Help with JL 300/4 settings

[valeech 10+ year member]

I have installed a JL 300/4 to power a set of JL XR525-CSi components. The XR525 will be my front stage and I am using factory speakers for the rear currently.

I have everything wired up but it doesn't sound too great. I don't have a great deal of experience with tuning an amp's settings.

Would someone be able to help me with the settings on the amp and the crossover networks to get the best sound. I understand "the best sound" is determined by a lot of things, but what are the best settings to power these components?

Any help is much appreciated!

-valeech

Click to read more...

 

[johnecon2001 5,000+ posts]

What are the settings you have to work with?

Do you have an aftermarket HU?

 

[Prowler573 5,000+ posts]

Set the gain(s) (also known as input sensitivity) according to the clearly detailed process found here.

Following that, as this amp is going to be powering a component set we want to route the frequencies those components are meant to produce (ergo the frequencies starting in the midbass regions and higher) you'll want the HP (high-pass) crossover engaged and not the LP (low-pass)

I don't know how low those JLs will play cleanly as I have never heard a set of them so I'd start somewhere in the neighborhood of 60Hz (this is after setting the gain according to the above) and make small adjustments up or down from there 'til you hit what sounds like the sweet spot to your ears with no distortion caused from too-deep bass being sent through them.

 

[valeech 10+ year member]

What are the settings you have to work with?
Do you have an aftermarket HU?

Here is a pic of the back of the amp:

http://mobile.jlaudio.com/products_amps_lineart.php?amp_id=254

Here is what I am thinking:

- I should make sure the 4 channel input is set because I am using seperate inputs for front and rear

- I want to turn off the filter (x-over) for the front channel because I am using a the XR crossover networks from the component set

- I will turn on the Filter on the rear channel as I am still using the factory speakers and use the high pass filter. I will set the filter based on preference as I have no reference as to what the factory speakers range is.

- I will adjust the gains based on Prowler573's input

Should my input voltage's be low or high? I have an Alpine head unit and I am not using any type of line driver on the front or rear input. According to the manual, the low voltage setting is for inputs up to 2v and high voltage is for inputs from 2v to 8v.

Does this sound like a good start? Thanks for the replies...

-valeech

 

[Prowler573 5,000+ posts]

- I want to turn off the filter (x-over) for the front channel because I am using a the XR crossover networks from the component set

You'll still want to keep the very low bass out of the components which that passive crossover will not do for you. You'll still want to engage a HP filter here as well.

Should my input voltage's be low or high? I have an Alpine head unit and I am not using any type of line driver on the front or rear input. According to the manual, the low voltage setting is for inputs up to 2v and high voltage is for inputs from 2v to 8v.

Whch Alpine do you have and what voltage are its preamp outputs rated for?

 

[hcoronado 10+ year member]

go to this page and look at the different settings JL recommends for your setup or at least try to match it to the one that is the closest to the equipment you have.

http://mobile.jlaudio.com/products_amps_pages.php?page_id=30

 

[Prowler573 5,000+ posts]

go to this page and look at the different settings JL recommends for your setup or at least try to match it to the one that is the closest to the equipment you have.
http://mobile.jlaudio.com/products_amps_pages.php?page_id=30

That's already been linked to (albeit indirectly) in Post #3 //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[valeech 10+ year member]

Whch Alpine do you have and what voltage are its preamp outputs rated for?

I have the cda-9811. The documentation says they are 4v pre outs.

-valeech

 

[Prowler573 5,000+ posts]

As the range for the 'high voltage' setting is between 2v and 8v I'd say that 4v fits into that range, eh? //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[hcoronado 10+ year member]

That's already been linked to (albeit indirectly) in Post #3 //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

the link takes you to the gain setting tutorials! which happens to be a death link and needs to be updated!

the link I place on my post takes you to the PDF's files JL has posted for everyone to see and match their equipment to those settings and it also takes you to the GAIN settings flash tutorial!

If he is smart enough he will go through them and figure out what works best for him.

 

[hcoronado 10+ year member]

I have the cda-9811. The documentation says they are 4v pre outs.
-valeech

Valeech when you get to the point of adjusting your Gain voltage with the DMM, switch the input gain sensitivity to HIGH position, that way you will get the correct voltage reading.

 

[valeech 10+ year member]

As the range for the 'high voltage' setting is between 2v and 8v I'd say that 4v fits into that range, eh? //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

That makes sense, I was just wondering is 4v a constant thing or does that change as you adjust the volume on the head unit? If it changes and most of the time I have it pushing say 1.5v would it be better if I set the input to low?

Valeech when you get to the point of adjusting your Gain voltage with the DMM, switch the input gain sensitivity to HIGH position, that way you will get the correct voltage reading.

I will give that a try, thanks!