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Acoustic and Audio System Design for Small Rooms - PART 5 By - Rahul Sarma, CEO, Menura Acoustic Labs In collaboration with Sound Wizard
In the previous part, the article discussed frequency responses of speakers and how they relate to the listening experience. That discussion is the perfect overture to this next topic of interest – system tuning and optimization.
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rossover Point Determination
Before system optimization, crossovers have to be set (usually in a DSP) at selected frequencies. The crossover point is the cutoff frequency below which audio is sent to the subwoofer(s) and above which audio is routed to the mains and surrounds. There are multiple considerations to keep in mind when selecting this crossover point. It takes significantly more electrical power to reproduce lower frequencies than higher ones, so this is the first calculation you need to make. Based on how much headroom you have available on your amplifiers, or even the loudspeaker sensitivity, you may be forced to move the crossover point higher than you desire. There are a few drawbacks to higher crossover points which make them undesirable for reference quality systems. As opposed to mains and surrounds, subwoofers drivers are made with significantly
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MARCH - APRIL 2021
Fig 1: Headroom trade-off while selecting crossover frequency larger diaphragms, which by their nature are usually too slow moving to have a good transient response at mid frequencies. Additionally, above 100Hz, we start to perceive sound AV-ICN TECHNOLOGY
a bit more directionally, which is sub-optimal (pardon the pun) for a truly immersive surround experience. Therefore, it is recommended to set crossovers at 80Hz or lower.
