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.
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.
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.If it's truly omnidirectional, I see tons of feedback issues down the road if you have any microphones
Some people use these hemispheres:
Electrotap - Hemisphere
But it seems like there could be a more elegant solution.
http://www.cd-konzert.de/Produkte/EBLdia.shtml - pro speaker & driver inside
cheap and simple - 12" pro fullrange, direct it up and try different reflectors (conical etc)))
cheap and simple - 12" pro fullrange, direct it up and try different reflectors (conical etc)))
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Thanks for the ideas. For simplicity, one full-range would probably be easiest. For example,
http://www.diyaudio.com/forums/full-range/131989-small-speaker-based-tb-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?
http://www.diyaudio.com/forums/full-range/131989-small-speaker-based-tb-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?
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).
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.
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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Don't ever use an omni in a live venue! Many live venues tend to be reverberant and an omni will agravate this situation immensely.
Unless you are trying to hide your playing in the reverberation.
Well, as a lot of playing I do is electro-acoustic free improvisation, a good venue will be a decent sounding room, and my point in doing this is to engage the acoustics of the room as an acoustic instrument wood.Don't ever use an omni in a live venue! Many live venues tend to be reverberant and an omni will agravate this situation immensely.
Unless you are trying to hide your playing in the reverberation.
Considering that the "average" of fundamentals only extends to just below 5 kHz..
Perhaps a Visaton B200 inverted and used as as a "walsh" driver in a 1.5 to 2 cubic foot aperiodic vented cabinet? (..and it could be made from cardboard "pipe".) EDIT: actually I think a custom "flight" case (with ABS panels) would be pretty nice.. top that removes to reveal the B200, ect.. (about a 9 inch square opening that's about 33 inches in length including the 4 inch removable top - with "wheels" and a collapsable luggage handle.)
If you want to go really loud (and lower in freq.) then use a subwoofer with a high-pass filter for the B200. (..which is also more portable.)
Perhaps a Visaton B200 inverted and used as as a "walsh" driver in a 1.5 to 2 cubic foot aperiodic vented cabinet? (..and it could be made from cardboard "pipe".) EDIT: actually I think a custom "flight" case (with ABS panels) would be pretty nice.. top that removes to reveal the B200, ect.. (about a 9 inch square opening that's about 33 inches in length including the 4 inch removable top - with "wheels" and a collapsable luggage handle.)
If you want to go really loud (and lower in freq.) then use a subwoofer with a high-pass filter for the B200. (..which is also more portable.)
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Ideally roughly as loud, though not quite as loud wouldn't be terrible -- I generally never go above 8 on the volume.
Some leeway here, but, yes, around that weight or less would be ideal.
60Hz, I'd say.
Ideal would be maybe 8" x 8" x 30" or smaller. I'm going to be carrying this on the subway with keyboards, laptop, and other sensors.
$350? Though again, the less the better.
I know these put some constraints on what I'm able to do, but I appreciate any help or suggestions. Thanks.
OK, this is roughly what was done in the 3" Tang Band design above, correct? Since the Fs of that driver is 105Hz, the quarter wavelength is about 32", just longer than the 30" long pipe used.
Anyways, I could imagine a similar design with a larger driver working for my application, as the PVC is lightweight. I could live with a relatively tall speaker as long as it were not too heavy.
However, assuming I were to pursue a similar design, the main issue seems to be the power rating of the drivers. The Eminence Alphas that are in my current keyboard amp seem to be rated at 125W RMS / 250W music, whereas even the Fostex FE206Ens are only 30W / 90W music. Suggestions?
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There are a number of acoustic instruments which are not omni-directional.
For example all wind instruments are directional, a grand piano is only omni- directional if the lid is closed, drums (other than bass drums ie kick-, kettle-drums and floor toms may be) are directional, string instruments have sound holes from which the bulk of sound emanates added to that the player masks a lot of the other, spurious output etc.
In fact I have problems thinking of an instrument which actually is omni directional, well a triangle might be and the largest organ pipes due to their fundamental frequency.
While it is true that many instruments are not omni-directional, many are multi-directional, or at the least not uni-directional.
The import of this perhaps becomes most obvious when integrating electric instruments (electric guitar) with acoustic instruments in an acoustic setting. Immediately the sound becomes an issue -- if the guitar amp is not positioned well, half the band won't hear the guitar; the easy thing to do is then to turn the amp up, which then, depending upon where one is listening, destroys the acoustic balance of the group.
Similarly with a keyboard as opposed to a piano. When playing the piano, the sound that I hear is fairly close to what the rest of the band hears. Whereas oftentimes when playing keyboard, I think I'm very loud when other musicians find it hard to hear me.
So again, while pure omni-directionality may not be the ultimate goal, a move a way from severe directionality is desired.
In this design would it be advisable to have a tweeter to make up for the loss of highs by placing the B200 off axis?
And, relating to my earlier question, would the B200 be able to handle power from an instrument amp?
Obviously I've been thinking a lot more about this.
If I could use a slightly smaller / lighter speaker, this might make sense. The Ciares seem to be able to handle higher watts than many other full ranges I've been coming across. The Ciare CH 250 looks promising.
1) Are there sources for Ciare in the US? I haven't been able to find many.
2) If not, are there suitable alternatives? High efficiency, wide frequency response, large power handling, not ridiculously heavy or expensive. The closest I've found is this: Beyma Speakers - Beyma 12GA50 fullrange speaker - Beyma 12GA50 500 watt 12" fullrange speaker for lead or bass guitar, organ and loudspeaker applications. Beyma 12GA50 fullrange speakers here.
3) Assuming I locate an appropriate full-range, to be pointed up with a diffuser above, what would be the simplest way to construct a suitable enclosure? At all advisable to use PVC or sonotube?
Thanks!
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