Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!
I was able to confirm your finding on my truck as well. It always seemed like the left front dash speaker didn't have much sound coming out of it. I reversed the connections on just this speaker and it sounds much better. All speakers are now wired for reverse polarity, sounds great and no ANC issues. Really strange this one location has the wires flipped.
The DSP likely doesn't control polarity is this would have to be done with hardware literally switching the input side going into the amps or reversing the terminals on the output side. It's not impossible to just unlikely because of the added cost/components that would be required. The DSP is controlling the arrival of sound by adding time delay to the input signal depending on where its headed. what we know for sure is that the signal is coming down from the head unit flat on 4 channels, front, rear, left and right. But has to be distributed through 12 channels after processing so it determines which part of the signal goes to which speaker adjust the gain for that channel and determines frequency cut off and adds any necessary delay for the speakers location but doesn't determine polarity as far is its concerned the speaker is just a coil of wire with zero polarity because it essentially is just that. now here's where it gets interesting, there are many different ways amplification to a signal can be done even outside the standard class A, Class AB, Class D and so on. What people are typically expecting to find in an amplifier is a single ended configuration meaning the negative wire is your ground reference and the input side swings the voltage between the + and - rails of the amplifier producing the AC input into the speaker. In this situation a simple check with a multimeter will tell you which is positive and which is negative. In the case of this amplifier you have a positive live and negative live that reference ground internal to the amplifier, this means your "-" wire is not your common or ground you now have identical signals that are opposite in phase on both wires this effectively doubles the voltage potential and allows to amp produce a lot more power without needing a large voltage difference between the rails. This is the same thing that happens when you take 2 channel stereo and bridge it into a single mono channel, when this happens testing for polarity by measuring voltage across the 2 conductors goes out the window because you're measuring voltage across 2 sources, Same idea as measuring phase to phase on a 3 phase AC power system. It doesn't matter which lead is on which terminal you will get a positive voltage reading. So in the case of the AMP you basically have 12 channel mono with positive live and negative live on each channel. Surround sound / stereo is controlled by the DSP to determine which part of the signal goes to which speaker. Phasing is controlled by which op amp has input coming in on its postive terminal and which has the signal entering on its negative terminal, but both wires carrie signal and swing positive to negative around ground and the speakers are a floating load.
This is exactly what I am asking. Does polarity change from mode to mode? If it does, then that would prove my "theory" that the system is auto-sensing and dictating within the AMP/ANC Module making the wiring to each individual speaker irrelevant.
I have to disagree on this. Electronically, a consumer cost of an $80 DSP can handle this solution. DSP is not what it use to be, it is not expensive, it is not all hardware but more software.
Is there a definitive way that you know that the HU is sending a flat 4 channels to the AMP/ANC module? The future "upgrader" in me hopes it is this way as this is something simple to work with, similar to the 4th gen. without Alpine where I could take the signal to a DSP and play to my hearts content. The last gen. with Alpine made this difficult as a separate volume knob was required in the system as the output from the HU was a fixed signal to the AMP and the volume knob of the HU controlled the AMP, not the HU.
Back to the DSP, this is the "natural" job of a DSP but you are not including the polarity or phase task of the DSP. What if it is at this point the system changes phase of a speaker to compensate for Surround Sound or ANC? If it does, which I do believe it does, there would have to be checks in the system, those checks being polarity because the system would have to know where the current phase is. ie, the system has to know, regardless of wiring, the current polarity of the speaker. From an "upgrader's" point of view, if those flat 4 signals are present from the HU, what I just wrote, really does not matter.
This is exactly what I am asking. Does polarity change from mode to mode? If it does, then that would prove my "theory" that the system is auto-sensing and dictating within the AMP/ANC Module making the wiring to each individual speaker irrelevant.
Understood but when using a DSP, you have left and right in a typical car setup. You can combine those channels electronically, create left, right, front, back, center and the output would be the basic expectation of an input to an amp. Your method of explanation gives a great understanding of old-school audio, please do not take that term as offensive as I bow to you but my original post and my response to this post is to understand and hopefully create a dialog among audio geeks so that we can finally figure out what is going on.......so I can selfishly upgrade my system to be the envy of every ear.
