i dont know much about ported boxes... what does the size of port effect? what about tuneing it? what does that mean and how does it make a differance?
well most people use ported boxes because they are louder.. depending on the tune depends on how much louder it will be .. it will be louder than a sealed box no matter where u tune it.. but the higher you tune it (to a point) the louder it gets.. different subs will require diff port sizes because subs will vary on how much air they move.. if you make a port hole to small for the sub it will create an unwanted whistle or such called "port noise" .. tuning a box depends on 3 things... the size of the box the area of the port opening and how long the port is .. the longer the port is the lower it will tune the box..a good SQ box is tuned in the upper 20 hz range with lots of port area to avoid any port noise... an SPL box will be tuned higher such as mid - high 40's. this box will be much louder than the SQ box because it is tuned higher.. the disadvantage is that it cannot pickup the lower frequencies that the SQ box can because as the sub plays below the box tune the sub loses control and will overexcurt which can cause damage.. this is when a subsonic filter is used on an amp to prevent it from playing those frequencies..