Improving piano sound in the home with a simple cost effective (affordable) and trouble-free sound reinforcement "kit":
Other factors being equal, pianos with longer strings and bigger sounding boards deliver not only more volume if needed, but a richer fuller, more spacious and musically powerful tone quality across the full range of the keyboard.
This applies to uprights as well as grands. This is why the 9-foot long concert grand is de rigueur for the concert hall---discriminating artists accepting nothing less.
The physical size, shape, and constituents of the room in which the piano lives and breathes also has great bearing on the presence, power, sustain, and lushness of the piano sound.
The typical living rooms---especially those with plush carpets and drapes---absorb and deaden a piano's sound, while providing little or no reverberation---the subtle but complex echo and re-echo experienced in a good hall---without which the sound is less rich, sustaining, and musically effective (more claustrophobic).
A further liability of the typical home piano room is that certain frequency ranges may be boosted or cut by factors such as room shape and composition, resulting in boomy and bass-heavy lows or a tinny and harsh high register.
The "kit" addresses these issues and more, and provides means to easily adjust these sonic factors to your individual taste.
The components of this system are mostly concealed, and require no modifications of the piano's inner workings or cabinetry, and are very unobtrusive and simple to use.
Also, a singer or other instrumentalist may easily plug into the system to form a duo with the pianist---both sounding as if in a spacious hall. The overall volume level (loudness) and balance is easily adjustable by the performers.