CurtPalme.com Home Theater Forum

[Elaine Benes]

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Hi I just bought a sweet pair of Celestion SL12's for my front main speakers. They are a tiny bit rough looking, but I stole them...

I tested all drivers for working condition when I bought them, and I ran them for about a week before auditioning a set of EV's to perhaps take their place, but decided to stick with the Celestions.

Now the bass drivers on one have stopped working...

I've taken them apart to the point where I can test all components with an ohm meter.

I don't know ANYTHING about speakers, and very, very little about electronics, but I thought I'd give it a try. The only thing I know to do with the ohm meter is check continuity. So, I get continuity across everything except one big black thing that looks like an oversized capacitor, SHOULD I get continuity across all components ???

[Curt Palme]

Hook an amplifier output directly to the woofer. It should work. If not, take it to a PROPER speaker repair shop, ASK if they can repair tinsel leads or replace voicecoils. If they say that the speaker should be replaced with a 'better' generic, stay away from the place. If it's Xover problems, then you can send it to me or also take it to a speaker place. Should be a relatively easy and $<100 repair no matter what.

[Curt Palme]

Hook an amplifier output directly to the woofer. It should work. If not, take it to a PROPER speaker repair shop, ASK if they can repair tinsel leads or replace voicecoils. If they say that the speaker should be replaced with a 'better' generic, stay away from the place. If it's Xover problems, then you can send it to me or also take it to a speaker place. Should be a relatively easy and $<100 repair no matter what.

[Elaine Benes]

Will it matter which lead from the amp goes to which lead on the speaker ?

Ie. if the connections directly on the speakers are not labeled + an - will I do damage by guessing wrong ?

[Elaine Benes]

The speakers themselves work fine when hooked directly to an amp.

The connections on the back *seem* to allow for bypassing the crossover, as there are "Bass" and "High" connectors.

I took pictures of the crossover, both sides.





The middle one of the three black things in a row, is the one that doesn't show any continuity when I measure across it. All other items on the circuit board DO show continuity when I measure across them, of course, I didn't remove the items from the circuit to test, so I guess I could be just measuring continuity of the entire circuit every time, eh ?

[Elaine Benes]

Well, the old "take it apart and put it back together without doing anything" seemed to do the trick yet again !

No idea why, but my woofers are now working properly again.

While I had the crossover out, I tested it with direct amp hook up on all the points I could see that were labeled as Bass, and it worked from all points, all I can think is somehow there was something preventing connection at the point where the crossover board was connected to the binding posts...

[Curt Palme]

If you hook the woofer terminals up backwards on one speaker, it will be 'out of phase'. Sitting directly between both speakers, you'll experience a complete lack of deep bass, as one woofer will be moving inwards while the other moves outwards. That will result in bass cancellation in the dead center between both speakers. If you listen carefully, you'll notice it right away.

Which brings me to a story that I think I posted before:

WHen I was first starting in pro sound back in 1985, Roland had a concert featuring a jazz/electronic band called UZEB out of Montreal I think. They had it in a small theater here, and of course since UZEB endorsed Roland, they all played Roland equipment. MIDI was all the rage back then, and the musicians were talented enough (VERY talented!) to play a number of instruments each, enhanced by the Roland equipment.

So I got invited with a whole bunch of other musicians/music store owners/etc to listen to these guys. I got there very late, one of the last people in the door, so I had to cross center stage to get to the other side where there were a couple of seats left. As I crossed center stage, I noticed this massive dip in the bass response coming from the speaker stacks on either side of the stage. Somehow, the whole stack was wired out of phase with the other.

Now, remember, I was 23, just starting in sound, and the room was full of about 500 pro and semi pro musicians, at least 1/2 of which had crossed center stage to get to their seat. No one noticed, or bothered telling the sound guys. I made a point of grabbing one of the roadie guys, mentioned that the speaker stacks were out of phase. THis was about 3 minutes before showtime. As I walked up to my seat, I looked at the stage, and saw this explosion of roadies coming out from the side of the stage, all running to the amp racks to reverse one set of speaker connections.

Needless to say, the show went on.. in phase..

[Curt Palme]

If you hook the woofer terminals up backwards on one speaker, it will be 'out of phase'. Sitting directly between both speakers, you'll experience a complete lack of deep bass, as one woofer will be moving inwards while the other moves outwards. That will result in bass cancellation in the dead center between both speakers. If you listen carefully, you'll notice it right away.

Which brings me to a story that I think I posted before:

WHen I was first starting in pro sound back in 1985, Roland had a concert featuring a jazz/electronic band called UZEB out of Montreal I think. They had it in a small theater here, and of course since UZEB endorsed Roland, they all played Roland equipment. MIDI was all the rage back then, and the musicians were talented enough (VERY talented!) to play a number of instruments each, enhanced by the Roland equipment.

So I got invited with a whole bunch of other musicians/music store owners/etc to listen to these guys. I got there very late, one of the last people in the door, so I had to cross center stage to get to the other side where there were a couple of seats left. As I crossed center stage, I noticed this massive dip in the bass response coming from the speaker stacks on either side of the stage. Somehow, the whole stack was wired out of phase with the other.

Now, remember, I was 23, just starting in sound, and the room was full of about 500 pro and semi pro musicians, at least 1/2 of which had crossed center stage to get to their seat. No one noticed, or bothered telling the sound guys. I made a point of grabbing one of the roadie guys, mentioned that the speaker stacks were out of phase. THis was about 3 minutes before showtime. As I walked up to my seat, I looked at the stage, and saw this explosion of roadies coming out from the side of the stage, all running to the amp racks to reverse one set of speaker connections.

Needless to say, the show went on.. in phase..

[AnalogRocks]

Curt saves the day

[AnalogRocks]

Curt saves the day