Audio Systems: event audio system

Question
Hello Cleggsan,
Some quick background that might help in the question....
I do a charity event every year that brings in about 4000 people. The venue is about 23,000 sq ft building with hard walls and concrete floors. 80% of the usage at the event is announcing and 20% is music. I am looking for a whole new system. I need an amp and 4 loudspeakers. I have all the cables and accessories but feel free to recommend whatever. It gets very loud at the event (charity boxing) and I need something that's got some muscle. Four speakers are plenty, but the problem now is my amp doesn't have enough power to push the speakers beyond halfway volume level. (This old system was just thrown together piece by piece)

I would like to stay around $3000 - $5000 if possible.
Thank you very much!

Answer
To do right, you need an audio/PA expert who can come into the space and take some measurements and maybe do some testing.  But, as a substitute I guess you are willing to wing it on power and common sense!!

You did not say what loudspeakers you are now using; they are the MOST important part of the system.  Not only the make, model and age, but their placement in the hall.  That is very important.

You may not be able to get more power; if the speakers are power limited putting more power into them can damage their internals.  And, 4,000 noisy people can create a big ambient noise to overcome.  With a hall the size you mentioned is pretty big; about 150 by 150 ft if it is square.  My suspicion is you will need more coverage than 4 speakers can give.

And, about power; it is very NOT linear. Doubling the power of the amplifier, for example, will not double the sound level.  It is because the hearing system is logarithmic.  I won't go into the physics but if you want to double the effective loudness of the system you must increase the power amplification by about 9db.  And to give you and idea how much power that is, 10 db is 10 times power level.  So, to get double the sound level you must increase the power input level by almost 10 times.  That translates into going from a 100w amp to a 1,000w amp; and, then you must concern with the power rating of the speaker system because the increased power by cause burnout of the voice coils in the speaker systems.  Thus it may require you either upgrade the speaker systems or add more of them in order to get the power levels you need.

So, to go further let me know the following in a followup reply:

Dimensions of the hall and the placement of the speaker systems; location and elevation.
Speaker systems by make and model or design and their age.

Then we can get a little more intelligent about the whole thing.

But, I like JBL, Peavey, Yamaha, Pioneer and stuff like that.  

Here is a technical link that may be of interest for tutorial level thinking:

http://sound.westhost.com/articles/pa.htm

See you next time with your followup.