EDIT: I dnt recall posting this in the TUT sections but since it's here and alot of people wanted a how-to build a sub, then i huess this is what it is. I dnt have pix of everything, so here is what i have and the little i know.
This sub Motor is from A Custom Image-dynamics "SPL" sub that ddbump sold meh....
What i used from Pierce audio Productions:
This has CF/paper back dustcap/cone
2 Nomex spiders
3" VC ID and WW coil
and a black coated die-cast aluminum std basket...
Steps before pix:
When choosing Random Cutom sub parts like i did, without references to common TS Parameters, the sub could turn-out unpredictable. No reference to anything here in my build but the moving mass, sd, and xmax of the subwoofer. Because PAP(pierce audio) has them for there parts ofcoarse. But I wanted to do it and it sounds great now that i did.
: You have to measure a few measurments:
POLE PIECE O
iameter: The Motor Pole-piece which can vary, but on mine was ~3.9" they usually are for 3" Voicecoils. I dnt have a caliper but i have a nice little tool. You can use anything that measures in mms, cms, inches, likely, but not always. This measurement is so you can choose a voicecoil inner-diameter.
iameter: Is usually 3" hence a 3" voicecoil. But measure just to make sure. Has to bigger then the pole OD obviously.
iameter: This minus the pole OD is the gap measurement.
iameter: You will likely need so that you will know how wide the voicecoil can be to fit in your motor gap, say 3mms, ? Depends but commonly i would say ranges between 1mm-5.5mms. Different amounts of voicecoil layers don't determine the width, it still varies on wire guage.
I cannot totally reccomend a gap-fill suggestion, but i believe that tighter gaps to the VC are more fore SPL/efficiency where as looser is for music. And a longer coil winding height may also create more force. What you can do with PAP is simply tell them that your VC ID is 3.9(if it is), and your gap measuremnt is ~4mms(if it is, which was mine). And you can still request 4 or 8 layers if you know the width will fit. Rather it is tight or loose is your decision, which is what YOU will have to learn the idealogoy of in order to step-up from a Newb builder, like myself. Experience in differnt variations is the key.
Also, is the "WW, or WH" I prefer saying WH, makes more sense to me. I am not an expert on the subject but i will give pointers:
EDIT: I will comeback and finish later, im bussy rightnow...I will not continue unless i get requests to do it.
In this first pic i am NOT measureming a gap, or anything! I was origionally trying to showoff the motor width...