At what point do frequencies no longer cancel each other out?

[SantiagoManager]

I was always under the impression that it was easy for subwoofers for example to cancel each other out as a result of the low frequencies. The reason I ask is in respects to a surround sound system, I'm wondering at what point I should crossover the surround sound speakers (cut off the lower frequencies), to prevent frequencies being canceled out. At what point should I crossover those frequencies? Thanks!

[JSModerator]

You are mixing 2 different things. Generally you stop worrying about wall reflections and modes above about 300 hz. The crossover depends on your other speakers. You want your subwoofer to take over before your other speakers reduce their output too much. In general you want to set the crossover as high as possible on the subwoofer and let the AV Receiver crossover take care of things. In general 120 hz is a good place to set the crossover on the receiver 🙂