i have 2 digital design 1508's hooked up to a jl audio 500/1 wired like this (pic below) is this wrong?

 

Depending on the impedance of your subs you are either wired to 8 Ohm or 4 Ohm. 500W is not enough for even 1 1508, let alone 2

 

I'm guessing you have the 12w1v2-4.
And your amp being 400.1

I don't know what they are wired to that way.. never seen that.

If they are dvc 4ohm subs they can be wired to 4ohms or 1ohm.
Parallel/parallel or series/paralles
Neither of which you have it wired at.
If your amp is not stable to 1 ohm then your options is this

http://a248.e.akamai.net/pix.crutchf...4-ohm_mono.jpg

Edit, your sig says you have 12w1 in custom enclosure so I assumed that is what you were referring to. You need to post what impedance your subs are for a proper wire diagram.

 

i updated my sig these arent going my truck.

thing is they were given to me so i dont really know the specs at all other then the stuff on the dd audio web site.

so i'm going to need something alot bigger then?

 

The 1508's will want somewhere around 600rms of a piece but will take about 800 all day long of clean power.

 

rearrange the wires on the back side of the picture,, so they match + to + and - to -