E90Post
 


Alpine HID
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > AUDIO/VIDEO + BLUETOOTH + Electronics/Alarm/Software > Noticeable static/hiss in tweeters after amp install



Reply
 
Thread Tools Search this Thread
      08-17-2012, 08:28 PM   #1
ibo
Private First Class
 
Drives: '09 BSM 335xi e90 LCI M-Sport
Join Date: Jun 2009
Location: Norcal

Posts: 178
iTrader: (1)

Noticeable static/hiss in tweeters after amp install

Hey all, I could def. use some help here. Searched but nothing helps so far. I recently upgraded to VP's HIFI upgrade. Upon concluding the install, I noticed a subtle but noticeable hiss (white noise?) coming from the tweeters. The level of hiss does not increase with volume.

Here are the steps I took to troubleshoot the issue.

1. Change ground location from rear fender well to battery/chassis ground behind the rear bumper plastic trim.

- No change.

2. Adjust gain on amp (first tried ARC mini and then tried JL XD600/6).

- Hiss increases and decreases with gain adjustment but even at minimum gain, the hiss is still noticeable.

3. Unplug RCA plugs.

- Hiss is gone.

4. Plug in ipod with RCA adapter.

- Hiss is not present, bliss.

5. Changed the ARC mini back to stock HIFI amp.

- Hiss is gone. I have to point out that even before the upgrade, I could hear a very VERY quiet hiss through stock amp/tweeter if I put my ear one inch from the tweeter. I've always just thought that this was normal. With new speakers and stock amp, the same QUIET QUIET hiss is there, which is significantly more quiet than the new ARC mini.


At this point, I've troubleshooted with VP plenty of times via phone and he graciously sent me a JL XD600/6 with new harness to test with.

6. Replaced amp with new JL XD600/6.

- Same hiss as with the ARC mini amp.

At this point I'm kind of stumped. I can use any help or suggestions that yall may supply. I'm starting to wonder if my head unit is crazy noisy and I've read somewhere online about audio vs chassis ground which confused me quite a bit. Any pointers will be appreciated. Thanks guys!
__________________
COBB Stage 1+ | Alpina B3 TCU Flash | ER Intercooler & Charge Pipe | Injen CAI | KW V3 | Apex EC-7 | Michelin PSS | OEM Performance Grills and Diffuser | LUX H8 | Luminics Krypton JDM Yellow | LLumar 35% Tint
ibo is offline  
0
Reply With Quote
      08-17-2012, 10:21 PM   #2
kmarei
Major General
 
kmarei's Avatar
 
Drives: 1988 E30 M3 Evo II
Join Date: Jul 2008
Location: Reston, VA

Posts: 6,469
iTrader: (32)

Garage List
Did you try another RCA cable?
Ideally a good quality one
__________________
This user has been banned from the 4 series forum because he doesn't sing its merits like the admins want us all to

kmarei is offline   Egypt
0
Reply With Quote
      08-17-2012, 10:37 PM   #3
ibo
Private First Class
 
Drives: '09 BSM 335xi e90 LCI M-Sport
Join Date: Jun 2009
Location: Norcal

Posts: 178
iTrader: (1)

Quote:
Originally Posted by kmarei View Post
Did you try another RCA cable?
Ideally a good quality one
Well, I've tried 2 different Technic harnesses from VP. Unfortunately both harnesses have the exact same issue. If so many people are using Technic's harness with no issues, I'm fairly sure that shouldn't be the culprit, especially not on two different harnesses.
__________________
COBB Stage 1+ | Alpina B3 TCU Flash | ER Intercooler & Charge Pipe | Injen CAI | KW V3 | Apex EC-7 | Michelin PSS | OEM Performance Grills and Diffuser | LUX H8 | Luminics Krypton JDM Yellow | LLumar 35% Tint

Last edited by ibo; 08-17-2012 at 10:47 PM.
ibo is offline  
0
Reply With Quote
      08-17-2012, 11:00 PM   #4
kmarei
Major General
 
kmarei's Avatar
 
Drives: 1988 E30 M3 Evo II
Join Date: Jul 2008
Location: Reston, VA

Posts: 6,469
iTrader: (32)

