Speaker Magnet

[delta3092]

Please redirect me if I'm on the wrong thread.

I was just wondering what is the difference between a single magnet speaker and a dual magnet speaker.

I hope somebody can help.
Thanks in advance.

 

[audioguru2]

A second magnet can add to the magnetism of the first magnet instead of using a bigger magnet.
If the second magnet is physically reversed then the speaker becomes shielded with a very low external magnetic field.

 

[Hero999]

If the second magnet is physically reversed then the speaker becomes shielded with a very low external magnetic field.

Doesn't that lower the sensitivity?

 

[audioguru2]

Doesn't that lower the sensitivity?

I don't think so.

 

[Hero999]

Why not?

If another magnet in phase with the speaker magnet makes the field stronger then another magnet out of phase the speaker magnet will make it weaker. Surely a stronger field means higher sensitivity and a weaker field means lower sensitivity.

 

[audioguru2]

I have seen speakers with two magnets. Bucking magnets are sold.
Maybe adding the second one is only for shielding, not for added magnetism.
A steel cap is also used in addition to a bucking magnet.

The strength of the bucking magnet is not as strong as the strength of the main magnet so the parameters of the speaker are not changed much.
The magnetic field of the main magnet is concentrated inside the speaker and only a small amout of external magnetism needs to be cancelled and shielded.

View attachment 40532

 

[KMoffett1]

I just knew there would be a market for all those magnetron magnets I've pulled from dead microwave ovens.  Lets see, (2 per magnetron x $4.50) + $20 excessive shipping charge...that's $29 per dead oven.

ken

 

[delta3092]

thank you masters. ;D

that cleared things up a bit.