutely right about the siren for the alarm being seperate from the car's horn.
So, last Friday I picked up a new siren for my alarm system. It cost $58 after 10% off (Pacific BMW price - matched at BMW of San Francisco).
It was such a simple install and the alarm arm/disarm sounds much better now. I am thinking about tapping into the lights with arm/disarm as shown on Ron Stygars site.
Just wanted to give you guys the update, and thanks again for your help.