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I will be doing some kind of LOC with my factory headunit so I can do aftermarket amps and subs. My question is should i be connecting my headunit directly to my LOC, by passing the amp or should I connect from the amp to the LOC? I read a bunch of threads and I see people doing both types. Some people say do directly from headunit, but then I read the voltage out of the heaunit is very low, blutooth quality suffers and there could be possible features missing if you by pass amp. Some people say from amp but then summing is needed, signal is amped and noisy, signal could be crossed over and eqed. What should I do? Dont want to lose any features. My installer is asking as well.
 

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I will be doing some kind of LOC with my factory headunit so I can do aftermarket amps and subs. My question is should i be connecting my headunit directly to my LOC, by passing the amp or should I connect from the amp to the LOC? I read a bunch of threads and I see people doing both types. Some people say do directly from headunit, but then I read the voltage out of the heaunit is very low, blutooth quality suffers and there could be possible features missing if you by pass amp. Some people say from amp but then summing is needed, signal is amped and noisy, signal could be crossed over and eqed. What should I do? Dont want to lose any features. My installer is asking as well.
My understanding is that it always goes HU-> LOC/DSP->Amp-> speakers

You'll sometimes hear LOC's and DSP's referred to as "preamps" by the old school guys and that basically says it all. I'm fairly new to all this but with my fairly limited understanding I can't imagine why anyone would instal the amp before the LOC.
 

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My understanding is that it always goes HU-> LOC/DSP->Amp-> speakers

You'll sometimes hear LOC's and DSP's referred to as "preamps" by the old school guys and that basically says it all. I'm fairly new to all this but with my fairly limited understanding I can't imagine why anyone would instal the amp before the LOC.
Normally you wouldnt but when you are trying to integrate with the oem system, there are a lot of strange things. From my reading, some cars have functionality in the OEM amp so if yoy by pass it, you lose features. So people do the loc after the factory amp to go to after market amps. Dont know if this is the case with this accord. What a pain these new cars are. In my old accord I could just drop any headunit in and I was set.
 

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LOC = Line Output Converter, it is used to take a signal that would normally drive a speaker and pad it down so it can be connected to an amp line input. Some amps already have LOCs built in "Speaker Level inputs"

DSP = Digital Signal Processor, used to manipulate the sound in the digital domain. Not a fan.

Preamp or line driver is not needed for the standard or premium systems.

Honda has two types of audio systems, Standard and Premium. The Premium uses and external amp. The Standard systems HU has Speaker level outputs and needs a LOC.

The output of the Premium HU is a balanced line level signal. The people that report a low output voltage have no idea what they are looking at. A balanced signal can not be connected to a standard RCA line input on an aftermarket amp unless that amp has balanced inputs.

Do some more searching, you will find what you need to do to replace the factory amp. What ever you do, do not cut any wires.

Jeff
 

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Discussion Starter #5
LOC = Line Output Converter, it is used to take a signal that would normally drive a speaker and pad it down so it can be connected to an amp line input. Some amps already have LOCs built in "Speaker Level inputs"

DSP = Digital Signal Processor, used to manipulate the sound in the digital domain. Not a fan.

Preamp or line driver is not needed for the standard or premium systems.

Honda has two types of audio systems, Standard and Premium. The Premium uses and external amp. The Standard systems HU has Speaker level outputs and needs a LOC.

The output of the Premium HU is a balanced line level signal. The people that report a low output voltage have no idea what they are looking at. A balanced signal can not be connected to a standard RCA line input on an aftermarket amp unless that amp has balanced inputs.

Do some more searching, you will find what you need to do to replace the factory amp. What ever you do, do not cut any wires.

Jeff
Can you be more specific? Bottom line, given my premium oem stero with factory amp, should i tap the output from the headunit or from the factory amp? What are the pros and cons of each?
 

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To my knowledge, the factory amp in the 9th gen Accords has no additional built-in functionality to the factory stereo system that would be gone if you were to bypass it by adding aftermarket amps.
 

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Yeah, I don't have the model that has the amp, but I haven't seen anything on any forums indicating that the amp does anything other than amplification and crossover duties.

As mercman said, if you tap in before the factory amp, you will need to make sure your new amp accepts balanced inputs. Not all do. If it doesn't, I believe you're guaranteed to get engine noise whine. Or you can buy a unit that converts balanced inputs to RCA outputs. I think AudioControl makes one.

If you tap after the factory amp, you'll need a DSP that can re-combine the outputs to the different speakers into one signal. That is, the factory amp has crossovers that send bass to the factory sub, highs to the tweeters, etc., so you need a device that can join that all back together. There could also be some EQ being done in the factory amp you'd need to undo, but I haven't seen anyone who's tested for that one way or the other.

I'd tap before the amp if I were you.
 

