FGX 40T Donating Members 142 Member For: 14y 7m 4d Gender: Male Location: WA - South of the River Posted 17/09/10 07:14 AM Share Posted 17/09/10 07:14 AM Hi I hoping someone can help. Just got a stereo upgrade - Alpine SPR-17S Component speakers(front doors and pillars for tweeters), Alpine SPR-17C Coaxial(rear doors)running through Alpine MRP-F600 Amp. I am getting a very annoying hiss from all speakers. The installer tells me it is from the factory unit and the hiss is simply being amplified and now more audible due to better speakers. It was installed using the high level inputs as this is what was recommended. After I took the vehicle back they tried using line level converters to RCA but still no difference. They did all the usual checks, earth length and connection - but still no good. In the end they turned the gain down on the amp. This helped a little with the hiss, but now the system is not as powerful. Very unhappy. I would prefer not to install another head unit as I wish to retain the factory appearance and functionality. Any advice would be appreciated. Link to comment Share on other sites More sharing options...
Dillz Three pedals are better then two.. Donating Members 15,637 Member For: 17y 5m 15d Gender: Male Location: Melbourne Posted 17/09/10 07:23 AM Share Posted 17/09/10 07:23 AM Does it get louder in line with the revs? Link to comment Share on other sites More sharing options...
bossmang FREAKY Donating Members 12,419 Member For: 14y 10m 15d Gender: Male Location: Melbourne Posted 17/09/10 08:09 AM Share Posted 17/09/10 08:09 AM is it alternator whine? as dillz mentioned going up n down with revs?could be a crappy grounding in the system somewherethere are a number of possible factors causing it, speaker wires/rca's too close to power cables, is everything grounded to the same point? etc etc Link to comment Share on other sites More sharing options...
FGX 40T Donating Members 142 Member For: 14y 7m 4d Gender: Male Location: WA - South of the River Posted 18/09/10 02:52 AM Author Share Posted 18/09/10 02:52 AM Thanks - The hiss remains constant - does not change with revs. According to the installer, it is a common earth - but I will check this and the location/length and quality of cable. I am going to try and get them to hook up an aftermarket head unit to test the integrity of their install. If the hiss goes, then I can assume they may be right and it is from the factory unit, if the hiss remains than it must be the install. Any other ideas? Link to comment Share on other sites More sharing options...
KeepLeft Member 240 Member For: 15y 4m 8d Gender: Male Posted 19/09/10 08:29 AM Share Posted 19/09/10 08:29 AM There is definitely a hiss the standard "premium" head unit. If that's what you're using for the input then I'm betting that's what it is. I'm waiting for someone to do the BA/BF RCA pre-out mod for the FG unit before doing any stereo mods to my car. Link to comment Share on other sites More sharing options...
hawlass Silver Donating Members 1,161 Member For: 17y 1d Gender: Male Location: left right out Posted 19/09/10 08:46 AM Share Posted 19/09/10 08:46 AM Was told by my auto sparkie most of our cars dont have enough earthing by a long shot. Easy answer is to fit a off the shelf earth strap between the engine and chassis, apparently solves a lot of common probs, and is a cheap easy first try I reckon.I had alternator whine on the ba, turned out to be a bad earth. Link to comment Share on other sites More sharing options...
FGX 40T Donating Members 142 Member For: 14y 7m 4d Gender: Male Location: WA - South of the River Posted 20/09/10 03:18 AM Author Share Posted 20/09/10 03:18 AM Unfortunately I do not even have the Factory premium - I have the standard Ford sound system (poverty pack) - Demo vehicle no choice. The Earth lead is the same size and quality as power lead and bolted to the chassis close to the amp. I will definitely get another Earth lead attached as suggested and let you know if this works/helps. However what do you mean re: the RCA pre-out mod for FG's. I know nothing about this can you elaborate for me please. Also when I spoke to the installer about patching in a headunit to test they said it was a lot of work and then made the following offer. They said they would will fit a new head unit, rewiring using RCA inputs (only charge for the headunit) and guarantee it will stop the hiss. If it does not, they will remove it (the head unit) and not charge me for it. I would really like to retain the factory system but it seems the only way to get rid of the hiss is with an aftermarket head unit. Someone did mention (on a forum site) it may be to do with the signal output from the factory unit only supplying a very small voltage (starving the amp for signal quality) as opposed the aftermarket units that supply a much stronger signal (more voltage). Anyone know anything about that? Link to comment Share on other sites More sharing options...
SimonT Member 18 Member For: 15y 10m 14d Posted 20/09/10 09:07 AM Share Posted 20/09/10 09:07 AM (edited) It's the factory head-unit. Premium is the same (what I have). Using all awesome gear, but factory head-unit = hiss. Worse through iPod connector, but still there through CD. Installer hooked up an aftermarket headunit via RCA. An entirely different type of sound. Clean, crisp, with an awesome dynamic range. No comparison to factory headunit. But I, like you, wanted to retain the factory headunit. So for now I'm putting up with sub-par sound, with terrible hiss, (not alternator whine), until it sh*ts me enough to install another headunit in the glovebox (FPV has the stupid Start button where an aftermarket head unit would normally mount).If anyone knows of a way to fix the factory hiss, I'm all ears. I'm using a Cache line-level converter, but from what I've read, the hiss is still there even with units like the Audison Bit One.Garbage In = Garbage Out.:-(SimonUnfortunately I do not even have the Factory premium - I have the standard Ford sound system (poverty pack) - Demo vehicle no choice. The Earth lead is the same size and quality as power lead and bolted to the chassis close to the amp. I will definitely get another Earth lead attached as suggested and let you know if this works/helps. However what do you mean re: the RCA pre-out mod for FG's. I know nothing about this can you elaborate for me please. Also when I spoke to the installer about patching in a headunit to test they said it was a lot of work and then made the following offer. They said they would will fit a new head unit, rewiring using RCA inputs (only charge for the headunit) and guarantee it will stop the hiss. If it does not, they will remove it (the head unit) and not charge me for it. I would really like to retain the factory system but it seems the only way to get rid of the hiss is with an aftermarket head unit. Someone did mention (on a forum site) it may be to do with the signal output from the factory unit only supplying a very small voltage (starving the amp for signal quality) as opposed the aftermarket units that supply a much stronger signal (more voltage). Anyone know anything about that? Edited 20/09/10 09:09 AM by SimonT Link to comment Share on other sites More sharing options...
hawlass Silver Donating Members 1,161 Member For: 17y 1d Gender: Male Location: left right out Posted 20/09/10 10:11 AM Share Posted 20/09/10 10:11 AM Does asl do anything upgrade/ rca preout mods wise? Products | Ford Upgrades Link to comment Share on other sites More sharing options...
FGX 40T Donating Members 142 Member For: 14y 7m 4d Gender: Male Location: WA - South of the River Posted 21/09/10 02:35 AM Author Share Posted 21/09/10 02:35 AM Does asl do anything upgrade/ rca preout mods wise? Products | Ford Upgrades I have emailed ASL with a run down of the issue. I will post their response as soon as they reply. Link to comment Share on other sites More sharing options...
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