Lookig for omni directional design ideas

[ChrisA]

Tried to google this but all I'm seeing is cheap "computer speaker" reviews and the like.

I'm looking for design ideas and want to at this stage cast a wide net.

I want to make a pair of omni directional speakers. I'd like good 360 degree sound. These are for a very specialized use. The listeners will be in an area (up to about 45 feet on a side) with the pair of speakers roughly in the center. I want good bass down to at least 40Hz and very good efficiently, I can select an amp later so it's specs are open but I'm looking at a mid size SET because I like that sound. So the speaker only need to be able to handle that much power (not a lot) Cost is an issue but is secondary to meeting requirements of good omnidirectional sound at moderate volume levels.

What I'm looking for is pointers to design ideas, drivers that might work, design plans or maybe problems I've overlooked. There has to be many design ideas I've not thought of. I'm in the information gathering stage. Next I'll thin down the ideas and test some prototypes.

The basic requirements again are: at least 40Hz, omnidirectional, good efficiently.

The best way to think of this application is "high fidelity sound reinforcement for a theatre in the round." Don't think about the typical home setup with the speakers and listener forming an equilateral triangle. For that I have some 70's vintage Infinity speakers.

 

[901Fixer]

There was a post a while back about some desktop computer speakers that were in the top of a tube facing upwards towards a flared cone. It would be best to use a driver with a dustcap so no filth finds its way into the voice coil gap and cause havoc. If you used a full range driver and a sub below it you could cover the whole range with two drivers. I'll look for the post with the pic.

 

[cuibono]

Hi Chris - there are several commercial omni designs around, and even a few diy ones on this site. One you might be interested in is Siegfried Linkwitz's Pluto speakers. It is very well documented, with lots of info on how to design them. The only caveat is they have active, line level crossovers and integral power amps - and the speakers are not high sensitivity. In fact, high sensitivity might make things a good bit harder to do.

As it was, I just moved back to Redondo, and have a pair of Pluto speakers. If you want, you can hear them sometime. Just email me.

Cheers,

Patrick

 

[901Fixer]

This was the thread, the speakers were still in their rough early stages.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=131989

 

[dlneubec]

Here are some links to my omnidirectional journey, from oldest to newest. There are lots of details in the threads. Most of these are hybrid omnidirectinoal(omni plus monopole), but may give you some ideas or understanding of the drawbacks you might encounter:

http://htguide.com/forum/showthread.php4?t=22445&page=6&pp=35&highlight=omnidirectional

http://htguide.com/forum/showthread.php4?t=25074&highlight=omnidirectional

http://htguide.com/forum/showthread.php4?t=26065&highlight=omnidirectional

http://htguide.com/forum/showthread.php4?t=28906&highlight=Soundrounds

http://htguide.com/forum/showthread.php4?t=29620