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Found 6 results

  1. Hey fellow bassheads, I’m new here, literally just joined. I understand the fundamentals of box design, but I’m a little old school. I don’t use fancy apps, or websites to design for me. I’ve heard lots about the proper port sizes and wondered, is there a real math equation that would give me the proper port size every time? I’m 16, have four DC level 1s, and am making a box like Steve did with Bucket o’ Bass. It’s going in an 01’ Silverado. I just want to make it pound me harder than my drunken uncle on a Saturday night. Any pro tips?
  2. I'm trying to figure out how many cubes and what to tune each side of a 6th order bandpass for a single sundown zv4 15 and how many sqin's the ports should be. It's a d2 rev2 and will be ran on a shark 3500.1 amp. Its going in the extended cab of my 2004 f150. I want it musical and loud lol. Any help would be greatly appreciated!! I new to building bandpass boxes and I could really use the help. Thanks!!
  3. So I think a lot of ported boxes are built with undersized ports and this is why I'm always trying to figure out just how much port do you need to have? In the past I've talked about Small's formula that uses driver displacement and tuning frequency to determine port area needed to keep you under the dreaded 17 m/s of port velocity. My big question is what effect does flaring the ports ends (or aero ports) have? I know it allows you to have higher velocities, but just how much? This is what I wanted to find out. To find out here is my testing apparatus: I used an old 1.5 cu ft box I had built before I knew what I was doing, a cheap MCM 8" driver, and flared and unflared round and slot ports I can attach to the outside of the box. Here are what my round ports look like. Its kinda hard to tell in the picture but the one on the left has a 3/4" round over on both ends giving it a nice flare. I purposefully undersized my ports by a significant amount. I didn't want to have to work hard to get port noise, and during the test I certainly didn't. All the ports are tuned to 35 Hz and they all have pretty much the same area. The flared ports are a little longer to take into account the flare and still keep the tuning the same. To do the test I played a 35 Hz tone through the driver and slowly turned up the gain until I could just start to hear chuffing. I then recorded the voltage going to the driver. I also turned up the gain until the port noise was fairly noticeable from a couple feet away and recorded the voltage. Here is what my setup looks like during a test: So what were the results? The non-flared slot port was the first to start making port noise, which comes as no surprise with its sharp edges and corners. The non-flared round port took a little more power but not much. The flared ports both took quite a bit more power before they started making noise. Turns out you can put about 2.5 times as much power into a flared port vs a non-flared port before you get any port noise. So 2.5 fold increase of power will increase your port velocity by about 37%, so port that would start making noise at 17 m/sec can now flow a little over 23 m/sec. Knowing this I should be able to reduce port size by 37% if I use well flared ports. Now we are getting somewhere! While I definitely learned some interesting info from this test, it also left me with more questions. While I can measure how much power increase it takes to make a flared port chuff I don't have a way of knowing how many actual watts it took or what my actual port velocities were and I really wish I did. I know that when it comes to fluid dynamics things don't scale linearly with size, just because a 2" port chuffs at 17 m/sec doesn't mean a 4" or 6" port will. This is why I think Small's formula, while certainly a good starting point, gives us a little too simple of an answer. Really just how much velocity can I push through a 75 sq. in. 4.5" wide flared port before I get a noticeable amount of port noise? I suspect its a lot more than 23 m/sec. I guess finding a way to figure that out will be my next goal. Anway, I hope you folks at least found this interesting, if not useful in some way.
  4. I have two alpine type R subs and I need some help on designing a new box for them. I will be putting them in a small suv so I was wondering which way I should face the subs and ports also. I need some suggestions on tuning and everything also so any advice is appreciated very much. I am looking at getting a new amp to run them too so thats up in the air for now.
