Well it doesn’t seem like there’s been another Reddit exodus, especially from looking at the user numbers for Lemmy. There hasn’t been a big screwup lately like with Meta or Twitter (but I think Bluesky is absorbing the Twitter refugees currently).

I used the textbook as Oppenheim in my graduate DSP course, with the textbook by Proakis as a secondary reference. I don’t really love the Oppenheim book. I’m not super familiar with the Proakis DSP book as a result, but I think his textbooks on Communication Systems and Digital Communications are very well written. The Van Trees I find really well written and I really like (however the topic is also most interesting to me). All of them require you to study them though, I’m not sure what you mean by that.

Really depends what you are into. For general concepts, Discrete-Time Signal Processing by Oppenheim and Discrete Signal Prcessing by Proakis are standard textbooks.

If you’re interested in communication or radar systems, array signal processing is very closely linked with discrete signal processing but with more linear algebra and statistical concepts. Optimum Array Processing by Van Trees is a great textbook for this.