[j.f.leonard]

So Ive upgraded my door speakers and tweeters to the Helix Match components and they sound great powered by my JL JX400/4. Since it is a 4 channel amp, I only wired in the front doors and the under seat subs and i have 2 separate 12s in the trunk. My problem is that I believe my system is lacking mid-bass, and I'm not sure how to achieve it. I would like to stick with my 4 channel amp, so should I replace the under-seat subs with the focal under-seats or something similar? Should I unwire the stock subs and wire in the rear deck speakers and upgrade those? What would my best option be for clear, full range audio? My 12" subs and component door speakers are fine, i just need more midbass. Thanks!

[mweisdorfer]

Originally Posted by j.f.leonard

So Ive upgraded my door speakers and tweeters to the Helix Match components and they sound great powered by my JL JX400/4. Since it is a 4 channel amp, I only wired in the front doors and the under seat subs and i have 2 separate 12s in the trunk. My problem is that I believe my system is lacking mid-bass, and I'm not sure how to achieve it. I would like to stick with my 4 channel amp, so should I replace the under-seat subs with the focal under-seats or something similar? Should I unwire the stock subs and wire in the rear deck speakers and upgrade those? What would my best option be for clear, full range audio? My 12" subs and component door speakers are fine, i just need more midbass. Thanks!

Mid-base should come from the the 4" door speakers and maybe the under-seat subs. I have the EPS (BMW IA) speakers & they produce a really clean sound as well as a nice defined mid-base.

I think you need to get a 6 or even perhaps an 8 channel JL Audio XD series. You can get a 6 channel new on eBay for around $450, if you play your cards right & are patient. An 8 channel might run you $550.00 on eBay. You could maybe use the 4 channel to power the underneath subs & just get the a 6 channel. If you have two 12" subs, I'm thinking your gonna need an entirely separate amp for those.

Jenhert xe200's are the very best under-seat subs for our cars, but they will run you $450.00 or so. There are only 2 vendors in the US that sell them. One in NJ & one in Portland, OR. Sometimes, guys sell them on this forum for $350.00, but they go really, really fast.

The guys on the the M3 forum like the ghost's from Bav Sound, but they are $600.00.

At some point, maybe consider getting a DSP. You could can an old school JBL MS-8 for around $250.00 used or the new Alpine PXE-0580S. This will help you really define your sound and of course give you surround sound.

[j.f.leonard]

Right now i have a JL JX1,000.1 powering my trunk subs and then the JL JX400/4 powering the underseats and the doors. Im looking to keep this amp setup, but improve mid bass and thats what im having trouble figuring out. Heres a pic of my current system:

[Gadgetsystem]

Originally Posted by j.f.leonard

Right now i have a JL JX1,000.1 powering my trunk subs and then the JL JX400/4 powering the underseats and the doors. Im looking to keep this amp setup, but improve mid bass and thats what im having trouble figuring out. Heres a pic of my current system:

That looks pretty clean what kind of radio are you using?

[j.f.leonard]

Originally Posted by Gadgetsystem

That looks pretty clean what kind of radio are you using?

Its the stock head unit. Before I did any of that I made a forum about replacing the stock HU and I was told its best to keep the factory one due to programming and stuff like that so I just did that.

[Gadgetsystem]

Originally Posted by j.f.leonard

Its the stock head unit. Before I did any of that I made a forum about replacing the stock HU and I was told its best to keep the factory one due to programming and stuff like that so I just did that.

Do you have logic 7 because I want to do this to my car but was told I can't because of the fiber optic cables

[kaigoss69]

What frequency range are you running the underseats at? Slope?

[j.f.leonard]

Originally Posted by Gadgetsystem

Do you have logic 7 because I want to do this to my car but was told I can't because of the fiber optic cables

No I have the HiFi system

[j.f.leonard]

Originally Posted by kaigoss69

What frequency range are you running the underseats at? Slope?

I think i have the under-seats low passed at 80hz maybe? I cant remember ill have to check tmrw.

[kaigoss69]

Originally Posted by j.f.leonard

I think i have the under-seats low passed at 80hz maybe? I cant remember ill have to check tmrw.

Well that would explain a lot...(if true)

You need to have each speaker set playing in their optimal frequency ranges.

Mid/highs 250Hz and up
Midbass (underseats) 70-250Hz
Subs 70Hz and down

So, the signal coming from the L7 amp subwoofer channels is roughly 250Hz and down. You need to split this signal between the sub amp and the channels running the underseat woofers. So, run another RCA between the sub amp "pre-out" (which is the same signal as what is coming into the amp) and the 4-channel. Then on the 4 channel, engage the HP filter at the same setting where you have the LP filter on the sub amp. My suggestion is 70Hz, but you may want to experiment with it. May be better at 60Hz, or 80Hz, depending on your preference.

Edit: You can also use the fixed RCA output on the LC2i to feed the 4-channel amp's channel pair connected to the underseats.

[david in germany]

Originally Posted by kaigoss69

Well that would explain a lot...(if true)

You need to have each speaker set playing in their optimal frequency ranges.

Mid/highs 250Hz and up
Midbass (underseats) 70-250Hz
Subs 70Hz and down

Exactly!

Most people ask too much of the door speakers thinking 4" mid bass.. Nope, 4" mid range. Under seat woofers are where the mid bass is produced.

[mweisdorfer]

Originally Posted by j.f.leonard

Its the stock head unit. Before I did any of that I made a forum about replacing the stock HU and I was told its best to keep the factory one due to programming and stuff like that so I just did that.

