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.
1 Worldwide, 2.5 percent of people infected with dengue fever die. 2  Dengue does not spread from person to person, but it possible to spread via blood transfusion and organ transplants. 3  In 1955 dengue fever was only reported present in 3 countries. 4  Today dengue is present in more than 120 countries.engue Fever Symptoms. Symptoms of dengue fever usually begin to manifest 3-7 days after being bitten by an infected mosquito, in some cases it may be up to 2 weeks before symptoms appear.