Please help unsuck my ram

[Spanka]

Hey guys, first off I'd like to say great forum!! I have learned so much here and acquired so much inspiration from reading others post that I took on the challenge of trying to unsuck my Ram factory Alpine system. I'm hoping to find someone here that has some experience with this truck to help me in my quest. I'm deep into trying to make this "upgraded" Alpine system sound good. I wont bore you with what I've tried because that list is of great length.. I'll just start with what I have now and where I'd like to go, if that is okay.

Hertz 3.5 in the dash (all 3), Hertz 6x9 3 way front and rear doors and Hertz 1" tweeters in the front door panels to add a little extra touch (the front doors are crossed over at midbass only.. should have went with a mid driver was unaware of crossover points at time of purchase). Two sundown SA 10s on a SCV 2000D in a Fox acoustics box, Fosgate 1/0 amp kit, LC2I LOC, 220 amp alt, dual batteries.

The doors and dash speakers are running off the factory amp and crossover points. It sounds amazing compared to the Alpine factory crap that was in there.. The LC2I is hooked into the factory sub channels 

The subs is where I keep having issues, I am not sure what frequency the factory sub channel operates and can not find any information. I'm assuming its low as I have unloaded a sub or two to the point of mechanical failure thinking the factory sub was protected by some kind of factory crossover point.. The Box is 1.35cf of airspace per side tuned to 35hz the subs displacement is .1 and calls for 1.0 to 1.25 of air space and sundown recommends 35hz port, so this box is built for the subs. The amp is more than enough to push these things so what is going on??? Seems like the bass rolls off on the SSF way to fast low pass is set to 95ish.. I need to get this thing meter set to make sure my crossovers are set correctly but having a hard time finding a competent shop here in the 4th largest city in America.. Oh and I have the SA D4s wired to 1ohm. The SCV remote comes with a clipping light and seems very accurate. I set the gain using a multimeter using the watts x ohms square roots system, calculated for box rise so 750 x 2 = 1500 x 2 = 3000 square root = 54.77 volts. I then pay close attention to the clipping light. 

1st question, since these subs are beast mode can i just leave the SSF set at 10? 

2nd question, should I set the low pass higher to something around 110 to 120? 

3rd question, how can I figure out the frequency coming to the amp?  

 

I have tried the LC7I to sum all channels but it seems like it wont get low at all using this method.  

[Charles Phillips]

You can damage your subs by allowing them to play below the tuning frequency of the box since the sub unloads and the ported box has a moderately slow roll off, meaning it will act like it's playing in free air and it's very easy to overpower a woofer in free air. I'd tune the amp subsonic filter to the tuning frequency of the box, and then set the high pass around 45, maybe a bit higher. To find the frequency going to the amp, use audacity to make test tones, or download them somewhere. You can always use one of the sweep videos on YouTube to find what you're looking for. These improvements should tighten the sound up a bit. 

[Parker Grundy]

I had an LC2I for a week or so, sounded like ass. Get a new head unit, imo

[Spanka]

unfortunately, Head unit change is most likely not going to happen.. waaaaayyyy to much money to get something as nice as the 8.4 factory unit that comes in these rams..... But i'd love to for sound quality sake.

 

As for test tones I used Itunes (paid subscription) search and can get pretty much anything as for as tones go and have set gains and such in the past with them.

So my system will be unable to play anything lower than port tune? without possible damage to my subs that is.?

So once SSF is dialed to 35ish and I have my low pass to 50 I start tones from 50 on up to say 110, how can I tell where the crossover points are (input signal) the tones lose their volume?

[WalledSonic]

1 hour ago, Charles Phillips said:

You can damage your subs by allowing them to play below the tuning frequency of the box since the sub unloads and the ported box has a moderately slow roll off, meaning it will act like it's playing in free air and it's very easy to overpower a woofer in free air. I'd tune the amp subsonic filter to the tuning frequency of the box, and then set the high pass around 45, maybe a bit higher. To find the frequency going to the amp, use audacity to make test tones, or download them somewhere. You can always use one of the sweep videos on YouTube to find what you're looking for. These improvements should tighten the sound up a bit. 

Thats overly conservative.  My box is tuned to 26Hz with SSF at 21Hz.  Full tilt, all day.

4 hours ago, Spanka said:

3rd question, how can I figure out the frequency coming to the amp?  

Use a DMM and individual test tones.  Unplug your subs and plug the DMM into the amplifier's speaker output terminals.

Play a frequency that you know plays fine and set a volume on your head unit.  Lets say for sake of convo that at 40Hz you get 20.0V.  Now play each frequency below that, measuring voltage each time.  When the voltage starts tapering off you'll know that something is causing attenuation in the signal.  Make sure your amp filter is set to full and SSF at a minimum while you do this step.  My buddy has a Jeep JK and we will be doing this process this weekend to ensure his stock system doesnt have some sort of filter for the sub output.

This is a similar method by which you set your SSF manually.  To set the SSF, mulitiply your 'full' voltage (let's say 20.0V at 40Hz for convo) by 0.707.  Play the frequency you want to set the SSF at, then turn your SSF up until your voltage reading on the DMM is 0.707 * full voltage.

[Spanka]

BRO!! just the information I was looking for! I'll let you know how this goes for me tomorrow, I will try to get this done tonight.  

[Spanka]

Okay I think I understand it. I set the gain using my MM and 50v using a 40hz test tone. So to set the SSF I will play the 26hz test tone then slowly turn up the SSF until I reach 35.35v ??

 

Sorry, I wrote that and when I read it back Its unclear..

 

I have already set my amp gain using my MM, Im running 50v on a 40hz test tone.

[WalledSonic]

Yessir, thats correct.  You can then verify it works by playing tones that are lower than that and noticing how low the voltage goes as you go lower and lower in frequency.  All that before you hook your subs up.  Then you'll be relying on science rather than your ear.  

Make sure you FIRST check you frequency range as mentioned above to ensure there isnt some fuckery going on in your signal.  My buddy's 2016 JK Wrangler has a 'stock' Alpine system also, and the 8" x 10" sub in the back doesnt seem to play anything in the 20s and lower 30s, which is why we will be checking his next weekend.  The stock DSP may be filtering out the lows, but we just dont know for sure yet.

[Spanka]

I have my suspicions this is whats going on in my case too.. because songs with 25 to 27hz are almost inaudible even with SSF set at 10. Unfortunately, I believe this is the lowest signal in the truck too.. so other than replacing the head unit this will be the best it gets for me huh? 

[Spanka]

Walled sonic.. You are in Houston Texas?? same here if so.