hi everyone, I am starting this thread as to request feedback as what to do with twelve small ~3" fullrange drivers. I got these from old computer speakers, they are harman cardon, all identical, sounds pretty decent in larger box then original crapy small plastic enclosure.
So I have 6 per side, which is not enought for line array, besides, I already built few line arrays, I like line arrays, but I do not need anymore. I was thinking about something omnidirectional, hexagon? Six fullrange speakers each on small flat baffle arranged horizontaly as hexagon? What do you think? Speakers would be used as computer speakers, or for tv, or for guest room. Nothing special.
One thing I am not too sure about is if I want to radiate the sound all the way to 360deg, or should I position two drivers per flat baffle, and have only 180deg radiation pattern.
So I have 6 per side, which is not enought for line array, besides, I already built few line arrays, I like line arrays, but I do not need anymore. I was thinking about something omnidirectional, hexagon? Six fullrange speakers each on small flat baffle arranged horizontaly as hexagon? What do you think? Speakers would be used as computer speakers, or for tv, or for guest room. Nothing special.
One thing I am not too sure about is if I want to radiate the sound all the way to 360deg, or should I position two drivers per flat baffle, and have only 180deg radiation pattern.
What about mounting the six speakers on the convex side of a hemisphere. If you could find two of those security mirrors found in some stores. Or find two cheapy fiberglass TV sat dishes. When switching from one dish service to another I notice that often they never pick these up. I think I saw several at a scrap building supply place yard.
Now the question is: what is the optimal spacing for multiple small drivers mounted on the face of a hemisphere? I was thinking of using 9ea vifa 3.5" drivers per hemisphere. Connect them up with the right pattern, 3 in series, and three of those series in parallel, should give you an 8 ohm load.
Now the question is: what is the optimal spacing for multiple small drivers mounted on the face of a hemisphere? I was thinking of using 9ea vifa 3.5" drivers per hemisphere. Connect them up with the right pattern, 3 in series, and three of those series in parallel, should give you an 8 ohm load.
this is what I have so far...
A) hexagon with all six drivers facing out
B) hexagon with 2 drivers per side, all six facing forward
C) hemisphere...this would be hardest to built
D) oval or round shaped box...I could find something in Ikea or Container store and reinforce it
E) IMP...Eickmeier Image Model Projector (improved Bozo) with four drivers on each side, some attenuated, remember that infamous Linkwitz Orion beaten by Behringer thread? (not too sure how it was wired)
A) hexagon with all six drivers facing out
B) hexagon with 2 drivers per side, all six facing forward
C) hemisphere...this would be hardest to built
D) oval or round shaped box...I could find something in Ikea or Container store and reinforce it
E) IMP...Eickmeier Image Model Projector (improved Bozo) with four drivers on each side, some attenuated, remember that infamous Linkwitz Orion beaten by Behringer thread? (not too sure how it was wired)
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The drivers are all voiced the same, as opposed to a tweeter, mid and woofer with different materials and T/S parameters. Also, you can use first-order XO's throughout for good phase performance. and there's not much stress on the tweeter and mids.
I see...thanks Scottmoose for explanation
hmmm...I do not know, six identical small full-range drivers are what they are, just an extended range mid...nothing more, one of them will never be as good as one dedicated tweeter, and three will never make one properly designed woofer, so I am not sure if the outcome would be something I would consider worth the effort...crossover optimization, different efficiencies and there would be one tweeter, two mids and three woofers...too complicated
hmmm...I do not know, six identical small full-range drivers are what they are, just an extended range mid...nothing more, one of them will never be as good as one dedicated tweeter, and three will never make one properly designed woofer, so I am not sure if the outcome would be something I would consider worth the effort...crossover optimization, different efficiencies and there would be one tweeter, two mids and three woofers...too complicated
how about this ? omni, line array-ish and no box sound. the speaker line being offset from the center makes the path from each driver a different length to the edge of the baffle, i think that would smooth out those effects. and, easy to build 
i have been surprised how much bass a 6" can give on a 16" x20" open baffle. i think it would work well.
i have been surprised how much bass a 6" can give on a 16" x20" open baffle. i think it would work well.Attachments
Make a single 4pi steradian point source speaker with a dodecahedron speaker. It can be suspended like a pendant light fixture.
