TNT, Welcome to RO:
You are looking at this as if there is a program out there that will tell you to use so much power in a room of a particular dimension, and yield a certain SPL when you do so. Am I correct in that ?
Do you have any understanding of speaker sensitivity ratings? Of the effects things like PEOPLE and FURNITURE in the room have on sound?
There are soooo many variables in your scenario. There are some programs out there, but they are linked to the equipment in some way.
JBL, for better or worse, might be a good starting point for you . Go to their website and checkout what they have. You might also go to the MIX Bookshelf and check out some of the publications thay have on acoustics and live sound. Yamaha has (had?) a great primer for live sound, and that book has been on the MIX site. And even this website has a place with some publications that you can learn from....Read up on all you can, baby!

Jim "If There Was a Magic Formula, I'd Be Outta Work!" Mooney

Live Sound Math

Thanks, was hoping some of the variables would be negligable. Pulling out the Yamaha Sound Reinforcement Handbook.

Thanks,
TNT

One thing that you will HAVE to learn and apply is the Fletcher-Munson curve. This deals with athe realationship between power (watts, rms) and decibels, and how one changes the other. Good Luck!

moonbaby wrote: One thing that you will HAVE to learn and apply is the Fletcher-Munson curve. This deals with athe realationship between power (watts, rms) and decibels, and how one changes the other. Good Luck!

Not really. Studies are showing that those curves are not the norm any more. Our society is exhibiting signs of serious threshold shifts earlier on. The ear is most linear at about 85dB. But, I don't of any shows that have been that low with success, unless the acoustics are excellent, and the musical genre lends itself to that.

Go to Crown's (the amp manufacturer) website. They have this calculator. It is simple. All you must know is the distance away from the speaker, the sensitivity of the speaker, and the desired headroom. This is really a moot point without knowing the amplifier's efficiency, speaker cable length, noise floor of the room, etc.

If you have some drafting exerience the program Ulyesses (spelling?) could be beneficial.

Cheers,
-Ryan-