how to determine the voice coil position when designing the driver?
Let us consider I have a top plate with thickness of 5mm and my length of the voice coil is about 15mm so do i need to consider that to 7.5mm as the center of the voice coil?
is there any info regarding this did anybody made their own drivers? how is this calculated?
Let us consider I have a top plate with thickness of 5mm and my length of the voice coil is about 15mm so do i need to consider that to 7.5mm as the center of the voice coil?
is there any info regarding this did anybody made their own drivers? how is this calculated?
For most applications you center the VC windings on the thickness of the top plate.
Overhung or underhung VC's are a whole different ballgame.
Overhung or underhung VC's are a whole different ballgame.
there are two types of motor systems generally so what i posted is the underhung version so for even the overhung i think it will be the same case i believe... if the top plate is perfectly symmetrical...
Notes:
Given:
lc - coil axial length
lm - magnetic gap length
Assumption:
voice coil centered in magnetic gap
Reasons for Departure:
a) asymmetric magnetic field (across gap)
b) face-up or face-down mounted woofer with high compliance suspension (cms) and large moving mass (mms)
Overhang (lc > lm) oh = (lc - lm)/2
Underhang (lc < lm) uh = (lm - lc)/2
Note that xmax > hang (h) because
a) the magnetic field extends beyond the pole pieces and
b) some overshoot may be sustained while still staying within distortion limits of the xmax parameter.
Regards,
WHG
Given:
lc - coil axial length
lm - magnetic gap length
Assumption:
voice coil centered in magnetic gap
Reasons for Departure:
a) asymmetric magnetic field (across gap)
b) face-up or face-down mounted woofer with high compliance suspension (cms) and large moving mass (mms)
Overhang (lc > lm) oh = (lc - lm)/2
Underhang (lc < lm) uh = (lm - lc)/2
Note that xmax > hang (h) because
a) the magnetic field extends beyond the pole pieces and
b) some overshoot may be sustained while still staying within distortion limits of the xmax parameter.
Regards,
WHG
Rhyth,
are you going into driver design and manufacture?
If so why are you needing to ask this question?
If not, then you will find many references refer to the VC overhang when the driver is at rest.
are you going into driver design and manufacture?
If so why are you needing to ask this question?
If not, then you will find many references refer to the VC overhang when the driver is at rest.
yeah actually its at the mid point but when I checked the klippel paper on the vc position its slightly different... http://www.klippel.de/uploads/media/AN_01_Optimal_Voice_Coil_Rest_Position.pdf
I believe, as stated in the Klippel paper, the center would be further in the gap, a slight offset due to the difference in the magnetic field. If the pole piece were to be extended this offset would be reduced by creating a more symmetrical field. A copper sleeve on the lower pole piece does help, but doesn't correct the external symmetry. Think its Wavecor that is currently doing this (among others I'm sure)
Well yes it is... Wavecor Balanced Drive
Well yes it is... Wavecor Balanced Drive
Hi
In a budget driver the placing of the voice coil can be / should be displaced from exact center of the magnetic gap to compensate for :-
1. Suspension non linearity
2. Voice coil inductance non linearity , AC Field
3. Motor structure non linearity , DC Field
Suranjan
In a budget driver the placing of the voice coil can be / should be displaced from exact center of the magnetic gap to compensate for :-
1. Suspension non linearity
2. Voice coil inductance non linearity , AC Field
3. Motor structure non linearity , DC Field
Suranjan
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