Hertz CS 300 S4 Cento Series 12" shallow-mount 4-ohm component subwoofer at Crutchfield
What are the frequency settings for a subwoofer? I have a subwoofer with 4 different frequency settings. I need powerful, punchy bass. Should the setting be positive or negative? - Quora
Pi Speakers - three Pi subwoofer performance data
Why do subwoofers have different frequency ranges? - Sound Design Stack Exchange
The Best Studio Subwoofers For Work & Enjoyment in 2023 | LedgerNote
The Best Studio Subwoofers For Work & Enjoyment in 2023 | LedgerNote
15EXP's response | nsmt loudspeakers
What Do Car Audio Subwoofer Frequency Response Specs Tell Us?