The trick in building a vented box is to get the right size enclosure and the right size vent. You can't be too far off on either of these factors or your speaker's performance will suffer. In particular, using a too-small box or a too-high vent tuning frequency can eliminate bass instead of increasing it.
Symptoms, which usually begin four to six days after infection and last for up to 10 days, may include. 1  Sudden, high fever. 2  Severe headaches. 3  Pain behind the eyes. 4  Severe joint and muscle pain. 5  Fatigue. 6  Nausea. 7  Vomiting.
The principal symptoms of dengue are: 1  High fever. 2  at least two of the following: 3  Severe headache. 4  Severe eye pain (behind eyes). 5  Joint pain. 6  Muscle and/or bone pain.7  Rash. 8  Mild bleeding manifestation (e.g., nose or gum bleed, petechiae, or easy bruising).engue hemorrhagic fever (DHF) is characterized by a fever that lasts from 2 to 7 days, with general signs and symptoms consistent with dengue fever. When the fever declines, warning signs may develop.