No matter which horn you decide on using, I suggest moving it from the stock location. Aside from being barely audible, this location can lead to bigger issues.
Many years ago, while zipping down the road on my '72 Combat, the stock horn decided to go awol. The bolt that secured the horn vibrated loose. (imagine that?) :lol:
The horn dropped down and began to make a nasty sound when the chain promptly started chewing. No problem hearing the horn then!
Luckily, the chain guard did it's job. It kept the horn from lodging and possbly locking the rear wheel.
If you must keep the stock location, use a healthy dose of Loctite.