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

Brightness isn’t just caused by the equation of the speaker’s frequency response to room size and dampening ratio as Erik mentions, but also due to other forms of noise in the chain. This could be found through:

- Poor resonance control in the speakers, rack, and components where vibration induces slurring, peaks, and nulls of certain frequencies. Great resonance control will result in much improved image solidity, making for more audible, impactful bass /and less noise through the rest of the frequency spectrum so sonics are more effortless and easier to discern.

- Jitter and EMI are usual culprits that induce high frequency noise into a system to a point where people find their system to be bright, peaky, piercing, and /or fatiguing. In such case it may be improved by using better components or cables, or introducing technologies or accessories that are designed to lower noise floor.

- Poor speaker and amplifier matching is a common challenge I see my customers and others face. Often times, people think their amps can properly drive a speaker just by looking at the specs. Some speakers require a lot of power, and it’s easy for many that are uninformed to look at the speaker sensitivity to the watts of an amplifier and be done with it. Sometimes they get lucky, but in most times, amplifiers cannot fully handle the impedance set by the speakers. Klipsch are great examples, since I know that while they claim to be of high impedance, many of them actually have an impedance dip in the midbass. Regardless, a few may look at the Klipsch’s sensitivity (say high 90s dB) and nominal impedance (usually 8 Ohm or greater) and believe a low power OTL amp would work well. Well, they’re wrong, as the OTL amp can’t handle the impedance dips, and this further makes Klipsch speakers sound “bullhorn-ish”. Sadly, even many solid state power amplifiers don’t deliver the high current needs to truly drive and control smaller speakers, which tend to be lower in sensitivity and lower in impedance. I’ve in many times guided customers to better amplification that simply wakes the speakers up to the point where no subs or larger speakers are needed.

Case in point, Erik suggests a very good point on treating the room to address and optimize  full-range frequency delivery, but it is one of many ways to address it. The whole system’s performance depends on any and all bottlenecks being addressed to a certain level.

Also, if your stew has too much salt, add more potatoes.  Same Yin-yang balance I'm trying to talk about here.

+1 to the OP and to blisshifi  😊

Mijostyn is correct about target frequency plots taken at the listening position.  You want a smooth response that slopes downward from the midrange thru treble.

@erik_squires  And just what do you think you are going to do about bass in any normally sized residential space? Most audiophiles know that bass below 100 Hz is poorly localized. The dimensions of the room are of primary importance followed by the number and positioning of bass/subwoofer drivers.  After that it is all about crossover programming and digital signal processing backed up by a lot of power. Bass has nothing to do with size.  Low bass is more about feeling, you either feel it or you don't. Most people don't. The initial impact of a bass drum occurs at higher frequencies. The vibration of the bass drum heads after that impact occurs at very low frequencies as long as the drum does not have it's damper on.  On Brittany Howard's Jaime the first cut History Repeats has a beautifully recorded bass drum with it's damper off. You can feel the pressure waves after the initial strike tapering over about 10 cycles. I can see it in my windows in the right light. It is not something you hear. There is absolutely nothing you can do in a room to make this happen other than blow out a wall. The problem for most audiophiles is that most systems do not project the power needed to reproduce this kind of bass. What a speaker measures at one meter means absolutely nothing. Most audiophiles do not even know what they are missing because they have never heard a system reproduce low bass like this.   In a 16 X 30 foot room It takes at least two 15" subwoofers each powered by at least 2000 watts. For really low distortion four 15" subwoofers.  The same applies for Imaging. Most have never heard a system image at the state of the art because very few systems can do it. 

If you want BIG sound under all circumstances get line source speakers such a big Maggies or 8 foot Sound Labs. Line sources composed of multiple drivers like the old Nearfield Pipedreams do not work well. It has been tried many times without much success. Point source speakers always produce a small image as if you are seated far away, even the big ones. What you see affects what you hear. When listening for imaging characteristics you always close your eyes. 

Happy Saint Patrick's Day to all you Irish folks