Teacher made me do a Process essay, so I'd thought I'd do it on installing a aftermarket subwoofer, problem is I procrastinated (or w/e) too much, RD was due last friday I typed it in 2 hours this morning. So it's pretty basic, just had to fill 2 pages double spaced and he doesnt know crap about crap. I know there's probably some mistakes in the essay, but I would like feedback. If anyone can tell me what you would grade this based on Grammar, sentence structure, etc... the teacher stuff. Now if there's really a english teacher that can give feed back that would be great //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif . (btw it tuend out to be 5 pages, I am thinking if I should throw in a quick guide to gain setting, but duno if i should waste the time). Keep in mind I did it this morning and there's probably some number errors, etc.. so try to be nice, but flame away //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif (doh! just notice the title was progress, not process, how do I change that?)
Bump In The Trunk
(Have you ever wanted more bass in your music? By installing a aftermarket subwoofer you can produce the sound you've been looking for. The extra bass to help enhance the musical experience in your everyday drive. Installing an aftermarket subwoofer isnt for everyone though, because if wired wrong can cause alot of problems. It’s a very easy procedure as long as you know what you are doing.)
Revised.
Choosing a location for where you plan on putting the subwoofer is an important step. Because placement help create the imaging of the sound. A good example is like when you go to a live concert and they have the speakers facing the certain different ways and at exact locations. Generally its not as big deal as speakers but there are some basics, in a trunk car it sounds better to have the subwoofers firing toward the back of the car, in a SUV, truck, or hatchback generally facing forward or up. Find the stop and see how much space you are willing to give up for the subwoofer box, and amp(s).
Now we pick the subwoofer you want to use. There are a lot of choices and sizes to choose from, so you have to do some research before choosing a good one. But make sure you find the most important information about a subwoofer. Keep track of the RMS (Root Mean Square) power handling which is how much power the subwoofer can take on a constant basis. Than you need to find the resistance of the voice coils, subwoofers are produced to have as many as 4 voice coils, generally the subwoofer’s manual, box, or model would tell you what the resistance of each voice coil is and how many there are. Always use the same subwoofer, size, and resistance of coils. Mixing and matching is a bad idea because it produces different sound waves and causes cancellation, which makes the bass sound sloppy and bad.
Wiring the resistance of the subwoofers to get your final resistance on the amp. This is pretty simple, and just requires basic algebra. First treat each voice coil separate; whither it’s on the same subwoofer or a different one. There are two ways to wire the coils, in a parallel, or in a series. To calculate the resistance in parallel wiring use the equation RT (resistance total) = (Ra x Rb) / (Ra + Rb). Where a and b is set by the 2 voice coils in use, for each additional voice coil in use you would need to add an additional resistance ®. (Ex. RT = (Ra x Rb x Rc x Rd…) / (Ra + Rb + Rc + Rd…)). To wire in parallel connect all the positive outputs of the voice coils together, than connect all the negative outputs together, so you would end up with just one positive and one negative cable to hook up to the amplifier.
Wiring in a series is calculated by the equation RT = (Ra + Rb + Rc…). The way it’s done is by starting at the amplifier, wire the cable into the positive output of the channel you are planning to use, hook it up to the positive of VC a, than wire the negative of VC (voice coil) a to the positive of VC b, than the negative of VC b the to the positive of VC c, or negative on the amplifier to finish the chain.
