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.
Once infected, a person experiences a severe, flu-like illness. Symptoms include high fever, muscle and joint aches, severe headache, nausea, vomiting and rash-just to name a few. In some patients severe Dengue Fever (a.k.a. Dengue Hemorrhagic Fever) can form. Symptoms include severe abdominal pain, persistent vomiting, shock, leaky capillaries, and circulatory system failure.