Near field monitor - low volume issue

Wish

Wish

Never Sarcastic....Honest
I've got a pair of JBL LSR25P near field monitors...a week ago I notice that one of the monitors has no real volume in the low end...the "woofer" is only a 5.25" speaker - but I used to be able to get some air moving and hear some THUMP from the monitors...but it's real quiet compared to the other monitor.

The tweeter is working fine, but no real volume on the woofer...the monitors are 4 years old...warranty only lasted 3 years, go figure...so I did some tests, swapped cables, and everything pointed back to the speaker.

I did some online research about blown speakers and one guy said to test the voltage across the speaker leads and if you get a reading of zero or infinity - the voice coil is bad. So I did that and got a reading of zero.

So blown speaker I think.

I track down a replacement speaker from JBL and it gets here today and I install it....

And I still have no real volume coming from woofer...if I crank the monitor on full, it comes nowhere near the level of the good monitor with the volume at about 1/4.

I can hear that the woofer in the low volume monitor is working....it's just got no power...

Any ideas on what could be wrong with this thing?


Muchos gracias...
 
Maybe there is something wrong with the Crossover...If it uses a Passive Crossover then maybe the Capacitor is Burnt out.....

If these don"t use a Crossover and are Bi-amped(Different Amp for Woofer and tweeter) then maybe there is something wrong with the Amp that powers the Woofer??

Something to look in to.....

Good Luck
 
Thanks for the reply....I think it needs to go to the shop...electronics repair is outta my league.
 
Wish14 said:
I did some online research about blown speakers and one guy said to test the voltage across the speaker leads and if you get a reading of zero or infinity - the voice coil is bad. So I did that and got a reading of zero.
Click to expand...

Only if you tested the woofer out of circuit. Otherwise, it could just as easily be a short in the wiring or dendrites in a filter cap across the tweeter or some such.

Make sure:

  • The choke isn't open (assuming a passive crossover; if it's active... I don't know how that works...).
  • The cap across the tweeter (if there is one) doesn't look blown.
  • There are no shorts in the wiring.
  • The amp powering it isn't hosed---swap the wires and make sure the problem doesn't move.
  • The input to the amp isn't screwed up---if the problem moved in the previous step, swap the inputs and see if it moves again.
  • If it's bi-amped, make sure there are no blown fuses.
 
I had the same problem with mine. It turned out it was the volumn control (pot). If you open the speaker, power on and connected to a source, short the red and white wires going to the pot. If the volumn comes on like normal, it's likely a bad volumn control.
 
You must log in or register to reply here.
Back
Top