How Do I Add a JL Sub to My Current Setup?

[cpthoneybadger]

I have a 2011 BMW M3 with the basic HiFi system. I replaced the two underseat mid-bass speakers with Earthquake SWS-8 subs and added a Rockford Fosgate P300-2 amp for them.

I used a PAC SOEM-T Line Out Convertor for the RCA output and remote turn-on. The Rockford Fosgate amp is running the two subs only and the factory amp is still running the other car speakers.

Current Setup:

2x Earthquake SWS-8XI (2 ohm SWS-8)

Rockford Fosgate Punch P300-2 300-Watt Stereo Amplifier

PAC SOEM-T Line Out Convertor

Amp Frequency: 175 Hz, since they really are mid-bass and replaced the mid-bass.

I wanted something more so I bought a JL 10w3v3-4 and a sealed box for the trunk. I got the sub at a good price brand new for $160. I thought I could replace the two SWS-8s and use the same amp, 300 Watts x 1 @ 4-Ohm Bridged. Since I'm new to this, I then realized that I would be without any mid-bass!

So now I am thinking of keeping the two SWS-8s and adding another amp for the JL. What are my options?

This is what I was thinking:

1. Add a Rockford Fosgate R500X1D. 4 ohms: 300 watts x 1 chan. $140
   
2. The RF R500X1D amp has Pass-through RCA so I can plug the RCA from the LOC into this and then out from this amp to the other RF amp that runs the SWS-8 subs.
   
3. Add two power distribution blocks: 1 for power, 1 for ground.
   
4. Do I need a crossover? I was thinking I could keep the amp for the SWS-8s at 175 Hz and the amp for the JL 10 at 80 Hz. The SWS-8s will still play the low bass frequency however.
   
5. How do I run the remote turn-on from the LOC?
   

What is the most efficient and cost effective way of adding the JL 10 to my current setup?

Thanks!

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[Jepalan]

You have a good plan. Hook everything up like you outlined, but add FMOD 50 or 60Hz high-pass filters to the RCA inputs on your mid-bass amp. Then set your sub amp LP cut-off to match.

Run the remote out from the LOC to the remote ins on both amps. The LOC should be able to drive remote turn on for both amps no problem.

Get FMODs here... FMOD - Parts Express Ships Fast and Ships Free.

 

[cpthoneybadger]

Thanks! Just to make sure I understand-

So the FMOD 50 Hz High Pass Filter will filter out anything up to 50 Hz? And it will go between the RCA cable that goes between the R500 amp and the P300?

Then set the R500 for the sub at 50 Hz LP.

Thanks again,

H

 

[Jepalan]

Thanks! Just to make sure I understand-
So the FMOD 50 Hz High Pass Filter will filter out anything up to 50 Hz? And it will go between the RCA cable that goes between the R500 amp and the P300?

Then set the R500 for the sub at 50 Hz LP.

Thanks again,

H

Yes that is correct.

 

[cpthoneybadger]

My RF P300-2 has high-pass and low-pass. Can I just put it at high-pass and 50 Hz? That way it will play the SWS-8 subs at 50 Hz and above?

Then put my R500 amp for the 10" JL at 50 Hz, so it plays everything below 50 Hz?

H

 

[timhof13 10+ year member]

You want the sub amp at 80hz, you can use the fmods to band pass the mids to play from 80- to like 250 hz or what ever freq you choose

 

[cpthoneybadger]

What I was getting at was - by having "high-pass" on my amp, can I just use that and play from 80 Hz and above? Would save me $30, not a big deal but would prefer to save it. My P300 amp, running the mids has the following crossover controls:

High-Pass (HP): 50Hz-500Hz 12dB/octave Butterworth

Low-Pass (LP): 50-500Hz 12dB/octave Butterworth

I'm new to this but my understanding is that putting it on High-Pass and 80Hz will play from 80Hz to 500Hz, then I can set my new amp, the RF R500 at 80Hz and it will play below 80Hz.

 

[Side Show 10+ year member]

I'd suggest you either have the 10inch running or the two 8's....not both

 

[timhof13 10+ year member]

I'm not sure you can band pass with that amp, I would assume you choose either hp or lp

 

[cpthoneybadger]

The 2 8s are for mid-bass. Otherwise I won't have any.

I'll see how everything sounds at LP. The sub for the 8s at LP 200Hz and the sub for the 10 at LP 80Hz.

 

[Side Show 10+ year member]

fair enough.... let is no how it sounds.....& make sure your mid's are bandpassed

 

[cpthoneybadger]

Like I said, I'm new to this - what is bandpassed and how would I do that? //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

The amp for my mids has Low-Pass (LP): 50-500Hz. If I put it at 80 Hz, that means it would go from 80Hz to 500 Hz. Is that worth anything?

 

[Side Show 10+ year member]

LP = low pass filter, so if you set it at 50hz it will play 50hz and below, if you set the HP = high pass filter it will allow everythin above 50hz to play.

maybe if you set you lpf on your headunit at 120hz and hpf on the amp at 80hz. and have the jl sub playing lpf 80hz

 

[cpthoneybadger]

I have the factory BMW headunit with navigation. It doesn't let me set anything.

I understood that HP = high pass filter it will allow everything above 50hz to play. That's why I was asking if I could set my RF P300-2 amp at HP and then 80 Hz. It will then play 80Hz to 500Hz, right? Would that be a problem? You can't SET a max on the amp, but the amps specs say "High-Pass (HP): 50Hz-500Hz", so I'm assuming it cuts off at 500Hz.

My R500 amp (for the JL 10") is a mono-block and has only low-pass.

 

[Side Show 10+ year member]

if you try let your mids play upto 500hz they wont last long at all...... does the jl amp have any rca outputs? does it let you set the rca output from that amp?