Picking your amplifier is as tricky as picking your subwoofer, since there are so many choices. But having your subwoofers specifications already known it makes it a little easier. First match the RMS output at the same resistance to the added up RMS power of the subwoofer(s) at that resistance. Never run an amplifier below its rated resistance, (Ex Do not run an amplifier rated at 2 ohms at 1 ohm). Than look for these specifications on the amplifier to help you decide what’s good and what’s not. You want an amp with a low THD (Total Harmonic Distortion) at the rated output, this way your subwoofers wont be messed up by the amount of distortion at high levels. Next find the dampening factor of the amp, for speakers generally anything over 100 is good, but for subwoofers the higher the number the better. The dampening factor helps how fast the amp stops a frequency note, and helps reduce distortion. The class of the amp is a factor as well, generally you will see three classes of amplifiers, class A/B, class D, and class T. Class A/B produces the cleanest sound but also requires a lot more amp draw from the electrical system to produce the same amount of power a class D or T can produce with less amps. Since bass notes are lower frequency’s the sound quality can’t be noticed that much, that is why it is better to choose a class D or class T for your subwoofer amps, they are more efficient and the difference in quality can’t really be hear human ears. Class T is basically a renamed class D, it’s renamed because a company had produced it’s own way of making class D amps and decided it wanted to call it a class T amp. The last thing you should look out for is the quality and reliability of the amp. Do the research and see what other people have to say about it.
Now that we have the subwoofer and amplifier combination it’s time to choose what to put the subs in. There are 4 main types of enclosures, sealed, ported, infinite baffle, and band pass. A sealed enclosure is most typically used, because it is the easiest to make, it makes a tighter punch, takes up less space, and produces about the same output at most frequencies. . A ported box produces the highest sound output at the frequency the port/vent is tuned to, but will not be so loud further away from the tuning Its great if tuned low (28-32hz) because it will be louder than a sealed box and that's the tuning frequency for better sound quality (as it can play more notes), it also takes approximately 1.5 times the space a sealed box would take. Infinite baffle is where you would mount the subwoofer to the back dash of the car, basically using the whole trunk as one huge box, it can be one of the best sounding ways to use a subwoofer, but most subwoofers cannot handle the stress of being used in a IB, so before doing this you have to make sure the sub(s) was designed to be put in an IB setup. Lastly the band pass box is used, it is a combination of both the sealed and the ported box. Its designed so one side of the subwoofer is in a ported box and the other is in a sealed. This is good at producing loud sounds at the exact frequency its ported side is tuned to, but generally doesn’t produce as much output at any other frequency like all the other setups. Plus it doesn’t sound as good; it’s used mainly for its loud output at the tuned frequency. Find what the company recommends the subwoofer put in, generally either sealed or ported. Than get a box to meet those specifications, you can build it, have it custom made, or purchase a prefab (pre-fabricated) box that meets the requirements.
Now you need to purchase all the cables and wiring required for installing this process, you have to find out the length it would take to run a power cable from your battery to the amp. Remember to always disconnect the negative battery terminal while doing any electrical work to prevent shock. Use the guideline of 100-600watts = 8 gauge, 600-1200 watts = 4 gauge, 1200-2000watts = 2 gauge, 2000watts+ = 1/0 gauge. It’s never harmful to use a larger wire than required just for safety. Always make sure you have a fuse within 18” of the battery on your power cable, the rating on the fuse should be the max draw of the amplifier in amps. The amplifier should state what kind of fuse rating to use. Than you have to get speaker cables (which hooks up the output on the amp to the subwoofer), use the guideline of 100-500watts = 12 gauge, 500-1200watts = 10 gauge, and 1200+ = 8 gauge. Finally if you do not have RCA output to the amp from your head unit that you can use get a LOC (High/ Low Out Converter), which you tap into the signal from a left and right speaker of the vehicle. Just wire the positive to the positive, negative to negative on the right speaker, than do the same on the left. Hook a RCA cable up to the LOC and finally to the amp. Than ground the amp to the vehicle chassis, always use the same size cable for the ground as you did for the power. Make sure the chassis where the ground will be is pure metal; sand it down and everything for the best possible connection.
Always double check all the wiring and make sure everything is in the right order. Than power everything one-step at a time, take the fuse out of the fuse holder. Hook up the negative power back to the battery, put the fuse in the fuse holder and hook it back up and test to make sure everything works. Do not turn the volume all the way up at first, do it slowly to make sure everything is okay. If everything is fine you’ve just setup an aftermarket subwoofer and I hope you enjoy your new bass.
