he Sound of a Bad Driver (Voice Coil) versus a bad Cross-Over (Capacitor).

Luger

I have a pair of early version SDA2’s. As you may recall, these have three woofers in the array. Over the years these particular speakers have been move round quite a bit. They have been problematic and seem to be getting more problematic. Case-in-point: the dimensional woofer seems to be operating as does the woofer in the lower positions [the low-frequency driver as per the original manual]. However, the woofer in the upper position [the Stereo Mid-woofer as per the original manual] occasionally, sounds "off": the sound is muffled, distant, maybe raspy and muted, especially with the vocal part of the program, which this driver tends to carry. It is so far just the left channel and so far just this single driver. It is also occasional (as opposed to intermittent).

If that is enough information work with, my question is: does that seem more indicative of a Cross-over issue or a driver (perhaps voice coil issue)? I recognize that these are vintage speakers and the crossovers should be recap’ed (and indeed, I was waiting to send these off but I don’t want to spend a lot of money on the crossovers if there is a problem with the drivers).
Your thoughts are greatly appreciated, Lou.

treitz3

Swap the right speaker with the left speaker first. Does the issue remain on the same side or does it follow the speaker?

Tom

F1nut

Spread your finger tips around the driver cone and with even pressure push the cone in, then let it come back out. If you hear a scraping sound and feel a roughness the voice coil has shifted

Luger

Thank you. I will try swapping the drivers on the weekend. I did the palpation test and no roughness, no scraping sounds, and it bounced back smoothly. Thoughts?

F1nut

You'll know more after swapping.

audioluvr

Muffled and muddy sounds like old worn out capacitors to me.

Luger

To follow-up; I opened-up the speaker cabinets (in anticipation of having re-capping done and to swap the drivers but didn't have to go that far). I checked all the speaker connections and, of note, found contact of the SDA interconnects lacking; I cut out the connectors and temporarily wired the interconnects directly to the wires coming from the cross-over. As it stands, all the drivers are working and the speakers as a set sound really good! I'm just going to sit tight until its time to pull the crossovers for service. Thanks.