There absolutely has to be a correlation between the two. The more intelligent a person is, the more self-aware, selective, and articulate they typically are. The less intelligent a person is, the more they lack the self-awareness, word choice, and social decency to monitor their volume of speech. The less intelligent also require more words in order to convey their thoughts (although they are usually not worth saying due to a lack of selectivity). Pairing incessant speech with abrasive volume levels creates the perfect combination for a disruptive, distracting, and indeed troublesome social environment.
The implications of this are most apparent in the educational setting. The classroom environment is judged on its potential for learning; a quiet, cohesive, and consistent atmosphere for the exchange and discussion of ideas. I can’t begin to describe how easy it is for a handful of noisy students to absolutely ruin a classroom setting. I’m sure it doesn’t take very long to think of several over places that noise level compromises the environment. The movies, restaurants, the library, public transportation…actually, the more I think about it, the more I realize that a high noise level is abrasive in all but a few social settings. Calling for help, cheering at stadiums, or alerting the public to a natural disaster may be the only times a high volume of speech is necessary.