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Discussion Starter #1
May I ask for someone who has stock premium audio to make the measurement of the frequency response on the SINGAL LINE BEFORE AMPLIFICATION? And can anyone confirm if the signal is actually differential balace with shields? Thanks!
 

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Discussion Starter #2 (Edited)
OK seems like nobody actually interested in this. Let me state my intention. The new Civic almost has everything in the audio integrated with iMID. If the stock stereo is removed and replaced by an aftermarket system, the function of iMID displaying song info, bluetooth, AUX input, etc., are lost. From all other Honda and Acura forums, people have revealed that the stock premium CD players DO SEND OUT FLAT DIFFERENTIAL BALANCED SIGNAL. This low level signal can be directly converted to RCA without using any DSP, like MS8, JL Cleansweep, etc., or any line level converter, yet have superior noise rejection if the receiving amplifier supports differential balanced input, such as JL amps. Since the EQ and crossover and DSP are done at the stock amplifier, the signal must be taken between CD player and amplifier. I am also more interested to convert my non-premium to premium audio and use the output to an aftermarket amp. But I have not done it because Honda parts listed the supposedly Premium CD Player as BASE, though with a different part number. So I want someone to test it out for me before I go to spend $250 for the premium CD player.

The conclusion can help the people who they want to upgrade audio and keep iMID functionality. In addition, it can benefit those without Premium system to switch to Premium if the result is satisfied with only spending $250 (+150 if panel is needed) instead of spending money to buy DSP with only mediocre results. So someone who is interested in audio, please help me out and verify the signal. Thank you.
 

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so you would be able to put aftermarket hu and control from steering wheel?
 

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Discussion Starter #4 (Edited)
I think you misunderstand the concept. The conept is, to directly amplify the signal output from Civic's Premium Audio, tap into the signals before OEM amplifier. People have done it in Accord, in 8th gen Civic, TSX, etc. and the results are very promising. It keeps stock control of everything-display, bluetooth, AUX, etc. while having aftermarket HU class performance, without the need to add DSP and introduce artifacts or line output converter. I have a EX sedan, so I need to buy the Premium Audio headunit for $250 and swap it out. But as I said earlier, since I see Honda listing the "Premium Audio CD Player" as BASE, I will need someone to do further testing before spending the money. I can't return the parts ordered ($250) if it has been opened, but the plug that plugs into the CD player is only like $8 shipped from eBay and HA11B is around $10 from amazon.com. The reverse (into radio) plug have 4 pairs of outputs (and shields) so I need the measurement from there. If I receive enough information, like the frequency response graph from each of the FL, FR, RL and RR output from CD player (again, not stock amplifier), I will start the project then let everybody know the result. I actually expect the graph to be around +/-1dB at max.

I am in the process of maing 1 harness and I will post picture once it's done so people know what I am talking about. Now it's just a picture taken from 8thgencivic.com


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dude, your ideas are genius, it's exactly what i'm looking to do, i wish i could help, i know this audio pro dude but wont be able to see him till maybe next week sometime, i hope somone can step up
 

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wouldnt you rather put in a better hu thats not hideous and try to keep steering wheel controls linked to it?
 

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Discussion Starter #7 (Edited)
dude, your ideas are genius, it's exactly what i'm looking to do, i wish i could help, i know this audio pro dude but wont be able to see him till maybe next week sometime, i hope somone can step up
Try to do a search in google about "mercman harness" you will have a lot of information. If you have a chance to take out the radio, take some picture on the back of the radio, the plug(s), and the wires (both top and bottom row) and take some notes. After reading Accord's CD player pinout (24pin), there should be no difference between premium and non-premium head unit. Only that the Civic has fewer wires. Next, to confirm if the output is "differential balance", try to see if you can find the "Shield" wires (#8, 9, 20, 21). #17 should be AMP TURN ON. Third, the RCA cables would connect directly to FL+/-, FR+/-, RL+/-, and RR+/- without anything in between, AND NOT THE SHIELD WIRES. I am attaching Honda's 24pin plug pinout graph, and look into the "Premium" section to see if you can find the "Shield" wires on the physical plug. There's also one thing that concerns me. In the Accord the subwoofer crossover is IN THE RADIO (It has an extra 8-pin connector), not the AMP. So I don't know if the Civic is the same. I hope not.


wouldnt you rather put in a better hu thats not hideous and try to keep steering wheel controls linked to it?
There are so many reasons why one would not put an aftermarket headunit in there. Some want the stock bluetooth that no other aftermarket come close in term of quality; some want to keep the iMID to display songs; some have navigation "Premium" head unit but want better sound quality; some live in area where crime is high...So I feel the finding actually can help lots of owners out. What do you think?
 

