What is the fault that developed? The driver became totally inactive? It’s making noise?
Multiple.
First sign is the left w371 suddenly flashing orange lights so I decided to stop. Move them closer now to 2m rather than 3m. Then calibrated.
Then I noticed only the left one flashing lights. I also saw the meter in GLM showing that one keeps going higher than the right w371.
Then I did some tests and discovered the left rear woofer failed (probably the amp) btw during disassembly yesterday that bottom amp was not hot.
Then having started to use the test controls I tested each driver one by one.
Right front distorts pretty badly well before the orange light comes on perhaps even -6dB. Hard to tell as it music is dynamic. The left one is better. It distorts maybe -1 or -2 dB before the light comes on.
Definitely I have noticed differences in recording techniques over the years. Each decade added true low bass. However around 2004 when the iPod craze started everyone was targeting for headphones. That brought a whole world of real bass into the picture.
One easy test if you have a pair is to solo each driver and play “magic” by Coldplay. That bassline is beautiful.