Welcome, Guest. Please Login or Register
Decware Audio Forums
11/22/14 at 00:35:48


Pages: 1 2 
Send Topic Print
DBK-12, Grrr! (Read 6715 times)
Loudy5
Ex Member



DBK-12, Grrr!
03/12/06 at 00:22:29
 
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.   Cry

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!
Back to top
 
« Last Edit: 03/12/06 at 04:21:34 by Loudy5 »  
  IP Logged
60ndown
Ex Member



Re: DBK-12, Grrr!
Reply #1 - 03/12/06 at 02:56:08
 
1.by switching from a wo to a db you have halved you surface area for drivers.

2.dvc driver? you sure your coils are not out of phase?

3.try insert close to bottom 2 inches close,

4. point opening towards rear of vehicle.

5. get a bigger amp Wink

6. sensitivity of new driver might be less than those in the wo

just my first thoughts?? dont give up on it, it is an excellent desighn Grin
Back to top
 
« Last Edit: 03/12/06 at 03:00:14 by 60ndown »  
  IP Logged
Loudy5
Ex Member



Re: DBK-12, Grrr!
Reply #2 - 03/12/06 at 04:04:01
 
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.
Back to top
 
 
  IP Logged
DirtDawg
Ex Member



Re: DBK-12, Grrr!
Reply #3 - 03/12/06 at 04:43:03
 
[quote author=Loudy5  link=1142126549/0#0 date=1142122949]First time poster, long time lurker!  
..... I am a newbie to the forums and am hoping to make this thing worth my time so far!  .....   [/quote]

Your time on the forum will be greatly enhanced if you can maintain a sense of humor. Grin

Many who have built a DB have the movable insert partially covering the port in order to tune it low enough for their needs. Moving the insert away from the port will raise the tuning frequency. Towards the port, even obstructing it slightly, will lower the freq.
Back to top
 
« Last Edit: 03/12/06 at 04:45:07 by DirtDawg »  
  IP Logged
Loudy5
Ex Member



Re: DBK-12, Grrr!
Reply #4 - 03/12/06 at 04:48:19
 
Quote:
"Your time on the forum will be greatly enhanced if you can maintain a sense of humor."


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?
Back to top
 
« Last Edit: 03/12/06 at 04:50:36 by Loudy5 »  
  IP Logged
Hotsauce
Ex Member



Re: DBK-12, Grrr!
Reply #5 - 03/12/06 at 09:05:43
 
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.

Back to top
 
« Last Edit: 03/12/06 at 09:07:49 by Hotsauce »  
  IP Logged
Loudy5
Ex Member



Re: DBK-12, Grrr!
Reply #6 - 03/12/06 at 14:36:55
 
[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!
Back to top
 
 
  IP Logged
60ndown
Ex Member



Re: DBK-12, Grrr!
Reply #7 - 03/12/06 at 14:53:42
 
stereo signal into a dvc sub ??? Roll Eyes ??? Roll Eyes Cry Cry Roll Eyes dirt??
Back to top
 
 
  IP Logged
Loudy5
Ex Member



Re: DBK-12, Grrr!
Reply #8 - 03/12/06 at 15:05:36
 
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.
Back to top
 
 
  IP Logged
gexter
Ex Member



Re: DBK-12, Grrr!
Reply #9 - 03/12/06 at 15:24:43
 
To my limited knowledge...
it depends on how its crossed over.. if the crossover sums the channel and then splits it back to stereo then there is not  a problem.
supposedly low freg are not stereo and are omnidirectional, but we have all been there before.

What I am saying is if its low enough it should not make a differance. What I believe is that it does make a differance, just how much is the question.
I always sum a sub output and then split the same signel just out of habit in car and home audio.

My concern is with a iso load having seperate coils and cone its not a big deal but considering that the possibility of two coils driving the same cone with a slightly and possible differant signel just is something I would not do.

Just because,, IMHO.

Dirt?

EDIT: missed that last post..

The P5002 is an excellent way to PUNCH up your sound system! Best suited for driving a 2-ohm DVC subwoofer, a pair of 8-ohm SVC subwoofers, or even four 4-ohm SVC subwoofers. A capacitor is recommended.






Back to top
 
« Last Edit: 03/12/06 at 15:38:37 by gexter »  
  IP Logged
Loudy5
Ex Member



Re: DBK-12, Grrr!
Reply #10 - 03/12/06 at 15:28:43
 
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.
Back to top
 
 
  IP Logged
gexter
Ex Member



Re: DBK-12, Grrr!
Reply #11 - 03/12/06 at 15:51:48
 
I know that we may be getting a little sidetracked but I don't think the sub signal is stereo, so your okay.  
not sure but thats what I think anyway.

It is my thought that I would seal everything up first and check everywhere for possible leaks.  Seal it with something you can peel off again. the woofer can bleed past the mount and the screws, the insert sides, the lid on the sealed part, the insert could be mountedbackwards.

try driving each of the coils seperately to get a feel for it.

best of luck.. I thought I knew some of these subs in and out at one time. But now I am just full of guesses
Back to top
 
« Last Edit: 03/12/06 at 15:55:47 by gexter »  
  IP Logged
Loudy5
Ex Member



Re: DBK-12, Grrr!
Reply #12 - 03/12/06 at 16:28:30
 
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!
Back to top
 
 
  IP Logged
J_Rock
Ex Member



Re: DBK-12, Grrr!
Reply #13 - 03/12/06 at 17:28:25
 
If you want to make sure the Voice coils get the same signal, wire the voice coils in series for a total load of 8 ohms. then wire this up bridged on your amp, resulting in 250 rms to the sub, 125 to each coil, just like your original wiring.

Chances are that since the amp is brideable, the inout is summed then amplified resulting in identical output on each chqannel, but if you wire it like above, you get the same power output, and can be sure the sub's coils get the exact same signal.
Back to top
 
 
  IP Logged
gexter
Ex Member



Re: DBK-12, Grrr!
Reply #14 - 03/12/06 at 18:11:41
 
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
Back to top
 
 
  IP Logged
Pages: 1 2 
Send Topic Print