NSB wiring and phase plugs...

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N

nerd of nerds

Member
Joined 2004
hello! i've had a case full of those 4" pioneer buyout drivers sitting in my basement for about a month now and i decided that it was time to build some arrays!

i've been experimenting with coatings on the cones to tame that 7khz peak and i think that i have...at least i can't tell its there anymore...


but after various mods i'm left with only 28-30 woofers so i'm saving some for a PC surround system and the rest are going towards my arrays...

there will be 12 nsbs per side and i'm a little confused on how to wire it...:dead: i need it to be around 8 ohms...

also, on the parts express page it suggested drilling a 1/4" hole in the dust cap but it seems like adding phase plugs would be much easier than accidentally stabbing in the dust cap 32 times and having to order another case of these:cannotbe:

what would the easiest method be to make about 24 phase plugs cheaply and quickly?

i had the idea of making 1 out of clay then making a mold out of it and casting some resing phase plugs filled with copper BBs so that it would magnetically atatch itself to the woofer:smash:

but i'll wait until i get some more ideas until i start on that...


thanks!
 
J

John Sheerin

Member
Joined 2003
jhsaudio.com
Copper is not a ferro-magnetic material. I'd try something else if you want it stuck on there... Also, if you use something that is a magnetic material like steel, it will change the flux path around the gap. This might be good, but it would more likely be bad. Le would probably go up, BL would probably go down a little. The easiest way might be to make wooden plugs - find a dowel rod of the right size and cut a bunch of pieces off, etc. Stick them on with a dot of CA or something so you can pop them off if you decide you don't like them.
 
N

nerd of nerds

Member
Joined 2004
John Sheerin said:
Copper is not a ferro-magnetic material. I'd try something else if you want it stuck on there... Also, if you use something that is a magnetic material like steel, it will change the flux path around the gap. This might be good, but it would more likely be bad. Le would probably go up, BL would probably go down a little. The easiest way might be to make wooden plugs - find a dowel rod of the right size and cut a bunch of pieces off, etc. Stick them on with a dot of CA or something so you can pop them off if you decide you don't like them.
Click to expand...


hmmmm...then these copper BBs must not be all copper...they stick in there pretty well...i have to use pliers to gem em out...

and a "dot of CA"? please explain...

and i have just been experimenting with different ammounts of watered down elmers glue...i think that 2 coats works well...but i'd recomend that you experiment a little...

a phase plug redirects frequencies...and i would guess that unless the driver was vented it would allow for more excurstion than a dust cap...i think...



any ideas on how to MAKE the phase plug?
 
R

RJ

Member
Joined 2004
Someone on another thread made phase plugs out of a copper rod used for electrical grounding. I don't have the link. Should have saved it.
He also painted the cones and covered the back of the frame and magnet with rope caulk.
CA stands for Cyano something. Crazy Glue.
 
X

x. onasis

Member
Joined 2003
Tho' I do like the "get a machinist buddy to do it" idea...., how about using a router, table and roundover bit to "pencil sharpen" a wooden dowel, then cut it to length?

We're talking about a 5/8" dia. (I think)
Drill an appropriate sized hole in a two-by board, then rip it to a size where, when the material is removed for the cutter bit itself, it can be clamped to the router table. You can then, gently push the dowel down into the hole and "sharpen" the end. After cutting to length, insert a washer/screw to magnetically attach or glue. (I'd put a large clamp on the dowel to limit the depth of cut and give yourself a handle to slowly turn it)

For wiring, check Dr. Griffin's Figure 12, pp 22
 
purplepeople

purplepeople

Member
Joined 2003
Make the phase plug out of hardwood dowel. The new JVC mini-system has them. I believe Planet10 has some for sale. If you're like me, you would DIY by screwing a lag bolt into a piece of wood, hacksawing off the head and turning it in a drill mounted to a bench vise. But that's very dangerous and I can't recommend it. Of course, the real problem is how to calculate, then reproduce the profile curve.

:)ensen.
 
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