| QFB |

The enclosures presented here provide maximum SPL over a narrow range of frequencies and are optimized for SPL competition. These designs use a non-classical alignment in which the vented enclosure’s resonance is carefully aligned with the response of a sealed box of the same volume to
produce a peak in the system’s output slightly above the tuning frequency. This peak may be as much as 12 dB when compared to a sealed box aligned for flat response.

Because all woofers operate as though they were unbaffled below vented enclosure resonance (i.e., tuning frequency) and because the tuning frequencies of these boxes is higher those of vented enclosures optimized for low-frequency extension and flat response in the passband, these woofer/enclosure combinations will not handle rated power below resonance.
If you use these enclosures for competition and everyday listening, you may find the sharp response peak unsuitable when listening to music.
Try closing the vent(s) to provide an acceptable response for music reproduction. However, do not forget to open them for the next competition!