2015 Alpine sucks.. changed everything but the HU

Hey guys, in an attempt to make this truck sound good I have spent tons of cash.. Unfortunately, I have failed. I need you guys help PLEASE!!

I wont go into the subs, boxes and amps I have tried because I'd have a book here that I'm sure no one wants to read. I will just list the current items that I have in the truck and why it still sucks.

Hertz 3.5 (all three), Hertz 3 way 6x9s front and rear doors, Hertz one inch tweeters in the headliner. The front door 6x9s were purchased before I knew what I was getting into and I should have just bought a mid diver but oh well. All of this sounds amazing and was a nice upgrade. I had this all on an aftermarket amp but for the sake of being simplistic I took it back to the factory amp and it does a good enough job pushing this equipment.

My problem is with the subwoofers... I currently have two Sundown SA10s in a Fox acoustics box wired to 1 ohm. Sundown recommendations for the enclosure is 1.0 to 1.25cf per sub ported and tuned to 35hz the sub has a .1 displacement. The Fox Box is 1.35 ported to 35hz, So the box fits these subs like a glove!! The amp is a Sundown SCV 2000D so plenty of power.. I have a LC2I hooked up to my factory sub wires for the preouts needed to provide signal to my amp. I have heard this setup in different applications minus the LC2I and in a different vehicle but these things get LOW, DEEP and LOUD!! So as you can imagine I was crazy excited to get this going in my truck..

Disappointment sets in..

My truck sounds nothing like the others I have heard, I mean NOTHING! It cant get low at all, 26HZ is inaudible and the lows from around 32HZ and below lacks in every way imaginable. So I did some research and found a way to test the signal my amp is getting (thanks walledsonic from SMD forum) thinking that Alpine may have put a crossover on the factory sub wires I used to feed the LC2I. What I found made me sick... This thing is crossed over at 31HZ to around 62HZ ALPINE!!

My only option now for a sick sound system is to change this headunit???

I have done a ton of searches to find an adapter or harness to add to my factory HU that will add full signal, I cant find one..

HOW DO YOU BYPASS THIS DSP!!??? How can I get a full range signal capable of 20Hz and up? Is the lowest frequency that this system can provides really only 32Hz???

Please, someone, anyone, HELP!!

I ahve no idea what I am talking about, juyst what I have read

Have you adjusted the LC2i acubass adjustment on the side to help with bass roll off at volume ?

This guys sounded like crap until he worked with the settings

https://www.youtube.com/watch?v=9e4BznU6qm0

Yeah, But I wasted my time.. I metered the Inlet wires to the factory amp before the LC2I its receiving a signal that is already crossed over 31Hz to 65Hz. No matter what I do after that it wont change anything. I just left my amp crossovers at 10Hz and 300Hz because it doesn't matter anyway.. The factory DSP is already filtering and its not providing a low enough frequency for aftermarket subs to really get nasty with...

Have you tried adding an aftermarket DSP? they usually sum the signals together to give you a full range out to your amps.

I tried the LC7I when I amped the door speakers but took it out when I took it back to the stock amp. Not sure that would help me much either though because I don't believe the truck produces a frequency lower than 31Hz after the factory amp. So even if I sumed the channels it would be 31 to 20khz or something which is not what I'm going for. I think I would need to tap a signal before the amp to get it if its there to be had.

Like I stated, I do not know a lot, but how low does 31 hz sound ?

Here is the project I have been working on, however I think your expectations are a lot higher than mine, I would be happy with just a nice bass presence, don't need my hair blowing around,

O crap, I don't have any hair .... lol

http://www.ramforum.com/f51/audio_upgrade-104348/

31 is lowish, but mid 20s is what makes your windshield flex and dash move and you feel it in your body HAHA.

Have you tried looking into the pac amp pro 4. This may help in what your trying to achieve. Also. I’m curious if the sub/box combo can achieve the 20hz your looking for.


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I'm just trying to tune to 25 and my box should be able to play down to that, the subs definitely can! I will look into that pac part you talked about.

I see a number of things that don't sound right in what you've been trying but I don't have a lot of time at the moment.

One big thing I see is that you state the subs want 1-1.25 cuft per sub and that the box is 1.3. Unless you mean that the box is split into two different chambers of 1.3 each, those subs will want more airspace.

Also, the Alpine amp and crossover network is crap. You should go back to aftermarket amps but start by getting a solid signal out of the head unit. I'm testing the new PAC unit in my latest build and besides a voltage issue (easily worked around and getting a replacement unit this weekend) it pulls the signal from the Alpine perfectly. Look for the thread titled Another New Alpine Interface for more info.

I'll add to this tonight if you haven't come up with a plan by then.

Yeah the box is 1.35 per side the subs want 1.0 to 1.25 each.. sub displacement is .1 after the sub is installed the total air space is 1.25 per side!! the subs want 35hz port tuning and the box is tuned to 35hz!

I just learned about the PAC unit so I'm researching it now. I do have a question maybe you can answer? It comes with a volume knob, does that mean you lose the factory volume control?

I'm not using the PAC for anything beyond pulling a digital signal (using the Toslink adapter) to feed my Mosconi DSP so I can't comment on the sub volume control. If you're going direct RCA out to your amps then the sub level control would be nice. It would only work if you have a dedicated sub amp though (Just adding that for anyone in the future since you already said you have a separate sub amp).

Tom

Are you using the crossovers in your amps?

Ttubbiola said:

Are you using the crossovers in your amps?

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No point, the factory DSP is set at 31hz - 65hz on the sub channel.

My amp is set at 10 ssf low pass 300..

ill use the PAC as the DSP looks like it has that function, not sure how good it is though. Or I will set my amps crossovers. I ordered that Pac unit I will let you guys know how it works out for me.

Spanka said:

No point, the factory DSP is set at 31hz - 65hz on the sub channel.

My amp is set at 10 ssf low pass 300..

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Yes but the PAC unit pulls the signal before the factory Amp/DSP. That's why it was perfect for my signal chain.

Yeah, in your situation I can see the application purpose. And I solute you sir!! for being on the same quest as I, for we want better sound in our "premium alpine" trucks!




Didn't we all just buy the upgrade because the Alpine badge looked cool on the center dash speaker anyway?

Ttubbiola have you tested the frequency of the signal you're pulling from the PAC unit? Do you know if its an actual full signal from 10hz to 20khz?


If so, I may just have some hair left after this endeavor..

Spanka said:

Ttubbiola have you tested the frequency of the signal you're pulling from the PAC unit? Do you know if its an actual full signal from 10hz to 20khz?


If so, I may just have some hair left after this endeavor..

Click to expand...

The digital signal I'm pulling is definitely full range as I've done frequency sweeps while testing and tuning.

Awesome man!! I'll let you know how it works for me tomorrow!