I've never been a fan of propping a cab on a crate or chair. It loses the low end. But I may give it another try.
You are not alone. It really depends on what part of the sound spectrum you focus on.
Here is the way I perceive my bass. As soon as I plug into an amp, it seems like the bass has a bit of delay. If I can only hear the lows, it feels like the sound is way behind where I am playing. Everything feels slow and lethargic and it takes a lot of mental energy to push ahead.
I would actually describe it more as pulling the sound through mud, but hopefully you get the idea.
Years ago I figured out that the sense of immediacy I want is encoded in the high end. Aiming the amp directly at my head does not totally eliminate the sense that the sound is delayed a bit, but it makes a huge improvement. I find it's even better if I use a fairly bright sound, as this helps overcome some of masking that occurs from other instruments competing for space in the mix.
I also found that the more I turn up the lows, typically the more unfocused and loose the sound seems. Also the more behind the sound seems. I think this is partly because musical instrument speakers prioritize efficiency over transient response. But it's also effected significantly by indirect sound and how it interacts with room acoustics.
For the record I have played through big biamp rigs that could create full range sound that was very HiFi right next to the rig. A big part of this is extended low frequency response that is somewhat hyped below 80hz. The other part is the mid and high range drivers were at ear level. In my experience this can be addictive for the players, but it may not translate very well to the audience. As the sound of bass travels over distance, it tends to become darker and more diffuse. The hyped sub 80hz energy tends to sound really awful in the distance.
Turns out I don't personally miss the heavy lows all that much, but if I can't hear the mids and highs clearly it sounds and feels awful to me.
Elevating the cab decreases and shapes the low frequency response. When the cab is on the floor, the sound travels down from the woofer to the floor and bounces back up almost perfectly phase. It's sometimes visualized as having a second virtual cab in the floor. Due to mutual summing with the floor, I believe you get 3-6dB more level. This depends on how much of the sound energy is absorbed VS reflected.
When you elevate the cab, the acoustic coupling is decreased. This is partly because the phase error between the direct and reflected sound waves is increased. In other words the direct and reflected sound are less perfectly in phase. I think it's also because the reflected sound wave has to travel more distance, so it has more time to decay. Inverse square rule says you lose 6dB for each doubling of distance.
Regarding the phase angle. You get a null/cancellation at the frequency where the distance to the floor equals 1/4 wavelength. The sound travels down 1/4 wavelength and then bounces back up 1/4 wavelength. Therefore, the reflected wave arrives 1/2 wavelength out of phase with the direct sound, which gives optimum cancellation.
FYI 1/4 wavelength for 125hz is 2.25', so I believe this represent what you might get if the center off your woofer is 2.25" off the floor. The point I am trying to make is you can tune the low-frequency response somewhat by varying how much you elevate the cab.
Keep in mind the same summing and cancellation processes are happening with the walls you may be near.
In my experience it has been hard to find a kick-back monitor that sounds great with bass. I have a GK 700RB 112 combo with a kick-back cab. To my ears the low end sounds sort of phasey/hallow when it's kicked back. Setting the cab flat on the floor improves the quality of the lows, but then I don't hear the extended, direct highs that I like. Elevating the cab eliminates the phasey quality but also thins out the low end. My preference is to elevate this cab.
I have played through several quality PA wedges, and had similar experiences with many of them. But a few of the really big ones could sound great with bass.
In my experience, elevating the cab often clears up the bass out in the audience as well. But it does take away the deep pillowy quality a bit. I prefer a nice clear and focused sound over deep and incoherent.
On occasion you can have it all: clear, focused, deep bass. But in my experience, this is not repeatable. When it does happen, it's due to serendipity.
Take what you think may be beneficial from my post and disregard the rest.
Good luck!
