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.
1 Dengue fever is a disease caused by a family of viruses that are transmitted by mosquitoes. 2  Symptoms include severe joint and muscle pain, swollen lymph nodes, headache, fever, exhaustion, and rash. 3  The presence of fever, rash, and headache (the dengue triad) is characteristic of dengue fever.
Dengue fever: Symptoms. The symptoms of dengue fever can closely resemble symptoms of influenza. They include fever, joint and bone pain, nausea, vomiting, headache, and fatigue. A rash may also occur about three to four days after onset of the fever.Symptoms may vary in character and severity between individuals.he symptoms of dengue fever can closely resemble symptoms of influenza. They include fever, joint and bone pain, nausea, vomiting, headache, and fatigue. A rash may also occur about three to four days after onset of the fever. Symptoms may vary in character and severity between individuals.