Is You Geeked Up? | Technology Blog for the Computer Geek | isyougeekedup.com

In my opinion, the correct enclosure is vital in getting the most out of your system. This is because the enclosure determines how your sub will react with the given airspace, tuning, and power. For example, a sub in a sealed enclosure will sound very different than one in a ported enclosure. Ported boxes are easy to identify because of the port opening. A combination of port area (length x height) and port length work together to create the tuning frequency. The tuning frequency is denoted by hertz (hz), usually in the 20-70hz range when speaking of sub frequencies. Sub frequencies are also why subwoofers are called “subwoofers” and not simply “woofers” which refer to midrange frequencies. A combination of size and tuning determines the output of a system more than the power or subwoofer itself. You could have a high end subwoofer like a DD 9515, but in the incorrect box, it could be outdone by a lower end sub in an optimized box.

The key to making the best box possible is simple: test, test, test. There is no one best design because every car is different and will react differently with different boxes. Through lots of testing, I found that my car likes large boxes and a 40hz tuning. I’ve gone up against many people with more than twice the cone area (double the amount of subs) and have come out on top, even though I’ve got half the cone area in a very restricted sedan rather than the open cabin of an SUV. During these competitions, your score is measured in decibels at your highest frequency. Therefore, it is extremely important to tune your box to reflect your highest outputting frequency. Right now, my box is tuned at 40hz and it also happens to hit its peak output at 40hz. That may or may not be the case for anybody else because as I said before, every car is different. Also, don’t forget to take your subwoofer into consideration. Most of the time, you will usually peak a few hz above tuning. E.g. a tuning of 32hz may result in a peak of 40hz, depending on the car of course. In essence, tuning at a certain frequency allows you to control your output and determine what note you want to play the loudest, which is important when taking your car into consideration. Hatchbacks generally hit their highest score at higher frequencies (50-70hz) and SUVs generally hit their highest score at a lower note (40-50hz), while my sedan likes lower notes in the 40hz range the best.

Once you figure out what note your car likes, you can then start optimizing your box by making some small changes. Generally, slightly larger boxes with lower tunings perform best for cars that like lower notes. Slightly smaller boxes with higher tunings tend to complement cars that like higher tunings. For music and daily driving, tunings between 30-40hz are generally accepted as a fair tradeoff between sound quality and loudness.

Some helpful links:
http://www.bcae1.com/
A great beginner’s site and excellent for reference of various concepts.

http://www.caraudio.com/forum/showthread.php?t=61853
A thread explaining tons of car audio terms

For more information, the CarAudio.com forums have been very helpful. Just search for whatever you’re looking for in the forums or post a question.
http://www.caraudio.com/forum/index.php

Car audio, one of my favorite hobbies. Some people go for sound quality and some go for loudness, or SPL (sound pressure level). I started out about two years ago with my first set of 12″ subs from Infinity, then moved up to a pair of 12″ Alpine Type-Rs. The amplifier I used was a Better Audio 1600M1 rated at 1600wrms (watts rms) @ 1ohm. The Type-Rs held up my SPL addiction pretty well until I started to compete in MECA, a somewhat local car audio competition league. It was there I learned that my Type-Rs had nothing on the big boy companies: Digital Designs , Resonant Engineering, American Bass, and TC Sounds just to name a few. These guys were pumping out scores in the 150 dB (decibel) range while I measured in at a measly 145.1 in the kick. I wanted something that was louder, lower, and capable of handling power. Not only that, but I didn’t want to spend over $400 in new subs.

The solution was Audioque. Not wanting to go into too much detail, I eventually ended up with a single 15″ Audioque HD3. Now the question is power. I started with a Treo SSX1500.1, but it blew up less than a month later which was because I was running the amp at .75ohms and didn’t have a good electrical system in place. Low voltage (10v!) + low loads (.75ohms) = fried amp. I then went with a modded MA HK4000D which puts around 3200-3500 watts @ 1ohm running on 12 volts. A higher voltage, say 14v, 16, or even 18v would make the amp put out even more power, but my weak Honda alternator and 2 batteries cannot maintain 14v for very long. Then comes the enclosure, which was a 4.5 ft3 tuned at 40hz with 4 4″ “aeroports”

The most recent score I have is 147.2 dB @ 40hz taken at the headrest during the Carl Casper Autoshow last year. During the earlier year prior, I was able to finish 2nd and 3rd in two different classes at the MECA world finals. I ended up finishing 1st and 3rd in two different classes at Carl Casper. Lastly, here’s a video of what I’m working with.