Garage List
Quote:
Originally Posted by ibo View Post
Well, I've tried 2 different Technic harnesses from VP. Unfortunately both harnesses have the exact same issue. If so many people are using Technic's harness with no issues, I'm fairly sure that shouldn't be the culprit, especially not on two different harnesses.
But technics harness has female RCAs
I mean the male RCA cable that fits into those, that goes to the amp(s)
__________________
This user has been banned from the 4 series forum because he doesn't sing its merits like the admins want us all to

kmarei is offline   Egypt
0
Reply With Quote
      08-17-2012, 11:20 PM   #5
ibo
Private First Class
 
Drives: '09 BSM 335xi e90 LCI M-Sport
Join Date: Jun 2009
Location: Norcal

Posts: 178
iTrader: (1)

Quote:
Originally Posted by kmarei View Post
But technics harness has female RCAs
I mean the male RCA cable that fits into those, that goes to the amp(s)
Thanks for clarifying this! I read in several places about the female RCA's, but the ones I received from VP are both male. I figured perhaps the newer harnesses have male ends, but now that you point this out, I suppose Ken may have cut the female heads and soldered the males on himself.

However, the current harnesses in my possession have a total length of RCA cable from the harness attachment point to the end of the RCA plugs that is only about 6-7 inches or so. I'm not sure how such a short run of cable can induce so much hiss.
__________________
COBB Stage 1+ | Alpina B3 TCU Flash | ER Intercooler & Charge Pipe | Injen CAI | KW V3 | Apex EC-7 | Michelin PSS | OEM Performance Grills and Diffuser | LUX H8 | Luminics Krypton JDM Yellow | LLumar 35% Tint

Last edited by ibo; 08-17-2012 at 11:36 PM.
ibo is offline  
0
Reply With Quote
      08-18-2012, 12:24 AM   #6
VP Electricity
BimmerPost Supporting Vendor

 
VP Electricity's Avatar
 
Drives: E91 XDrive
Join Date: Jan 2008
Location: portland oregon

Posts: 3,176
iTrader: (3)

Sigh. Technic changed the harness in the last production run to male RCA. I thought they were getting a little longer but no such luck.

The stock amp is relatively flat from around 3K to 20K, so it *ought* to play any hiss present without attenuation:



But you also pulled the foam out from in front of the tweeters, yes? The stock tweeters would have louder hiss now as well, wouldn't they?

Did you say on the phone that one side was louder than the other? If you swap the RCA, does it move?

I'm worried that it's the HU too. Have not run into this before...
VP Electricity is offline   United_States
0
Reply With Quote
      08-18-2012, 12:38 AM   #7
ibo
Private First Class
 
Drives: '09 BSM 335xi e90 LCI M-Sport
Join Date: Jun 2009
Location: Norcal

Posts: 178
iTrader: (1)

Quote:
Originally Posted by VP Electricity View Post
But you also pulled the foam out from in front of the tweeters, yes? The stock tweeters would have louder hiss now as well, wouldn't they?
I didn't pull out any foam in front of the tweeters. Was I suppose to? I just removed the backing foam, removed the stock tweeter, installed the new tweeter, and then replaced the backing foam.

Quote:
Originally Posted by VP Electricity View Post
Did you say on the phone that one side was louder than the other? If you swap the RCA, does it move?
Nope, I didn't say that one side was louder than the other. I just mentioned that without rear speakers for fill, I find myself panning the audio a little to the right side to balance the perception of left and right volume when sitting in the driver's seat (left side speakers are closer to the driver, thus seem louder). If I moved my head to in between the driver and the passenger seat, I wouldn't have to pan the audio.

Quote:
Originally Posted by VP Electricity View Post
I'm worried that it's the HU too. Have not run into this before...
I really hope it isn't, but if it is indeed the front head unit wouldn't the new tweeters hiss with the OEM amp as well?
__________________
COBB Stage 1+ | Alpina B3 TCU Flash | ER Intercooler & Charge Pipe | Injen CAI | KW V3 | Apex EC-7 | Michelin PSS | OEM Performance Grills and Diffuser | LUX H8 | Luminics Krypton JDM Yellow | LLumar 35% Tint

Last edited by ibo; 08-18-2012 at 12:50 AM.
ibo is offline  
0
Reply With Quote
      08-18-2012, 12:54 AM   #8
VP Electricity
BimmerPost Supporting Vendor

 
VP Electricity's Avatar
 
Drives: E91 XDrive
Join Date: Jan 2008
Location: portland oregon

Posts: 3,176
iTrader: (3)

Taking the foam sheet out can help with detail.

