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ported boxPrinted From: the12volt.comForum Name: Car Audio Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc. URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=109035 Printed Date: October 31, 2024 at 6:24 PM Topic: ported box Posted By: rival904 Subject: ported box Date Posted: November 18, 2008 at 8:41 PM Ok, theres a few questions in here, so brace yourself.
First off, I have a set of woofers here I am going to try and build my first ported enclosure for, they are Pioneer TS-W3001D4. I cant find anywhere how much volume the actual woofer takes up, any one got an idea other than the packing peanuts? For a single woofer, they call for 1.25cu.ft, with a port dia of 3in (which if I converted it to a rectangle it would be a 1x7 correct?) at 3.5in deep. Do I have to account for the volume the port takes up or no? If I wanted to build an enclosure for 2 woofers, with 1 port, would I just double the port? So instead of 1x7@3.5in deep I would do a 2x7@3.5in deep? Also, is it good to round the internal edges of all the ports on the inside to reduce port noise? Any help would be much appreciated. ------------- 2004 F150 STX 4x4 Eclipse CD3100 (4) Pioneer TS-W3001D4 Powerbass 3XL 6x8 Powerbass 600.4 Replies: Posted By: whiterob Date Posted: November 18, 2008 at 10:43 PM Generally, a 12" sub is going to take up around 0.1 cubic foot. If you are going by Pioneer's recommendations then they probably take that into account already.
Unless Pioneer's recommendations include the port displacement then you will need to take them into account. You did calculate the port area correctly but that port design is going to be way too small. By that I mean the cross sectional area of the port is too small which means you will have port noise. For a round port it would not be as noticeable, though you still could have some at higher volumes, but for a slot port I would suggest you make it larger. Rounding the edges will help lower air turbulance but not enough to be effective. If you made it for two subs you would have to recaculate the length of the port. You don't simply double the cross sectional area of the port and keep the length the same. I would suggest you download WinISD and use the port calculator that it has to figure out the port size. Posted By: rival904 Date Posted: November 18, 2008 at 10:47 PM I have WinISD, but dont have parameters on these woofers.
------------- 2004 F150 STX 4x4 Eclipse CD3100 (4) Pioneer TS-W3001D4 Powerbass 3XL 6x8 Powerbass 600.4 Posted By: rival904 Date Posted: November 18, 2008 at 10:52 PM also, I am almost 100% sure that this sub is way over .01, I am having doubts if it will even fit in 0.8cu.ft
------------- 2004 F150 STX 4x4 Eclipse CD3100 (4) Pioneer TS-W3001D4 Powerbass 3XL 6x8 Powerbass 600.4 Posted By: whiterob Date Posted: November 19, 2008 at 7:42 PM rival904 wrote: The displacement of the sub is going to be around 0.1 cubic not the enclosure you use. That means the sub is going to take up around 0.1 cubic foot of the enclosures volume. That is what I though you were asking. You don't need the sub's parameters to calculate the port length in WinISD. Just enter in the volume of the enclosure and the dimensions of the port. Then it will calculate the length of the port for you. If you want the sub's parameters just e-mail Pioneer and they will send them to you. Posted By: rival904 Date Posted: November 19, 2008 at 7:54 PM whiterob wrote: Sorry, I mean the actual sub displacement is closer to half a cu.ft probally more. ------------- 2004 F150 STX 4x4 Eclipse CD3100 (4) Pioneer TS-W3001D4 Powerbass 3XL 6x8 Powerbass 600.4 Posted By: stevdart Date Posted: November 19, 2008 at 8:48 PM That sub might displace close to .2 cu ft. But here's the thing about working with a sub whose tested parameters are not published and available: you are working with a sub whose purpose is nothing but SPL. Gleen what info you can from the manufacturer's published data; e.g. that it can be used in a small box. With emphasis on "3000 watts", Pioneer is clearly marketing this sub for street SPL. I would venture to say that if you did have the tools and resources to test this sub's parameters, you would arrive with a set of numbers that would confound you when you plug them into WinISD. Audiobahn, too, has several sub models that you can't work with in a box building program. What is confounding is that when you are attempting to arrive with some kind of decent Q in the design of the box, you find that the port has to be 3/10 of a mile long or that the box should be 12 cu ft...things of that nature. Confounding things. There is likely good reason why Pioneer isn't publishing tested data on this line of subs. So you should use all the resources that you have available to come to some sort of conclusion. First, you have the limitations of your car's available space. Then, you have a sub that wants a lot of power applied, so think about building double walls and braces into the box. Also, consider available space for the port structure (the recommendation of a round 3" port with a short length is a clue that the sound from this sub probably won't be hurt too much by port noise. Remember, it is intended for SPL, not sound quality). But consider using a larger port opening area and thus a longer port length anyway so that you are not intentionally permitting added noise from the port. And I'll add that a rule of designing rectangular port openings is to make them as square as possible. One inch wide is too narrow, regardless of the corresponding length. Another resource, and one that is perhaps used most often, is to look at what everybody else is doing with this sub model. You'll find examples of 2.5 cu ft per sub (at least I did when I did a search). Whatever you come up with, allow the generous thickness of baffles and added displacement of port structures to your final product. You will eventually end up with a monster heavy box, even if the net internal volume is just one cubic foot. And give the sub plenty of power. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times. Posted By: rival904 Date Posted: November 19, 2008 at 8:54 PM Hmm. Well I did some remeasuring and I wont be able to get 4 of them in there, not ported atleast. Sealed I will be able to do, and so I plan on building the box and what not this weekend and throwing it on the meter and seeing what it will do.
