Aftermarket stereo hiss and poor FM reception

RT2012z · 04-25-2015, 07:01 AM

Two days ago I replaced my factory BOSE system in my 370Z with a Kenwood DNX691HD. Two problems now.........one is a constant hiss as soon as the unit is powered up, not engine whine but a hiss as soon as the unit is powered up with no volume on the stereo.

Problem #2 is that I now have poor reception with my FM tuner. There were zero issues with the factory BOSE system that I pulled out so I know its something to do with the Kenwood install.

I live about 45 minutes out of Detroit and reception is terrible for local stations, with some not even able to be received on a channel scan, but gets better the closer I drive to the city. I was in downtown Detroit yesterday and reception was 100% for every station I tuned however when I left I noticed the reception get progressively worse the further away I drove. I have a similar Kenwood deck in my other vehicle with neither of these issues and my uneducated guess is that its something to do with the BOSE amps and speakers.

Can anyone offer any remedies to these problems? Any help would be appreciated, thanks.

RonRizz · 04-25-2015, 07:42 AM

hiss may be due to mis-matched output level of head unit to input of amp.
check your settings on your converter. radio reception issue......did you connect 12 volt switched to your antenna adapter??

RT2012z · 04-26-2015, 09:46 AM

Quote:

Originally Posted by RonRizz

hiss may be due to mis-matched output level of head unit to input of amp.
check your settings on your converter. radio reception issue......did you connect 12 volt switched to your antenna adapter??

Not sure, I'm bringing it back to the installer tomorrow and he's going to troubleshoot. When I ran the grounding issue by him he advised that there was a ground wire tagged 'for Subaru only' so he didn't ground it. He wasn't sure whether or not he should actually ground it because of the warning tag.

RonRizz · 04-26-2015, 12:41 PM

Not a ground issue, its a power issue... The antenna adapter needs a switched 12v positive to turn on the antenna booster. That's typically the source of reception troubles 'round these parts! lol

RT2012z · 05-04-2015, 06:59 AM

Thanks for the 411. I have a different booster and harness with RCA outs on order, when they come in and the car goes back to the installer I will pass along your info.

SouthArk370Z · 05-04-2015, 09:04 AM

The hiss may be caused by having the gain on the preamp and/or amp set too high.

The reception problem could be caused by a bad wire from the antenna to the head unit. Or the Kenwood tuner is less sensitive than the Bose. There may be a setting in the Kenwood to adjust sensitivity - sometimes labeled Local/Distance (Loc/DX).

Overlimit · 10-24-2016, 02:59 PM

I am also experiencing this issue. My Headunit is a Kenwood DDX9903s.

Bump

bigaudiofanat · 10-28-2016, 09:19 AM

Quote:

Originally Posted by Overlimit

I am also experiencing this issue. My Headunit is a Kenwood DDX9903s.

Bump

Do you have an amp between your speakers and your head unit?

turtle64b · 04-19-2020, 01:32 PM

Any resolution on this?!

I bought a 2011 Z with a Kenwood aftermarket head unit already installed. I lived near Seattle after I bought the car, so I received enough radio stations to fill the 6 presets on the radio. I have recently moved to small-town Texas and that has changed.

I get one radio station nearly perfectly. All others, yes, all others, are either static or do not come in clear enough to discern anything. My wife's car gets maybe 30 stations clearly.

I think that it may be the FM booster? but I am neither certain on how to confirm this, nor do I know how I could resolve it.

turtle64b · 04-29-2020, 01:16 PM

Bump

bigaudiofanat · 04-29-2020, 05:21 PM

Quote:

Originally Posted by turtle64b

Any resolution on this?!

I bought a 2011 Z with a Kenwood aftermarket head unit already installed. I lived near Seattle after I bought the car, so I received enough radio stations to fill the 6 presets on the radio. I have recently moved to small-town Texas and that has changed.

I get one radio station nearly perfectly. All others, yes, all others, are either static or do not come in clear enough to discern anything. My wife's car gets maybe 30 stations clearly.

I think that it may be the FM booster? but I am neither certain on how to confirm this, nor do I know how I could resolve it.

That to me doesn't sound like you need a FM booster of any sort. It sounds like the FM antenna adapter behind your radio isn't wired correctly. There is a blue wire coming off that adapter. That should be going to REM or Amp turn on of the aftermarket head unit. Some aftermarket head units have a dedicated blue wire for powered antenna.

turtle64b · 05-09-2020, 09:35 AM

Quote:

Originally Posted by bigaudiofanat

That to me doesn't sound like you need a FM booster of any sort. It sounds like the FM antenna adapter behind your radio isn't wired correctly. There is a blue wire coming off that adapter. That should be going to REM or Amp turn on of the aftermarket head unit. Some aftermarket head units have a dedicated blue wire for powered antenna.

