Please suggest bookshelf with best bass response under $4000 pr.

Who knows, I haven’t heard them all .
That said, my Totem Signature 1’s ,2200$ new, I paid 900$ for mine 3-4 years ago do not require a sub for the acoustic jazz and classical I listen to .
As most rock is engineered to have big bumps at 80 to 120 hz don’t see why they wouldn’t work there..
The Totems are solid and clear down to 50hz which is all that is required unless Bach organ pieces are your main listening fare . Even then clarity of the reproduction of the next octave above is all you need to be fully into the music .

I second PMC monitors - the newest twenty5.22 are really better than the older versions. Great sound staging and definition. Bass mass is not more than other monitors but they go lower and most important keep the PRAT (pace rhythm and timing)! If you want more bass mass try to get that with source and amplifier. Compared to monitors with 8" woofers (slower) the PMC´s are more satisfying. 

There is nothing slow about the 8" woofer in Audio Note AN-J's. ATC sealed bookshelf speakers with proper amplification have a certain speed to them I haven't heard in any ported design. For straight up bottom end go with Isobaric designs like Neat Momentum, Totem Mani-2, various Wilson Benesch etc...

I just got focus 160s. They’re discounting heavily now if you can find new at a dealer. 
Huge bass, incredible sound and imaging.

I've been through the speaker challenge for a small room. I chose the ATC SCM-19. You need some power, but they do very well in a small footprint. Excellent detail and speed. They are right at budget as well.