I'm currently working on finishing up my system with a sub. I purchased a Dual voice coil Alpine Type-R 10inch and the amp is a MTX 6500D. I finished all the wires today and tested to see if everything works and it does, except that the sub doesn't even hit hard at all.

I wired it at 2ohms, then 4ohms, then bridged it at 4ohms and it keeps hitting the same. I adjusted the gain ect for each time I changed the wire cordination. Same goes for the head unit bass setting.

So why doesn't it hit at all? I've installed 3 systems in the past and never had this problem. And it should hit since the MTX amp is 250RMS at the least, and the sub wants 20 - 150 Watts RMS and maxes out at a 1,000 watts.

 

Bad grounds, small power connections, poor or incorrect speaker wire connections to the amp will all cause the type of problem you describe.

A bad amp or sub will cause it too.

You could try hooking a buddy's amp up to your stuff and see if it works better or hook your amp to a buddy's system to test it.

What are the specs on the sub? Are the coils 2-ohm or 4-ohm?

The amp is only "rated" for 2-ohm stability.

If the coils are 2-ohms each (1221D), then you can only wire the sub for 4-ohms (series wiring) or 1-ohm (parallel wiring) if using both coils.

If the coils are 4-ohms each (1241D) , then you can only wire the sub for 8-ohm (series wiring) or 2-ohm (parallel wiring) if using both coils.

This amp is a single channel amp so it doesn't have a "bridged mode" unless maybe connecting two of them together.

Your best power is going to come from a 2-ohm load on that amp, so I'm hoping you have the 1241D. Just tie the positives together to the positive on the output of the amp. Do the same with the negative and you should be fine.

I realize you have installed other systems, but I state these simple things just to make sure that you haven't over looked anything, besides it helps me help you.

Another thing that can cause dismal bass output is a poor enclosure. What type of enclosure are you running?

 

Is you sub a dual 4 ohm? This would have been then optimal situation. With the MTX 6500D you would hook up one voice coil to each chanel. Do not bridge the amp, it is not designed to work that way. If your sub is a dual 2 ohm then you will need to wire the sub in series and connect it to the main channel, please read your amps instruction manual to find which one is the main. If you don't have it, I'll check mine once I get home today.

If you sub is a dual 4 ohm then your amp will be running in 2 ohm and producing right at about 600W or more RMS . So you should be producing enough to make that thing hit.

Are you running this off an aftermarket head unit? If so, which one? Is your HP filter on? Make sure to check all your Head Unit settings.

 

Yep, it is a dual 4ohm coil and I did run it to run at 2ohms. I have a Alpine 7894 HU and all the setting are on max bass and sub is turned on. The sub only seems to somewhat work when everything is set to max then when I put my hand slightly on the sub I feel it. I'm gonna go over all my connections again to see if thats it, but I'm pretty sure they are all good.

 

Also my subwoofer is a 10 inch (1041D) not the 12inch (1241D).

 

Ok, well I did a few tests and here's what I came up with.

Took out my sub and attached my friends sub that we know works from his system. Wire it up and it doesn't work , so we know my sub is not causing this.

Then I take out my amp and replace it with his 800 kenwood comp amp and attach it to my sub. This way I can see if my amp was bad. Well after wiring it back up and testing it... it came out to be the same exact problem.

So either their is something wrong with the wiring (All grounds are tight, battery cable's are tight ect...) or their is something up with my new alpine unit that is isn't sending the full signal to the amp...?

 

I know you said that the bass setting was turned all the way up but did you also turn up the sub-woofer output setting. I have a Alpine deck also and it has the dual pre-outs with the subwoofer output and you have to go under the menu and turn the subwoofer setting on and then it should be under the same menu where your fade and balance are. You need to turn this setting up to give you the maximum bass response. You can also control the amount of bass with this setting. Hope this helps.

 

It's either got to be the head unit settings, or an RCA is loose. Try pulling the head unit and running the sub off a different Pre-amp out (like the Front RCA's).

 

Unfortunatly I do have the setting on and I have it at +8 and only recive little bass.

When I have everything on the amp turned up to max and +8 for subwoofer, and +3 on the bass in the HU, then the sub somewhat hits but you only hear it if you put your head close to it and it sounds pretty bad. I also double checked the wires and eveything is connected... So I'm REALLY baffled

 

Do it! Now! j/k

You really should try it though, it will tell you if it's head unit or not. If it does work then you have a busted sub Line out. If it doesn't try connecting a buddies head unit and see if it works, then you'll know for sure if it's your head unit.

 

Just finished tring that 5 mins ago and it is the same exact thing. Hits the same way in the front RCA's as with the Sub RCA . This is really starting to tick me off... how come it all of a sudden has to be hard for me .

The only thing I can think of is maybe the RCA cable is defective? Would the RCA output matter this much on how it hits...

 

If the interconnects (RCAs) are cut or pinched enough to break the conductors it could certainly affect performance.

I know this is a stupid question, have you verified that the amp is turning on?

 

I have done this earlier today. 12.5 volts from the batter and to the amp. The amp light also turns on. And the amp is putting something out since the sub does move... its just not putting out much at all.

I called Circuit city road shop and asked one of the installers their and he said he owns a 6500D and similar has happened with his... but he's been using it for quite a bit he said. But then once I said that I changed the amps and same thing happened, he said I pretty much stumped him. He said he would possibly take a look at it if he's not busy and try to help me out... only problem is my car is in tons of peices.

 

A bad RCA will cause this. Now you need to try plugging in a different RCA, if that fixes it then the problem is found. If it does not, try swapping your friends head unit into your car and see if his does works, if it does the you know it's your HU. If none of that fixes it then check you wiring again . I'm willing to bet it's you head unit RCA's not putting out signal for some reason.

 

Couldn't the head unit's pre-amp output be screwed up?

He could try a a high to low level converter. That would eliminate the pre-amp output.