Just installed this exact system twice this week, but with Morel Dotechs instead of Virtus (from the last batch they had). No hiss.

The iPod into the amp(s) sounds fine, so it's not the Virtus tweeter or crossover set up wrong.

Any difference from different sources?
VP Electricity is offline   United_States
0
Reply With Quote
      08-18-2012, 01:06 AM   #9
ibo
Private First Class
 
Drives: '09 BSM 335xi e90 LCI M-Sport
Join Date: Jun 2009
Location: Norcal

Posts: 178
iTrader: (1)

Quote:
Originally Posted by VP Electricity View Post
Taking the foam sheet out can help with detail.

Just installed this exact system twice this week, but with Morel Dotechs instead of Virtus (from the last batch they had). No hiss.

The iPod into the amp(s) sounds fine, so it's not the Virtus tweeter or crossover set up wrong.

Any difference from different sources?
No difference. I specifically tested all the sources possible (CIC hard drive, radio, ipod, DVD) with the volume all the way down to 0 or just muted. The same hiss is present.
__________________
COBB Stage 1+ | Alpina B3 TCU Flash | ER Intercooler & Charge Pipe | Injen CAI | KW V3 | Apex EC-7 | Michelin PSS | OEM Performance Grills and Diffuser | LUX H8 | Luminics Krypton JDM Yellow | LLumar 35% Tint
ibo is offline  
0
Reply With Quote
      08-18-2012, 02:10 AM   #10
udm328i
Private First Class
 
udm328i's Avatar
 
Drives: '08 328i coupe SprklnGraphite
Join Date: Jun 2009
Location: Bronx, USA

Posts: 174
iTrader: (3)

Garage List
2008 BMW 328i  [4.50]
sorry about your hiss, and sorry about this
but how do I tighten this speaker directly next to side view mirror, it seems a little loose
Attached Images
 
__________________
ZSP/ZPP/BMW PE/ BMW CF STRUT BRACE/ EIBACH PRO STREET S COIL-OVERS / H&R WHEEL SPACERS/ M3 SPOILER

Last edited by udm328i; 08-18-2012 at 04:06 PM.
udm328i is offline   No_Country
0
Reply With Quote
      08-18-2012, 08:44 AM   #11
dmatre
Second Lieutenant
 
Drives: 2011 328i Sedan
Join Date: Apr 2011
Location: Charlotte, NC

Posts: 284
iTrader: (0)

I've noticed that my system also has a VERY SLIGHT amount of tweeter hiss when the car is powered on.

BUT ... with the car running, there's enough ambient noise that the hiss is undetectable, so I don't feel that it's a problem at all (for me). I can't hear the hiss if idling in the garage, so you can bet that on the road it's a non-issue as well.

On my system, the hiss is definitely proportional to the gain, but I've got the gains rather low, so that resolves that issue. (The system will still get uncomfortably loud with the gains set low)

Is your hiss bad enough to hear it if the car's running? Or are you checking it with the car powered up but not running?
dmatre is online now   United_States
0
Reply With Quote
      08-18-2012, 09:08 AM   #12
Technic
Lieutenant General
 
Technic's Avatar
 
Drives: 2012 E92 M3, 2014 528i
Join Date: Apr 2005
Location: Ft Lauderdale, Florida

Posts: 10,776
iTrader: (16)

Garage List
2004 M3  [0.00]
Quote:
Originally Posted by ibo View Post
Thanks for clarifying this! I read in several places about the female RCA's, but the ones I received from VP are both male. I figured perhaps the newer harnesses have male ends, but now that you point this out, I suppose Ken may have cut the female heads and soldered the males on himself.