Dodecahedron Speaker for Desktop 3D Printers | MAKE
Dodecahedron Speaker for Desktop 3D Printers | MAKE
hmm, open baffle would be easy...
dodecahedron would be super cool, doable still, even I would have to make two of those...I have plenty of those 3" auras...
or I could built both, the open baffle audioguest is suggesting
and two dodecahedrons
X is not too far if he is in Virginia, I am in Bethesda, MD
dodecahedron would be super cool, doable still, even I would have to make two of those...I have plenty of those 3" auras...
or I could built both, the open baffle audioguest is suggesting
and two dodecahedrons
X is not too far if he is in Virginia, I am in Bethesda, MD
One of the main issues with multiple drivers putting out the same thing is the comb filter effects they will create. 2 drivers may be worse case. With many drivers the cancellations get filled in better by the other drivers that have their cancellations at slightly different frequencies.
The vertical line array idea mentioned above (audioguest) may be the best arrangement, especially if it tilts back maybe 10 degrees (metronome shaped cabinet). In the upper-midrange and treble there will be the comb filtering issue (due to the size of the wavelengths). I'd recommend using a passive crossover such that only the top driver puts out anything above 800HZ - 1kHZ. If you added a separate woofer to handle below 200HZ (with a crossover), you might be surprised how good they could sound. Glue acoustic padding to the inside surfaces of the cabinet, rather than just fluff out in the middle - much more effective. Then glue more acoustic padding in any internal corners, and at the ends (top and bottom) of the enclosure. Any variation of thick felt (1/4 inch +) makes a great first layer, and on top of that foam rubber works real well for this. Fabric stores have this stuff much cheaper than "audiophile" distributors.
Most open baffle speaker designs I've seen have "cavity effect" issues on the back side, or the baffle board isn't "dead" enough, so becomes a resonator. Plus Xmax becomes a huge issue if the drivers are EQ'd enough. I wouldn't rec. an open baffle.
The vertical line array idea mentioned above (audioguest) may be the best arrangement, especially if it tilts back maybe 10 degrees (metronome shaped cabinet). In the upper-midrange and treble there will be the comb filtering issue (due to the size of the wavelengths). I'd recommend using a passive crossover such that only the top driver puts out anything above 800HZ - 1kHZ. If you added a separate woofer to handle below 200HZ (with a crossover), you might be surprised how good they could sound. Glue acoustic padding to the inside surfaces of the cabinet, rather than just fluff out in the middle - much more effective. Then glue more acoustic padding in any internal corners, and at the ends (top and bottom) of the enclosure. Any variation of thick felt (1/4 inch +) makes a great first layer, and on top of that foam rubber works real well for this. Fabric stores have this stuff much cheaper than "audiophile" distributors.
Most open baffle speaker designs I've seen have "cavity effect" issues on the back side, or the baffle board isn't "dead" enough, so becomes a resonator. Plus Xmax becomes a huge issue if the drivers are EQ'd enough. I wouldn't rec. an open baffle.
thanks everyone for input
so first I may use those 12 identical full range drivers, and make what audioguest is suggesting, with small variation, that is I will put the tweeter on top, thanks for input Bob
this build should be easy and fast, weekend should be enough...I am not building hi-end stuff here, not expecting great bass, it may be used with sub later, but with decent tweeter, and six full-range drivers per side, it may sound decent
dodecahedron may take some time...
X, I have about fifty of those 3" auras...you are welcome to a dozen or two anytime
so first I may use those 12 identical full range drivers, and make what audioguest is suggesting, with small variation, that is I will put the tweeter on top, thanks for input Bob
this build should be easy and fast, weekend should be enough...I am not building hi-end stuff here, not expecting great bass, it may be used with sub later, but with decent tweeter, and six full-range drivers per side, it may sound decent
dodecahedron may take some time...
X, I have about fifty of those 3" auras...you are welcome to a dozen or two anytime
If you do a search for papercraft polyhedra, you'll find many sites that have pages like this.
http://www.korthalsaltes.com/pdf/half-truncated-icosahedron-black-and-white.pdf
which looks like this, and has 6 large faces.
http://www.korthalsaltes.com/photo/half_archimedean_solids/half_icosidodecahedron.jpg
This is almost the hemisphere, I was suggesting before.
Could be made out of foam core easily. Score to fold, and reinforce the inside of the fold.
http://www.korthalsaltes.com/pdf/half-truncated-icosahedron-black-and-white.pdf
which looks like this, and has 6 large faces.
http://www.korthalsaltes.com/photo/half_archimedean_solids/half_icosidodecahedron.jpg
This is almost the hemisphere, I was suggesting before.
Could be made out of foam core easily. Score to fold, and reinforce the inside of the fold.
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