Ask S&V

Q I’m curious to know if there’s any criteria for home theater component selection based on room dimensions. I want to focus my search on equipment that’s an appropriate match for my space. —Bill King / via e-mail

A There is one set of criteria that exists for selecting home theater components based on room dimensions: THX certification categories. The idea behind this system is to provide guidance for choosing receivers, amps, speakers, etc. that will enable you to achieve THX reference level (85 dB SPL with 20 dB of headroom) in a particular space.

Ultra2 is the top THX certification category. Components meeting this spec are meant for larger home theaters—up to 3,000 square feet with a 12-foot seating distance from the screen. The category directly below it is THX Select2, which covers products that are a good fit for home theaters up to 2,000 square feet with a 10-to-12-foot seating distance from the screen. There’s even a THX category for small rooms: THX I/S Plus. This is meant for lower-end receiver-plus-speakers systems designed for snug spaces where you typically sit 6 to 8 feet from the screen.

The only downside to THX certification categories is that you need to, um, buy gear that’s THX certified. A few companies—Onkyo, for example—routinely seek out THX certification for their products, but many other manufacturers don’t bother, or only offer a smattering of THX-certified offerings.