Driver Prospects for Open Baffle Mischief

[wrenchone]

Attached is a photo of two drivers I'm considering for OB line array duty. The round one on the right is the infamous Pioneer NSB driver. I purchaed a box of these a couple of years ago. The oval driver on the left is a Samsung speaker currently on sale at Electronic Goldmine for ~$1.50. I'm thinking that the oval shape might present fewer difficulties with breakup modes, but I suspect both drivers would benefit from cone treatments. Suggestions? Also, if someone still has the TS parameters for the Pioneer drivers, please let me know. I have no parameters for the Samsung driver, which no doubt was destined for TV duty. Preliminary scans with an impedance analyzer show a resonance at 180 Hz. I had line arrays of its smaller brother ( also a Goldmine buy) going a month or two ago ( 16 pieces/side, cardboard baffles), and the midrange sensitivity was amazing. Absolutely no bass, though, even with an 18" wide baffle. Time to finish my subwoofer amp...

[wrenchone]

Bump - Has anyone treated the Pioneer NSB drivers for soother response? Still looking for those T/S parameters....

[norman bates]

If I remember correctly, the nsb had a pretty nasty spike near 8khz.

You can find if you search hard enough, all sorts of tweaks including poking a hole in the dust cap with a hot soldering iron.........

I wouldn't expect much bass at all on a baffle 18" wide..........

If the driver is 14" from an edge, I'd expect a dip near 500 then a feq (+3 to +6db) hump at 250hz............... Then drop like a rock below that.........

Line arrays are tricky.
You can run a nearfield on but you have to be closer than the line length, or make it floor to ceiling then hope for the best...........

Combing is a problem............... on a flat array with full range drivers, you'd need to boost the upper octaves or else no highs.
Read on the kuze array.
http://www.parts-express.com/project...oject=Kuze3201


Here are some nsb stuff
with a qts near .6, I'd expect even if it was mounted on a wall, It'd be 3db down at 130hz and rolling below that............

http://ratch-h.com/69centwonder.html
http://www.ratch-h.com/269-469spectra.html
http://ratch-h.com/NSB.html
http://ratch-h.com/ami.html

Actually freq response looks similar to the pioneer a11 but that driver has a lower qts of .35 and fs = 70 instead of .6 qts and fs near 110hz............... and the a11 has more high end..............

But the a11 is $13 in >4 lot quantity while the nsb were inexpensive.....................

The nsb waterfall looks better than the pioneer b20...........

Norman

[wrenchone]

I'll be pairing the arrays with a subwoofer and adding a line of tweeters for the high end. I never expected the arays to rumble... The 18" was for the cardboard baffles I used to audition a line array of Samsung speakers very similar to the ones in the picture, but somewhat smaller. Due to the form factor, the Samsungs will pack really close. making combing less of a factor.

I'd heard about the nasty NSB frequency bump, and I wouldn't be surprised if the Samsungs have something similar lurking in the upper end of their response curve.

Instead of using my old DBX subwoofer, I may gin up a pair of bass cabinets and use them as stands for the line arrays. I have some Vifa 8" woofers I got from BG Micro a while back that would make some OK small subs using a couple of pieces per side.