Please Suggest An Electronic Crossover

Well truthfully, those old Infinity crossovers sucked due to how they were optimized.  They were optimized for frequency but not impedance I suspect in large part due to the tools available at the time.  Very demanding for amplifiers but they don't need to be.

They don't need upgraded parts.  They usually need a complete re-think. I know this is anathema, but this is a case where a good modern crossover builder with better tools can come up, and they have, with much better circuits, but to do this you need to know how to analyze a speaker.  Most arm chair speaker hobbyists don't and it's a long learning curve. 

If the problem is in the bass, my suggestion to use a hybrid set up can resolve your issues without adding too many phase/impedance/slope matching problems which all crossovers ( line level or speaker level) have. 

Maybe look online to see if you can find a person selling new crossovers with better impedance characteristics is also a good option for the Infinities.

Call Phil Marchand, 585-423-0462.

I am using a dbx venue 360 With a 12v linear power supply very transparent ordered a passive line level high pass crossover from Marchand electronics  as a experiment and use the dsp for only bass

 I have two Berringers (I upgraded to the DBX).  Both for sale and one was modded by Smiles Audio from the UK (losses 2 of the 6 inputs but off the charts improvement).  

Xilica brand and then probably look at either the xp 4080 or the more expensive xd 4080. The XD uses fir filters but you can probably get by with the xp. Unlike a lot of x-overs these actually have good musical tone and good chip power to handle using filters for notches etc as you do corrections. These are very popular with the klipsch crowd