db drive mono amp and 2 12's

I've read the section on setting gains but i'm still having hell getting my subs to hit hard and i don't know why. (truck is 2006 dodge ram 3500 diesel quad cab. )  I am working with two DB Drive Okur K9 12's in a custom built, ported box,  my box volume is based on the specs provided for the speakers but it's just a hair small, so i filled it with polyfill at a rate of 1 pound per cubic foot of airspace.  the port length is correct according to the drivers specs, drivers are wired down to one ohm.  The drivers are seperated in the box and each has it's own port.    I have a pioneer 4300dvd head unit with some sub controls on it as well as filters etc.  powering the drivers i have a DB Drive Okur A7 2000 watt mono amp. I also have a DB Drive E7 3x 3way electronic crossover.  (I don't know if this is relevant since they are working to my satisfaction but i have a DB Drive A5 125.4  4channel amp powering the door speakers also. Which are pioneer 6x9s in the front and pioneer 6.5s in the back).  O Gauge power and ground wires, big 3 upgrade, and two big batteries.   I'm sorry if i'm reposting but between the head unit, mono amp, and crossover i can't figure out how to get all the settings right to get the most out of my subs.  any help would be greatly appreciated.Jay

Beyond .5 pounds per foot, you are actually decreasing your available airspace. Dial that back a bunch, and see what happens. Also, you can't have the stuffing stacked right on the port opening inside the box. You have to keep EVERYTHING away from the port opening at least one diameter... This means if you have a 2" port, then you can't have anything (stuffing included...) closer than 2" in any direction to the port itself.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Ok, i rebuilt my box so that now its only one chamber for both drivers.  i completely eliminated all of the stuffing from the box. I have the manufacturers recommended amount of airspace in the box (assuming that if you double what they recommend for one driver since there is two).   The manufacturer recommends one 2x4 port 24" long for each driver.  I have two 3" round ports 24" long.  Still just not hitting that hard.  Its almost like they start to hit hard but then it's just distorted noise but you can't feel the bass anymore if you turn it up.  Are the manufacturers specs just "safe" numbers to keep you from blowing your doodie up?Jay

that sounds to me that you might have your port tuned too high for the kind of music you want to play. when you try to play a low low note then the subs sound like they are just flapping around with really no output. this usually happens when you play a note that is below the tunning of your box. ive never actually dealt with those subs before so i cant tell you if they like a bigger or smaller box. some subs hit harder in a small sealed box. some subs arent really suited to work well in a ported box. for the most part the manufacturers specs are there to give you a good balance of sound and output.

a buddy of mine recommended doubling the port size so it could move more air.  he says that the manufacturers specs just give safe numbers.  Is this a good idea?  anybody got any suggestions for what to try?  its a major pain in the ass to get my box in and out of my truck, otherwise i wouldn't mind trial and error quite so much.  thanks in advance

Jay

if you just made the port bigger without adding any length to it it would just raise the tunning even more and probably sound worse. problem is that if you add length to the port then you take more volume out of your box for your subs to use. my advice would be to go to a sealed box and see how you like it.

so should i use the manufacturers recommended airspace for a sealed enclosure.  May be a stupid question but justt making sure.Jay

yes

Call up DB Drive. They will be able to tell you all the specs to build your box to depending on what kind of response you want from it. You can tune the boxes to hit high, low, or just have a decent flat line with decent response throughout the base curve. Worth a shot. And I know you shouldn't share a port. You get better sound and harder hits when each sub has its own compartment and separate port.