No High End from RB-81

[ACV92]

I just received a set of RB-81's and one of the speakers barely puts out any high end. I checked all of my connections and swapped the speakers left-to-right to make sure it wasn't a source issue. Next, I opened the speaker up to check all of the wiring and rebuilt the tweeter to make sure the diaphragm was set right.

Nothing I did changed the problem. Would this be a bad diaphragm or crossover problem? Any help is greatly appreciated.

[Professor Thump]

Check the DCR on the tweeter and verify that the capacitor going to the tweeter, (I believe it is marked C1 from memory) draws current when connected. The tweeter should measure about 7 ohms but you need to detach the x-over to measure it accurately.

The last thing is to check the solder joint on the PCB at the output of the crossover to the tweeter.

[ACV92]

If I checked the right one, it measured around 5.6 ohms. I was checking the mid-sized yellow capacitor going to the tweeter positive output on the board. The tweeter plays but much quieter than the other. The solder joints appear to be fine.

A little more testing process detail, for a layman, would be much appreciated.

[ACV92]

Klipsch tech recommended swapping the grilles, the tweeter is attached, to see if the problem stayed with the cabinet, e.g. crossover, or followed the grill with the low output tweeter. When I switched them the problem followed to the other cabinet. So, I ordered a tweeter assembly. It'll be here on Friday. I'll post the outcome.

[Professor Thump]

It sounds like you found the problem. Good Job!

[ACV92]

Thanks for your help Prof. I received the tweeter on Thursday. Swapped it out and the problem was gone, except for the fact that I like the sound of my KG 5.5's better. Don't get me wrong, the RB-81's are a good sounding speaker. The upper range detail is a little lacking and the midrange is quite strong compared to my old 5.5's. I am comparing a floorstand to a bookshelf speaker though, further testing is inevitable.