Does anyone have a notch filter for NSB's?

[GuyPanico]

I cant seem to find a post or a site where they notched out that 7khz peak NSB's have. Does anyone have a notch filter they would care to share?

[sreten]

Hi, if you mean NS3's, /sreten.

[thylantyr]

Alternative;

You can lacquer cone treat the paper cones, 4 - 6 coats,
to tame the gremlins and drastically improve the sound
without using filter design. Fix it mechanically not electrically
using this tool ->

[GuyPanico]

Just the person I was hoping would post I was thinking about lacquering them, but didn't know if it would be enough to really do anything to that huge peak. Would it happen to help the dip at 15khz by any chance too?

Can you recommend a good ported design? I'm going to do 8 per side, all the same volume. Just lots of internal bracing.

[thylantyr]

I crossover my NSB array at 1.7khz - 2.25khz, 8th order.
When I was doing full range listening tests, treated and
untreated cones, the treated cones sounded drastically better.
Everyone who has done it also makes the same comments.
4 to 6 coats of lacquer on the paper/dust cap {not rubber surround} worked best for me. You can do mechanical stuff to
improve the NSB sound but you may desire to tweak further with electrical tweaks.

If you have some spare NSB's then the experiment is easy,
but if you don't have any spares, you have to becareful.
I run my line array with 16 NSB per tower and 10 PT2 planar per tower, 1.5 cu. ft. per chamber, 4 NSB per chamber, tuned to
100hz with 6" hole in the back of each chamber. I designed the ported box to provide a midbass peak on purpose to create more upper midbass without stressing out the NSB's and if there is too much midbass, I use the equalizer to tame the peak. I find it
easier to attenuate the peak than to boost bass, a different
approach.

The ported issue is a simple one, build a 4 driver test box and see for yourself what you like. I think 75hz - 100hz tuning is ideal for these little drivers. If you want to boost power handling,
inject oil based ferrofluid using a syringe into the dust cap,
but that liquid is expensive, $100 a bottle. // lol // I drove one
NSB with 200w clipped amp playing heavy music for 10 minutes
before the driver failed {400w peaks}.That's how much
power handling increased with fluid installed. // lol //

My 4 NSB test box was good. But when the array was completed
with 16 drivers, it was very dramatic in performance especially when you do low impedance wiring and have a proamp behind it.
You might be amazed at 8 NSB per tower, but if you do a 16
NSB with port, low impedance, fully active, high power, the
performance will shock you.

[GuyPanico]

What is the length of the port you are using?

[thylantyr]

1 3/8" length {speaker wall thickness with round over} - hehe