bigsteff_dc

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Oct 22, 2011
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I have a pair of L100T's and one of the woofers start to make a popping sound when they're driven hard. What causes this problem? Is it the driver or the crossover? (NAD 2400 THX amp, Adcom 350 preamp, NAD CD)

:whistle:
 

jacobboe89

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Jul 15, 2011
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it could be coming from many places , the amplifier could be the source of the poping , but i would say the speaker is more likely the source . chances are that you are overdriving the speaker or the amplifier . back the volume off a bit when you notice this . any time you have audible distortion you are approaching damage and even the speaker is rated for more than the amplifier is capable of delivering , it is still possible to overdrive the amplifier or the speaker . but if you are not satified with simply backing down the volume when this happens , i would beleve to be worth while to cautiously try to investigate the source of this , but i would guess that you just simply pushing your system to its limit .
 
The foam surround on the L100 speaker is famous for rotting away. Take the speakers out and inspect them. You can have a speaker shop replace the surrounds if the voice coils are not damaged.
But...that's probably the issue, seen it many times.
 


There is very little limit when the edges of the speaker cone are missing.
 

jacobboe89

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i am not sure what the surrounds are made for your l100's but the few pair i have seen don't have foam , they have some type treated material . still worth a look at as every thing eventually breaks down (rots) , and a compromised surround could be easy to solve , but you could have one of many problems from the speaker or crossover or your amplifier and woofers would be a good place start by doing a visual inspection and if you come up with nothing , then i would try to see which cabinet this is originating from . if you can determine which speaker , i would then switch left and right speakers , move right to left and left to right at the amplifier outputs and then see if the noise moves or stays on one channel of the amp. if your noise stays on the same channel of your amp; this suggest your amp has a problem . if the noise follows the speaker that would suggest the speaker has a problem .

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The old vintage jbl L100s used a treated cloth material. The new version like a lot of cheap speakers use foam surrounds. Foam surrounds are pretty easy to replace yourself or take it into a shop to do it.

I have a few 4311s and 4312s which are the pro series. The L-100s were based on the 4311s for the consumer market.