You don't lack bass, you have too much treble

Good room acoustics is more important than equipment. Without controlling frequency response and reverb time, it sounds like the room, not your gear. The proper balance of absorption and diffusion is critical to hearing what's coming out of your speakers. 

@koestner 

Pink Noise has the same energy level at all frequencies. No roll off. That's what makes it useful. 

I use a SPL meter on a tripod, and

do not like pink noise.

I use 1/3 octave test tones, like found on Amazing Bytes CD. Last one sold, $9.99 was me, I snapped it up. Actually the one on discogs for $42. delivered is a good price, most often $75. + delivery.

I don’t use LP test records, something might be off, CD’s always sound the same.

After measuring and adjusting in some manner, still using test tones: then adjust to your preference by ear.

I might revise Erik's statement, also true: you might have too much midrange, too much presence, which can be appealing, especially vocals, but in the same way, lessens the balance of the bass, and in many cases, at our age of reduced sensitivity to highs, you might find yourself boosting the highs.

Eurythmics Sweet Dreams will help you with final highs adjustments after measurements.

Flat frequency response at the listening position is way too much treble.

Details by themselves alone unbalanced are a defect not a +...

This defect can come from the gear synergy or pieces but often  the first thing to look  at   and the last thing to look at is always acoustics and room acoustic to improve things ...

The OP is right as usual ....

😊

Flat frequency response is indeed what you want for accurate reproduction. Music has a natural high end roll off, but if your speakers don't reproduce the entire spectrum, you will have an artificial rolloff.