07-10-11, 04:15 PM
I've got a 2005 sts with the 15 speaker and nav system. It was vandalized and the harness to the radio was cut and radio stolen. We've found a replacement radio pigtail at the wreckers replaced the head unit but the vocals on every audio source are very low. We've now got two head units two amps and the results with all are exactly the same, sounds like a karaoke machine. Something must be off in the wiring but we're not sure what to check, ideas anyone please?
Did they take the amp in the trunk or upset its power?
07-10-11, 08:04 PM
No the amp remained and we also tried switching it out with another. We've tried with two different hu and two amps and the result is always the same very faint vocals. We've had a tech 11 on it and can send a test sound to each speaker. I've read that the vocals could be cancelling out due to a problem with speakers being out a phase. So we disconnected a speaker at a time to see if that made any difference and it didn't. We've also checked the amps ground and it seemed ok. The only place the wiring was touched to our knowledge was right behind the head unit. It seems that somewhere we must have a wiring problem but with the large number of signal wires going from the hu to the amp we really aren't sure where to begin. Thanks for your responses and ideas!
07-10-11, 09:30 PM
What model year navigation radio did you purchase? If you are absolutely certain every signal has been successfully reconnected and in the same position, the radio may require reprogramming. I'm suspicious of wiring though. Some connectors have more than one wire that is the same colour but is used for a different signal.
07-10-11, 10:40 PM
the navagation head unit came out of a 2005 sts, which matchs ours, the pigtail came with the radio and was about a foot long so it was pretty simple based on how the wires are bundled to ensure a match... at least we think it was. All splices were soldered and wrapped.
What sort of programming are you referring to, is it something that can be done with a tech 11 we do have access to one of those?
Does anyone know how BOSE splits the signal is it done at the head or at the amp? There is a positive and negative wire for left front, right front, left rear, right rear, center channel and amplifier audio prompt. As well as a single wire for subwoofer. Which lines would the vocals travel upon (sorry if this doesn't make sense I am by no means an audio expert)
07-11-11, 01:32 AM
If there is no chance something is wrong with wiring, and the amp is verified as good, you may require the radio be reprogrammed. This involves downloading the correct "calibration" into the radio. A Tech2 can be used, but you will require access to the GM SPS (Service Programming System) to do this. The scan tool only facilitates loading the calibration into the radio. The software comes through the SPS system and the calibration version can vary depending on the software in the amp and potentially, other modules (even within the same model year). This is why so much (electronic) service now is based around the VIN and not model year. Take clusters for example... my dealership doesn't show many part numbers in their system anymore. The expectation is they will use a Tech2 to scan the module to obtain the correct part number for replacement purposes. I'm not entirely certain reprogramming will solve your problem but eliminating the other items I mentioned decreases other possibilities. There is also a chance the radio you installed may be faulty.
If I'm not mistaken, the radio generates LF, RF, LR, RR, centre channel and subwoofer audio but the amp takes care of much of the audio processing.