Instructables

Step 15: Enjoy the sweet, sweet music

This array can be used either as a hanging sphere(oid), or as two hemispheres. Either way, the radiation pattern can be quite interesting. I like to put the lids in when they're in hemisphere mode.

You're going to need a few things to use your speakers, now that you've got them.

-- Eight channels of amplification. With the money you saved on speakers, you could by a Stewart DA-70-4 for each hemisphere. Or, to keep the whole thing on the cheap, get four t-amps .  Currently, I'm running some class D amplifiers I found on ebay.

-- A source of interesting sound. I am a MaxMSP user, so I've used that software with the nbody~ from the PeRColate collection to create simulated body resonances of string instruments. You can also do this all for free with Pd .

-- I use it to make electronic instruments, or electronically processed acoustic instruments, sound more "real" and blend with other instruments.
 
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Madsengell4 years ago
in order to simplify the amplification, these speaker distrubutional hubs (or the like) might do it, although i don't know how it affects the amplification. Can anyone help there?
http://www.nextag.com/speaker-distribution/compare-html
will they be connected in parallel then, and in that case would it still be sufficient just to connect to your amplifier?

dhnobles7 years ago
Someone should be sure to mention that how you wire the speakers (series/parallel combo) should depend on the impedance of the source you are driving them with and the impedance of the speakers. Most home stereos have an 8ohm output and most aftermarket and good OEM automotive speakers have a 4ohm impedance. BUT some OEM automotive speakers have 12 and 16 ohm impedances. So be sure you check the speaker (look at the magnet its usually printed there) and adjust your design accordingly.
   This is a very cool idea for outdoor speakers on a patio or deck. It could be wired so each bowl is 1 channel of a stereo out put with 4 speakers in each bowl so you have a left channel bowl and a right channel bowl. Its been quite a few years since I did series and parallel circuits but I think I have it correct below. Feel free to make corrections if I am wrong.
    Most stereo receivers can have from 4 - 16 ohm nominal impedance speakers connected to its outputs. If the 4 speakers are wired in series the impedance is additive and so 4 * 4ohm speakers = 16 ohms total impedance which will be fine for most receivers. 4 * 8 ohm speakers = 32 ohms which would be too much impedance and, I believe,  would seriously degrade the volume though would not damage your amp.
    If you were to wire the 4 speakers in parallel this might be a problem as the total impedance is 1/Rtotal = 1/R1 + 1/R1+ .....1/Rn or R1*R2/R1+R2. Using the second equation if you connect 2 - 4 ohm speakers in series you have an 8 ohm circuit. then if you connect these 2 - 8ohm pairs in parallel you will have 8 * 8 / 8 + 8 = 64 / 16 = 4 ohms which will also work with most receivers.  If you connect all 4 speakers in parallel then you would have 1/4 + 1/4 + 1/4 + 1/4 = 1/16 ohms and this would not be good for the output transistors of you amp or receiver.
   I hope I got this right and it is of some help. I am going to try this myself and use the speakers outdoors hanging from the roof of the porch.
Maybe it's just me, but for somebody who just wants an interesting speaker to play music, not in order to try and make more realistic electronic instruments like you, wiring the speakers up would be more efficient. You save on terminals (one per hemisphere) and it'll be easier if you bring it with you somewhere in order to hook it up to an iPod or something.
ya i get it but how i will conected to the radio
you need to put it through an amp and connect the speaker outputs to the red & black inputs on the sphere
shikaku6 years ago
are these in series or in parallel?
mzed (author)  shikaku6 years ago
Neither. Each speaker is wired directly to it's own terminal.
shikaku mzed6 years ago
so to have an input, it would have to be split and thrown into all those terminals? that seem like a lot of wires going in. so i should install all the termainals on the top to keep wires from all over it? or do i just not get it?
shikaku shikaku6 years ago
oh you do have them installed on top... i see. ok...im dumb