Question: How do I get a full range signal from the OEM Amplifier

[DarkFury]

This thread is a spinoff of another, just to try to get a specific answer to the question above.

Here is a quote that I want to confirm...

Audiocontrol LC8

Originally Posted by minirx7

From what i understand the rear speaker wires arent true full range output (hence there is also a sub woofer in the rear), which explains why you arent getting a deep bass sound.

I read up and found out that the door speakers receive a signal from 120hz and lower while the dash speakers get 120hz and higher.

If this is the case, then i can run the dash speakers to my amp to run components and then run the door speakers wires to run to the amp to power the subs.

Has this been confirmed as true? Does the front door inputs play all signals from 120 Hz down and the dash play all signals from 120Hz up? Technically this would be a "full range" signal if that is the case. Right?

As of right now, as shown in other threads, I am just trying to figure out the optimal way to configure an Audiocontrol LC8 processor... I just got off the phone with one of their techs and he confirms that you need to get a "full range" signal through the combination of inputs in order to sum them for your aftermarket amps.

Furthermore, he suggested one of 2 ways to do this...

1) Use all 4 input signals (dash, front door, rear panel, and sub) into the LC8, sum them then send the signal first to a 4 or 6 channel amp (mids and highs) and use a "passthrough" off to a second sub amp for your deep bass or...

2) Use 3 input signals (dash, front door, and maybe the sub) into the LC8 then sum them up to create a full range signal from the main output to your mids/highs amp and Channel 4 (sub) output to your sub amp.

Personally, I'm leaning towards option #2 right now as I want to use the remote volume control on the LC8 to adjust the sub level, however I'd really appreciate anyone's input on this information about getting a "true" full range sound since I don't have an RTA to prove or disprove it either way.

Thanks in advance for your help.

[DarkFury]

EDIT: Never mind... I think I found my answer here:

FAQ - Audio Upgrades

From El Duderino...

The F door speakers play from about 120 all the way down. The front dash speakers play from 100 and up, with a significant rolloff at about 16kHz. The R deck 6x9s play from 100 Hz and up with a slight rolloff at about 18k. The R deck "sub" plays from 50 and down and is the least-eq'd signal from the amp.

BTW... if anyone has found any different info, please feel free to respond.

[minirx7]

I decided finally to buy the LC8 and take my chances. Small investment so i decided to try it.

[djjasond]

So a couple things... The El Duderino numbers are for a 300c with SoundGroup II. Can't say that this would apply to base models or SRT models. Just a word of caution for other readers.

The next thing is that the best way (in theory at this point) to get full range signal and keep your factory integration would be to use the peripheral or pac "add an amp" product. I saw it at CES but it doesn't appear to be released yet. It is a harness that goes between your factory deck and factory amp but provides a full range rca out. This would eliminate the need for cleansweep's, LC8's, rockford 360's, etc. Supposed to be around $149 whenever in hell they release it.

I've been using an LC6 with ycables for close to a year. For my 4x75 amp, I summed the rear deck and front doors using ycables on the outs of the LC6. Sounds great and powers my door / deck after market speakers just fine. The LC6 had kind of a summing feature in that if you had something plugged into the input next to the sub input but did not have anything connected to the sub input, the sub OUTPUT would use the INPUT from the channel next to it. I put my front door inputs there so that is now coming out my sub output. Hope that makes sense. Put another way, it allowed me to use the front door inputs for two purposes... to be summed with the rear deck and to be used as the signal for my subwoofer amp. The front door sub output via the LC6 worked ok when I first hooked it up but didn't hit as hard as I remember from my previous car. I had to turn the gain up on my sub amp to be happy so I then went and bought a phoenix gold line driver/eq and placed it between the LC6 sub output and the subamp. It gives you like an 8 volt preamp out. Incredible difference on that subamp. I didn't need it for my other speakers. My set up sounds great to me.

Now that being said, the front doors are 120hz and down but the rear deck is 100hz and up. I think an audio purist would tell you that combining these two would give you a bump in the 100-120hz range. In theory, I should have summed the rear deck and front door, using an LC6 or LC8, to an eq, then using a test cd, hook up a Real Time Analyzer to adjust the eq to get back to a flat full range signal (basically what a cleansweep does). However, SoundGroup II also bass boosts at low volumes and rolls bass off at high volumes. Kind of a double whammy. I mostly listen to hip-hop so having a little extra low end doesn't bug me. This overlap and boosting is why folks are opting to use cleansweeps, 360's, etc to get a truer flat full range signal. I'm not a huge fan of the separate volume knob though. I am personally looking forward to the add an amp product. If it delivers what it promises, it will get you that full range signal without an extra device and volume knob. Only time will tell. I'm not sure what type of sound you'd get by summing front doors, dash, rear deck, and subs on you LC8. Seems like overkill because they aren't sonically exclusive of each other. Lots of overlap in that mix. Keep us posted.

[DarkFury]

Thanks for the reply Jason...

I too have Soundgroup II on my 300C Heritage.. so El Duderino's advice does pertain to my interests here.

Actually, when my LC8 comes in... based on what everyone has said so far, I think I'll just sum the dash, front and rear speakers (and leave the sub channel alone)

This way, I'll still get a "fade" front to rear for my mids and highs... and still have volume control on the subs (on channel 4). Pretty much that was the advice of the AC folks.. and it sounds reasonable.

BTW... I too listen to alot of hip hop and rap (I grew up on Miami Bass... 2 Live Crew and Jam Pony Productions style) so I'll like havin' alot more bottom.

I'm definitely getting excited about finally getting this system together. For me, getting the tunes in line comes first, before most exterior / performance mods.