View Full Version : when to remagnitize?

louped garouv
10-01-2004, 12:52 PM
i have a pair of Altec Model 19 studio monitors....

the bass response is dramatically lower in one speaker than the other. But i do not hear any cracking or humms or anything else, its just that the bass is not as pronounced as the other speaker -- could this be a sign that the driver needs to be remagnitized or something else need work? (obviously or they would both sound great)

thanks for the insight, and the great forum.......:banghead:

BTW -- surrounds, cones , etc seem to be in great shape as well....

scott fitlin
10-01-2004, 01:47 PM
Have you checked everything? Have you swithed the speakers around from channel 1 to channel 2 to make sure its not something in your electronics? Are you sure its not something in the passive crossovers?

You have alnico magnet 416,s? If you do, you can send the woofer to Great Plains Audio, they will regauss your woofer, for a reasonable price!

First find out everything you can to make sure it is in fact the woofer!

louped garouv
10-01-2004, 01:53 PM
but i did switch the amps channel feed and the same speaker had the lacking bass.....

how would one check the passive crossovers.......

switch which cabinet the woofer is mounted in?


hope to be :smthsail: soon enough

thanks again Scott....

scott fitlin
10-01-2004, 04:36 PM
There are others here who are more knowledgeable about the passive crossovers than I am.

People like RobH, Bo Putnam, Giskard, Mr. Widget, and Oldmics, and John come to mind!

What Im saying is to make sure it is in fact the woofer so you dont send the woofer out, get it back and still have the problem!

If it is the woofer, you can send it to Bill at Great Plains Audio in Ok city for remagnetization!

scott fitlin
10-01-2004, 04:39 PM
If you switch, I mean put the right channel speaker on the left channel of the amp, and see if it plays the same or the problem goes away!

10-01-2004, 05:02 PM
I would check the crossover first. The woofer woud be the last thing to look at. I have had a few tours at great plains and have had the chance to discuss magnets with bill and according to bill they just do not go dead just like that. Alnico might lose a charge if you were to drop it from say 6 feet to the floor,but then you might have other issues as well and if you were to fry the voice coils the heat can kill the magnet as well but in normal use in the home enviroment i do not think so.
Switch the suspect woofer to the other cabinet and if it still has lower output then maybe it is the woofer. If you trace it to the woofer then check the tinsel leads at the terminals. My guess is that if your amp is good then it is your crossover. You can repair the thing or maybe go for a complete overhaul with new resisters and caps.:)

scott fitlin
10-01-2004, 06:53 PM
http://www.hostboard.com/cgi-bin/ultimatebb.cgi/ubb/get_topic/f/3729/t/1118 If it does, in fact, turn out to be the crossover, heres something that might be of interest to you.

Earl K
10-02-2004, 07:38 AM

I'll just chime in about an often overlooked element . That is differing acoustical room placements for the two speakers.

The reality of my setup is that one speaker setup is nearby a door that exits into a long hallway while the other is close to a room corner. These two types of placements give quite different amounts of perceived bass. This setup continually throws me curve balls when I swap things in & out. The hallway side always sounds like it's missing about 1/2 octave of LF extension .

Obviously, to check for this , one has to swap each cabinets position for the other. A real PITA !

<> Earl K

10-02-2004, 08:14 AM
I am a newbee with a pair of JBL L200B speakers and experienced the problem with one speaker that appeared to have a lower volume/output then the other. As Earl K stated placement can be very important. I had the side of a large sofa blocking the weaker speaker and after I swapped the speakers around and moved the sofa away the output/volume of both speakers was identical. Rich.

10-03-2004, 01:07 PM
Hi louped garouv

I don&#180;t know of these speakers but if they are older models: it sounds to me like one of the woofer have got a stiff surround. If so there is only a matter of time when the other speaker to will loose its bass responce.

I would have the surrounds checked befour starting to move the cabinets back and forth in the the room (the surrounds could look fine but could start to stiffened)

Another possibillity is ther is a shorted cap in your x-over. There is often a cap mounted paralell to the woofers terminals. If this cap is shorted it will have a dramatic influence to the woofer.

Hope it could help finding what&#180;s wrong with your speaker


scott fitlin
10-03-2004, 01:53 PM
No, the surrounds on the 416 woofer used in the 19,s dont get stiff, same surround as my 421,s pleated accordion surround with viscous damping fluid!

They just dont get stiff.

I tend to think theres a bad component in his speakers crossover!