magnets
05-13-2005, 03:27 AM
#1
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Location: Columbia, SC //Goldsboro, NC
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magnets
can someone please explain to the purpose of the magnet on speakers, and how size relates to quality if it does at all.. because I always thought the bigger the magnet the better the speaker
05-13-2005, 07:00 AM
#2
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Join Date: Apr 2003
Posts: 265
The amp sends voltage to the voice coil. As we all learned in Physics 101, sending a current through a wire creates a magnetic field. This field interacts with the field created by the stationary magnet attached to the speaker basket. Since the voltage sent by the amp is alternating current, the magnetic field created by the voice coil is quickly switching back and forth between positive and negative. The fixed magnet always has a positive field. Back to physics. The negative field on the coil is attracted to the positive field of the fixed magnet. That pulls the coil into the field. The coil is attached to the cone so the cone moves in as well. The voltage through the coil quickly switches to positive. Everyone knows that like magnetic charges repell each other. So the coil is now pushed away from the magnet and the cone moves out. Now speed things up to where they happen between 20 and 100 times a second for subs and up to 20,000 times a second for treble and you get sound.
The size of the magnet is a great marketing tool aimed at people like you. I really don't care how big my magnet is. I look at the BL or the strength of the magnet. Different materials have different strengths. Neodynium (sp?) magnets are usually small but they are extremely powerful. They are also expensive so you don't see them that often on subs.
-Robert
how size relates to quality if it does at all.. because I always thought the bigger the magnet the better the speaker
-Robert
05-13-2005, 10:28 AM
#4
Originally Posted by Robert_J
The amp sends voltage to the voice coil. As we all learned in Physics 101, sending a current through a wire creates a magnetic field. This field interacts with the field created by the stationary magnet attached to the speaker basket. Since the voltage sent by the amp is alternating current, the magnetic field created by the voice coil is quickly switching back and forth between positive and negative. The fixed magnet always has a positive field. Back to physics. The negative field on the coil is attracted to the positive field of the fixed magnet. That pulls the coil into the field. The coil is attached to the cone so the cone moves in as well. The voltage through the coil quickly switches to positive. Everyone knows that like magnetic charges repell each other. So the coil is now pushed away from the magnet and the cone moves out. Now speed things up to where they happen between 20 and 100 times a second for subs and up to 20,000 times a second for treble and you get sound.
The size of the magnet is a great marketing tool aimed at people like you. I really don't care how big my magnet is. I look at the BL or the strength of the magnet. Different materials have different strengths. Neodynium (sp?) magnets are usually small but they are extremely powerful. They are also expensive so you don't see them that often on subs.
-Robert
The size of the magnet is a great marketing tool aimed at people like you. I really don't care how big my magnet is. I look at the BL or the strength of the magnet. Different materials have different strengths. Neodynium (sp?) magnets are usually small but they are extremely powerful. They are also expensive so you don't see them that often on subs.
-Robert
cliffs notes: magnet size is nothing to be concered with unless you have like a 32oz magnet structure on a 15" sub with 28mm of xmax.
05-13-2005, 11:33 AM
#5
my bostons got some neoymium magnets and if you just based performance on magnet size, you'll think they're 'weak'. neodymium are super strong in relation to their size. magnet size isn't everything like robert mentioned.
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