However, the current harnesses in my possession have a total length of RCA cable from the harness attachment point to the end of the RCA plugs that is only about 6-7 inches or so. I'm not sure how such a short run of cable can induce so much hiss.
The last version of the HiFi harness has male ends as it is now dedicated to XD600/6 installs in the OEM amp location due to most customer requests.



If according to you there was a "QUIET, QUIET" hiss when the OEM amp was plugged in then you will have an increase of such hiss when a more powerful aftermarket amp is plugged in if the chassis ground is used. That is what you are having now, apparently.

My suggestion is to remove the OEM HU, unplug the Quadralock in the back, and take a close look at pin 12 (ground). Make sure that the radio pins and the Quadralock pins are having a solid contact without any wiggling.
__________________
-2015 F30 320i, Imperial/Oyster, 8AT: August 2014 ED
-2012 E92 M3 Jerez Black/Rust Brown, M-DCT: September 2011 ED
-2008 E90 M3 Melbourne Red/Bamboo, 6MT: Gone
-2007 MK5 GTI United Grey/Grey, DSG: Gone
-2004 E46 M3 Carbon Black/Cinnamon, 6MT: Gone
Technic is offline   United_States
0
Reply With Quote
      08-18-2012, 11:00 AM   #13
JohanW
New Member
 
Drives: E91 2006
Join Date: Jun 2012
Location: Sweden

Posts: 28
iTrader: (0)

Quote:
Originally Posted by dmatre View Post
I've noticed that my system also has a VERY SLIGHT amount of tweeter hiss when the car is powered on.

BUT ... with the car running, there's enough ambient noise that the hiss is undetectable, so I don't feel that it's a problem at all (for me). I can't hear the hiss if idling in the garage, so you can bet that on the road it's a non-issue as well.

On my system, the hiss is definitely proportional to the gain, but I've got the gains rather low, so that resolves that issue. (The system will still get uncomfortably loud with the gains set low)

Is your hiss bad enough to hear it if the car's running? Or are you checking it with the car powered up but not running?
I have the same problem as you. Not noticeable when the engine is running and proportional to the amp gain. Increasing the volume of the head unit doesn't increase to volume of the noise except when the HU volume is very near its max.

If the volume of the HU is zero there will be no noise at all but it's enough to increase the volume one click for the noise to appear.

No noise if a smart phone is connected directly to the amp.

I have the relay from technics harness very close to my rca-cables. Could the relay cause any interference?
JohanW is offline  
0
Reply With Quote
      08-18-2012, 11:03 AM   #14
ibo
Private First Class
 
Drives: '09 BSM 335xi e90 LCI M-Sport
Join Date: Jun 2009
Location: Norcal

Posts: 178
iTrader: (1)

Quote:
Originally Posted by dmatre View Post
Is your hiss bad enough to hear it if the car's running? Or are you checking it with the car powered up but not running?
I'm doing the latter, which makes any sort of hiss much more apparent. Like you said, when the car is running, with engine and road noise, the hissing pretty much gets drowned out. But with the ignition off, it's a slap in the face


Quote:
Originally Posted by Technic View Post
If according to you there was a "QUIET, QUIET" hiss when the OEM amp was plugged in then you will have an increase of such hiss when a more powerful aftermarket amp is plugged in if the chassis ground is used. That is what you are having now, apparently.

My suggestion is to remove the OEM HU, unplug the Quadralock in the back, and take a close look at pin 12 (ground). Make sure that the radio pins and the Quadralock pins are having a solid contact without any wiggling.
Thanks for chiming in. I was worried I'd have to remove the HU. Sigh...I guess I'll have to tackle that when I have the time, just to be completely sure. How hard is this to do?
__________________
COBB Stage 1+ | Alpina B3 TCU Flash | ER Intercooler & Charge Pipe | Injen CAI | KW V3 | Apex EC-7 | Michelin PSS | OEM Performance Grills and Diffuser | LUX H8 | Luminics Krypton JDM Yellow | LLumar 35% Tint
ibo is offline  
0
Reply With Quote
      08-18-2012, 03:40 PM   #15
ibo
Private First Class
 
Drives: '09 BSM 335xi e90 LCI M-Sport
Join Date: Jun 2009
Location: Norcal

Posts: 178
iTrader: (1)

