First time poster, long time lurker!  

Anyway, I just built a 12" Deathbox and am unimpressed so far.  I am hoping it is just a tuning thing for I have not spent a lot of time messing with it yet.  

I have a 2000 GMC Yukon and have a WO I built several years ago loaded with Xtant 10" subs I was originally going to use.  However, I did not want to take up that much space and thought I would try a DB for a DVC Orion NT12 I had laying around.  Before this, I had the Orion in a 1 CF internal volume sealed box as per the recommended specs.  Quite musical with plenty of bottom end but not enough output to fill the truck.  I am pushing the sub with a Rockford P5002 which i believe is rated at 125 wrms x 2 at 4 ohms in stereo.

Anyway, I built the box and have found the same issues I have read from other intial impressions.  It is peaked in the upper frequencies and has very little low bass out output.  It is loud and punchy but the sound quality is poor and there is no lower extension.  I have the lp x-over set at probably 70hz.  I have moved the insert from one end to the other with little change in response.  I have not sealed the insert yet but had the pieces cut with very tight tolerances.  (Before loading the sub I could move the insert relatively easily.  With it installed there is a ton of resistance so i think it is air tight enough for tuning.)  I have an active crossover I could probably install pretty quickly to try and force the response i am looking for but i was hoping I wouldn't need it.  

Sorry this was long winded!  I am a newbie to the forums and am hoping to make this thing worth my time so far!  The wicked one is simply awesome and i hope this will be too. Any insight would be greatly appreciated!

Thanks for the reply.  

I am pretty sure the coils are wired correctly but it is worth a shot to check.  It is currently facing the tailgate. As for the amp, it should be able to push the 12, but I agree that more would be nice!  :-* As for the insert location, do you mean 2" from the end opposite the vent opening?  I intend to spend some quality time crawling around the back of the truck tomorrow sliding this insert around.

Quote:


Ha yeah, I frequent another forum where a sense of humor is required for a pleasant stay.

I slid the insert so it was just barely overlapping some of the vent.  Maybe I need to bring it farther?

[quote author=Hotsauce  link=1142126549/0#5 date=1142154343]I have the 10" DB, but mine sounds best with only about 1¼" of the port open.  It looks wrong, but it sounds right.

You have the voice coils parallel, right?  Just checking.

John C.

[/quote]

Nope, I currently have the coils wired in stereo.  They are 4 ohm coils and I don't think my amp would tolerate a 2 ohm bridged load.  I borrowed a laptop with a tone generator and some simple testing software to try to dial this thing in today.  Now if only this damn rain would stop in PA!  Thanks for the suggestions so far!

I am not sure how I should be wiring it otherwise though.  The amp is a Rockford fosgate p5002 http://www.rockfordfosgate.com/products/product_details.asp?cat_id=2&series_id=6... and it is not stable at 2 ohms bridged.  I have the internal crossover set at 70hz (ish).  I dont think bringing it up to 8 ohms is the answer either though.

I have run this sub before in this fashion with better results in the sealed enclosure.  The signal is crossed over in stereo but i agree that a slightly different signal through the cone sounds like a bad idea.  Maybe this is the wrong amp for the job, but it is all i have right now with enough gusto.

Ok, I just spent some time sliding the insert around with my laptop plugged in, feeding sweeps from 25 to 250 through.  It is definatley better with the insert slid all but 2" down over the vent opening.  I didnt bring it down that far before.  As for the signal, I hope you are right gexter.  I don't know how else i would wire it at this point.  Everything is glued and caulked but the insert so far.  Hopefully with that sealed, i will gain a little more.  I don't know what kind of shape my sub is in, but something crazy happens at 20 hz with moderate power! Anyway, thanks for the insight so far.  It is getting better little by little the more i mess with it!

I don't think the wiring is the problem but the wiring possiblities are there.

But after enough messing around we will see what happens.
I use a sealer called draftstop that is a removeable type of silicon like sealer that comes in a tube..

Once it dries you can remove it at a later date to move the baffle.

I like the baffle in the 10 DB about 1 1/2 from the bottom I just have to throw more power to it.

you have good ideas and help here so don't give up. If all else fails and the box is good its the driver.
( meaning that driver is not suited for the box)

check out the Dayton series II in a 12" specs
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-120
I think that this is the driver that Decware uses in its HT 12 DB

this is not an expensive driver but Decwares pick for marketing and they stand behind there stuff.

Having said that, too bad you can't use a WO

i haven't read all of the posts...
but if you've built the insert EXACTLY like the plans, it means that if you set it as low as possible, only about 2" of the port would be unobstructed. i have mine tuned like that, loaded with a cheap 12" and it goes down to about 35hz in-home.
sealing the insert really makes a diffrence.
i was extremely upset after i've built my db-10, during tuning. the box sounded like crap. i sealed it up real good and locked it in place with 4 drywall screws on each side. the sound tightened and it got lower.
what i've noticed with db-10 is that the more rough edges you round, the smoother the box sounds.
i haven't had time or patience to play with the db-12. i like the db-10 a lot more.

[quote author=trashfire  link=1142126549/15#17 date=1142259190]Speaking of the insert, I'm looking at building a DB12 of my own here very soon.  I'm baffled (pun..) by the insert in the plans.  For the side view, which way is it facing, left or right?  I've stared at them for 15 minutes and studied the picture at the bottom but can't quite figure out the portion after the cutout behind the woofer.  The half wall of sorts is throwing me off.  Do the sides go all the way down or do you trim them short?  The picture isn't clear enough to zoom in on and get an idea of what I'm supposed to build.

If someone has a picture from their build of the butt end of the insert, I'd be most appreciative.  

Thanks [/quote]

they extend all the way down on 3 sides and the fourth side is removed to allow air to flow.

It definately requires a minute to look and figure out what is going on, but I had no problems putting it together.  I put together a cut sheet and intend to post it if anyone thinks it is relevant.  Just notes right now but I can easily type it up.

Ah right, good point.  Scratch that.

Yeah that would probably work.  I won't be much help until this weekend though.  I am working in Baltimore this week and the plans are in my shop in PA.

On it's way.  Thank you very much.

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