How exactly does a subwoofer work?

[HHR Ed]

the bigger the magnet, generally the more efficient the woofer will be. when the current is going through the voice coil, its electromagnetism is affected by the magnetic field of the strong motor, which causes the voice coil (which is attached to the cone) to move more air.

kind of like comparing an Xplod to a BTL. stronger motor (along with other characteristics) is a means for a louder woofer with higher sensitivity.

http://www.bcae1.com/speaker.htm

http://www.bcae1.com/speakrat.htm

Thats not really true,

Larger motor has very little to nothing to do with efficiency and sensitivity.

[Bumpindemlowzz]

great responses guys thanks.

[Guest]

Thats not really true,

Larger motor has very little to nothing to do with efficiency and sensitivity.

i know its not really that true, hence i put "generally"

edit: but then why does lets say, the example i gave, the xplod and BTL. both being 12" speakers, giving lets say 100w to each. the btl would be louder since its much more efficient since the motor has a MUCH stronger force (and other things)

[HHR Ed]

BL, and motor force is kinda like Torque for a car motor vs. Horsepower.

A strong motor doesnt mean a woofer will be sensitive, it just means that it will have the strength to push a more massive cone and be able to push through power compression.

In the higher SPL range over 155 dB, tremendous air pressure is placed on the cone as it moves. So alot of force is need to push against this air resistance, thats when powerful motors are needed.

But sensitivity and efficiency is more based on the coil charachteristics and mass and weight of the moving parts as well as how the suspension allows the cone to travel.

[MickyMcD]

But sensitivity and efficiency is more based on the coil charachteristics and mass and weight of the moving parts as well as how the suspension allows the cone to travel.

This.

Cheers,

Mick

[tripleb45]

this is teaching me something

[fritosaregood]

no one has mentioned the top plate. isnt that what the coil is repelling from (when it is turned into an electromagnet)

[Boon]

no one has mentioned the top plate. isnt that what the coil is repelling from (when it is turned into an electromagnet)

The top plate, AFAIK, is more for focusing the energy of the motor into the gap.

[Forevrbumpn]

top plate is kind of light a lens, it focuses on the magnetic field, different top plates will achieve different results- narrow, or widen the magnetic field, with a loser, or tighter VC gap, or taller top plate, or shorter top plate, or you can use a top plate with a split design, to created a dual magnetic field, for more coil travel, more linear excursion, without causing distortion, or losing motor strength

There is also Under hung design, and over hung design

1 the coil is taller than the top plate

the other the top plate is really tall, maybe 1.5" tall, and the coil is really short 1.5" tp vs a 0.75 vc example

Power handling is mostly dependent on coil surface area, to dissipate heat, and wire gauge has a little to do with that as well

Different wire gauge gets you lesser or higher ohms common wire gauge is about 24/25g on a 2.5" coil, 22-18gauge on a 3" coil, and about 18-17gauge on a 4" coil

How many layers a coil has, 2, 4, 6, 8 layers determine other factors, like mH - Le of the coil, which will deal a lot with the efficiency of the coil/cone assembly in the magnetic gap

A lot of people are using lesser layers, and much longer winding widths now to produce higher efficiency woofers, to create higher Bl, and lower handling woofers

[Bumpindemlowzz]

Nice to know thanks guys. Im always up to learn something new.