Not totally true anymore. If you have a major programming job, keep the stock head unit and swap it in for that purpose. Otherwise, there are a few nice options out there.

[j.f.leonard]

My system is not the L7, its the hifi system so I have the technic 676 harness feeding rcas to my speaker amp and then i have my lc2i sending rca signal to my sub amp. I will have to check what I have all my filters at later today, thanks for the input! Also, I would like to replace my head unit because the one I have is old looking and the display is messed up.

[mweisdorfer]

Originally Posted by j.f.leonard

My system is not the L7, its the hifi system so I have the technic 676 harness feeding rcas to my speaker amp and then i have my lc2i sending rca signal to my sub amp. I will have to check what I have all my filters at later today, thanks for the input! Also, I would like to replace my head unit because the one I have is old looking and the display is messed up.

If you want an OEM look, look into Dynavin 7. If that's not important, you just need a double-din. Crutchfield has a good selection and can tell you what will fit.

[j.f.leonard]

Originally Posted by mweisdorfer

If you want an OEM look, look into Dynavin 7. If that's not important, you just need a double-din. Crutchfield has a good selection and can tell you what will fit.

I was told that the stock head unit is the only way to clear codes or something like that so im afraid if I go with something like Pioneer i will lose crucial features...

[mweisdorfer]

Originally Posted by j.f.leonard

I was told that the stock head unit is the only way to clear codes or something like that so im afraid if I go with something like Pioneer i will lose crucial features...

Not really. I don't have a stock head unit, and I can clear codes.

Just keep the stock head unit, and if you run into something that you can't clear and it's evident that you need the OEM head unit to do that, your good.

Keep in mind, I have logic 7 with the MOST system. All I did was use a most loop where the logic 7 amp was & where the head unit was.

No issues

[j.f.leonard]

Ah okay gotcha. Ive been busy lately but I do plan to go and make sure my filters are set right hopefully tomorrow and ill keep the discussion posted with what i find out. Im expecting that I have them set close to where they need to be, and that my issue is that my underseats are 4 ohm speakers i believe and my doors are 2 ohms which matters because obviously at any given volume the doors would be louder than the underseats if they are in fact 4 ohm speakers. But, if im wrong im always up to learn what i can.

[mweisdorfer]

Originally Posted by j.f.leonard

Ah okay gotcha. Ive been busy lately but I do plan to go and make sure my filters are set right hopefully tomorrow and ill keep the discussion posted with what i find out. Im expecting that I have them set close to where they need to be, and that my issue is that my underseats are 4 ohm speakers i believe and my doors are 2 ohms which matters because obviously at any given volume the doors would be louder than the underseats if they are in fact 4 ohm speakers. But, if im wrong im always up to learn what i can.

You can get door insulation. That will help make the system sound more "true". Amazon & eBay sells this stuff made by Noico. It's 80mm thick. You can get 36 sq feet of it of $64.99. 687 have to buy the special roller, but that's only $10.00. It's rated 5 stars with almost 600 reviews. Literally, 96% gave it 4 & 5 stars.

[j.f.leonard]

So i checked all my filters and they all seem to be set in the general area that they should be, so whats the next step? I adjusted my head unit for a couple minutes to play only the under seat subs and they play midbass but it just isnt very loud which i believe is because of the impedance (4 ohms i think vs the 2 ohm impedance of my doors). So, should I get better under seat subs or try to find a nice head unit?

[david in germany]

Originally Posted by j.f.leonard

So i checked all my filters and they all seem to be set in the general area that they should be, so whats the next step? I adjusted my head unit for a couple minutes to play only the under seat subs and they play midbass but it just isnt very loud which i believe is because of the impedance (4 ohms i think vs the 2 ohm impedance of my doors). So, should I get better under seat subs or try to find a nice head unit?

The factory speakers are VERY capable of sounding good. Double check your crossovers. Under seat woofers should be set to receive 250hz and below and door speakers should get 250hz and up as mentioned before.

The door maids will measure at 2 ohms resistance but add the passive filter and tweeter to the mix and they will measure more like 3.2 ohms. That is not your issue.

Set your crossovers and gains correctly and it will sound good.

Also why are you using the lc2i? Does the technics harness not have a full range output?

[j.f.leonard]

Originally Posted by david in germany

The factory speakers are VERY capable of sounding good. Double check your crossovers. Under seat woofers should be set to receive 250hz and below and door speakers should get 250hz and up as mentioned before.

The door maids will measure at 2 ohms resistance but add the passive filter and tweeter to the mix and they will measure more like 3.2 ohms. That is not your issue.

Set your crossovers and gains correctly and it will sound good.

Also why are you using the lc2i? Does the technics harness not have a full range output?

Okay. First, i have upgraded door component speakers running off of a JL JX400/4. I use the signal from my 676 technic harness for that amp. I am using the lc2i to send signal to my sub amp as I had issues with the preout signal for whatever reason and was recommended the LC2i by many people. I have checked all of my filters on the amps and everything is right around where it should be. I am not saying the stock under seats sound bad, I am saying they arnt as clean as my upgraded doors and they definitely are not as loud at any given volume which I believe comes from the difference in impedance if there is one.

[david in germany]

I think the stock hifi woofers are also 2ohm. The impedance isn’t your issue.
The 400/4 looks to only have crossover variation to 200hz but I also doubt that would be an issue.
How are your gains set? Multimeter like JL recommends (voltage output), SMD DD1 or by ear?