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 rash may appear over most of your body 3 to 4 days after the fever begins, and then subsides after 1 to 2 days. You may get a second rash a few days later. Symptoms of dengue hemorrhagic fever include all of the symptoms of classic dengue plus.