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The factory amp also has inputs for the ANC L+R signals. When you bypass the amp the ANC is disconnected.

Check out my other posts and you will find out what you need to do.

Jeff
 

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Discussion Starter #9 (Edited by Moderator)
Yeah, I don't have the model that has the amp, but I haven't seen anything on any forums indicating that the amp does anything other than amplification and crossover duties.

As mercman said, if you tap in before the factory amp, you will need to make sure your new amp accepts balanced inputs. Not all do. If it doesn't, I believe you're guaranteed to get engine noise whine. Or you can buy a unit that converts balanced inputs to RCA outputs. I think AudioControl makes one.

If you tap after the factory amp, you'll need a DSP that can re-combine the outputs to the different speakers into one signal. That is, the factory amp has crossovers that send bass to the factory sub, highs to the tweeters, etc., so you need a device that can join that all back together. There could also be some EQ being done in the factory amp you'd need to undo, but I haven't seen anyone who's tested for that one way or the other.

I'd tap before the amp if I were you.
I see what you are saying. Thank you for the info. Let me ask you this, if i grab the signal from the headunit, does it require cutting of the wires? Also, if I do this before the amp, wouldnt I still need the loc? I wouldnt do summing since the signal is already full range but i would need the rca outputs it generates(I would shut the summing off).

The factory amp also has inputs for the ANC L+R signals. When you bypass the amp the ANC is disconnected.

Check out my other posts and you will find out what you need to do.

Jeff
Hi mercman,

I am having a shop,do my install soon. Is there some thing I can buy from them that will allow me to tap my headunit?

Can anyone answer this question - can a loc be used to connect the headunit to aftermarket amps?

This has been the most stressful build ever. I am running jl hd amps, so they should be able to handle balanced signals.
 

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The Premium HU outputs a balanced signal. The reason for this is that balanced lines offer superior noise immunity. All recording studios and live audio use balanced audio lines. A balanced line needs to connect to a balanced differential input. The reason is a that a balanced line has no ground or shield, instead, it sends the audio signal on two equal but opposite phase wires. The differential input adds the two opposite phase signals into one signal and in the process cancels all of the noise picked up along the way.

In order for this to work both signal wires must be the same, a difference of just an ohm can cause a major reduction in noise cancellation. This is why you can't just cut off the end of an RCA cable and solder it to the factory wires. You need a true balanced cable to do this.

Lastly, you need to integrate the MUTE and SW12 signals into your amp remote signal to avoid pops.

Jeff
 

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The Premium HU outputs a balanced signal. The reason for this is that balanced lines offer superior noise immunity. All recording studios and live audio use balanced audio lines. A balanced line needs to connect to a balanced differential input. The reason is a that a balanced line has no ground or shield, instead, it sends the audio signal on two equal but opposite phase wires. The differential input adds the two opposite phase signals into one signal and in the process cancels all of the noise picked up along the way.

In order for this to work both signal wires must be the same, a difference of just an ohm can cause a major reduction in noise cancellation. This is why you can't just cut off the end of an RCA cable and solder it to the factory wires. You need a true balanced cable to do this.

Lastly, you need to integrate the MUTE and SW12 signals into your amp remote signal to avoid pops.

Jeff
Thank you for your response. While I Understand what you are saying conceptually, I am not an electrician nor do I have a degree in electrical engineering. You need to dumb it down for me a little :wink

Practically, what are my options? Imhave my shop doing my install in a few days. I think most small install shops like mine will look at you sideways. What should I do?
 

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A shop will do one of two things

Take the signal after the factory amp by cutting your factory wires or running wires from each speaker. They will than sell you a fancy LOC or DSP to try to recombine the factory amp outputs. This is sloppy and will sound like crap no mater how much money you throw at it.

Or

They might try to splice into the output of the HU and not knowing anything about balanced lines will connect the (-) outputs to the RCA shields and short half you signal to ground. This will also allow the line to pick up noise along the way. They will then try LOCs and ground loop isolaters to try to clean up the signal.

In both examples you have a damaged factory harness, a sub par system and a big bill for the installation time and extra equipment.

Jeff
 

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Discussion Starter #13
A shop will do one of two things

Take the signal after the factory amp by cutting your factory wires or running wires from each speaker. They will than sell you a fancy LOC or DSP to try to recombine the factory amp outputs. This is sloppy and will sound like crap no mater how much money you throw at it.

Or

They might try to splice into the output of the HU and not knowing anything about balanced lines will connect the (-) outputs to the RCA shields and short half you signal to ground. This will also allow the line to pick up noise along the way. They will then try LOCs and ground loop isolaters to try to clean up the signal.

In both examples you have a damaged factory harness, a sub par system and a big bill for the installation time and extra equipment.

Jeff
And this is exactly what I am afraid of. So I am screwed? No good options?
 
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