March 20, 200520 yr i'll have to look up the 9:1 thing...the end correction thing i was right about..lol..kewl..hehewheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
March 21, 200520 yr Author Damnit....I think im just gonna make another wedgeuse both 3" ports on the sideNo slot port, to much work when i can just use both round ones
March 21, 200520 yr 9:1 is about tuning variance. Under 9:1 is Good. Over 9:1 is bad. 15:1 (15"x1") is very bad... within reason. Bad = tuning frequency will change due to swirling / turbulence. I dont remember the long version of the expanation... it was posted a while ago by one of the big wigs from JL's tech area.~~~~~~~~~~~~~~~~~~~~~~~~~~That wedge box would be cool, if the port didnt open up right behind the moofer. That makes it much easier to unload the woofer. I've played with a coupld of boxes where the internal port mouth is right behind the motor, ranging from 4" wide to box wide (~26" iirc)... makes it MUCH easier for a woofer to unload. Lemne see if i can find a pic.
March 21, 200520 yr okay, i cannot. Must have fell victim to the recent cleanup.Anyhow, imagine an enclosure with 3 woofers across the face and a 4"H x 12"W port firing out from under the middle woofer. This port terminated ~6" into the box, right under the motor of the woofer. The middle woofer excurted much more noticably then the left & rightmost woofers. We ended up inverting the middle one, to try to buy wave space.Now, this still applies to single woofer boxes, it was just much more apparent in the one that I made above. BTW - that one was trashed after the middle coil started smelling. Built a new one with two corner ports.-Nick
March 21, 200520 yr versus two 3" ports even longer.15" long for 1One 3" vent is not even close on the correct vent area.
March 21, 200520 yr ok..so 15:1 is bad due to swirling and turbulance...makes since as the confined area of the port will tend to increase velocity, correct?whereas a port say 2x7..will allow a greater volume of air to leave without increasing the velocity, even though the area is roughly the same, correct? am i along the correct path here?i'm also thinking the tall, narrower port will in essence be harder for the air to work in due to the confines...hence, increasing the turbulance. help me out here so i understand the reasoning, theory the 9:1 rule...wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
April 5, 200520 yr O.K i had an ideaMake a slot port wedge enclosureCenter port ( under sub)then make it go all the way back to the back of the enclosuremake a whatever degree bend it is and continue the port up the back of the enclosureIf this is possible i can make a bigger enclosure( which will sound better)<{POST_SNAPBACK}>what car is this going in???
April 5, 200520 yr ok..so 15:1 is bad due to swirling and turbulance...makes since as the confined area of the port will tend to increase velocity, correct?whereas a port say 2x7..will allow a greater volume of air to leave without increasing the velocity, even though the area is roughly the same, correct? am i along the correct path here?i'm also thinking the tall, narrower port will in essence be harder for the air to work in due to the confines...hence, increasing the turbulance. help me out here so i understand the reasoning, theory the 9:1 rule...wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee <{POST_SNAPBACK}>its also got to do with the perimeter.say you have a 6x6 port gaining you 36 sqin or port.the perimeter of the port is 24 inches.now, make that port 18x2 - the perimeter for the same port area is 40 inches. that is a big difference.
April 5, 200520 yr Author O.K i had an ideaMake a slot port wedge enclosureCenter port ( under sub)then make it go all the way back to the back of the enclosuremake a whatever degree bend it is and continue the port up the back of the enclosureIf this is possible i can make a bigger enclosure( which will sound better)<{POST_SNAPBACK}>what car is this going in???<{POST_SNAPBACK}>94 integraRight now the DD's are in there bumping away
April 5, 200520 yr ok..so 15:1 is bad due to swirling and turbulance...makes since as the confined area of the port will tend to increase velocity, correct?whereas a port say 2x7..will allow a greater volume of air to leave without increasing the velocity, even though the area is roughly the same, correct? am i along the correct path here?i'm also thinking the tall, narrower port will in essence be harder for the air to work in due to the confines...hence, increasing the turbulance. help me out here so i understand the reasoning, theory the 9:1 rule...wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee <{POST_SNAPBACK}>its also got to do with the perimeter.say you have a 6x6 port gaining you 36 sqin or port.the perimeter of the port is 24 inches.now, make that port 18x2 - the perimeter for the same port area is 40 inches. that is a big difference.<{POST_SNAPBACK}>Correct-o-mundo.More surface area can lead to more chuffing, given the same port area.
April 5, 200520 yr ok..so 15:1 is bad due to swirling and turbulance...makes since as the confined area of the port will tend to increase velocity, correct?whereas a port say 2x7..will allow a greater volume of air to leave without increasing the velocity, even though the area is roughly the same, correct? am i along the correct path here?i'm also thinking the tall, narrower port will in essence be harder for the air to work in due to the confines...hence, increasing the turbulance. help me out here so i understand the reasoning, theory the 9:1 rule...wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee its also got to do with the perimeter.say you have a 6x6 port gaining you 36 sqin or port.the perimeter of the port is 24 inches.now, make that port 18x2 - the perimeter for the same port area is 40 inches. that is a big difference.Correct-o-mundo.More surface area can lead to more chuffing, given the same port area.ok..kewl..so area and perimeter are important...nice. i'll make a note of that.. so, increased perimeter, while maintaining area, can lead to "chuffing", and an increased chance of noise?don't ya love learning?!?! thanks guys...gimme more!!wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
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