The right audio amplifier?

Minimum operating voltage 4.5V. The output power scales with the square of the supply voltage.

Only works at 5V, limited to a watt or two depending on the speaker impedance.

Hello,

Excuse me for not responding for a long time.

I disassembled my wired speaker (AC-691N from Juster), this speaker makes the right sound power for me.
Its 2 speakers are 1W 4 Ω. The amplifier is an LA4192 (8S8).

How should I interpret this? Can you tell me with this information an amplifier, the same or slightly better power?

The LA4192 drives upto 2.3W into 4 ohms, with a 9V supply. The 9V supply is what allows that level of power. Assuming a sinewave the max (sinusoidal) power from a supply of voltage V is:
V^2 / (8 x R), where R is the speaker impedance.
For bridge mode its V^2 / (2 x R).

OK, thanks for your answer.

But does that mean that I don't need more than 2-3w amp? Would a 3W 4 ohm speaker make good power?

Correct if indeed you need that much.
A lot depends on the speaker’s housing, that can make it sound a lot louder. I have a hand held sound generator that only produces 500mW and that can be turned up way too loud.