@Hattrick17 While it can be fun to discuss "what if" scenarios there is an expectation that the poster does some preliminary research to see if it makes any sense to begin with.
You mentioned two things in your opening post.
One was to replace digital room correction software with an EQ for home theatre. That's just not practical. EQs are generally two channel devices and if someone has a 7.2.4 system we're looking at 13 channels, which would require 6 EQs (7 if you want separate EQ for each subwoofer).
Room correction software also does time alignment to take into account the distance from the listener to each speaker. Something an EQ can not do. Not entirely true. If you use your ears which is the best source of calibrating a room in my opinion EQ works just fine, it has been done this way for decades. Hence why not use EQ for room correction? It can work just fine being 95% of movie content is LCR the rest is fill. Using a calibration mic is a piece of cake and is a nice part of using room correction software. But really do we need to do it this way?
EQ hardware can be done and has been done. It may not be as fast and easy as using Room Correction software but room EQ has been done with Equalizers for decades prior to software. Agreed there are many speakers in a modern HT. Front channel weren't even needed for decades in older theaters. In fact many homes don't need them either if the front L&R can cover center spread. The narrower the spread from L&R the less need for a center channel thus stereo can cover almost audio content from movies.
Room calibration software includes a calibrated mic and quickly measures all speakers. To due that properly with an EQ requires a measurement microphone, recording software like Room EQ Wizard and taking manual measurements for each speaker. That's a lot more work. FYI I am very versed with using room correction software like Dirac Live for over 6 Years. I never just use the final correction that Dirac provides for my room solely. I always tweak using my ears. There are those that just EQ the bass frequencies as that's the hardest part to get right. Whether you can EQ the main speakers also depends on the directivity index as some speakers can't be corrected with EQ because their off axis response differs too much from the on axis response. Home theatre is very different from pro audio as there is much more reflected sound in a typical residential application than there would be in a hall.
Really? It sounds like you never went to a concert in a Basketball or hockey arena!
Suggesting the use of EQs for crossovers exhibits a lack of understanding of what crossovers do and how they work. Maybe it was just a poor choice of words. It
was I already apologized for that in this thread. I meant Electronic Crossovers. The header of the Post was jacked up when I created it. Probably due to multitasking and not really proof reading well enough. Yes, that was poorly worded by me when I created the thread again I apologize and do know the difference. Crossovers provide filtering while EQs just provide sound shaping. You have to apply a high pass filter to the tweeters to prevent damage. Sending frequencies to a driver outside their designed operational range also introduces distortion. An EQ on it's lowest setting does not provide enough cut off to do this.
Applying filtering at the pre-amp stage is nothing new though. Those are active crossover networks vs passive and if you have used PA equipment then you have surely seen these. It would not make sense to use passive crossovers with the power and SPL requirements of a PA. Even the powered speaker cabinets used by many small bar bands use active crossovers with internal amps. Applying this to the home / DIY market is not trivial though. The crossover has to be tailored to each specific pair of speakers, just like passive crossovers. I have only seen variable devices that do this in the pro audio domain, like the DBX 234. Unfortunately you can not take a device like that and use it as an active crossover for home speakers. Those devices are designed for large speaker arrays in large halls. That's very different from what a 2-way or 3-way home speaker requires. That is a whole other topic and I won't go into the details but good crossover design for residential speakers is a lot more complex when you start getting into impedance curves, phase angles and different orders of slopes.
Some companies have come out with programmable digital crossovers though. I've seen these used by UK mixing engineers where they chose their own drivers and then used a programmable active crossover to do the filtering in the digital domain and then drive internal power amps. The digital crossover allows for much easier adjusting and fine tuning of the system to get a flat speaker response. You need the right measurement equipment though to do this properly. There have been some DIY speaker builders that have experimented with digital crossovers but I have not seen many. The software for passive crossovers is easily available and they can be cheap to build, and a passive speaker will work with any amp. Moving to active crossovers is still relatively complex for the DIY builder. That could change with software. It should be possible to design a programmable crossover where you simply enter the speaker parameters and it calculates the crossover points and slopes and phase adjustments but you need a big enough market to drive its development.
Thank you for your comments. The concept of the thread was to create conversation which obviously I did.