head unit hiss (sync3)

[Emilbadal]

Yes, I tried the forscan method, but it didn’t do anything(I still get the error for missing that digital module c missing error). Can you confirm the forscan code to disable the engine noise enhancement?

Did you try a Mustang GT head unit (ACM) that does not have the engine noise module? Or use Forscan to turn off the signal coming out of the head unit?

I talked to a guy who makes custom harnesses and has been making sound systems for Mustangs for years. Hextall said there should not be static coming from the head unit if it has been configured correctly. He said the ACM is actually quite good and just needs to be setup correctly to turn off the Ford OEM engine noise and EQ.

https://www.harnessbyhextall.com

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[NotMarc]

I don't think the balanced or unbalanced theory is very accurate, my amplifier is capable of receiving high output/ speaker level signal and low level as well, but yet the hiss is there either with low level or high level signal, and also there has been way too many people with all kinds of processors and line output converters and Amp DSPs who all have the issue at different levels. So basically what I'm trying to say is that the ACMs are trash and there's no other way than adjusting the gain levels to balance the noise and signal ( I just got so frustrated that I set my amp gains to minimum and left it there). I have 2 ACMs, one from factory and one when I upgraded to Sync3 with HD Radio and SAT radio and both have exactly same issue. As I have mentioned before somewhere here, I tried even grounding the ACM to chassis and Battery even to no avail. Just be patient and lower your expectations(I know it's sad!)

Just to be clear my system is unlistenable with the DSP connected. I'm going to try to set my amp gains/dsp input and output levels to at least get some signal through. As it stands, a 1k test tone has the DD1+ showing 0.0 volts, 1k tone acknowledgement, and the distortion light on at all times. This was with the Head Unit volume at 30 (because it doesn't clip post forscan). I measured the Head Unit output at I believe it was a clean 3.4 volts which is above the Daytons ~3.2 volt max. I'm going to turn down the Head unit (maybe to volume 25?), lower my amp gains to 0 and then try to work my way up.

 

[NotMarc]

Did you try a Mustang GT head unit (ACM) that does not have the engine noise module? Or use Forscan to turn off the signal coming out of the head unit?

I talked to a guy who makes custom harnesses and has been making sound systems for Mustangs for years. Hextall said there should not be static coming from the head unit if it has been configured correctly. He said the ACM is actually quite good and just needs to be setup correctly to turn off the Ford OEM engine noise and EQ.

https://www.harnessbyhextall.com

Have you spoken with them recently?

 

[19-kilo]

Have you spoken with them recently?

yesterday, 23APR2020. Yes.

 

[Emilbadal]

I just wanted to share my recent finding in regard of the system hissing issue. As I mentioned before, I set my amplifier’s gain(input sensitivity) to minimum to minimize the hiss coming from my speakers. The hissing was barely noticeable, but the music volume was also low. Today, I decided to try changing the ACM’s output from low level to speaker level in(keep in mind, my amp is capable of receiving high level input as well as low level). And long and behold, the music volume is back to normal without the hissing get louder! This is by far the best result I’ve gotten from the factory ACM and I think I can finally settle and be happy with it.

Disclaimer: Please make sure that your aftermarket Amp or DSP is capable of speaker level inputs. I’m not responsible for any damage that you might do to your equipment or vehicle following my post. Make sure your equipments are compatible and make educated decisions.

I hope this helps

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