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.
Symptoms of Dengue. You can notice the symptoms of dengue in 3 â 6 or within 15 days after being infected. The symptoms can happen in stages. Usually, the symptom starts with a chill, then headache, pain in the movement of eyes, followed by a low backache and loss of appetite.