Yesterday I saw a car with his stock alternator 65 AMP, he had 4 speakers (2 front and 2 rear), as well as 2 10" subs).
According to him both subwoofer are 500watts peak (guess 200w rms), and a "low end" amplifier. He had a very deep bass, but in his HEADUNIT it was set to the minimum (bass was set at -8), more than that it would cause a very noticeable distortion.
My questions are: 1.. What most of the time cause a distortion in the subwoofer? (low watts in the amplifier in comparison to the speaker, too high gain set in the amplifier?)?
2.. How should you acommodate the subwoofer in your car (SEDAN)? facing up? facing the back seats? facing the outer side of the car trunk?
oh yeah, he also claimed that NO capacitor was installed, I asked him to turn the volume up (upto the half) and NO light dimming.
what do you think? and how could you reply to my questions?
1) it depends. oftentimes people clip amplifier signals to the sub, subsequently resulting in failure. clipping can be caused by not supplying adequate power to your sub and turning up your volume or gains to compensate. the system gets louder, but the crests of your waves have been "clipped" and the woofer receives distortion. B) mechanical failure. supplying too much power to a particular sub can over exurt its mechanical limits and the suspension fails.
2) bass is omnidirectional. however, if you aim the subs forward into the rear of the seats from the trunk, it is bound to cause cancellation. that is, the waves from the front of the subs fire into the cabin area, but then some of the waves diffuse around the rear of the box and up through the rear deck, resulting in the two cancelling each other out (running into eachother). what you could do is completely seal the trunk. this would be the best bet. or you could face the subs rearward out to the trunk. but this will cause you to rattle and irritate me. i wouldn't like that very much. thus, sound deadening (the trunk) would be the best cure for this ill. also, be sure to secure some foam behind the liscence plate as well.
your friend probably had his amp gains hiked all the way to max. that's at maximum sensitivity. the slightest rotation of the volume knob is going to result in the maximum power output of the amplifier. any more than that, and the amp will attempt to compensate by pushing unclean, distorted, clipped garbage signals to your sub. i.e., you are asking the amp to provide more power than it is capable of providing. solution: get a better/more powerful amp.
"bass is omnidirectional. however, if you aim the subs forward into the rear of the seats from the trunk, it is bound to cause cancellation. that is, the waves from the front of the subs fire into the cabin area, but then some of the waves diffuse around the rear of the box and up through the rear deck, resulting in the two cancelling each other out (running into eachother). "
I would really like to fully understand what you're saying. Wanna learn how and why and where it reacts differently. Also, what do you mean by diffuse? Also, rear deck... where's that at ?
imagine the sound waves as just that- waves. now, when you have two subs facing eachother, you generally want to reverse the polarity on each sub, so that when one is pushing out, the other is pulling inward. the reason is because when one wave from sub 1 comes into contact with a wave from sub2, you want the top of 1 wave to come into contact with the bottom of wave 2. this amplifies the wave and makes it that much larger. as opposed to if you were to have the top of wave 1 meet the top of wave 2. they would cancel eachother out. if they meet eachother identically in this fashion, the result would be a complete lack of sound all together. the same thing exists with the above stated scenario. except only SOME of the waves are cancelled, resulting in decreased output. that is, some of the waves from the subs reach the ear of the driver in the cabin just fine without interference. while some of those that diffuse (spread over a wide area) around the back of the enclosure and up through the rear deck (where your 6x9 might be found) and meet some of the waves firing through the seats. when they meet, they cancel eachother out. strangely enough, if you were to open your trunk, the waves that might have otherwise caused cancellation would fly into the atmosphere resulting in a louder cabin for the listener. remember to think of sound in waves.
the type of enclosure and it's positioning are critical to the response of the sub or subs. look up any article on subwoofer "loading" and you'll be able to read all about how things like corner-loading a sub will affect the response or output.
I have a JVC Deck, a 550 watt scosche amp pushing two 10's, another 200 watt amp pushing mid ranges, and my lights dont dim. I also have the gain turned 1/2 way. I have the subs wired parallel...which the amp doesnt like because its suppose to run 4 ohm when bridged. Sounds good though...Pounds wicked.