|I have three JL 13"W7's in three ported sub enclosures. I am in the process of re-positioning 2 of the three subs, The Installer is a strong believer that the new Sub boxes should be sealed? Can someone help me understand the reasoning behind this?? I thought ported theory would be pushing more air, therefor more BOOM????|
|it depends on the speaker design. non-ported enclosures with non-ported type of speakers are GENERALY more efficient at lower wattage/listening levels. |
speakers designed for ported enclosures of a specific volume and port size will provide more BOOM.
look at the paper work and specs for your speakers and that will determine your box specs.
(Message edited by G3revenge on March 22, 2004)
|Generally ported subs are louder but not as crisp with lower SQ. They way I think is port your subs in enclosed areas like v drive lockers and behind observor seats. Seal exposed subs like at the drivers feet.|
|My experience would support Darren's comments. I too have 3 subs (unfortunately not W7's) and wanted to have some boom, and some of the tighter bass. So, I ported 1, and sealed the other two. I like the results.|
|Would you guys please comment on the sealed bandpass box (with one half sealed and the other ported) at the driver's feet? Seems like that might keep the sub more protected from elements and the sealed half will prevent overextension. |
At the driver's feet, you could face the port forward into the big gunnel area - it's not a really enclosed area since it wraps all around the boat, but it's not really free-air is it? Should totally give the bandbass effect that subs inside a car give, right? Could this be too boomy (rumbley)??
|To do a band pass box properly you need a lot of space, I don't think you would have enough unless you are doing a 8" or something.|
|Tom, First off I hope you dont melt any more W-7's I would think that a ported box would let the heat get out and make your subs run cooler, but thats another topic. I have heard a few cars with 13-W-7's that have a ported box and because its enclosed in a car its sounds good, I bet if you were to take that same box out and put it in your boat it wouldnt sound as tight, it would be a more rumbely boom than a tight boom. In a boat the sounds escapes. I would think you would want to keep the bass as tight as you could, So I think your installer is 100% correct. I have found on my boat that the Passenger side W-7 hits harder than the drivers side W-7 whats the differance between the 2. The passenger side has a smaller box, With the type of power your running I think you can make your boxes a bit smaller. My friend Harrold was running 2 "12" W-7's in his SAN his didnt hit that hard. After doing some research he found out the Installers made the sub box just a bit to big. So I tend to think that the W-7 likes a smaller sealed box than JL says. IMO I would go with what your installer is saying and try it out. You have gone with the ported box and you said you were not happy so IMO this would be the next step. I think you willl find that you will be able to cross your subs over much lower and have deeper lower hittin bass |
|To get the most with the least space (what all boaters want) the sealed option is usually the easiest and best way to go. |
If however you are bent on using 2 woofers in one box, you could consider the "Isobaric" configuration. It's not for me but...... If you're not familliar with this it is a configuration using 2 subs in a small sealed box. They can be facing or opposing one another. The significance here is the Vas or area of the woofer is essentially cut in half. You get an increase in effieciency if wired in parrallel but the max SPL is not increased due to still being excursion limited to the speakers used. You can also experience a slight decrease in distortion in the configuration where the woofers are facing each other due to some cancellation of some of the non linearities.
At least this is what I've read.
|There is one other option to think of and this is not something that many people do. Its called a 7th order box, one sealed box very small and then you put another woofer in front of that with the front woofer ported so that the back woofer drives all its sound thru the port in addition to pushing the front woofer. A long time ago we would use this for small enclosures and it would produce a lot of sound. Its pretty old school and takes a little work but it sounds pretty good. |