Altec driver regaussing

[invalidbuffa]

I was reading about remagnetizing drivers on the GPA website: https://greatplainsaudio.com/alnico-magnets-degaussing-losing-magnetic-field/

Is there a simple test I can perform to determine if my 416As would benefit from regaussing? Is it just a matter of measuring the driver's sensitivity?

Thanks

 

[twiiii]

You might try measuring free air resonance, you can do that with out to much difficulty. measuring sensitivity can be frustrating with out calibrated test equipment and knowing the prescribed testing procedures. A 416 is a woofer where the voice coils is equal or smaller in depth compared to the magnet poll. If you had a 411 woofer or a 3156 you might have an issue, but they have ceramic magnets. Yes your 416's can be affected, and you will have an improvement in any event. I would go for it, you might find out you have other issues, too and that a re-coning will in addition make them like new. Such a deal. I would compare costs of repairs and shipping with buying new. Remember I would think the paper of today is superior to the past, but only GPA can tell you the exact differences if any...

 

[invalidbuffa]

Thanks. Now I have some things to think about...

Would one of those speaker measurement systems from PE tell me anything useful? I've been putting off getting one until I had a good reason to.

 

[toddalin]

Woofer Tester 2 from PE will determine the BL which is directly related to the strength of the magnet.

I had some JBL AlNiCo 2205s reconed at OCS as 2235s and had them re-shot. On WT-2, the BL was still low so they shot them again (no charge) and it rose above factory spec.

You have to remove the speaker and be prepared to put coins on the cone to perform the test.

 

[johnlcnm]

Measure the Qes or the Qts. Refer to "How to Design, Build, & Test Complete Speaker Systems" by David Weems. The electrical Q or total Q will tell you the condition of the magnetic motor system.