Hopefully someone can help me out as I have done some research but starting to lose my mind as to what to do. Heres the gear:

Car: AWD TJ Series II Magna

Gear:

CDE-103EBT Alpine head unit
fronts: 6.5 Type S Co-axials
rears: 6 x 9 Type S
Sub amp: zx400.1 Kicker monoblock (400w @ 2 ohm, Mine tests at 505w @ 2 ohm)Kicker zx400.1 (http://www.crutchfield.com/S-rMT2zCrUp2f/p_206ZX4001/Kicker-ZX400-1.html)
Sub: 12 inch Type R Alpine SWR 1242D 4 ohm, wired to run at 2 ohm (500w RMS)Type R Sub (http://www.alpine.com.au/products/product.asp?modelID=221)
Box: 1cu ft sealed firing forward through the ski hole (actual cube is under 1 ft because of sub displacement) its the standard one from Aerpro with some additional deading and caulking by me. Sub box link (http://www.ryda.com.au/Aerpro-SB12100-12-Sealed-Sub-Box-p/sb12100.htm)
8 gauge wiring kit

Problem: Sub seems quiet for what I would imagine 500w RMS should do.. When I open the boot when playing a test tone, it dramatically increases sound in the cabin, but not the same effect when playing music as much.

So far I have:

-checked voltage to the amp, with car running it is 13.85
-checked phasing, doesn't seem to make a difference
-turned the sub to point to the rear, makes the sound a little more full, but muddy at the same time, no improvement or loss when opening boot.
- tried to set the amp gain using a multimeter using the check voltage when at 3/4 etc test. (no improvement, just gets me to set the gain up too high)
- tried placing a heavy blanket around the gap between sub box and ski hatch to direct more bass into cabin. no change.


I see videos of guys on youtube with mirrors shaking, sub smashing out bass, even when sealed. I chose sealed because I do want SQ over SPL, but theres just a lack of volume I feel.

The other questions I have is the settings on the HU seem to affect the sub, like turning on the HPF, turning up the bass setting (not the subwoofer, as it has an additional volume gain for sub) setting the bass focus hz. etc. Do you by default run your system with defeat on or use these settings?

I have also purchased a KTP-445 which is an inline amp for your 4 channel off your head unit converting the lines into 45w RMS and this will power the 6x9's and 6.5s but it is yet to arrive, sometime next week apparently.

Should I switch to a ported box? could the box really be causing this much issue when it falls in the size and design that Alpine recommend for a sealed box for this sub?

Link to the manual and reference material for the sub Info here - Sub is SWR 1242D (http://www.manualnguide.com/dl/13370/)

on your amp there should be a switch saying HPF LPF and OFF you want to switch it to LPF,
also i wouls run 4 gauge cable trust its workd better. on your h/u is there a SW setting if it tuned off turn it on.
check rcas incase on of the might a came out which wont make it as loud and might stuff something most like sub

Turn the sub around and move it closer to the tail lights. It's called rear loading!

By the sounds, if the hpf is effecting the sub, you have got your rca in the wrong hole. Sub needs to on 5 or 6 / 15 on the Alpine units to do anything.

Yeah mate ski hole is no go....... move it to the back pointing into the middle of the boot

This morning after re-setting the works and starting again, it sounds much better, but I am sure as shit that it should be thumping in my brain. I'll have a crack at moving it towards the rear, but the problem I have is I still need to use the boot. We have a little girl who I need to throw the pram in the back from time to time as well as shopping etc.

The Amp is on LPF, the RCA's are all plugged in correctly and tightly. What do most people run, ported or sealed? and has anyone run both with a distinct like for one or the other?

