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DIY Amp Sub and Speaker Replacement with Infinity Head Unit (no nav)
First, I apologize if there is a thread regarding this specific topic already on these forums - I spent a considerable amount of time pouring over them and the best DIY builds I have seen, thus far, have either utilized the non-infinity head unit or have replaced the head unit all together. I didn't want the infinity audio package but delivered my new SX (02/15/2011) the sales manager has misread the invoice and I had, in fact, purchased a SX with the infinity sound (plus the other goodies); I really liked the panoramic sunroof and upgraded rims so I ran with it, and as a result, I am now attempting a build using the infinity head unit with all of my own parts on the back end on what seems to be a voyage into the unknown I want my own system on the back end but I want to preserve the other goodies the car came with - bluetooth, UVO, steering controls, USB in, etc. and I would like input from the community on both my parts and approach:
Here are the wiring diagrams for both the head unit and the amp from Kia Global Information System (KGIS) (anyone may register for free)
- Back of the head unit: Global Service Way
- Amp inputs and outs: Global Service Way
If I am reading these correctly, which I believe I am, the head unit uses a digital S/PDIF out to the exterior amp - yeah, not something I really wanted to deal with or have much experience with either. I am doing this build on a budget of about $1,600 so I had to think of ways to get around this.
First, here is the digital to audio converter I will use (yes, I am using one capable of translating a 5.1 to analog signal because I want to be able to continue to upgrade the head unit [software wise] and have it still function with my system: Amazon.com: GefenTV Digital Audio Decoder: Electronics
IF anyone knows the digital out is only a R/L signal, please let me know so I can save a few bucks Also, does anyone know if the bluetooth audio would use a separate line out to the amp based on the airing diagrams above? I can't see any indication of such but I could be wrong. Also, if anyone knows a cheap/easy way to build something to go from 12V to 6V for the adapter, please let me know - I am hitting up you-tube tonight to see what I can shake out of it learning-wise but any input here would be appreciated.
Because I know this more interesting, here is the processor, amp, and other speakers I plan to install:
- JBL MS8 - 8 Channel Sound processor (I am going to keep the infinity center channel and run it directly from the processor with a fairly low volume just to be sure the front sound staging is where I want it to be when I tune) - $475 new and sealed off eBay; a steal
- Soundstream A/B Rub5.800 Amp (4X70 @ 4-ohms, 4X115 @ 2-ohms, 1X340 @ 2-ohms) - Yes, I know this amp can run hot but I am putting it with good ventilation in the trunk. I love the warmth of the sound and they were rock-solid last time i used this brand. If am completely off my rocker here, please let me know! - $190 Amazon.com
-12W3V3-2 - JL Audio 12" Single 2-Ohm Sub - Great synergy with the 5-channel amp and RMS will be in the sub's sweet spot for power. Unsure if I will use a sealed or vented box - feedback welcome! - $178 eBay.
Focal 165 VB 6.5" Components - I am NOT reusing the mid/highs on the crash! However, I am also uneasy about tweeter placement/how to do it so any feedback here is also welcome! - $200 eBay
Focal 165 CVX 2-ways - Seems to do the job in the back. - $218 eBay
Again, there seems to be good synergy and I have really tried to do my homework but I am also a noob so, please, help a brother out!
Yes, I will fully document this build for all to see on these forums once I am underway.
Thank you in advance!
Another way to approach this without trying to intercept and decode the SPDIF is to us a line out converter post-factory amp. If you choose to let the factory head unit drive the center channel and dash speakers (or leave them out), you could use a 6 channel LOC for your door speakers and sub. I would recommend using an Audiocontrol LC6i 6-channel LOC and run the speaker level inputs from all 4 door speakers and the sub to it. Then just run the RCAs to your 5-channel amp. This way would also keep the integrity of the factory multi channel processing intact.
wow, glad to see someone knows their sh!t about car audio.
all I can say is I prefer the sound of a vented sub to a sealed one...
Good luck with the build!
Ported vs. sealed is strictly up to the end-user preference. If you like tighter, precise bass get a sealed enclosure. If your tastes lean towards boomy/vibrate the neighborhood bass then go with a ported enclosure. Ported boxes will also get more attention from outside of the vehicle.
Rob, thank you for the input; I thought about tapping into the lines after the amp and, I know this sounds silly, but it didn't seem "clean" in my mind. I know the sound processor is still effectively fixing the output from the factory amp but I was hoping to just remove that element from the equation. If my tapping directly into the SPDIF doesn't work, that will be my fall-back plan.
On a side note, do you (or anyone else reading this posting) know where I could possibly go/who or what entity I could contact to get more information regarding the outputs from the head unit?
Rob, this was also my thinking and because I lean more towards listening to rock (Smashing Pumpkins for life!), I think the sealed box is in the lead at this time
I know exactly what you mean by wanting a "cleaner" signal. Not silly thinking at all. I just hope that KIA/Infinity used a standard compression/encode/decode multichannel format that can be directly decoded by your DAC. I really hope it works!!
Originally Posted by Verata
Easy! Just install a solenoid activated valve in the port of your sub enclosure and wire a switch. Have the best of both world's. LOL. Hmmmmmm actually that could be cool and one-of-a-kind.
Originally Posted by Verata
In all seriousness, I'm going to go the sealed route. It makes the necessary enclosure size smaller and my trunk space is at a premium with 2 kids. :smile:
I was also poking around other forums, here and elsewhere, and noted there a protocol called "CAN BUS" which helps parts within a car talk to one another and the stock infinity amp has this as an input; my best guess is it would help the amp determine what channels to pump out Bluetooth calls through (if I understand correctly).
As such, I know there are those who have used their sound processors to just combine the output from the stock amp and to those individuals, I ask: when using Bluetooth, does the voice of the person you're speaking with come through all the channels or only out of certain channels?
I too am looking to upgrade the audio in my Kia Sorento Platinum, and have learnt a few things so far..still along way to go
1. The SPDIF from the head unit cerainly provides L and R channels data to the amp, but I am not yet sure if the head unit also decodes the L+R into centre and sub, and sends those signals down the SPDIF, or whether the external amp itself creates the centre and sub from the SPDIF L+R.
2. The CANBUS is used for a number of things (a) the steering wheel controls are all encoded and sent to the head unit via a single CANBUS wire. If you buy a head unit that is not CANBUS compatible, then you will need to buy a CANBUS decoder if you wish to retain all the functionality of the steering wheel controls (b) The CANBUS is used by the head unit to control the external amp. The volume, rear/front fade, left/right proportion, equaliser (low, mid, high) signals are all sent to the external amp via the CANBUS (c) the reverse gear position (to enable the reverse camera), whether the head lights are on or off (to enable the dimming of the head unit backlight) are, i believe, also all sent to the head unit via the CANBUS.
There is considerable rework to do if you wish to not use a CANBUS head unit, or a non SPDIF. The steering wheel controls alone may be impossible - there are however cheap CANBUS audio decoders. You would also need to run all speaker pre amp signals to the amp from the dash if you don't use SPDIF.
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