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First HT DIY Subwoofer for a noob on a budget..

31681 Views 99 Replies 7 Participants Last post by  jeffrobinson
Good evening gentlemen,
I'm a noob who bought a pair of Phoenix Gold Ti15d's from Sonic years ago planning to stuff them in a suv. Fast forward 9 years, they were never installed. Want to build a home theater sub for the kid and I need the right box the first time due to a state employee budget. Picked up a Bash 300w amp at partsexpress for one Benjamin. Phoenix recommended a sealed 1.5ft for sq, or a 3.5ft ported w two 4x9.75in ports. Are these still the best choices? Those were speced for car use and that was a long time ago. I have bassbox pro 6 and cant figure it out. Everybody says go low for home theater and I'm stumped. Anybody up for a little bench racing? Specs are:
Fs: 26.21HZ
Re: 1.75 Ohms
Qms: 9.26
Qes: 0.594
Qts: 0.558
Vas: 114.63 liters
Mms: 283.15 grams
Cms: 130uM/Newton
BL: 10.89 Telsa-m
SPL(1w/1m): 88 db
Sd: 792 sq cm
Xmax(field): 36.2mm p-p
Size of enclosure is dosent matter, its in my living room. I want low, right? My front mains go to 65hz, receiver is Yamaha with YPAO room eq, room is 15 by 20 or so with 12ft ceilings and hardwood floors. Use will be 95% movies, 5% metal. Anybody feeling like helping out?:huh: Thank yall in advance, Jeff.
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I have a friend...:D
My old man used to say "it's not what you know but who you know".

Proper application on a smooth cabinet with sharp corners will result in no problems. I used a water based contact cement, easy to apply with no harsh smell.
Can laminate smoothly cover screw heads when they're slightly countersunk?
I can only tell you what I did. I filled them in and sanded the cabinet smooth, it was my first attempt at laminate and I was determined not to have any issues later on.
Great, I wasnt sure if screws could be used under laminate to begin with. Clearly they can, thanks again.
As said after screwing fill with filler leave a couple days and sand flat.
Make sure the box is flattened as good as otherwise any marks will show.
You can use spay glues cut each bit to about an inch over each side then away you go.

Sent from my GT-I9505 using HT Shack
If you're willing, the PSW10 can offer you an excellent learning experience especially since your needs are for 95% movies. Hook it up to your system, all it needs is a RCA cable from the receiver to the sub amp. Watch a few movies known for low frequency content, get a feel for the low frequencies that it can produce, which will be non existent below 30 hz.
Build your Phoenix Gold sub and watch the same movies. Your Phoenix Gold subs are capable of true 20 hz extension, the difference will be night and day. Search the house for the Polk, it will be found hiding somewhere. :bigsmile:
This is awesome :D Looking forward to seeing a build thread with some pics.
Me too! :reading:Think I'm finally about to start the build. Special thanks to MikeP.:hail:
You're welcome. :T Did you try hooking up the Polk to see what it would do?
You bet. I was suprised by the "low frequency" content. Expected more output at the upper bass freq, got more at the bottom. I have a feeling my opinion of "low frequency" is gonna change when my build is complete. :)
Hey Mike, getting close to build time and a couple questions are on my mind. First, the wife demanded the smallest enclosure possible, so I went with the 6ft^3 20hz boxes. I managed to get the ok for both subs :D. After factoring in the cost of the laminate and mdf, I realized that these enclosures may be around a while. These Phoenix subs are old, but never installed. What if I build these and the subs suck, or fall apart? Can you recommend a current, affordable driver that likes a 6ft^3 20hz box?
Second question, trying to keep these 6 cube boxes as small as possible, and wondering if hardwood bracing inside an mdf cabinet is ok? Lets say I used oak bracing. What would a minimum total cu ft of bracing add up to and still be effective?
If you want to future proof the cabinets then you need to change the porting from two 3" flared ports to two 4" flared ports or a slot port.

Once you decide on either 4" ports or a slot port and what the cabinet dimensions are then we'll figure out the bracing.
Here is my plan. Allowed .2FT^3 for the driver based on the spec sheet, and about that much again for bracing. Will be adding a second layer of baffle over the front to flush mount the sub.I think i was able to lower the tune a little more by lenghtening the back port board, but that reduced the available box volume for bracing a little also. Hence the question about minimum bracing and or reducing the size of said bracing by material selection.
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Tweaked a hair to lower the tune a little. Hoping .25ft^3 is enough bracing. MikeP, your thoughts? Dont have a clue if it matters, but it will be oriented like the picture, on its side. With a .75in thick laminated top, 2in larger than the box it self, layed on top of the fully enclosed box. Trying to match exsisting furniture design.
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The design looks good. You'll need 2 vertical braces, one front to back in the middle with a relief cut out for the driver and one running from side to side.
Cool, now I should head back to your enclosure volume calculator and see how much volume that frame with a 3in x .75in size will occupy, correct? If under .24, I can add more bracing, if over .24, I need to increase the box volume a little, and port length to get back to 6ft and 20hz, correct? Or leave it alone if its within 10%, as I think I've I read you tell other rookies in the forums?
Using that design with 3in by .75in material, I came up with 0.182944 cu ft of bracing out of .24 allowed. Add a couple little horizontal braces inside the slot, or bad idea?
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