  5. Some Ideas I have and some I've used on aero ports, and a few how to things for flaring the pvc. Here's a pic or two of the end result, I've done these myself, really easy. (Looks pretty good, huh?) A lot of beginners, myself included, have built their own box, and have completely missed the tuning they wanted. My first box took me two weeks of sanding and swearing, but I built the port to a certain size the local shop told me to use. That box worked just fine, and I go thinking I can build another one tuned with the same subs and volumes. I built the second box in less than three days, painted too. Well, tuning has nothing to do with the actual volume of air in the port. I had such high hopes, the box was solid, painted, and the tuning was at 67 hz when I was shooting for 33-ish. here it is, still fresh paint too. I was stoked, and when I tested it, I almost cried. So I had this solid box I just built, and the tuning was way the hell off. If you are in this situation, I've got a possible solution, for cheap. A removable plate with interchangeable aero ports, or PVC tubes. BUT FIRST! You should determine what the tuning should be. If you aren't nerdy, it's alright, neither am I, just study the next part for a bit. What tunes a box? First, consider what the sub is doing. It's transferring mechanical energy to the air around it. An enclosure is a defined space that controls this mechanical energy in the air. Portions of that energy, depending on the frequency, will bounce around and push back on the sub's cone. This is called loading. It makes bass! (Note, there is such a thing as TOO MUCH loading) Unloading is when the air bounces IN SYNC with the cone, there fore NOT pushing on it, allowing it to travel further, reaching the mechanical limits of the spiders and surround. This is typically bad, as the soft parts act almost as bump stops as the cone flies forward and backward freely, which quickly wears and tears the parts, and alignment becomes an issue as well. Not to mention distortion caused by said alignment. Unloading is bad for just about any driver, and enclosures seek to provide an environment that controls the amount of pressure that interacts with the cone so this doesn't happen. Fortunately, unloading occurs at select frequencies that depend on the air (or enclosure) around to woofer, it's own characteristics, and the power applied. All drivers have a certain frequency where they will resonate in open free air and unload. This is also the resonant frequency, or the Fs. This varies widely between drivers, even ones of the same size. The important part is that the enclosure is tuned to provide a lot of restriction at or closer to that frequency, Fs. This pushes the Fs of the whole sub/box assembly lower, usually to a point where it's not music anymore, just wind. Say a random 12" driver resonates at 35Hz in free air. Just about any reasonable sized enclosure will provide some loading, but using both the volume of air it interacts with and the port's restriction to control the 'breathing' of this air will provide the cone with restriction, so loading occurs, and bass is created! What does all this mean? The volume of air in the box, and the restriction to flow on that air, tune the enclosure. There's a few more things to it, but that's it in a nutshell So, this is where you either ask a local shop, or look up the TS parameters from the manufacturer. Or ask around the forum here, there's plenty of folks here that will help, or at least offer advice. There's plenty of calculators for the port tuning, but don't blindly punch in numbers and build it. Do some research, chances are, some one has either built a box for the same driver, or can help you find TS for the driver. Some shops will sell you a design. Seriously, Google it. Or Bing, whatever. Okay, so, port tuning. Well, it's determined by cross sectional area and length of said area. Kinda like PORT SURFACE AREA, not volume. I had two boxes with 750 cubic inches of port volume, and the tuning didn't give a damn. Turns out, I needed roughly 42-ish square inches of cross sectional area, and a tidy 11.7" something port length for two 4" round ports to tune my setup to 34-ish. Perfect! The port for the first box had a port of exactly 3" by 12.5" by 20" long. 3x12.5= cross sectional area, or roughly 38". this resulted in a tuning of about 31 hz. Given the Fs of my subs, 26.7hz, this did great. With the second box, I kept the VOLUME of the port the same, and had a Cross sectional area of 8" by 12.5" by 7"long. Yeah, way too much area, and 7" long, total failure. So I went into a short lived depression, wanted to sell the whole car right then. Got my head back on straight and visited my local shop. "Aero ports" I went home and researched for days, learning about tuning. At first, I drowned. Saw the weird math symbols and freaked out. But I wanted to learn. And I progressively