One flaccid sounding Rogers LS7 speaker

[davstev]

Hi folks. I'm having some trouble with a nice pair of Rogers LS7s, a two way design.

One speaker sounds great but the other is weak. It suffers from sightly lower volume overall, and from a whooshing sound when ear is next to tweeter, but no music signal coming through the tweeter. The musical midrange is there though, coming from the woofer, but no bass.

So my questions to AKers: would you think i have a fault in my crossover; maybe a bad cap or resistor?

If i had a tweeter issue or a dead tweeter, would it produce this whooshing sound when ear is next to it?

Why no bass at all? Seems strange that the woofer is putting out midrange but I'm not hearing bass. Maybe there's a blockage in the cabinet port? Foam getting in the way?

Thanks for helping me think this through. I might get to the point of swapping tweeters to see what it might tell me, but it's not likely just that. No bass remains a full mystery.

I DMM tested the woofer, it's reading a decent 7 ohms resistance.

 

[GordonW]

Are the woofer and tweeter outputs from the crossover, reversed? As in, the woofer output going to the tweeter, and the tweeter output going to the woofer?

I know that sounds outlandish- but it COULD completely explain the observed symptoms, I think...

Regards,
Gordon.

 

[davstev]

Gordon, thanks for the ideas. Wish it were that easy, but it's not that. I just checked the wires coming from the crossover board to the woofer and tweeter, and no.

 

[Fairlane]

First thing I would do is pull the blue electrolytic capacitors and replace them. You could also jumper them and see if the sound comes back first. Just do it at low volume.
Have you swapped sides with the speakers to make sure its not the source?

 

[davstev]

Thanks for this, Fairlane. When you say "you could also jumper them and see if the sound comes back first. Just do it at low volume.", Can you elaborate a bit? Thanks.

Yes, I've tested on two amps and it's definitely the speaker not the source. Considering swapping tweeters too, just to see if I can determine if it's the crossover or tweeter itself.

 

[Fairlane]

Sorry, take a wire or a set of jumpers consisting of a wire with two aligator clips on either end. Then connect them to each end of the capacitor legs essentally bypassing the capacitor with a direct connection. Do this and see if you get sound change in either driver. If you do chances are that cap is bad.
This has worked for me a number of times with the latest pin pointing why the T-27 tweeter in one of my KEF Corellis was very low on output. Jumping out the offending cap proved to me the tweeter was fine. Replaced the dud cap and restored normal sound.

 

[davstev]

Sorry, take a wire or a set of jumpers consisting of a wire with two aligator clips on either end. Then connect them to each end of the capacitor legs essentally bypassing the capacitor with a direct connection. Do this and see if you get sound change in either driver. If you do chances are that cap is bad.
This has worked for me a number of times with the latest pin pointing why the T-27 tweeter in one of my KEF Corellis was very low on output. Jumping out the offending cap proved to me the tweeter was fine. Replaced the dud cap and restored normal sound.

Great, this sounds pretty doable. Thanks for the tip, and I'll let you know. No risk to blowing the tweeter out, without the current limiting effect of the capacitor though?

 

[Fairlane]

For a quick test you should be fine. Just keep the volume down.

 

[wmgwizard]

While it sounds completely rudimentary and you probably already checked, but....

Are you 100% certain both speakers are connected in phase with the amplifier, + to +, - to - ???

Check internally where the crossover is connected to the terminals as well.

 

[davstev]

While it sounds completely rudimentary and you probably already checked, but....

Are you 100% certain both speakers are connected in phase with the amplifier, + to +, - to - ???

Check internally where the crossover is connected to the terminals as well.

I did check the phasing yes via the speaker outputs. And the speaker terminals are connected directly to the crossover PCB.

 

[davstev]

I think the problem is in the crossover, for sure. I tested the speakers, they're fine. All internal wiring is good too.

Tested the capacitors, all good. The inductors.... How to test them? I did try testing with the continuity tester on my DMM... But there was no response. Didn't get a beep from any of them