In this video I show you everything you need to know about subsonic (a.k.a. infrasonic) filters. The subsonic filter is used to protect your subwoofer from damage due to playing low and loud. It is easy to set all you need are test tones and a multi-meter. If you found this video helpful then you can support DIY audio content on Patreon for as little as $3 a month: https://www.patreon.com/DIYAudioGuy All Patrons get early access to videos plus exclusive Patreon - only content! Or you can help out with a one time donation: paypal.me/diyaudioguy A special thanks to HIFI Vega and 123Toid for their help with this video. Check out their channels: null null Affiliate* links to items used in this video: Parts Express: Ultimax Subwoofer: https://www.anrdoezrs.net/ko79nmvsmu9BAABCDEHC9BDHBFGIJ?url=http%3A%2F%2Fwww.parts-express.com%2Fdayton-audio-um10-22-10-ultimax-dvc-subwoofer-2-ohms-per-coil--295-510&cjsku=295-510 Amazon: Kenwood Amp: https://amzn.to/2UyJQRa Digital Multimeter: https://amzn.to/3cTsYLv *As an affiliate/associate marketer I may earn a small commission from qualified sales.