Thanks for the advice! I did check that the blue wire on the antenna adapter was connected to the remote turn on from the aftermarket head unit.

04-25-2015, 07:01 AM	#1 (permalink)
RT2012z Base Member Join Date: Oct 2014 Location: Canada Posts: 33 Drives: 2012 370z MT Rep Power: 10	Aftermarket stereo hiss and poor FM reception Two days ago I replaced my factory BOSE system in my 370Z with a Kenwood DNX691HD. Two problems now.........one is a constant hiss as soon as the unit is powered up, not engine whine but a hiss as soon as the unit is powered up with no volume on the stereo. Problem #2 is that I now have poor reception with my FM tuner. There were zero issues with the factory BOSE system that I pulled out so I know its something to do with the Kenwood install. I live about 45 minutes out of Detroit and reception is terrible for local stations, with some not even able to be received on a channel scan, but gets better the closer I drive to the city. I was in downtown Detroit yesterday and reception was 100% for every station I tuned however when I left I noticed the reception get progressively worse the further away I drove. I have a similar Kenwood deck in my other vehicle with neither of these issues and my uneducated guess is that its something to do with the BOSE amps and speakers. Can anyone offer any remedies to these problems? Any help would be appreciated, thanks. Last edited by RT2012z; 04-25-2015 at 07:26 AM.

04-25-2015, 07:42 AM	#2 (permalink)
RonRizz A True Z Fanatic Join Date: Aug 2011 Location: Pine grove, Pa Posts: 2,132 Drives: 2 feet, 3 pedals Rep Power: 6774	hiss may be due to mis-matched output level of head unit to input of amp. check your settings on your converter. radio reception issue......did you connect 12 volt switched to your antenna adapter?? __________________ P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

04-26-2015, 12:41 PM	#4 (permalink)
RonRizz A True Z Fanatic Join Date: Aug 2011 Location: Pine grove, Pa Posts: 2,132 Drives: 2 feet, 3 pedals Rep Power: 6774	Not a ground issue, its a power issue... The antenna adapter needs a switched 12v positive to turn on the antenna booster. That's typically the source of reception troubles 'round these parts! lol bigaudiofanat, axmea? and Ghostvette like this. __________________ P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

05-04-2015, 09:04 AM	#6 (permalink)
SouthArk370Z Premium Member Join Date: Nov 2010 Location: South Arkansas Posts: 8,435 Drives: 2014 Challenger Rep Power: 324197	The hiss may be caused by having the gain on the preamp and/or amp set too high. The reception problem could be caused by a bad wire from the antenna to the head unit. Or the Kenwood tuner is less sensitive than the Bose. There may be a setting in the Kenwood to adjust sensitivity - sometimes labeled Local/Distance (Loc/DX). __________________ Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

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05-04-2015, 06:59 AM	#5 (permalink)
RT2012z Base Member Join Date: Oct 2014 Location: Canada Posts: 33 Drives: 2012 370z MT Rep Power: 10	Thanks for the 411. I have a different booster and harness with RCA outs on order, when they come in and the car goes back to the installer I will pass along your info.

10-24-2016, 02:59 PM	#7 (permalink)
Overlimit Base Member Join Date: Jun 2010 Location: 951 Posts: 151 Drives: F80 M3 Rep Power: 32	I am also experiencing this issue. My Headunit is a Kenwood DDX9903s. Bump

04-19-2020, 01:32 PM	#9 (permalink)
turtle64b Track Member Join Date: Jun 2015 Location: Granbury, TX Posts: 550 Drives: '11 SC Blue 7AT Rep Power: 3365	Any resolution on this?! I bought a 2011 Z with a Kenwood aftermarket head unit already installed. I lived near Seattle after I bought the car, so I received enough radio stations to fill the 6 presets on the radio. I have recently moved to small-town Texas and that has changed. I get one radio station nearly perfectly. All others, yes, all others, are either static or do not come in clear enough to discern anything. My wife's car gets maybe 30 stations clearly. I think that it may be the FM booster? but I am neither certain on how to confirm this, nor do I know how I could resolve it.

04-29-2020, 01:16 PM	#10 (permalink)
turtle64b Track Member Join Date: Jun 2015 Location: Granbury, TX Posts: 550 Drives: '11 SC Blue 7AT Rep Power: 3365	Bump