Horn sounds slower

[BubbaDuke]

I have a "Dixie" horn in my car.  And it seems to be playing a lot slower than I remember.  Could this be the result of my horn relay, my horn button, or is the horn itself going.  This was installed when I got the car, and i noticed that the positive cable comes from my alternator, is this normal or should it come from my battery?   Thanks

[Johnnys440Charger]

Cable should come from the Battery. 
Use a relay.
Make sure the Dixie horn is gounded.
Hook the positive wire from the compressor to 87.
From the battery with an inline fuse hook a wire to 30.
Hook a ground wire to 85.
Hook a wire on 86 and run it to one side of your new horn switch.
Hook the other side of the new horn switch to a hot wire.

[doctor4766]

I have squirted a little lube into the holes on the compressor that the horn lines come off and this generally helps to speed them back and keep the compressor moving freely.

[Bob T]

I put a set into a mates Coronet a few years ago and they draw 25A, so also make sure that the supply cable can handle this current otherwise the last few "notes" dont play. And yes, use Relays most definately.

The horn button is only a contact to "ground", this is what should turn the relay on when you push it as Johnnys440 "how to" shows

If no relays are used at the least it will burn out the contacts on the horn ring and at worst it will melt the wiring and then you've got real problems. 

Lube would help on the compressor as Doc says too.

[440]

I would say the ground contact is weak. My horn is funny in the way if I push it just light enough for the horn to play it plays really slow, if I push it fully it plays quickly. Mine is hooked up straight to the horn though and I'd like to install it properly with a relay one day.

Also if it's in front of the radiator support and driven in the rain it is susceptible to moisture and corrosion which can slow it down.