Design criteria for HiFi application powered subwoofers are actually different form most mainstream powered subwoofers that are designed for home cinema purposes. Those woofers are ported and tuned around 60Hz with high SPL for maximum impact in LFE applications.
HiFi subwoofers however have different requirements because HiFi systems are listened at a lower more realistic volume level and need to go a bit lower in frequency with a flat response from 10/20 to about 80 Hz adding only lower octaves to the existing HiFi speakers.
For this purpose we are designing a special subwoofer that will be presented here soon.
Parts used in this project