What does phantom power provide for certain microphones?

Phantom power is specifically designed to deliver a consistent voltage, typically 48 volts, to condenser microphones, which are often reliant on this external power source to operate. Unlike dynamic microphones, which generate their signal from the sound waves striking the diaphragm, condenser microphones require a power supply to polarize the diaphragm and to allow for the capture of sound with higher fidelity. This is why the provision of 48V power is critical for them.

The other options highlight functions that aren't directly associated with phantom power. For instance, while condenser microphones can benefit from improved sound quality due to their design, the primary role of phantom power isn’t to provide extra gain. Additionally, battery backup is not relevant to phantom power, as it specifically pertains to microphones needing direct power from a mixer or interface rather than a battery. Filtering capabilities are also unrelated; while some microphones have built-in filtering, phantom power itself does not provide any filtering functions.