Dipole Using $.69 drivers

[DougL]

I was curious what the dipole speaker sounded like, and I have some 69 cent drivers. I mounted 2 in a Shallow u baffle 15 by 12 with 4" "wings".

Fired them up over the weekend.
Other than the expected issues of no base wth a fs 105 hz driver on a small baffle and poor virticle hgh frequency dispersion of an "MM" speaker, they exceded my expectations by a wide margin.

They are on test baffles of abismal woodworking. I can post pictures if anyone is interested.

Has anyone else done any simular experimentimg?
I'd love to compair notes.

Doug

[johninCR]

That's kind of how I got started on dipole line arrays. I just used 5 drivers and that foam filled posterboard. I was floored by the results and made a second one to use the pair as my desktop speakers until a few days ago when one of them got wet.

[JinMTVT]

did just the same kind of test rig last week

here is a picture :



cheapo car door drivers (civics 1988-95 )
10 of them

nothing under 100-150hz

plenty ( to much ahah ) of mids
and nothing much after 13-15k

but for what the drivers are, the SPL before untolarable distortion levels are really high!

and sensivity is good also
( thought an impedance of 4.5ohm does help )

[johninCR]

When looking for cheap drivers for this kind of thing, I go and listen to whatever the electronics shops have. I just hold it in my hand and listen on and off axis for the quality of sound. I bring a couple of pieces of cardboard with me with different size holes and try the better sounding ones with the small cardboard baffles to get a feel for the Qts to see if it's high enough to generate at least some bass on OB. It's readily apparent. You can even just wrap your hands around the outside of the basket to form a mini baffle and get a feel for what it will do on OB.

The difference in sound between drivers is dramatic, but you can find some really sweet super cheapies. My favorites are some $1.50 B&K 4"ers.

[Chris8sirhC]

Where do you get those B&K 4''ers? I currently have a line array of those parts express .49 that is 16 units high. Its weaknesses are that it doesnt have that much in the bass dept, but its not all that noticable with the music i listen to most of the time. Also the highs are a bit lacking from comb filtering and lack or response above 15khz. What it does do very well is the human voice and the rest of the midrange.

[johninCR]

At an electronics store here in Costa Rica. I've been waiting on 80 more that were supposed to be in 3 months ago. I never could find anything about them online.

Mine roll off pretty steeply just above 10K. To fill in the high end I put a highly efficient Pyle titanium bullet tweeter in the center of the array. I tweak each with small pieces of foam rubber stuffed down in the throat around the bullet plug which totally eliminates the harshness and brings out the detail without losing much sensitivity. I use an Lpad to balance it with the array.

How much distance do you have from the floor to first driver. If
you have room, just put a pair of cheap 12" woofers in a W baffle at the bottom of the array. It will really help fill out the sound. Just use a single coil and do a first order rolloff starting at say 120hz. If you like to listen at loud levels on occasion, you may want to add a cap to roll off the bass for the array drivers below 120hz. Those little drivers in free air can handle very little power below Fs and will burn out easily. That will also clean up their sound above that point because right now they are struggling trying to play those lower frequencies. Even though you can't hear it, they are trying.