Dual Titanic 12"MKIII sub

[mfishmike]

I had a couple of these drivers left over and decided to build a sub. I'm about done, ended up with 5.25 cu ft after bracing, port, & 2 driver displacement numbers are in. Running a 4" flared port, tuned at 19.75 hz.
Cabinet is solid.....130 lbs without baffel, drivers, or amp.....

I have three questions. Hope I'm not asking too many.........

1. What about the polyfil? I'm lining the walls with the 1 & 1/2 and 2 1/2" eggcrate foam on the 5 remaining walls. I have left over polyfil too, but don't want to eat up more interior room unless it will help......

2. I have a leftover QSC 1450 amp and intend to drive the two drivers together using the left and right channels together coupled with the output from my receiver & a trusty Y-adapter. I'll use the high impedance barrier strip inputs on the amp. Will this setup give me clean bass or is this just a P.A. amp?

3. I bought the parts to build a woofer impedance filter for each driver. Is this necessary? The graph shows two impedance spikes without the filters around the 15 to 20 hz range. If I use them will it reduce distortion, or just create other problems. Will the insertion loss be noticed in the output, even with this amp?

Any thoughts or suggestions would be appreciated.....
Super forum here.....keep up the good work!!!!

[ThomasW]

Given that you're going to line with foam I doubt that you'll need any polyfill.

The amp should be fine not sure about the high impedance thing.

No you don't want to make or use zobels for a subwoofer.

Insertion loss is where the output drops as a result of putting something in a circuit.

[mfishmike]

Thanks for the input.....the UPS truck just left and now, I have leftover xover parts.......I didn't want to build the Zobels if it wouldn't help....
Many thanks again,

Mike

[mfishmike]

What a performance!!

Thomas,

I got the dual Titanic sub up and running and what a stunning performance.

Very smooth and tight bass for those music DVD's and lots of slam in the movies. The cabinet material is 1 & 1/8" particle board material heavily braced with a 2" thick bottom and 2"glue/screw blocks in all corners. Weighs in at 187 lbs. The QSC does a great job too. For those really loud music DVD's or CD's, the QSC gives me the ability to adjust the drivers. What I like the best about it is that at the really low volumes, I get the cleanest bass I've ever heard out of a sub or pair of mains.

With the purchase of the QSC 1450, both Titanic MKIII 12's, & other materials, I'm looking at about a $950 investment. Not a bad DIY project.

Thanks for your inputs.....
Mike Cason

I've posted my last DIY project at Yahoo groups below: 200 lb. mains with two Lambda drivers, 2 Scan Speak mids, & a HI VI Planer tweet in each cabinet.

http://groups.yahoo.com/group/mfishmike

[JonMarsh]

Glad to hear it's worked out well and you're happy with the results- certainly a lot of bang for the buck, it sounds like.

Just today we saw some posts on another site which is DIY oriented, from a guy who has a company building subs- he charges around $3K for something like what you've just put together for yourself.

Congratulations, and have a good holiday weekend.

Regards,

Jon