Question about gain and tuning a Lc7i and 5 channel Amp

[1aespinoza Premium Member]

It was an easy fix, you grounded the RCA jackets to the HU chassis.

Dang it! I have been operating on one set of RCAs for ever. Thanks man. I will try this.

 

[1aespinoza Premium Member]

I've set by ear forever.

Same here. For my own gear, I do it by ear.

 

[JasoninDLH]

Correct. From the amp, disconnect the RCAs that come from the LOC. The picture below points to where you will connect your multimeter test leads. Be cautious that positive and negative do not touch each other. The guy in the video made that pigtail to avoid this issue. Set multimeter to A/C volts. After downloading that 1000 Hz. test tone, play it on your radio at ~75% volume. Now sweep the gain on the LOC until you read the 5 volts that your amp can handle. Boom, Jalapeno solutions. Before reconnecting the RCAs to the amp, turn down the gain at the amp. Turn it up judiciously after that with the radio at ~75% volume.View attachment 47064

So I have an amp that has an input value of 14v and my LC2i has a 9.5v preout. I wouldn’t have to worry about testing with a DMM (as shown) to set the correct gain on the LOC. I would just put the gain all the way up on the LOC? And keep the gain on the amp as low as possible?

Strangely, the more I know…the more I don’t know. On previous builds I would just wing it and push some buttons here, turn some dials there and call it a day.

 

[1aespinoza Premium Member]

So I have an amp that has an input value of 14v and my LC2i has a 9.5v preout. I wouldn’t have to worry about testing with a DMM (as shown) to set the correct gain on the LOC.

Correct.

And keep the gain on the amp as low as possible?

No. For the sub amp's gain setting, you go by the sub you will be using. Formula for that is-
A/C Voltage= Square root of Watts × Ohms.
If you want your 4 Ohms sub to play 300 watts. 4 × 300= 1200. Square root of 1200= 34.64 A/C volts.

Strangely, the more I know…the more I don’t know

Yup, I know that feeling all too well.

On previous builds I would just wing it and push some buttons here, turn some dials there and call it a day

Yup, this too.

 

[JasoninDLH]

Correct.

No. For the sub amp's gain setting, you go by the sub you will be using. Formula for that is-
A/C Voltage= Square root of Watts × Ohms.
If you want your 4 Ohms sub to play 300 watts. 4 × 300= 1200. Square root of 1200= 34.64 A/C volts.

Yup, I know that feeling all too well.

Yup, this too.

Thanks for the info! Super excited to finally dial this stuff in after 25 years of winging it.

 

[chornet44 10+ year member]

Deleted

 

[Barry Lubline]

Is anyone familiar with this issue. I have a 2018 Chevy Malibu LS with a "NON BOSE" factory AMP. Ok, I followed all the directions specified. I literally tapped into the front and rear speaker outputs from the Factory amp. I ran those leads to an Lc7i Front and then the rear. I bought a brand new Lc7i by the way. I ran the RCA's from the Main channel outputs of the Lc7i controller, to the left and right 1 and 2 channels of my "Alpine R-A90S 6 CHANNEL POWER AMPLIFIER". Before I even worry about the low bass channel, I saved that for later. I have the Lc7i grounded and then powered directly from my distribution block. Originally I 2 LOC's from my radio outputs running everything, so in order to use the Lc7i, you have to use the leads from the factory amp in back, so I completely disconnected the 2 RCA LOC's that I had previously wired from the output of the radio all together. On the controller, under the lid/ hood, I have the 1st and 2nd channel jumper in summed position, the Auto Mode is active, GTO is active, all else set to factory specs and I can see the power light is on and the channel confirmation lights are on for the Lc7i. My speakers are wired directly to my Alpine amp. Before I was ready, I tested the output taps at the factory amp and they work on an external speaker just to be sure I have a signal. I still get no sound from my speakers. I get no sound at all and if I even turn the Threshold up just a tiny bit for the main channel, it starts to whine loudly, so I backed it off and disconnected the controller completely and put my system back to the way it was. There is most definitely a step missing here and I would love to use this new controller. I truly know how to follow the directions and have experience with installing aftermarket car audio, but I am stumped.
P.S.- Just a reminder, the speaker outputs are disconnected at the radio since I redirected the speaker wires, only, from the speakers directly to the Alpine amp. So there are no speaker outputs connected to anything, behind the radio
If anyone can relate has answers much appreciated.