I run a cheapo 12" Sony sub in a sealed box....... but at the back of the boot facing the middle and it gives out heaps of bass

Wont give you brain damage but it does a good job

Ive tried it pointing through the parcel shelf, and it sounded like it had about 1/3 of the power

amp is 200 rms and the sub is a 500 rms you badly under powering it bigger amp would help

No, amp is 400W at @ 2ohm, rated at 505watt. Sub is 4 ohm DVC, wired at 2 ohm... they are basically matching other than loss of watt through natural wiring. Ive triple checked that stat time and time again.

i would myself get a bigger amp.
how many RCAs on the bak of ya hu

ok i guess u have have two RCAs one front one bak

but still the sub is 1500w peak and 500w rms i would recommend aleast a 700w amp

only two thing i can think of is that your amps not giving enough power out, or you have wire it wrong (giving the amp the wrong load), i would never reccomend having an amp putting out less power than your subs wrms but i guess that there isnt much you can do about that now as you already have the amp

I ran 2x 12" earthquake subs from just 2 channels of a 4x40W amplifier. (so 2x40=80, bridged approximately doubles power so up to 80W RMS per sub)

It was good for about 134.1db in sound off comps - from the boot it would give anyone in the front seats a really good back massage. So my opinion is that subs don't HAVE to have a big amplifier.

However, it was a ported enclosure and they work well with low power, but sealed do need more.

What I'm saying is that your amp with a tested 500W RMS is perfect. You would probably only use 10-100W 90% of the time.


I think that your sub is in too small an enclosure, reducing the subs ability to function. Basically it's a big suction cup, preventing the sub from moving.

If it was possible to port that box, it might loosen the sub up a bit, but then will probably sound boomy and might spoil it completely. But if the box is ported, you could then front the sub up to the ski port and the entire boot will act like a sealed enclosure.

Is there someone you can swap subs with? Go to a shop and ask to put one of their demonstrator subs into your car for 5 minutes. That will at least tell you that your head unit + amplifier are doing the right thing and you'll know the sub + enclosure aren't working together.

If you bought them from a shop, they should be more than happy to help you diagnose the problem.
Of course they'll be hoping you spend more money with them, but you don't have to. :)

+1 enclosure. its kinda small. and sealed.

Quick question:

How is the sub wired? Are the dual voice coils definitely run in parallel and not series?

The last thing you want is the sub presenting an 8ohm load to the amp! This would be halving your power.

Also, if you do opt to try a ported enclosure, remember that for performance, generally speaking, you will require a larger enclosure if it's ported.

Not the be the bearer of myths.

More power won't help here. Generally if you double the power, you yield an extra 3db. Nothing great. The benefit you will get from having say a 700WRMS amp is the lower distortion at the same output as a 500WRMS amp of the same series / class. This is why when I went from a 400WRMS Jaycar amp to a 600WRMS Audison, no real increase in loudness, just in the quality.

Porting the box will indeed get you a high efficiency enclosure. This will only be true for the octave above the port tune. If he is unhappy with the output at 30Hz then this will fix it much cheaper than going down the power route.

With sealed boxes, the smaller they are the more efficient ( very minimal ) they are with the trade off being the -3db point. Since he has a smallish box, it should actually be pretty loud, abiet boomy.

As said they problem may be in the wiring of the woofer or the gains. Really your gain should be set at 5/8th + if you have your volume at 3/4 of the maximum. Then as mentioned your Sub control should be around 4-6.

I have spent a bit of time talking to the guys I bought it off, coupled with some good advice from another mate in car sound (sorta) and the problem has been resolved. Spent the afternoon rebuilding a box sealed slightly larger (1.1Cu ft after sub) and made an airtight seal around the sub and the porthole.

Advice was to trap the sound into the cabin space. I have just spent the last hour in the car driving back from the Gold Coast listening to my new install and box (thanks dad!) and its perfect now!

I basically unplugged everything and started again, reset head unit, coupled with the new box and its putting out enough thump and sound quality, that I am over the moon! Got some finished works, cosmetic stuff to do, but its firing hard and well.

Thanks for the help guys, I did try repositioning the sub, but I think the port hole sealed up and set in properly is the way to go for a sealed box!