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-   -   Omni-directional for live performance (http://www.diyaudio.com/forums/pa-systems/166303-omni-directional-live-performance.html)

Dogue 4th May 2010 03:25 PM

Omni-directional for live performance
 
I'd like an omni-directional speaker for use in live performance (primarily keyboards and electronics).

Here are some design goals:

-Capable of handling signals from keyboard/laptop
-Omni-directional so it excites the room in ways similar to acoustic instrument
-Integrated digital amplifier (perhaps from 41hz.com kit or similar)
-Simple design
-Loud enough for live use
-As small and lightweight as possible

I have not built speakers before, though I have built various guitar effects pedals and the like and can read schematics and solder. I am a musician, but I have not found anything quite like what I want, so I'd like to build something.

What advice do you have? Thanks a lot.

MaVo 4th May 2010 04:01 PM

Tendencially difficult, i guess, since for omnidirectional behaviour you need small drivers without waveguides or horns and for live performance (higher spl) you need big drivers with waveguides or horns.

For a hifi omni design, check siegfried linkwitz homepage... i think its called pluto.

Glowbug 4th May 2010 04:03 PM

If it's truly omnidirectional, I see tons of feedback issues down the road if you have any microphones :)

Dogue 4th May 2010 04:46 PM

Quote:

Originally Posted by Glowbug (Post 2175515)
If it's truly omnidirectional, I see tons of feedback issues down the road if you have any microphones :)

Yes, I had thought of that...I don't currently have plans to use microphones. Perhaps occasionally electro-magnetic pickups, but probably not air microphones.

Some people use these hemispheres:

Electrotap - Hemisphere

But it seems like there could be a more elegant solution.

Flaesh 4th May 2010 05:06 PM

http://www.cd-konzert.de/Produkte/EBLdia.shtml - pro speaker & driver inside :D

cheap and simple - 12" pro fullrange, direct it up and try different reflectors (conical etc)))

Flaesh 4th May 2010 06:30 PM

http://www.diyaudio.com/forums/multi...tml#post439519

Dogue 4th May 2010 08:38 PM

Thanks for the ideas. For simplicity, one full-range would probably be easiest. For example,

http://www.diyaudio.com/forums/full-...-3-bamboo.html

Though I'd probably want a more efficient speaker and one with better bass response.

My current keyboard amp has these specs:

Power Amplifier – 50-watts RMS/channel, (100-watt RMS total)
Speakers – Two 8” Eminence Alpha, 125-watt, 8 ohms
Horns – Two 80-watt 3.5X3.5 Ferro cooled dynamic
Frequency Responses – 70-17 kHz
Crossover – 3 kHz

Ignoring stereo for the moment, what would one suggest for components?

Would it be possible (or advisable) to build something like the PVC design above though with a larger, more efficient speaker?

el`Ol 4th May 2010 08:38 PM

Suggestion:
Take a really large fullrange driver with high Fs and a very strong motor (e.g. Ciare CH321) and pack it in an ML-pipe with length ^= quarter wavelength of the driver's Fs (130 cm for the Ciare).
A diffusor cone on top, of course.

Dogue 4th May 2010 08:51 PM

Quote:

Originally Posted by el`Ol (Post 2175799)
Suggestion:
Take a really large fullrange driver with high Fs and a very strong motor (e.g. Ciare CH321) and pack it in an ML-pipe with length ^= quarter wavelength of the driver's Fs (130 cm for the Ciare).
A diffusor cone on top, of course.

Thanks for the suggestion. While that may sound quite nice, I worry that it would be larger and heavier than what I need (I'm going to be carrying this around in addition to keyboard, laptop, etc.). Ideally the speaker would be around 20 lbs. (9 kg) or less and fairly small. Is this a pipe dream? (Pardon the pun).

gooki 5th May 2010 03:43 AM

Quote:

Thanks for the ideas. For simplicity, one full-range would probably be easiest. For example,

Small speaker based on TB 3" bamboo

Though I'd probably want a more efficient speaker and one with better bass response.
The problem with wanting better bass means you'll need a bigger driver, and a bigger driver will no longer be omni directional at high frequencies without a diffuser.

Quote:

Ideally the speaker would be around 20 lbs. (9 kg) or less and fairly small. Is this a pipe dream?
All depends on what compromises you are willing to accept. Try an answer these questions.

How loud do they need to be? (compared to your keyboards current speakers)
How heavy? (already answered - 9kg)
How low do they have to go? (a specific hz would be nice)
How large can the be?
How much are you willing to spend?


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