All venues have uneven low frequency response due to room properties. The modal response of rooms at low frequencies causes large peaks and dips in the overall response of a system. In a global sense EQ is not effective in eliminating these response anomalies – one location is improved only at the risk of making others worse.

Ai advocates solving this problem in a more natural way. By using multiple subs distributed around the room, low frequency response will be smoothed out both in frequency and in space. Placing multiple subs in multiple locations, each sub will excite the room’s modes in a different way. While the response of any single sub will still have the anomalies suggested above, the total combined response is much smoother than any of the individual responses. In essence, they balance or average each other out, resulting in a much smoother overall response. Utilizing two different types of subs: ultra low frequency (ULF) subs, which cover 25 Hz to 90 Hz (different for the different ESP sizes) and broadband (BB) subs, which cover the range from 50 Hz to around 130 Hz, the Ai approach can optimally even out the response at virtually all locations in the room.

The ESP Sub line uses single band-pass cabinets that give the driver a shallow roll off above and below the tuning frequency. Using a single band pass design gives a combination of desirable characteristics: a less complex crossover, high power handling, shallow roll offs, higher efficiency, as well as lower overall distortion due to the driver’s output being acoustically filtered. The ESP Subs use a multi-tuned port that smoothes the overall response of the sub.