Ultimate 12" DIY Subwoofer

[qx56]

sweet. Can you post final pics? also have you tried to eq the 25hz and lower?

[onyxbfly]

[Show spoiler]

Originally Posted by Big Daddy

Dj has done a good job of itemizing the cost of the DIY subwoofer.

I bought the Carver amplifier around 1990 from a dealer that was closing shop. It was the open box demo model and I paid somewhere around $300+ for it. Actually, I bought three Carver amplifiers, one two-channel preamp, a tube Carver CD player and years of enjoyment. Recently, I had the amplifier upgraded, for around $360, but that should not count as the amp was fully functional and I did it mainly because I had the upgrade-itis bug.

If you are curious, you can you can add the following items to the cost, but the total cost including the following will still be under $1,001,100.

• 2 Spacer Rings: $20
• One Can of Spray Paint from Wal-Mart: $3
• Long Black Screws: $2
• Dolly: $20
• Labor: $1,000,000 (Bad Back, Herniated Disc, Hernia, Diaherra, Diabetes, PE, ED, VD, Possible Legal Action).

Originally Posted by Big Daddy

• The previous diseases are all associated with wasting your time on DIY projects instead of kissing your spouse's a$$.

Could be true...I spent about a year on my DIY project and could possibly be one of the reasons why I'm single today....... Although she would never admit it....

[v_squared123]

I tried using winISD to plot the frequencies the two TC sound subwoofer drivers in the dayton audio cabinet would make and i ended up with this

[v_squared123]

I entered all the drivers data in winISD correctly into a sealed cabinet and i get a -3 db reading of approximately 43 hz! This cant be the deep extension that big daddy is raving about is it?

*the number of drivers listed in winISD is obviously 2

[qx56]

He's got a lot of subs so if it sound the best to him it must be a pretty good one. Plus without eq. Sealed subs always lack low end. I hate to bring it up but if you want to see some serious lfe setups you gotta check out the diy thread over at avs. Those boys don't play.

[Blu-Dog]

Originally Posted by v_squared123

I entered all the drivers data in winISD correctly into a sealed cabinet and i get a -3 db reading of approximately 43 hz! This cant be the deep extension that big daddy is raving about is it?

*the number of drivers listed in winISD is obviously 2

I'd be careful with the estimates from any software program. They give the logical result, on a slope, but something that optimizes at 43 hz is also delivering at much lower ranges as well. You can't tell where it's actually delivering, at at what volume, until you actually use a microphone and scope.

One of the interesting things about Big Daddy's experiment is that his design is going to use factors that frankly, are almost impossible to predict in that space. Further, he's using extremely precise drivers, powered by an amp that takes few, if any prisoners. The loss from the configuration of the box, or resonance space, may be overcome simply by having an avalanche of horsepower.

Further, in a muscular setup like that, what shows up as a steep dropoff on the winISD calc is still audible - and being pushed without letup by the amp. You can feel that kind of thump, not just hear it. What should be lack of response due to resonance space vs xMax - something winISD does very well - may be rendered irrelevant by the juice Big Daddy is hosing those drivers with.

Your calcs may very well be right. In a similar box with maybe a 300 watt supply, it may be absolutely correct. Powered by one of Big Daddy's nuclear reactor amps, the effect can be quite different.

[Blu-Dog]

Originally Posted by qx56

He's got a lot of subs so if it sound the best to him it must be a pretty good one. Plus without eq. Sealed subs always lack low end. I hate to bring it up but if you want to see some serious lfe setups you gotta check out the diy thread over at avs. Those boys don't play.

Sealed subs, when powered adequately, not only have skull-cracking low end, that low end is clean. It's a lot easier to get a cheaper driver, give it moderate juice, and get the same depth - but there is a price, and it's in port-chuffing, "unloading" at high volume, and massive resonant space requirements.

I built my JL Audio 12w3v3 drivers as sealed units, and loved how clean they were - and was disappointed in their low-end output. So I put them in a ported arrangement, and they're quite nice - pushed by 500 watts apiece, and they take it just fine - and both of them together can't match my JL Audio Fathom 13", just a single driver in a sealed unit. If I didn't have the Fathom, I couldn't have made the comparison, because they are really sweet in their tandem arrangement.

I haven't gone the "DIY Ultimate" route because I have way to many lesser drivers laying around, and I need to use them up before I start buying real monsters to do that with. It's a "may as well stay married" thing. But what will deliver depends on the juice fed to the drivers, and their ability to take that over time.

I'm not a fan of these massive, telephone booth sized subwoofers. As straight proofs of concept, they're just fine, but like most people, home theater is done in an actual living space. Having folks come over and wonder where the handle is, just wanted to get a beer out of the bloody thing, usually just winds up with everyone confused when it's time to explain it's a subwoofer.

Big ports are OK, but I fear for the children. One may crawl inside, and when you fire up your sub, they shoot across the room like cannonballs and then you have to deal with "Daddy, Daddy, do it again" and all that craziness. Sealed is just better on several levels, but you have to pay a lot to get the value out of it.

[qx56]

Well put. That's what I was trying to say. Ported is great if you have the power on tap. Unfortunately I dont think I have the power for my 12s when I build them so I will moat likley do round or slot ports.

[RocShemp]

Originally Posted by Blu-Dog

Big ports are OK, but I fear for the children. One may crawl inside, and when you fire up your sub, they shoot across the room like cannonballs and then you have to deal with "Daddy, Daddy, do it again" and all that craziness.