Sound Quality in Outdoor Environments

[Jack Walton]

Hey all - new here and was wondering whether somebody could point me to a study or information that deals with the relationship between the degradation of sound quality (and volume) and external factors in an outdoors environment. I'm interested in what the impact of more plants, or a body of water would be on sound quality and volume for example. Don't care whether it's a pretty academic source.

Thanks!
Jack

 

[Aptone]

Is Oakland complaining about the volume of your music?

 

[twiiii]

There are published tables on air absorption versus frequency versus distance versus humidity. There are also tables that give coef. of absorption of different materials from concrete to glass and I believe different forms of astro turf and grass. But they are not going to tell you what to do with the figures. For that you need some education. There maybe some on line courses, I'm not sure I had to go to an old fashion brick and mortar school. We used HP 41 calculators. I'll give you a hint, wind will screw up sound reproduction out doors contrary to what some folks think. After designing and installing systems for foot ball, and base ball stadiums I would say highs above 7 kHz are useless unless the wind is dead still or behind the speakers back. A lot can happen to sound after traveling 150 ft and by the time it reaches over 400 ft you just keep your fingers crossed. As for sound fall off it 6 db every time you double the distance un less you have an infinite line array.

So if you start out with 132 db at 4 ft by the time you get to 160 ft you are down to around 100 db. And considering a crowd can easily reach over 104 db and you need at least 10 db signal to noise for limited voice frequencies in an out door setting with little reverberation, that means your speakers can only be around 60 ft away.

Meaning life has become very difficult unless the stadium is partially covered and you can hang speakers from the over hang of a roof.. But in that case you have potential reverberation to blur the sound. If not maybe there are light poles in convenient locations to mount speakers. Its the art of compromise.

If you are just thinking about your back yard. Just figure you need 10 db more level than indoors and that you need to mount the speakers against the house or a wall facing the area your interested in to get any kind of bass response at all. 10 db means 10 times the power, or you need to buy speakers that are 10 db more efficient. $$$$$$$$$$$. Outdoors ain't cheap. External limiting or Amps with Power Guard will help protect your speakers and amps from premature failure, more $$$$$$$$.

 

[Lapslah]

I'm afraid there are far too many variables for you to get a meaningful response from a general question. If you can be more specific you may get a better response. Even then, what you're asking is kind of like "Can someone tell me how to do open heart surgery?" - the simple answer might be "cut here", but you'll need a lot more knowledge before you're to be handed the knife.