He uses FP8000Q for top speaker, FP10000Q for subwoofer. Many customers will choose FP22000Q, FP14000 for subwoofer special power amplifier for subwoofer.
But if your subwoofer size is relatively small, such as only ten inches, 12 In inches, FP10000Q is also fine, but the bass effect will not be as amazing as a special subwoofer amplifier.
Of course, the power of your subwoofer must be within half of the RMS power of the amplifier, so as to ensure that it will not damage the audio system.