What amp would you need for a 15 inch sub?

The amplifier you need for a 15-inch subwoofer depends on the sub's power handling specifications and impedance. Generally, a good rule of thumb is to match the amplifier's RMS power output to the subwoofer's RMS power rating, typically between 300 to 1500 watts for a 15-inch sub. Additionally, ensure the amp's impedance matches the sub's impedance (usually 2 or 4 ohms) for optimal performance. Always consider your specific subwoofer model's requirements for the best match.