5thgenrams.com
Regardless of what the DSP is actually doing I can assure you the system does not monitor phase, when I changed out my door speakers I wired them for the correct polarity as opposed to matching the factory wiring and ended up with a horrendous drone from the ANC system. The destructive resonance created by the ANC was in phase with the sound it was trying to counteract and would just continue to increase in amplitude trying to cancel the noise. Reversed the wiring to match the factory wiring and everything functioned normally. Here is a link I posted in a different thread that tells the tale of ANC and reversed phase at the doors. rsonedecker is correct, the ANC system only uses the door speakers for the ANC cancellation.
subwoofer swap
One thing I have noticed and its not related to the ANC, but related to the fact that RAM has piped the exhaust note into the cab through the speakers is now its noticeably louder when driving more spiritedly, there are multiple sounds that come through the speakers at fixed volume regardless of...
As far as the signal coming in flat, this is second hand info from another forum, I have not tested this myself they also indicated that just like the 4th gen alpine the volume knob controls the DSP/Amp and not the volume level of the output at the HU. I have not tested this personally since I have no intention of replacing the factory amp/dsp.
No offense taken, that's what these forums are for, the exchange of ideas and reverse engineering these trucks to make them do we want, and often not necessarily what the MFG intended. My post is part what has been verified and part my theory through minimal testing not saying its correct by any means, just like yourself just exchanging ideas. Which leads me to this one:
Some don't like/want the ANC, some do, some can't tell the difference. One thing we can all agree on, we want the best possible sound out of the system. My experience this far mixing the phasing sounds like crap and creates ANC issues. Having all the speakers in phase with one another matching the factory wiring sounds pretty good and has no ANC issues. Rsonedecker is saying the system when wired in the correct phase sounds much better than the factory wiring with all speakers reversed but the trade off is no ANC others have said the same thing in other threads. So here's the idea reverse all the speakers to get the phase matched correctly + to + and - to -. Then reverse the ANC input coming from the 4 mics and, in theory this should reverse the ANC output, allowing for the best possible sound and the ability to keep the ANC for those who want to keep it. All this can be done at the connections at the amp not sure how difficult it is to repin the connectors at the amp, biggest headache is probably the fact you don't have much working room under the seat. @rsonedecker i know this is subjective but on scale of one to 10, 10 being the best how much better is the sound with all speakers phased correctly? Trying to determine whether repinning 32 wires is worth the effort.
No. The mics for the phone are separate and disconnecting ANC at amp via the harness does not affect the phone. I can attest to this. I disconnected the 4 +'s on the ANC mics and it took me less than 5 minutes. A pic is all I needed and there was enough room to work by sliding the seat all the way forward.
So far for the people that have disable the ANC they have all used the pick method to unpin the mics. the ANC mics are specific to that system if you look above your head on the headliner you'll see two mics above the driver and passenger the smaller one closer to the windshield is the voice command and phone the bigger ones are the ANC mics. I popped one out to see if they plugged in and could just be unplugged but they are hard wired, best advice is too leave them alone, not really designed to come back out once they've been installed without removing the headliner.
I did not test for polarity with the apps (was too inconsistent on my phone) but I did pay close attention to + and - on the speaker terminals and wiring harness when I replaced mine. For me, I had to reverse Metra wiring harnesses on all speakers with expection of the door 3.5s. I can't tell you what that means as to whether they were in or out of phase though. Again the application was just too inconsistent on my Android device and just because the wiring was flipped on the door 3.5s doesn't mean it was out of phase.
. FWIW, I changed the dash speakers, correcting the polarity of one to put it in phase. Then I changed the front doors, also correcting the polarity in one to put in phase. Then everything up front was in phase. No ANC issues. I then changed the rear speakers, also correcting the polarity of one, boom, major anc issues. I could have gone back and flipped the wiring and it might have fixed the issue (or not) but I really wanted to keep everything in phase and was pretty sure I was going to add an amp/sub, which almost certainly would have caused ANC issues anyway, so I opted to just disconnect the ANC. 