 

[Barry Lubline]

Is anyone familiar with this issue. I have a 2018 Chevy Malibu LS with a "NON BOSE" factory AMP. Ok, I followed all the directions specified. I literally tapped into the front and rear speaker outputs from the Factory amp. I ran those leads to an Lc7i Front and then the rear. I bought a brand new Lc7i by the way. I ran the RCA's from the Main channel outputs of the Lc7i controller, to the left and right 1 and 2 channels of my "Alpine R-A90S 6 CHANNEL POWER AMPLIFIER". Before I even worry about the low bass channel, I saved that for later. I have the Lc7i grounded and then powered directly from my distribution block. Originally I 2 LOC's from my radio outputs running everything, so in order to use the Lc7i, you have to use the leads from the factory amp in back, so I completely disconnected the 2 RCA LOC's that I had previously wired from the output of the radio all together. On the controller, under the lid/ hood, I have the 1st and 2nd channel jumper in summed position, the Auto Mode is active, GTO is active, all else set to factory specs and I can see the power light is on and the channel confirmation lights are on for the Lc7i. My speakers are wired directly to my Alpine amp. Before I was ready, I tested the output taps at the factory amp and they work on an external speaker just to be sure I have a signal. I still get no sound from my speakers. I get no sound at all and if I even turn the Threshold up just a tiny bit for the main channel, it starts to whine loudly, so I backed it off and disconnected the controller completely and put my system back to the way it was. There is most definitely a step missing here and I would love to use this new controller. I truly know how to follow the directions and have experience with installing aftermarket car audio, but I am stumped.
P.S.- Just a reminder, the speaker outputs are disconnected at the radio since I redirected the speaker wires, only, from the speakers directly to the Alpine amp. So there are no speaker outputs connected to anything, behind the radio
If anyone can relate has answers much appreciated.

 

[Barry Lubline]

I have an Lc7i running the front speakers on the main channel, rear on the 2nd channel, and then no speaker inputs for the 3rd channel but I do have a sub running from the channel 3 output. This all ends up at a kenwood xr901-5 powering 4 coaxial speakers and a 12” sub.

I know for a fact the installers didn’t take their time tuning the system. It doesn’t sound bad but I feel it could sound better. The gain settings on the LOC are all in their default setting. The gain on the amp is at about halfway for the front, rear, and sub settings There’s also a bass boost on the amp turned up to 3db.

From what I’ve read and watched, this LOC can and should be tuned so that the amp doesn’t have to have the gain turned up as high.

How would I go about matching the gain on the LC7i and my amp?

Is anyone familiar with this issue. I have a 2018 Chevy Malibu LS with a "NON BOSE" factory AMP. Ok, I followed all the directions specified. I literally tapped into the front and rear speaker outputs from the Factory amp. I ran those leads to an Lc7i Front and then the rear. I bought a brand new Lc7i by the way. I ran the RCA's from the Main channel outputs of the Lc7i controller, to the left and right 1 and 2 channels of my "Alpine R-A90S 6 CHANNEL POWER AMPLIFIER". Before I even worry about the low bass channel, I saved that for later. I have the Lc7i grounded and then powered directly from my distribution block. Originally I 2 LOC's from my radio outputs running everything, so in order to use the Lc7i, you have to use the leads from the factory amp in back, so I completely disconnected the 2 RCA LOC's that I had previously wired from the output of the radio all together. On the controller, under the lid/ hood, I have the 1st and 2nd channel jumper in summed position, the Auto Mode is active, GTO is active, all else set to factory specs and I can see the power light is on and the channel confirmation lights are on for the Lc7i. My speakers are wired directly to my Alpine amp. Before I was ready, I tested the output taps at the factory amp and they work on an external speaker just to be sure I have a signal. I still get no sound from my speakers. I get no sound at all and if I even turn the Threshold up just a tiny bit for the main channel, it starts to whine loudly, so I backed it off and disconnected the controller completely and put my system back to the way it was. There is most definitely a step missing here and I would love to use this new controller. I truly know how to follow the directions and have experience with installing aftermarket car audio, but I am stumped.
P.S.- Just a reminder, the speaker outputs are disconnected at the radio since I redirected the speaker wires, only, from the speakers directly to the Alpine amp. So there are no speaker outputs connected to anything, behind the radio
If anyone can relate has answers much appreciated.

 

[1aespinoza Premium Member]

P.S.- Just a reminder, the speaker outputs are disconnected at the radio since I redirected the speaker wires, only, from the speakers directly to the Alpine amp. So there are no speaker outputs connected to anything, behind the radio
If anyone can relate has answers much appreciated.

I do not know the Chevy radios that well but in the Dodge radios, if they do not sense a resistance on the output side they will turn off the signal output. The solution is to add a load resistor to trick the radio that the speakers are still connected.
You connect these like a speaker.

 

[Barry Lubline]

1aespinoza​

You hit the nail on the head , good answer, see below from Audio Control, that's exactly what I found too, thank you. We know now the Outputs do not know there is any speaker yet since going directly to the Lc7i, so I ordered the AC-LGD's, that should fix it. Thanks again for your response. Happy Holiday

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LOAD GENERATING DEVICE & SIGNAL STABILIZER​

Since there is no resistance on on the high level speaker lines, the factory amp doesn’t think that there are speakers connected to it, so it won’t output a signal or the output will intermittently drop out.
This is a perfect opportunity to install our AC-LGD! You can find the AC-LGD Lineup here! It will stabilize your factory system by putting a load on the factory outputs!