Instead of trying to guess "How much acoustic treatment do I need?" or trying to cram an entire 4 years of college-level acoustical education into weeks of endless online searches, let us help you make the best choice for addressing the unwanted echoes and improve speech intelligibility in your worship facility. In the contact form let us know your about your room (what are the floor, walls and ceilings mostly made of), the room size, the problem you wish to address and the timeframe you are working with. Also, if possible, send any pictures and/or video that you want us to see when coming up with the best plan of attack for your room.
Acoustic projects for churches typically run in the "thousands of dollars". A smaller project will require around $1,000. A middle of the road sized project will be in the $3 to 5,000 range. A fairly large project will run $10 to 15,000 and a big project will cost $25 to 50,000. Converting a big room that sounds like an empty gym into one that sounds like a church is safe to estimate around 20 cents per cubic foot. (L x W x H)
All prices are in USD.