If you google DF you will find very god explanations of how it rarely goes above about 20 or 25.
And the motor force factor is obviously more on the 4 Ohm version. More moving force results in a lower Qes, hence lower Qts. Motor force factor = (BL x BL)/Re.
Even though the 4 Ohm version have higher moving mass, the greater motor force overcompensate this.
a few questions if i may, in the expression F = B I L how is L not accounted for in I?
and can someone hopefully provide a math to english translation of F/l=k (I1 I2)/d?
and force is greatest at 90 degrees....
my apologies to the OP for the off topic, to the point i do have my reservations about running low impedance loads on certain amplifiers. and in the quest of better Fi and more power i've paralleled drivers to lower imp loads for more wattage(insert tim the tool man taylor grunt) only to notice image stability suffers to wit i'm looking into what Joe Rasmussen is into these days.
and can someone hopefully provide a math to english translation of F/l=k (I1 I2)/d?
and force is greatest at 90 degrees....
my apologies to the OP for the off topic, to the point i do have my reservations about running low impedance loads on certain amplifiers. and in the quest of better Fi and more power i've paralleled drivers to lower imp loads for more wattage(insert tim the tool man taylor grunt) only to notice image stability suffers to wit i'm looking into what Joe Rasmussen is into these days.
Because I depends on L (length of the wire making up the coil) and the cross-section (guage) of the wire i.e. its resistance/impedance.
//
//
is that where topology takes hold, i can wind a lengthy coil on a small diameter or wind the same length of wire on a large diameter and wind up with a shorter coil?
so which results in a greater Bl?
so which results in a greater Bl?
Last edited:
The longest wire gets the strongest motor - all other the same. Motor (coil + former + magnetics) drives the cone.
So there is a trade of wire length, mass, impedance, wideness of of gap, height of coil vs. height of magnetic gap (overhung, underhung i.e. coil higher than gap or shorter). A lot more than one can immediate think of 🙂
//
So there is a trade of wire length, mass, impedance, wideness of of gap, height of coil vs. height of magnetic gap (overhung, underhung i.e. coil higher than gap or shorter). A lot more than one can immediate think of 🙂
//
Last edited:
After playing around with solid state amps for a while, I now prefer 8ohm drivers. I think all amplifiers I measured so far get significantly higher distortion with 4ohm impedance.
There are examples of the same problem in amplifier books too (D Self I think). Many output transistors usually compensates this pretty well, but the ones I measured only had single or double output transistors.
There are examples of the same problem in amplifier books too (D Self I think). Many output transistors usually compensates this pretty well, but the ones I measured only had single or double output transistors.
hummmm.... that raises the question/debate about whether low level distortion adding to the output is being perceived as beneficial.
Last edited:
I think the driver will add most of the total distortion if the amp is fairly good, but some amps add a lot of high order harmonics, and that is generally not sought for.
There are many views on distortion, even some discussion on distortion from amps cancelling the distortion from the driver etc.. It's up to everybody to have their own opinion.
I just wanted to add to the discussion that there can be downsides to the low impedance.
There are many views on distortion, even some discussion on distortion from amps cancelling the distortion from the driver etc.. It's up to everybody to have their own opinion.
I just wanted to add to the discussion that there can be downsides to the low impedance.
Well, I was wrong about the mass... I assumed that the same gauge wire was used so to go from 8->4 ohm would to me mean half the length. But as the coil need to carry higher current, the gauge is to be heavier... hence the heavier coil.
It's heavier but has half the impedance. Must mean it has about 2 times the area if it has the same length.
So my bet is: the same length.
??
//
Last edited:
Non of them.
B is a strict magnetic property. L is again, length of wire in gap. or did you write "bi" ?
xmax is about spider properties, cone suspension, gap length and coil height as xmax includes a distorsion qualifier.
//
Last edited:
As we can see, a 4 Ohm version of a driver have lower BL than a 8 Ohm version, this means it have less wire (less turn because of thicker wire) in the gap but the increased current flow compensates or overcompensates that less wire.
Last edited:
Driver design deals with a mass of inter-dependant variables, and much has to go into empirical proto-type testing.
Nope. Just check the mentioned Faital 12HP1060, the two versions have exactly the same coil length and gap depth.
Last edited: