Make Simple Subwoofer Box with My Design (Part I)

A few years ago, I and helped by my brother are both making the speaker box subwoofer. 
This subwoofer system is aimed to equip me amplifier system, that is still lacking in bass tones (low frequency).
is complete, which I designed amplifier system consists of 2 speakers left and right woofer for bass, 2 speakers tweeter for treble the left and right speakers and 1 subwoofer for low bass tones. the result is quite good, although homemade. This system has been tested to the computer when I play the game 3D FPS. sound effects in games such as: sound from tank fire, grenade explosions, bomb explosions seemed to deep bass, open and clatter.  steady when playing games use a sound system like this. if you want to buy so it can also, select the active speaker is equipped with a subwoofer speaker. but if I’m alone, more satisfied if you assemble and experiment itself but the results are also available. 

at that time, I had absolutely no knowledge of making the speaker box. more likely to the “trial & error”. 
The first experience of making soft wooden box speakers with a bad result at all, not producing solid bass sound and even sounds excessive noise, because the wood is not strong to hold the vibration speaker.
turns out there are several things that affect the final result sound produced by the subwoofer speaker box.

1. active crossover system (subwoofer filter) or a low pass filter 
   at first I tried some filters or filter circuit subwoofer subwoofer but the most fitting is the subwoofer filter circuit which is equipped with frequency regulator. frequency regulator is used to determine the desired output low tones of frequencies between 20 Hz to 75 Hz. Subwoofer frequency selection for normally ranges from 20 Hz to 100 Hz, and the bass frequencies above 100 Hz is more appropriate handled by the woofer speaker. Schematic electronic circuit Subwoofer Filter (Low Pass Filter) and PCB layout, which is equipped with frequency control can be viewed by clicking HERE. 
2. type of timber to box 
   I think, The best wood is teak that hard and has been refined surface.
3. You must use a special type of speaker Subwoofer, instead speaker Woofer. 
4. output from the subwoofer filter circuit must be fed into the power ampilifier that has sufficient power and maximum power specifications with the speaker specifications. 
   eg if you use the speakers Subwoofer with 200 W maximum power it can use power amplifiers with power 150 W.

continues to Part II, please click HERE.