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As it says. Does it matter where you put the port at in the box???? like if you use the end of a box as the port or put one right in the middle. Also I am thinking about using 5 15's. It is going to be daily driver with 5 amps. I can use one big box like this sub sub port sub sub sub Or one box with 3 subs on bottom and one with 2 like this sub port sub <---port---> sub sub sub See in 2nd design end of box is used to create the port on bottom subs. but on top set it is just a port in the middle of the box. If I do same internal air space per driver and same port average per driver. Will the shape differencepf box . or port location in the box different the sound between the two??? so would I get the same output from the 2nd design as the first. I just feel safer with two different boxes, but if it comes to it I will gladly use just one. give me pro's and con's of each please
-------------------- KING KONG aint got **** on me. WOW have been gone a long time. But I am back baby. Former 2003 meca MR5 world record holder. UGLY 1991 brown explorer, BUT was able to do 151 on cert. lin x at the head rest at 42hz!(with cheap audiobahn 15s with about 60 percent of the power allowed that year. lol) Posts: 1123 | From: Indianapolis, In, USA | Registered: Jul 2001
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sorry two things. first it was shape of box* and 2nd the first design was suppose to look like this sub sub <--port--> sub sub sub please give pos and neg's for spl and daily driving thanks
-------------------- KING KONG aint got **** on me. WOW have been gone a long time. But I am back baby. Former 2003 meca MR5 world record holder. UGLY 1991 brown explorer, BUT was able to do 151 on cert. lin x at the head rest at 42hz!(with cheap audiobahn 15s with about 60 percent of the power allowed that year. lol) Posts: 1123 | From: Indianapolis, In, USA | Registered: Jul 2001
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port position can make a huge difference. from my experience it is best to keep the woofers to one side, and the port on the other. if you're not setting out to make a comp car, then it might not make a big enough difference to worry about. it's all about trial and error in the end though. to many factors - box shape, woofers exact position, ports exact position, port tune, box volume, xover point, response requirements, etc... keep the shape efficient, and enough room for the air to move with minimal turbulance and you should be fine. do make it so you can play with the port length, as that will all in all make the largest difference, once it is installed.
-------------------- 2005 Black VW Golf TDI Alpine/DEI/Image Dynamics/CDT Posts: 736 | From: Albertville MN USA | Registered: Mar 2000
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thanks I understand in wall it matters. But this is a question in general that has puzzled me. Just port placement in box in general will it vary sound from one box to another just from the placement
-------------------- KING KONG aint got **** on me. WOW have been gone a long time. But I am back baby. Former 2003 meca MR5 world record holder. UGLY 1991 brown explorer, BUT was able to do 151 on cert. lin x at the head rest at 42hz!(with cheap audiobahn 15s with about 60 percent of the power allowed that year. lol) Posts: 1123 | From: Indianapolis, In, USA | Registered: Jul 2001
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yes, it will change the response curve. will you be able to hear the difference? probably not, unless the change is drastic enough to create a huge void/spike. these changes could likely be easily measured by electronic equipment though.
just like everything to do with this type of stuff, in the real world, you cannot really say which way will work best. every vehicle has a ton of different factors that play into how the speaker/box/interior interact.
btw, it isn't just in a wall that port placement makes a difference. there is always an optimum location for everything, based on the requirements that are placed on it. it just so happens, with a walled type vehicle, that port placement can make a huge difference. this is because the sound waves from the port and the speakers get to interact very close to where the pressure is metered. both of those waves are quite powerful, and can effect eachother greatly. there is A LOT to be had from small changes, including port placement. that is exactly what seperates the men from the boys in this sport.
-------------------- 2005 Black VW Golf TDI Alpine/DEI/Image Dynamics/CDT Posts: 736 | From: Albertville MN USA | Registered: Mar 2000
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Put the subs and ports where you like, as long as if follows the most important rule of all:
For optimum balance, the center of the subs should be the exact same distance from the port. basically, if you have three 12" subs, and wanted to port the box, then you would put the 3 subs: and then put the port here ------ so each of the three subs is equal distance. also, it might still work to do it like this:
[] the [] is the port. but it will never be as good as the first example.
-------------------- Visit Crystalmobilesound at Carl Casper on Feb 20-22 in Louisville KY!! Posts: 506 | From: chicago, Il | Registered: Dec 2001
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For SPL, the general rule of thumb is placing the port further away from the mic than the woofers...
Posts: 358 | From: .. | Registered: Apr 2002
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I have a question. Why would you want to use 5-6 subs in a daily driver?I can get one 15 to hit way harder than 5-6. Tguy is right for the port placement on one side and the subs on the other. There is a reason for this too. Its more complex than I would like to get into right now. Do a search..... You'll find tons of stuff.
Forget all the text book stuff on port placement. It was derived for a speaker operating in a theoretical half space know as an infinite baffle. In a car, the physics are much different. Im an engineer and Ive been into the theory for years and it is very complex. The best thing to do is experiment. Plan on building a bunch of boxes and try different tuning frequencies for each one... Make the air in the box move. ALL of it! Put a baffle in the box to control the air and make it travel 1/4 of a wavelength of your tuning frequency from the sub(s) to
Posts: 1259 | From: Fullerton. CA ,USA | Registered: Oct 1999
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