A processor under $300 will do the two things that matter most: delay each channel independently and split the signal with adjustable crossovers. Beyond that, the differences are channel count, equaliser resolution and how much you will hate the tuning software.
Channel count decides your ceiling
A four-channel processor handles a front stage plus a subwoofer if you stay passive at the front. Going active on the front requires six channels minimum: two tweeters, two woofers, and a subwoofer output. Buying four now and going active later means buying twice.
What to check before buying
- Channel count against what you might build in two years, not today
- Whether time alignment is per channel or only per side
- Equaliser bands per channel: 10 is workable, 31 is comfortable
- Whether it accepts speaker-level input, if you are keeping a factory head unit
- Whether tuning needs a laptop or works from a phone
The software matters more than the specification
You will spend hours in the tuning interface. A processor with excellent specifications and software that crashes, or that requires a Windows laptop balanced on the passenger seat, will get tuned once and then left alone. That is a worse outcome than a simpler unit you actually adjust.
Speaker-level input
If you are keeping a factory head unit, you need a processor that accepts speaker-level input and ideally one that can undo the factory equalisation curve. That is a different product from a plain DSP. Our factory integration guide covers the distinction.
Once installed, work through our DSP overview in order rather than reaching straight for the equaliser.