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There are so many reasons why one would not put an aftermarket headunit in there. Some want the stock bluetooth that no other aftermarket come close in term of quality; some want to keep the iMID to display songs; some have navigation "Premium" head unit but want better sound quality; some live in area where crime is high...So I feel the finding actually can help lots of owners out. What do you think?[/QUOTE]

yes i want honda blue tooth and imid display of songs, exactly
 

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i'll do what i can but i know theres some peeps on here that already ripped out their units and replaced with aftermarket, so somoeone thats got access please chime in
 

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Discussion Starter #10
I doubt anyone replace the premium cd player with aftermarket yet.
 

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Discussion Starter #11
Seems like nobody is actually doing testing. So I will be doing this. I have the harness almost ready, just need to wait for the radio to come and see. Will be connecting to TruRTA in Windows to test out the system response.
 

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Discussion Starter #12
OK have the radio in today. The back of the radio has the usual 24-pin main harness, 20 pin sub harness that I think connects to USB or iMID or whatever, 14-pin analog input harness, antenna adapter, and an 8-pin (supposed to be) subwoofer output that non-premium systems don't have. Not sure if the main output has frequency from 20-20k. Otherwise will connect 2 pins to the subwoofer output. Will test after Christmas.
 

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Discussion Starter #13
OK the premium cd player is a direct fit to stock EX sedan(also a Clarion) panel. I think it won't fit the Alpine panel (LX, HF, Hybrid). Everything works as expected, dash lights do turn on when I turn on the lights, but now I get a Sub level control as an extra. I doubt I will use it anyway. The sound is very very clean, bass is tight even I don't have a subwoofer in the car. Much better than using non-premium cd to DSP (not to mention amping non-premium without DSP, lol). But I have some little things that I need to fix before I can conclude the setup works. Also I will need to check the output frequency response.
 

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So how did you acquire the premium head unit?


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That sounds reasonable I might look into that


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Discussion Starter #17 (Edited)
Reasonable but not as an easy task as one might think (actually harder than I originally thought). I actually removed one of my reply because I am dealing with noise issues right now. I connect the low level output to the OEM input of PXA-H650, did AntEQ, etc. and took a picture. It looked pretty flat but I am not confident about it. And since installing this unit I have pops from speakers, as soon as the PXA-H650 is turned on. So I have pop whenever I open my door, close it, insert the key, press the harzard, etc. No noise with exact same equipment before the premium CD is installed. Strange. So that I believe the pops get in before the input of H650 because I can "turn it down". May be H650 doesn't like low level on OEM (speaker level) input? Is it due to impedance or voltage? I am not sure. Will try to verify tomorrow. In addition I have a new harness that converted to RCA right at the reverse harness. I heard that people plug into H650's AUX input and use it as main. I may try it also. Otherwise I will plug directly into my JL amp and see. The reason I want to keep H650 is because it has time correction though. Anyway, are you familiar with the noise I am talking about?

BTW the sound is good that I can live with it without a subwoofer, lol. And I haven't been able to "enjoy" my car stereo for 6 months. Though I still need to fix the problems I am facing.

I have attached the two AntEQ measurement and calibration for both Premium (left) and non-Premium stock EX sedan (right). As I have said before, I am not 100% confident about the measurement of Premium CD player.
 

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Idk much about the science behind music haha but I'd love an internal amp, I want to put two 6.5" kicker slim subs in the back deck, without an amp being mounted in my trunk haha but I'd love the increase in sound quality for sure I'd love if you can figure out the issue with the popping, if you need any help just pm me and I'll try to do what I can I'd love to improve the sound system with stock look


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Discussion Starter #19
No you still need an external amp with the Premium CD player. You know, should need an amp with differential balanced input. I suspect the noise getting into the system because the speaker level input on the H650 doesn't invert and sum the signal. May be it just take both signals and modify it to preamp. That combined with the head unit's low voltage is a disaster. Well, just think about it, when noise getting into the system, you sum both noises from + and - line without inverting. This is what I think is happening. I have been looking into another forum and they say H650's AUX input (RCA) does take care of the differential balanced line. Otherwise if that doesn't help AND the JL amp (which HAS differental balanced input) would not take it, I will stop the project.
 

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Wow Well good luck you've gone over my head haga


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