4" vs 5" voice coils

if a larger voice coil has better thermal capacity and therefore lower power compression at high power, this could explain a lot

(this is a theory i have just thought up) :lol:

discuss

smiley36 good luck

it's impossible to wind up around here... smiley36

Mechanicaly, larger voice coils sit further up the cone in relation to a smaller VC. This would add stiffness to the cone in an important area.

well well well, i thought the cone just tapered in faster to a smaller base

actually thinking about it, ive never had a 4" coil driver apart. only 5"s, so never compared.

saul wrote: well well well, i thought the cone just tapered in faster to a smaller base

actually thinking about it, ive never had a 4" coil driver apart. only 5"s, so never compared.

Prefer 5"VC drivers myself.

IMHO, PD1850, V18-1000, PD186 have something special about them.

One thing I can't stand with newer high power 4"VC drivers, is tendency to attach weaker strength magnets, then stuff 4" VC, of approx 10 miles long in an effort to acquire BL, which inevitably increases Qes, and reduces sensitivity.

there's another reason....

true enough, however the greater weight of a 5" voice coil will reduce sensitivity all things equal versus a 4" coil, so, as usual with speakers it is a balancing act.

i guess your preference will depend on what you want out of the unit - for sheer power handling, cone control and output, then 5 inch motors are going to have an advantage, but for sensitivity and tonality then 4 inch motors might have it - a bit like the sound of an 1850 versus the fane 18xb.

thats my take on it anyhow

Just to clarify, When I said about the larger coil sitting further up the cone, I didn't mean that some of the cone is on the inside of the coil. It's just that it sits further up on a larger diameter. Mechanically, a larger coil give a more stiffening strength to the cone. It is also related to the overall diameter. Years ago it became obvious about coils size when the first 24"PD came out, it was quite a slow response speaker. Then the 21 happened, same coil but the response was much better. to me , it was clear that a 6"coil is better on a smaller cone. I've seen lazer pictures of the celestion speaker where you can see the coil trying to twist its way through the centre of the cone, demonstrating what force is applied to the neck of the cone when in operation.
Baring in mind the debate about handling power, slow/fast response with a four/five inch coil, Perhaps B and C plus others who produce 4.5" coils have the answer.

so we're talking the same science then

im not sure i agree on the 4" quality vs 5" sensitivity thing, because there are too many drivers that do the opposite. especially looking at "real" subwoofer efficiency (it has too much to do with the BL and coil size surely)