From the photos, it looks like the tinsel lead closest to the camera needs touched up. In its current state, it could be making intermittent contact.
What exactly do I need to do?
From the photos, it looks like the tinsel lead closest to the camera needs touched up. In its current state, it could be making intermittent contact.
What exactly do I need to do?
The tinsel lead needs touched up with some fresh solder. If you don't have experience with a soldering iron and/or don't have a steady hand, I'd get someone more experienced to do it for you. You don't want to slip and burn a hole in the cone or surround.
When I push the cone in and out I do hear a rubbing sound.
Could have shifted the magnet or coil just enough when you sat the speaker down to stop rubbing ?
PS. Every time I read your name I think of Trouble/Manic Frustration.
From the photos, it looks like the tinsel lead closest to the camera needs touched up. In its current state, it could be making intermittent contact.
Also, in testing, you're changing the conditions when you play one Cd at regular listening volumes, then play others at reduced volumes with loudness on. The stresses on the woofer are not the same. The worst case scenario is at regular volumes with loudness on or major bass boost. The speakers will try to give you what it can but these are relatively small 8" drivers and the laws of physics will only allow so much bass and cone excursion with this design before real physical limits are reached and exceeded.
IMO, Try to test using your familiar CDs and normal listening volumes where you did hear distortion before, it may be volume or frequency related. Try using without loudness and the. Try using some bass cut and see if at the same volume level but without some bass frequencies if the distortion changes or goes away.
If these speakers can't match or reach the bass levels you desire without distortion (in both speakers), then you need a subwoofer. If it's just one speaker and not the other despite all attempts to adjust it to eliminate the distortion, then you need a new used JBL 116H woofer (easier and likely cheaper) or a full recone with OEM JBL parts.
When the problem is present on certain recordings it's more pronounced on these same recordings at lower volumes with the loudness button on.
Hmm, on these recordings, try swapping the channels left to right and see if the problem follows the recording channel, not the speaker. If not, its definitely the speaker. If yes, that particular track is somehow exceeding what the speaker can do bass wise. Even at reduced volumes, the loudness control adds more bass boost as the volume is reduced. In a ported speaker, this can exceed its low frequency cutoff and the driver cone unloads.
When you test again, see if there is a lot of visual motion / vibration, or even perhaps some excessive excursion as if someone is really wobbling the cone. A much less likely issue is the amp or preamp "motorboating" or low freq. oscillating.
A question is what are your music sources - digital or analog, and if analog, tape or vinyl record system? If vinyl, there can be issues with arm-cartridge resonance, acoustic or vibration feedback, or tracking / groove wear issues which can create all kinds of audible but sometimes intermittent problems.
Have you tried simply pushing in on the woofer to see if the coils rubbing ?
Here is the spec sheet for the L19's;
http://www.cieri.net/Documenti/Cataloghi/JBL/JBL - L19 (1977) - Depliant (English).pdf
Would these replacement woofers work with the L19;
https://www.parts-express.com/visaton-w200-8-8-woofer-8-ohm--292-584#lblProductDetails