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About Page:
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Info about the sub
The sub is a 6th order bandpass box. The small front chamber is 25.3 liters and is tuned to 58 Hz using a single 4" port giving a vent mach of 0.04. The larger rear chamber is 165 liters and is tuned to 19 Hz using four 3" ports giving a vent mach of 0.01.
The box has a nasty peak centered around 70 Hz. Due to my small room I'm expecting room gain of around 4-5 dB/Oct starting at around 50 Hz. This will leave a dip between 50 and 65 Hz which I'll probably use as my level to EQ everything to. The sub is 15.75" deep by 27.5" wide by 47" tall externally and although I haven't weighed it yet I'm guessing it weighs over 250 pounds. I used 0.75" particle board to build it because my local Menards didn't have any MDF and it would have taken 4 days to get any. So I used particle board and doubled up the largest sides of the box so that they are 1.5" thick. This should prevent cabinet flexing. To finish it I just sanded it and painted it flat black. Eventually when I get more money I'll put some flat black formica on it so that it matches the rest of my speakers, but for now it looks alright.
The subs are wired as a single 4 ohm load and powered by an Adire Audio AVA250 power amp. It pumps 250 watts to the subs and has a built in crossover, level control, phase control, and has a slight bass boost at 25 Hz. I'm struggling a little bit setting the phase properly, I'm getting a fair amount of destructive interference between my box and my Eosone RSF 1000 towers (2 powered 10"ers each). I'll get it set right eventually.
I've only done some minor tweaking and I don't have an SPL meter yet, so I don't have any numbers but so far I'm very happy. This thing moves a lot of air! I am however going to make a small modification I think I'm going to make a new base for the box to sit on in order to raise it up about another 4" or so. Right now it is only 2" off of the ground and the air doesn't seem to be getting out very well. As a temporary fix I put a few inches of magazines (Maxim and Home Theater Guide) under each leg and that really made a big difference. Running test tones shakes the hell out of my floor. The box sounds very good for music especially at moderate levels it is very tight and there is very little overhang. At very high levels it moves lots of air, but sounds a little strained. It gets plenty loud for anything I'll ever need it for though. I haven't watched much as far as movies yet, I quickly ran it through Saving Private Ryan and it performed excelently. I meant to play U571, but it is at my folks place so I can't. I wish that I had the Haunting DTS so I could test it out with some good low stuff. I'll write some more info as I test it more.
Overall the cost of the sub breaks down something like this:
3 JL Audio 8W6 drivers -- 210
1 Adire Audio AVA250 amp -- 180
Misc. Box supplies -- 80
Total -- 470
**NOTE: I made my base, it is basically a piece of quarter inch plywood with chunks of two by four on each corner. It has 1.5" by 1.5" pegs that stand up an inch above the two by fours so that the sub can't shift off of the base. This new base gives me another 3.5" of height off of the floor, so total the ports now have 5.5" of breathing room underneath the sub. Raising it up like this made it sound a ton better than it used to. I'd recommend to anyone making a sub to have any downfiring ports at least 5-6" off of the ground. It really made a difference on mine.
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