Box build help

[zjKrawler]

I’m wanting to make a 4th order for 6 Skar evl d4 12s. At the moment powered by 2 Skar 3500.1d strapped and wired parallel for .7 ohm. Planning on 2 more so each strapped stack will run 3. I’ve been researching and using apps and software and it’s all kicking my ass. I have a comp in 1.5 weeks and at the current setup in a ported box at 12.6 cubes net with 98 sq in of port per side ( 2) ports.3 subs shared chamber twice for 6. I’m only getting 143.3db @ 37hz I’m pleased but I don’t think I’m anywhere near max output that I can hit. Dual alternators one for vehicle one for audio 160 amp each dual 800 amp xs power for vehicle and dual I think 1200 amp for audio all doubled 1/0 wire all the way back. Any suggestions or help anyone can offer?

[KaviGambinoTeamCES]

I used to run 4 EVL D4 12s @1ohm on a Taramps MD 8000.1 in an 05 Tahoe 390 CES alt 0/1 gauge big 3 and 5 Eaton AGM bank in a ported box subs up port back in the c pillar (where 3rd row seat was removed) roughly 6 or 8 cubes I think with 2 4in aero ports tuned to 31 hz peaked at 42-44hz and that was the first build I hit 150db in. Just my thoughts… what are you clamping out of them 3500s? Possibly a bigger amp set up I think the sk-3500 is rated @1ohm 3500 14.4v what Is ur voltage like? 

[zjKrawler]

Strapped I’m ar 7000 rms and 10000 max. I haven’t seen it drop below 12 v it usually runs at 12.4-12.8.. I know at 6 evls im slightly under powering them but I don’t think it’s by that much being 1250 rms each.. the mat only says by 500. At times I actually feel as though I’m sending to much power to them maybe that’s because I’m strapped at 2 ohms wired at .7 I’m not sure.. I’ve been out of this world for years and just getting back into it so a lot has changed since the early 2000s..

[Arthur79]

If you have more 1/0 I would add 2 more runs back (and make sure you double up on ground leads as well).  Running dual 160a alternators, even assuming both of them are putting out the full 160 and it's getting to the back for the amps, you are still pretty shy of what a pair of 3500.1s are wanting.  That's why you are seeing your voltage dip down as low as 12.4.

 

That voltage drop means you're not getting near the rated output of the amps and worse, when the voltage dips into the 12 volt range, you are likely driving the amps into clip (which is why it might seem like they are pushing the subs too hard despite their RMS rating, driving subs with a clipped signal will toast the subs, even if it's significantly lower power than they are rated for).

 

A lot of guys here are converting over to Lithium batteries.  The Lithiums can maintain a higher voltage and consistent amperage draw for many minutes before having to turn down the system and allowing the alternator(s) to recharge them.  They recharge faster than wet cell/AGM batteries as well.  The drawback of course being that they are expensive.

 

Being only a week and a half out to your competition, unless you've got a bunch of money burning a whole in your pocket, you are probably stuck adding additional runs and making sure you've done your big 3/big six runs under the hood.

 

Past that, definitely look into some bigger alternators, those 3500.1s are going to need 350 amps each to reach their full potential.  Even a pair of 300/320 amp alternators and plenty of OFC runs from the engine bay to the battery bank next to the amps will stiffen up your power and more than likely get you a few/several more dBs without changing anything else.

 

Hope this helps!

[zjKrawler]

Thank you for the advice. I’ll give it a try.