Sound Reinforcement Speakers (1 Viewer)

[Travis G]

Hello everyone, I feel like the prodigal son. It's been awhile but it's hard when you don't have the internet.
My father-in-law asked me to design him some speakers for him to play a small local night club (I am thinking maybe 20 - 40,000 ft^3). I have never designed a full range speaker before (only woofers and subwoofers). I agreed to help but now I'm wondering if this is too hard a project for such an inexperienced designer such as I.
I guess what I am worried about is directivity; too little and the system will feed back. With too much directivity it might sound way too bright in the back and boomy in the front and in the middle. There will be only one microphone so feedback probably won't be TOO much of a problem ( It will be just him and his electric guitar).
The ways I know to control directivity is to use horns, larger front baffels, larger loudspeakers, and higher crossover frequencies. But since all the books I have read are mainly about designing hifi speakers I'm feeling a little lost.
So to the point I have a few questions:
1. Is it reasonable that I can design decent loudspeakers for this purpose with sound meter, my ears ( I think I have pretty sharp ears), a volt/ohm meter, and a test cd?
2. If I go with a 3-way system (two-way L/Rs and horn woofer [designed with the help of Bass Horn Design], what sizes of drivers would be good for the L/R pair?
3. What range of crossover frequency would be most likely to be good for the L/R pair?
I would greatly appreciate ANY helpful advice/criticizm.
Travis

 

[Hank Frankenberg]

Well, line sources solve some problems re sound reinforcement/PA type applications.

 

[Thy Luc]

Have you seen this article?
Nice system using JBL's, one horn, one 10" midrange,
dual 15's for midbass per cabinet,
..... and four 18's for subs ... (I think)..
http://www.audioheritage.org/html/pe...ues/system.htm

 

[Mark gas]

whats your buget and how much power will you be using?

 

[John E Janowitz]

There was an article in Audio Xpress about a full range horn speaker system. It was a W shaped horn that I believe had the rear chamber vented out to the front as well. This thing was capable of something like 138dB from 100Hz up to 16KHz, and compared very well to some expensive Turbosound speaker they showed in the article.

It's not an easy project to build, but it's a proven design that you can build yourself.

John

 

[Wayne A. Pflughaupt]

Travis,
As you can see, this is not the best forum for this topic. I think you will be able to get all the answers you need at the Live Audio Board.
Regards,
Wayne A. Pflughaupt

 

[Travis G]

Hank, by line sources do you mean imaginary lines from floor to ceiling from which all the sound eminates (well in a perfect world)?

Thanks Thy, thats a cool link I am about to read it now.

Mark, the amount of power that will be used is going to depend on how much is necasarry to achieve (just guessing) average levels of ~ 80 dB at the back. The budget is basicly as cheap as possible and still have speakers that won't distort appreciably or self destruct. I may have him use a compressor to keep the peak levels low enough so we can get away with less dynamic range.

Thanks John, I'm probably going to buy Bass Horn Design since it's only $20.

And thanks Wayne I will repost my questions there.