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.
Recognizing Symptoms of Dengue Fever. 1  1. Expect an incubation period of four to seven days. Once you are bitten by a mosquito that is carrying dengue fever, the average time for symptoms to begin is four to seven days. 2  2. Take your temperature. A high fever is the first symptom to appear. 3  3. Watch for flu-like symptoms.