Experts tell me, is it better to have high or low speaker impedance?

The speaker impedance is mainly matched with the power amplifier.

The greater the impedance of the speaker, the smaller the output power, so there are basically no 16 ohm speakers now.

Home speakers are generally 4-8 ohms.

The output of 4 ohms is twice as large as that of 8 ohms, but the requirements for the power amplifier are higher, requiring large output current and low internal resistance. Suitable for Class A amplifiers.

The impedance of 2 ohms is only suitable for car speakers, because car speakers do not have bass, and the requirements for power amplifiers are not that high. As long as the rated output power is large, you can use 2 ohm speakers, and the output power will be larger.

Car horns are only suitable for 2-4 ohms. Because the output power of the car amplifier is small.

If equipped with 8 ohm speakers, the sound will be very small.