did. I determined the cross sectional area I needed, and searched through a bunch of calculators, and figured it out. And if I can do it, so can you. Just research it. So, once you have your numbers, what? A rule of thumb, sort of, is the 1x8 rule. Say you design a port that's, well, 1"x9" in cross section. This would result in a lot of turbulence as the air is pushed in and out of the port, creating annoying not-awesome-bass noises, and also reducing output, as that energy in the air is lost to turbulence. Less Bass! So keep that in mind if you have a slot port. Not really a problem with round ports, just make sure they are large enough to let it breathe some. Some folks claim that 12-15 Sq. In. of cross section for each cubic foot, won't go into that here, but it is something to consider. I visited my local hardware store with a notepad, and wrote a list of all the pvc stuff I could possibly think of using. I also brought a tape measure, checking how long this was, all that. Brainstorming. So, with prices and numbers all over the notebook, I went home and tinkered around with the calculators and Google Sketch-up, fitting the right pipes in. It occurred to me, I can get a butt connector for whichever diameter I choose, and glue it into a plate that bolts over the old port. I went with two 4" tubes, the cross section matched what I needed, and it also was simpler than one 6" because of the length(I only had 16" from old port front to back of box, 6" would have been a side port) for the desired tuning. I only needed one 24" section of 4" and two butt connectors. Cut a board, glued the butts in, and went around the old port rim with some weather stripping. Bolt it together good and snug, and it's fixed! Now it makes big bad bass just like the first box did. Here's what it looked like. And yes, that wiring was ugly, it wasn't like that for long. You can see a bit of the weather stripping, too. Don't forget to also calculate how much of the box's internal air the port(s) take up, or in my case, frees up. This is pretty easy in Sketch-up, just make it a group and pull up entity info, it normally tells you the volume of the group, unless it's not really square or off or incomplete. If you are frustrated with using Sketch-up, here's a link that should really help. How did I flare the ends of the PVC? Cheapy heat gun and a perfectly shaped brass bell. I had the bell nailed to a stump, laid the heat gun where it blew on the last inch of the PVC. You might have to use a small bowl or cup, anything that you can find that will spread the pipe when it's hot. BE CAREFUL NOT TO OVER HEAT THE PIPE! Or to heat it too fast, it can crack. Take your time, rotate the pipe A LOT. PRESS GENTLY, and heat it evenly, you'l feel when it's soft, it won't spin as easy, it'll grip a little. Never force it to bend, it's patience here. Also, some types of PVC will hardly bend at all, even under heat. And have an open bottle of water nearby to dump in the pipe when you want it to hold the shape you've bent it to. A little singe might occur on the outer lip of the flare, but I found that this can easily be sanded off. If you want a video, there's quite a few of them, some are not the best, but the idea is the same. THERE IS NOT A ONE SIZE FITS ALL ENCLOSURE! One enclosure may work extremely well for a particular driver, but that doesn't make it the worlds best enclosure. On top of that, each make and model of vehicle will affect the output of the enclosure, regardless of type, as the vehicle itself acts as ANOTHER ENCLOSURE! If a 6th order bandpass is totally nuts in the back of someone's truck, that doesn't mean it'll in a SUV or car, or even a similar truck. Each vehicle bounces the mechanical energy around differently, so even if you had an 'Ideally Tuned Enclosure', it wouldn't perform Ideally in a vehicle, as the vehicle acts as a larger enclosure, and chances are it's not an '"Ideally Tuned Enclosure"' for your 'Ideally Tuned Enclosure'. If you give up completely and are fine with paying for a ready made box built just for you, could I suggest PWK designs? (Google it!) Pete totally blows me away in terms of speaker knowledge epicness. He sure as hell knows how to build a box. Any input from those with greater knowledge is openly welcomed, including correcting me if I'm wrong. Congrats if you've read the whole thing! Hope this helped.
  6. Drivers: (2) Sundown x10 V.2 Desired internal volume after bracing and driver: 2.15+ Desired tune: 30hz link for my design in sketchup: http://www.mediafire.com/download/rjdfh30ejcejl61/SubBox_forX10s.skp My questions are: did i measure the port lengths correctly? the numbers i came up with are close to the ports on the model. is there enough surface area? I got the number from the sundown website for the 1st version, and added a bit, 31in^2 on one, and 29 almost on the other.
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