Luckily, it’s not the amp, it is the speakers that are lacking in bass. Any self-powered sub with speaker wires in/speaker wires out will solve your problem.
I just added this 800 wpc self-powered sub to my small office system.
https://www.rockvilleaudio.com/rock-shaker-12-wood/
On sale, in your budget, 90 day trial with free return shipping (I bet you keep it like I did).
It gives a nice fullness to my bookshelf speakers. Don’t over-do it, just a bit, un-noticeable until you turn it off.
Your speakers are 89 db sensitivity (better than my Wharfedale Diamond 225 87 db)
Your amp is 30 wpc, more than my Luxman’s 10 wpc.
Your woofers are 5-1/8" diameter, they can be great but can only move so much air. Mine are 6-1/2", same thing.
When your sub’s amp takes the low bass job away, the bookshelf speakers then do a better job with upper bass/mids/highs and thus imaging improves along with detail ... no distortion from trying to do what they cannot do.
You will be happier at lower volumes after you add a sub to those speakers I bet.
I just added this 800 wpc self-powered sub to my small office system.
https://www.rockvilleaudio.com/rock-shaker-12-wood/
On sale, in your budget, 90 day trial with free return shipping (I bet you keep it like I did).
It gives a nice fullness to my bookshelf speakers. Don’t over-do it, just a bit, un-noticeable until you turn it off.
Your speakers are 89 db sensitivity (better than my Wharfedale Diamond 225 87 db)
Your amp is 30 wpc, more than my Luxman’s 10 wpc.
Your woofers are 5-1/8" diameter, they can be great but can only move so much air. Mine are 6-1/2", same thing.
When your sub’s amp takes the low bass job away, the bookshelf speakers then do a better job with upper bass/mids/highs and thus imaging improves along with detail ... no distortion from trying to do what they cannot do.
You will be happier at lower volumes after you add a sub to those speakers I bet.