Also, you guys had said that I couldnt do a 1x7 and keep the same length? Would I simply use the WinISD program to get the port lengths or is there another way? Also, whats the best way to get the wires outside of the box in a sealed situation? I normally just tie a knot in the wire, on the inside of the box, drill a hole just barely big enough for the wires, and put a large dab of liquid nails on the inside between the knot and the box and then pull the wires quickly, hopefully sealing it all up. This box I was going to try and use fiberglass resin to seal the inside 100%, what would you guys suggest? Will the resin mess with the wires or whats the trick? ------------- 2004 F150 STX 4x4 Eclipse CD3100 (4) Pioneer TS-W3001D4 Powerbass 3XL 6x8 Powerbass 600.4 Posted By: whiterob Date Posted: November 20, 2008 at 10:12 PM rival904 wrote: It's not that you can't use a slot port with those dimensions it's more that you shouldn't. The port noise will be much more prevailent with that size port. You could try to use binding posts on your enclosure. That will be a more professional way of running the wire through the enclosure. Simply drilling a hole in the enclosure and running it through is fine. If you use caulk and some resin it will work fine. https://www.parts-express.com/pe/showdetl.cfm?Partnumber=091-1247 stevdart gave a good explanation. With many of Pioneer's subs they are made to fit in small enclosure configurations. This means, with ported designs you will need either a small cross sectional area on the port or a very long port. So if you do change Pioneer's recommended port size you will need a much longer enclosure. WinISD would be able to help you out with this. stevdart was also right on with the slot port recommendation. You should go with as square of a slot port as possible. That way you will have less air turbulance which means less port noise. If you go sealed then none of that really matters. Just stick with an enclosure around Pioneer's specs and you will be fine. I was thinking of the wrong sub previously so stevdart is probably right with it taking up around 0.2 cubic foot. Pioneer's recommended enclosuremay account for that so check that for sure. Posted By: aznboi3644 Date Posted: November 21, 2008 at 12:08 AM the pioneer "recommended" enclosure sounds like complete dog crap
Posted By: rival904 Date Posted: November 21, 2008 at 10:06 AM whiterob wrote: I havent really worked much with resin, but it wont eat the wires or anything of that nature? Also, if the wires move on the outside it causes a little movement on the inside of the box, that wont affect things either? And when you say I should go with as sqaure of a slot port as possiable, then I should stick to like a 3x4 instead of a 1x7? If thats the case then why do alot of ported boxes I see have a slot port running the whole width of the box, I would think its because it wont have air flowing on the sides of it, just in the middle, is this correct? ------------- 2004 F150 STX 4x4 Eclipse CD3100 (4) Pioneer TS-W3001D4 Powerbass 3XL 6x8 Powerbass 600.4 Posted By: stevdart Date Posted: November 21, 2008 at 5:50 PM A long, thin port is less accurate than a more square design and has greater air turbulence. Keep any port design at a 8:1 ratio or more square. One inch is too narrow to use. One and a half inches on the short width would be the narrowest I would design with. 3 X 4 is 12. 1 X 7 is 7. These don't compare, but if you were just throwing out numbers to qualify what "more square" means then you are right that the 3 X 4 is better. Use a rubber grommet for the wire through the box if you are concerned about chemical interaction. For myself, I haven't heard any stories of wire insulation being damaged by resin. And if the wire, in whatever way it's secured through the box, is secured completely, there won't be movement of the wire inside the box when the outside part of the wire moves. But if there is some movement, no harm done. For your question of ported box designs, the easiest way to build a slot port is to use the effective inside width of the box for port opening length. It keeps the construction at its simplest for both the design and the building of it. Some premade boxes have poorly designed slots, so don't put much into those designs, but many are correctly built. If a slot opening is 12" on the long side and you want to maintain an 8:1 ratio at a minimum, then the width of the slot should be no less than 1.5". Then, if you wanted to lengthen the port for better tuning accuracy, you could widen the slot design to say, 2", and work the port length out again using that larger square inch opening. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times. |
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