engine knock? appreciate your thoughts

[ghall]

Hello, I'm the original owner of a 1992 Subaru SVX LS-L, currently with
120,000 Km. For the past 10 or 15 years, I've been leaving it parked in my
garage over the winter and take it out for runs in the spring/summer for no
more than a total of about 100 Km. This year, my SVX has developed an
engine knock. I'm unable to directly attach a few short video recordings I
took of the knocking due to web site restrictions. Instead, I uploaded
them to my OneDrive and include the link below. I'm hoping that someone,
based on their experience, might be able to suggest what they think the
source of the knock might be. Any and all thoughts are welcome. Here's a
few more details:
- knock is the same whether engine is warm or cold
- rate of knocking increases/decreases with engine RPM
- engine performance is fine; idling smooth
- I tried some SeaFoam in the oil -- didn't seem to make any difference
- since then, I changed the oil with full synthetic 5W40 weight

Here's the link to my recordings:
https://1drv.ms/u/s!AtnY_qTU7zVviONS...Ny7Mg?e=IelgT0

Thanks in advance for your thoughts,
Gary