How Speakers Work and an Intro to Building a Subwoofer Box

courtesy goes to: www.digispeaker.com for the picture, thanks digispeaker!

BEFORE WE START: I, for one, am very open to constructive criticism but any comments that seem to be hurtful to others and/or this instructable can and shall be removed. Thank You

Alright, so before we begin we need to get some basic information down on what you are going to learn in this instructable. Ill be teaching you:

Technicalities of speakers and subwoofers
Choosing a subwoofer
Formulas for turning a subwoofer enclosure
Choosing wood for your box/enlcosure


And if you like this instructable and would like to see a photo step by step instructable on how to build the box please send me a personal message.

Now it seems like a lot, but a lot has to go into tuning a box if you want it to sound and look great. 20% of the sound and its quality come from the subwoofer, 80% comes from the enclosure and how the whole thing is tuned.


THE ATTACHED FILE IS ALL OF MY INFORMATION IN ONE DOCUMENT IF YOU WOULD LIKE IT

Step 1: Technicalities of Speakers and Subwoofers

Now i'm sure we all know this but a speakers works by taking an electrical  signal and turning it into sound waves, these sound waves are produced by the vibrations of the cone in which makes up the speakers. When looking for speakers you want to look for quality cones, not to thin, not to thick and stroung enough to handle powerful vibrations. Take this into consideration when looking at materials found in the cones of speakers or subwoofers you are looking at.

To reproduce sound speakers have to have a range in which what types of pitch they can hit. This is called "Frequency Response" and is measured in (Hz). 20 Hz -- 20,000 Hz is typically the correct range for speakers. Subwoofers, as you may have guessed are in the lower range of the scale (20 -- 200 Hz). Also when looking for a subwoofer, visit the brands website and see if they have a response curve chart for that speaker/subwoofer. When looking at these charts you want to try and find one that has a relatively flat line. What this means is, no matter what the frequency is at, whether it be high or low, as long as the power is the same, the sound will not become any louder or quiter.

Speakers Volume is measured in Decibels or (dB). When looking at speakers/subwoofers you're going to want to look at the decibel level and sensitivity rating. A 3dB jump usually takes twice the power; a typical home audio system runs at 75dB -- 105dB while speakers at a rock concert can get all the way up to 115dB -- 121dB. If you want your speakers to make the room as loud as can go with as little power as possible, try finding a speaker you like thats has a high sensitivity rating.

Step 2: Choosing a Subwoofer

Now when choosing a subwoofer there are a few things to take into consideration: Size, Power, Price... and maybe even the SAF (Spouse Approval Factor) ^-^

1st: Size, I hear a lot that the bigger the driver, the louder it is, this is true only because of the amount of air being moved by the subwoofer itself, although when you get a bigger driver you are also giving up better accuracy because of the slower movements of the driver. 12" are what most people get, although 10", though they may be smaller, give a lor more accurate and a lot better range with sound.

2nd: Power, now this is where the fun comes in, now you get to choose, do you want a sub that will blow the cobwebs of your wall or rattle the rust off your car? Then you're going to want to get a higher power rated subwoofer. Now when looking at wattage, it's important to remember that wattage is actually a measurement of heat, this be the reason why you want to keep your amplifier vented and not covered. But basically, the higher wattage power rating on a subwoofer the more heat it can take thus meaning the more power it can handle. When looking at power handling you want to look at the "Nominal Power Handling" number, or, RMS. This tells you how much wattage (heat/power) it can handle normally, where it will sound the best. Don't forget to check with one's spouse before making a decision xP.

3rd: Look at the price, as with everything, the more expensive it is doesn't mean the better quality it is. Look into details and if you're looking at a different retailers site, or even Amazon.com, then don't be afraid to go look into more detail at the dealers site and see if the information given is actually ture. And just like everything else in this world, compare, look at reviews, and test if you can.

Step 3: Formulas for Tuning a Subwoofer

Now that you know the basics of speakers and subwoofers, how they work, and you've chosen one; it is time now that we build a box.

BEFORE I SAY ANYTHING: Building your own box will not necessarily bring better quality to your sound, professionally made boxes can be as good if not better.

Step 4: Choosing Wood for Your Box

You're going to want to get 3/4" MDF Board. make sure it is MDF Board and not particle board OR solid wood. Particle board is made with wood chips and resin and will fall apart so easily its ridiculous, Plywood is okay but i would go with MDF Board. this is because the fibers are verytightly packed together and the density is the same throughout. This will keep the sound equal thoughout. If you choose plywood the type of plywood you get is up to you, just make sure it is a minimum of 3/4" no matter what.