High-end solutions of the seventies and eighties! At a time when the development departments of large companies were still allowed to show what is technically feasible, even if it does not yield a profit. This time will not come again, but you can get many unforgotten devices of this time from me!
I also planned and built my home theater myself! Prepared for 35 channels, and realized at a price for which others only can buy voodoo cables*)! Expensive with "professionals" is often not good (or at least indirectly proportional to the performance), and self-performance in my experience usually better! (Builder who has continued after 3 incompetent contractors themselves). Gladly I mediate you the help to the self-help!
*) With these "money makers" I have nothing to do, I got a realistic view on these things during my studies in the subject "electrical engineering"!