JL audio amp installation problem

[ghaitma]

help!!!!
I have a 2004 X5 with standard radio no nav. After reading the "How to add a subwoofer amp to the X5 factory audio", I decided to add a JL audio
250/1 amp and a 10w3v2d4 sub to boost the low bass. I follow the setup procedure from JL audo: configure the sub coils in parallel to achieve 2ohms and adjust the amp to 22.4 volt ac. After doing all that, I can not hear any difference. When I play with the input sensitivity, I have huge bass but the sound is awful. Can somebody tell me what I am doing wrong?

[el_duderino]

First off, that instruction that you followed is how to get maximum power out of your amp. It doesn't have anything to do with matching levels with the rest of your system.

I would take a pencil, mark where your process indicated max power was acheived, and then turn it down from there until you get where it sounds best.

Also, where is the bass EQ boost set? Try turning it off all the way (if that amp has it).

Make sure your HU bass setting is in the center.

Your Crossover is set to LP, 90-70 Hz or so, right?

[ghaitma]

Thank you very much el duderino for helping.
It is setup almost as you recommend. The filter freq is set to 85Hz. The LF boost was set to 3 but I will turn it off. The HU bass and trebble was turned down to 0 for the purpose of setting max output. I am afraid that matching levels is where I am lost but I will try using your recommendations. But I have a couple of question about them.

1)You say that the HU bass should be set at the center. Is that for the purpose of setting the amp up or is that the way it should be all the time?

2)I am a novice and I do not understand when you say take a pencil and "mark where your process indicated max power was acheived" and turn it down. Can you please explain it in more simple term.

[el_duderino]

The place where you have your input sensitivity screw set, after you follow JL's instructions properly, is the place where your amp makes maximum power with the input signal you have to work with.

This may be a higher setting than what sounds best.

So use a pencil to mark where your setting is now, to retain this setting as a maximum ceiling, and then turn the screw until it sounds good.

And your bass control on the HU should ALWAYS be set to center, unless the song you are listening to doesn't have enough bass in the recording and you need to turn it up to make it sound right. If you have your bass control on your HU way up, that could be a LOT of your problem. I suspect that your music already has a lot of bass in it and you don't need to add any more.

[ghaitma]

Now I understand clearly what you mean. But when I follow the jl audio setting, I have 22.4 vac with the input sens. off. Only with everyting off,I achieve that voltage with a slight move of the input sens. There is not much room to maneuver. I am going to try again and report everything again with more accuracy.

[el_duderino]

Originally Posted by ghaitma

Now I understand clearly what you mean. But when I follow the jl audio setting, I have 22.4 vac with the input sens. off. Only with everyting off,I achieve that voltage with a slight move of the input sens. There is not much room to maneuver. I am going to try again and report everything again with more accuracy.

1. Are you using the speaker wires out of the OEM amp, or the signal wires into the OEM amp, for the signal to your JL amp?

2. Where is the input sensitivity switch on your JL amp?

[ghaitma]

I follow the steps described in the homepage of this site under stereo entitled "How to add a sub amp to your factory amp". I do not know exactly where but the way it is behaving I think it from the output of the oem amp. does that create new issues?

The input sensitivity is located in the back next to the input voltage switch.

[el_duderino]

Originally Posted by ghaitma

I follow the steps described in the homepage of this site under stereo entitled "How to add a sub amp to your factory amp". I do not know exactly where but the way it is behaving I think it from the output of the oem amp. does that create new issues?

The input sensitivity is located in the back next to the input voltage switch.

Sorry - let me rephrase - "In which position is that switch?"

If you are using the speaker wire outputs from the factory amp, that switch needs to be in the right position, and it might be in the wrong position.

[ghaitma]

You are right the input voltage is set to the high position (right). If I set it to low (left) it is even worse. The input sensitivity is a little potentiometer which I can turn clockwise for more gains and counterclockwise for less. This is the control which I don't have enough room to adjust. It looks like the amplitude of the signal in is already to high and its amplified version is clipped even with no gain.

[el_duderino]

Hm... that is unusual. What volume is the radio set to? 50%? 25%?

JL is down in your area - have you called them?