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Discussion Starter · #1 ·
This is my first DIY build of any sort. I have a multi-purpose space that I use for my home theater and even with spouse approval the subwoofer was taking up too much space for my liking. We have two shelf towers, one on each side of our TV and the bottom two shelves were rarely if ever used. To me this seemed like an opportunity to gain floor space and improve the performance of my home theater.

For this project I decided to use Tidal Audio 12" 4ohm DVC drivers. These are a OEM brand of Image Dynamics one of the best SQ brands in car audio. The drivers can be found for $80 with free shipping online as a discontinued product.

Driver T/S parameters:
Nominal Impedance (IMP) 2/8 ohms
DC Resistance (Re) 1.8/7.2 ohm
Resonant Frequency (Fs) 20.9Hz
Electrical "Q" (Qes) .397
Mechanical "Q" (Qms) 4.172
Total "Q" (Qts) .363
Equivalent Volume (Vas) 5.92 ft3
One Way Linear (Xmax) 17.0 mm
Cone Area (Sd) 545 cm2
Sensitivity (Spl) 88.6db
RMS Power Handling (Pwr) 50 to 400W RMS

I decided to build sealed boxes with a total internal air space of 1.83 cubic feet, which gives me a slightly less than optimal QTC of .769

I am extremely busy with a 2 year old son and working 52+ hours a week so this will be a long and slow build. When I started this build I had nothing but hand held tools and even that was limited.
So, needless to say the project started by collecting tools and equipment.

Tools Supplies and Equipment:
Craftsman circular saw for $50
Bosch Router for $40
Router bit set for $30
Right angle ruler $10
2 10" clamps, 2 18" clamps and 2 26" clamps for about $50
Two boards of 3/4" MDF cost about $65
2 Tidal Audio subs $160
iNuke 3000DSP for $260
Misc: silicon, glue, sand paper, screws, wiring, etc $120
Noctua NF-R8 fan mod: $14

Total cost: $799

Here are some pics...
 

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Discussion Starter · #2 ·
The theater room picture is from my non-optimal main seating position.

Related equipment list:

Denon X4000 receiver
Pioneer SP-FS51, C21, and B41 Speakers
LG 42LM5800 42" LED TV
LG BP620 Blu-Ray
Motorola DCX3400 DVR
HSU VTF-2 (currently second subwoofer not pictured, off to the right along the wall)
 

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Very nicely done - the end result looks just like it came that way from day one. Does it rattle? Looks like it might be possible during deep bass passages. Is there any damping material inside the cabinet? If not, you may want to consider adding about 1.5 pounds of loose fill. Not only will that help minimize vibrations from the backwave, it will also fool the driver into thinking the cabinet volume is larger. That could help with the QTC as well.
 

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Discussion Starter · #4 ·
No damping materials at this time.. Just bracing and 1.5" thick front and top panels. I was hoping to live with the sub pre polyfil so that I could notice any change when I do eventually fill it. Thank you for the compliment and advice. Currently there are no rattles that I can hear. However when I do my tuning with tone sweeps we'll really find out.
 

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Nice use of that space! :T It looks like it was meant to go there from the start. You could even put a square black cloth grille over it and you'd never even know it was there, but then you'd be hiding what is always a fun thing to see :D
 

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Discussion Starter · #7 ·
Thank you all for the complements. Today I was running some tone sweeps to EQ the system and found the subwoofer surround to be loose from the basket. I was able to re-glue the surround to the frame, however I am still getting a noise like port chuffing that is coming from the center of the speaker. I do not feel any air flow at this time from anywhere but the center of the cone. This only happens at frequencies below 23hz at high volume, could this be exceeding the limits of the sub in general? I don't think I have ever bottomed out a subwoofer or exceeded xmax. Also distortion measurements in REW shoot to over 30% at these lower frequencies where otherwise they remain less than 2% and usually less than 1%.
 
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