Does anyone know where the HIFI head unit is grounded? I know of two audio ground points, one on the rear of the driver rear fender well and one on the front of the same fender well.
__________________
COBB Stage 1+ | Alpina B3 TCU Flash | ER Intercooler & Charge Pipe | Injen CAI | KW V3 | Apex EC-7 | Michelin PSS | OEM Performance Grills and Diffuser | LUX H8 | Luminics Krypton JDM Yellow | LLumar 35% Tint
ibo is offline  
0
Reply With Quote
      08-18-2012, 05:53 PM   #16
taibanl
Brigadier General
 
taibanl's Avatar
 
Drives: 2011 335d
Join Date: Sep 2010
Location: Syracuse

Posts: 3,289
iTrader: (4)

Garage List
2011 335d  [0.00]
Quote:
Originally Posted by ibo View Post
Does anyone know where the HIFI head unit is grounded? I know of two audio ground points, one on the rear of the driver rear fender well and one on the front of the same fender well.
I have a base HU that is grounded back at the fenderwell so I suspect HiFi is also grounded there. Do you have a brown cable that says audio running from the front of the car to the fwd part of the fenderwell ground point?
taibanl is offline  
0
Reply With Quote
      08-18-2012, 07:13 PM   #17
JohanW
New Member
 
Drives: E91 2006
Join Date: Jun 2012
Location: Sweden

Posts: 28
iTrader: (0)

If the noise are present over the complete frequency band it doesn't sound like a ground loop problem (correct me if I'm wrong).
If you have a grounding problem it's very common that the pitch change with the engine rpm.

There are several threads about the same issue but I haven't read one with a solution.

I don't know if spectrum analyzer for a smart phone could be used to find out the fourier transform of the noise.
I think I will try that to know if it's white noise.
JohanW is offline  
0
Reply With Quote
      08-20-2012, 12:22 AM   #18
ibo
Private First Class
 
Drives: '09 BSM 335xi e90 LCI M-Sport
Join Date: Jun 2009
Location: Norcal

Posts: 178
iTrader: (1)

Quote:
Originally Posted by JohanW View Post
I have the relay from technics harness very close to my rca-cables. Could the relay cause any interference?
Just FYI, I tested both harnesses in my possession, one with the relay and one without. While the relay itself produces a single "click" sound when the remote signal is sent from the head unit (expected, as it is a relay), I did not hear any interference caused by it's inclusion nor proximity from the RCA's.
__________________
COBB Stage 1+ | Alpina B3 TCU Flash | ER Intercooler & Charge Pipe | Injen CAI | KW V3 | Apex EC-7 | Michelin PSS | OEM Performance Grills and Diffuser | LUX H8 | Luminics Krypton JDM Yellow | LLumar 35% Tint
ibo is offline  
0
Reply With Quote
      10-01-2012, 12:08 AM   #19
balu4k
New Member
 
Drives: 2009 328 XI Coupe
Join Date: Sep 2012
Location: United States

Posts: 8
iTrader: (0)

Hi, Any solutions to this hissing problem. I have the same exact problem after the JL xd600/6 install, i hear the noticeably hiss from my mids even when the HU is off ( ignition on ) or even when HU is playing CD at volume zero. I don't hear the Hiss if i disconnect the RCA's. Mine is HIFI system on E92 2009 model. I even hear the hiss even after lowering the input gain, but the hiss sound is little less but still noticeable.
balu4k is offline  
0
Reply With Quote
      10-01-2012, 01:08 AM   #20
ctuna
Brigadier General
 
Drives: 325xi 06 wagon MT
Join Date: Jan 2010
Location: Santa Cruz, Ca

Posts: 3,982
iTrader: (0)

No hiss on my JL its grounded on the battery.

No hiss on my JL its grounded on the battery.
04 wire all the way to the battery lugs . Theoretically
it shouldn't make a difference as long as you have a low resistance
ground but my kit came that way(equal length power and ground) and it works. I didn't here anything when I was running the stock speakers alone
on it either. Gains are not set high on the Morels and are zero on the rear stock speakers.
ctuna is offline  
0
Reply With Quote
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 06:55 AM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST