What's the deal with all these 8 ohm micro speakers?

[HeadphoneManiac]

On Digikey and other consumer electronic websites, you can find a ton of micro speakers with impedance as low as 8 ohm. I assume they're not fit to use in actual headphones since it's rare to find headphones with impedance less than 32 ohm nowadays. But why 8 ohm? Is it some magic number?

 

[rationaltime]

I guess the magic number is the power supply voltage.
If you have say 1V drive you need a low impedance load.

I do not consider Digikey a "consumer electronic" vendor.

 

[mehboob]

The 8-ohm impedance is not a magical number but a standard primarily used for compact speakers in consumer electronics due to the balance it offers between power efficiency and driver design. Lower impedance speakers, like 8 ohms, draw more current from an amplifier, allowing them to produce higher output with lower voltage, which is ideal for devices with limited power supply, such as portable gadgets and IoT devices. However, for headphones, higher impedance (like 32 ohms or more) is preferred to match the output characteristics of headphone amplifiers, reduce current draw, and minimize distortion over longer cable runs. The 8-ohm standard for micro speakers caters to different use cases, emphasizing efficiency in compact, low-power systems rather than the higher fidelity required for headphones.