View Full Version : what tuning? what amp? how big?

01-20-2014, 10:34 AM
so i was planning to put a DC audio XL 18 in my ext cab truck. but im tryna keep it as cheap as possible while still being a good system. i am now looking at a XL 15 instead. i know DC recommends 3.5 cu ft. now i want to have the box sitting in the back seat. it can go from the drivers side wall to just over the middle line and up almost the roof if needed. so how big is normally good? and what would be a good amp for it? on SHCA they just have 1 rms and watt rating for any size sub. what is a good tuning for it in a ext cab? i wanna get real low if i can but still have the regular good bass too. and lasty what power upgrades should be done? or is it better to just **** it up and do a 18?

01-20-2014, 11:13 AM
If you're after good low end extension you'll need to build the box larger than the manufacturer suggests. Their recommendations are normally for tuning at ~35Hz, which is best for all around performance and SPL, not low bass response. Of course, that sub will get low tuned at the mid 30s but it will fall off more quickly and at ~30Hz, which kind of kills the lows. I haven't modeled that sub but I would guess that 4.5-5 cubes at 30 Hz would be a good box for low end extension while still having decent sound pressure. If you're looking for low end extension in a small box, look for a sub with a high EBP. That sub's EBP is ~66 and for what you're after, an EBP above 80 would be much better. You can find EBP by dividing Fs by Qes.

As for amps, the CT Sounds 1400.1 is a great match for that power handling at 1Ω but I wouldn't be scared to run that sub on double rated power, in which case the 2200.1 would be a good choice.

As for power upgrades, you should do a big three upgrade and you should have at least 100AH of battery. I would suggest a 100AH second battery, all wiring in zero gauge and a 200 amp HO alternator. Although, a factory 140 amp alternator would be okay but not ideal.

01-20-2014, 11:37 AM
wow, thanks. i'm supposed to be able to get around 5.0 cu ft in that area not to the roof so that outta work fine. now all in all is it worth what i would save to do a 15 instead of a 18? now i real new to buildin my own system. what all is in the big 3 again? and another question i have is why not run a bigger amp and just 1 bigger battery? just curious why most people use extra batterys instead of a big alternator

01-20-2014, 03:11 PM
also, how much are your amps? also does your shop have access to alternators? id like to be able to get the powering all at the same place. amps, alternator, battery, wiring. the whole thing besides the sub