SPL is Sound Pressure Level which is an acoustic measurement for the ratios of sound energy and are rated in dB. The purpose of subwoofer design here is to produce the highest SPLs without any emphasis on smooth frequency response or linear output capability.
You’ll get a high SPLs with this system, but the system will come at the expense of smooth frequency response, it is a “one-note” bass system, emphasizing on narrow frequency range in the bass region. But it is also possible to design the system which can feature both high SPLs and smooth frequency response.
You can use these systems to create a high SPL system, the sealed, vented and bandpass.
The most important driver characteristics for designing a system for peak SPL are, a high power rating, a high volume displacement (Vd). Linearity and frequency response aren’t so important because the driver will operate over a very narrow range of frequencies.
Consider how much power you can provide to your SPL subs, ensure your amps can provide that power level and able to deliver it to the subs with minimum loss. Use the largest power cable there is to ensure the voltage delivered to the amp wont dip at peak power level, and also use larger speaker cable gauge to make sure the cable’s impedance is lower than that of the subs.
Also make sure your car’s power system can give the required current for the amp to provide the power to the drivers. You might have to upgrade the alternator so it can supply more current. For example, you can’t use 2kW amp in the system if the alternator isn’t rated to deliver enough current to that amp for it to reach its rated output.
Use a class D amp for the bass to minimize current draw, these amp tend to be more efficient than other type of car audio amp.
