stereo question- whine and crossovers
06-19-2003, 03:31 AM
#1
Intermediate
Thread Starter
Join Date: May 2001
Location: Goodyear, AZ
Posts: 47
Likes: 0
Received 0 Likes
on
0 Posts
stereo question- whine and crossovers
Hello all,
Here's my situation. I hope someone can give me some good advice. I have been battling the annoying engine whining noise that can be heard thru the speakers. As the rpm's go up so does the high pitch noise. The stereo consists of MB Quart 3 way separates and reference 2 way separates and 2 8" fosgate woofers, all powered by 2 fosgate amps mounted on the back of the rear seats- and a cd changer but I don't think that matters to the situation.
Anyway, this was all installed at a highly recommended local Audio Express. I think they did a quality install and used quality wires and cables and found good grounds and everything.
The stereo had the whine before this system was installed too (the only things left from the old system is the head unit- a cheap Aiwa, and the 10 regular speakers). So I brought it back and they finally figured out that one of the MB Quart crossovers was not working right. They disconnected the line in wires and almost all the whine went away- as did sound from 3 speakers. But there was still a little whine left- not real bad and definitely a huge improvement from before, but it's there. They said the engine has a "natural whine" and that it was as good as it would get. I can handle the current level of whine but what do you guys think? Is there a situation where there will be the faint whine no matter how good the install is?
My second question is MB Quart doesn't just sell the crossover and I don't want to buy the 3 speaker set just to use the crossover it comes with. I'm not very stereo smart, but would there be anything wrong with using a different brand crossover for the one set of speakers? I see MTX ones for about $10 on ebay. Or can I just connect 2 sets of speakers to the one crossover that does work? Or, does anyone have a spare MB Quart or other crossover they want to sell?
Any advice is appreciated.
Thanks a lot!
Jay in Az
'90 S4, white/black
Here's my situation. I hope someone can give me some good advice. I have been battling the annoying engine whining noise that can be heard thru the speakers. As the rpm's go up so does the high pitch noise. The stereo consists of MB Quart 3 way separates and reference 2 way separates and 2 8" fosgate woofers, all powered by 2 fosgate amps mounted on the back of the rear seats- and a cd changer but I don't think that matters to the situation.
Anyway, this was all installed at a highly recommended local Audio Express. I think they did a quality install and used quality wires and cables and found good grounds and everything.
The stereo had the whine before this system was installed too (the only things left from the old system is the head unit- a cheap Aiwa, and the 10 regular speakers). So I brought it back and they finally figured out that one of the MB Quart crossovers was not working right. They disconnected the line in wires and almost all the whine went away- as did sound from 3 speakers. But there was still a little whine left- not real bad and definitely a huge improvement from before, but it's there. They said the engine has a "natural whine" and that it was as good as it would get. I can handle the current level of whine but what do you guys think? Is there a situation where there will be the faint whine no matter how good the install is?
My second question is MB Quart doesn't just sell the crossover and I don't want to buy the 3 speaker set just to use the crossover it comes with. I'm not very stereo smart, but would there be anything wrong with using a different brand crossover for the one set of speakers? I see MTX ones for about $10 on ebay. Or can I just connect 2 sets of speakers to the one crossover that does work? Or, does anyone have a spare MB Quart or other crossover they want to sell?
Any advice is appreciated.
Thanks a lot!
Jay in Az
'90 S4, white/black
06-19-2003, 07:15 AM
#3
Addict
Rennlist Member
Rennlist Member
Jay,
First, there is no such thing as 'natural whine'..well, maybe a girl I used to know but not in stereo's. You've got noise pickup somewhere in the system. I would imagine that you paid a pretty good price for your installation and as 'pro's, they should be able to fix it. If it ws there earlier, then it's most likely due to the head unit/wiring but again, they should know how to fix this. As John mentioned, there is a supprssor/filter under the cover. Here are some questions you can ask, things to check:
-did they leave the suppressor in the power feed to the head unit or did they change it? If they changed it, did they put in a power suppressor and where?
-did they use single point grounds for the amps/head unit? This means that the ground wire for each unit all go to one place on the chassis.
-given that one side seems to have more whine, did they:
1. switch Left and right audio inputs to the amp to see if the louder whine also switched? If it does, then the main culprit is 'upstream' of the amp...between the amp and the head unit. If not, then you need to look at the amp/speakers
2. I wouldn't think the crossovers would be the cause of this. Try switching Left and right side crossovers..if the whine doesn't switch, then it's not the crossover. Although I'm not a stereo expert, my bet would be that you've got noise getting into the system and that one channel of your amp or head unit is more susceptible (doesn't reject as well).
3. Try feeding the amps from a seperate, external source instead of a head unit. A bit of a kludge to set up but the stereo place ought to be able to try this...if the whine goes away, then it's either the head unit or noise pickup in the wires from the headunit to the amp. If it goes away, try using the existing wires to connect the external source to the amps..if it goes away it's the headunit and you can try putting additional power suppression filters on the +12 and/or checking the grounds...or replacing the headunit.
Just some thoughts...hope you get it fixed. The MB's I put in sound great and it's a shame that you can't get the full enjoyment from yours.
Jim
First, there is no such thing as 'natural whine'..well, maybe a girl I used to know but not in stereo's. You've got noise pickup somewhere in the system. I would imagine that you paid a pretty good price for your installation and as 'pro's, they should be able to fix it. If it ws there earlier, then it's most likely due to the head unit/wiring but again, they should know how to fix this. As John mentioned, there is a supprssor/filter under the cover. Here are some questions you can ask, things to check:
-did they leave the suppressor in the power feed to the head unit or did they change it? If they changed it, did they put in a power suppressor and where?
-did they use single point grounds for the amps/head unit? This means that the ground wire for each unit all go to one place on the chassis.
-given that one side seems to have more whine, did they:
1. switch Left and right audio inputs to the amp to see if the louder whine also switched? If it does, then the main culprit is 'upstream' of the amp...between the amp and the head unit. If not, then you need to look at the amp/speakers
2. I wouldn't think the crossovers would be the cause of this. Try switching Left and right side crossovers..if the whine doesn't switch, then it's not the crossover. Although I'm not a stereo expert, my bet would be that you've got noise getting into the system and that one channel of your amp or head unit is more susceptible (doesn't reject as well).
3. Try feeding the amps from a seperate, external source instead of a head unit. A bit of a kludge to set up but the stereo place ought to be able to try this...if the whine goes away, then it's either the head unit or noise pickup in the wires from the headunit to the amp. If it goes away, try using the existing wires to connect the external source to the amps..if it goes away it's the headunit and you can try putting additional power suppression filters on the +12 and/or checking the grounds...or replacing the headunit.
Just some thoughts...hope you get it fixed. The MB's I put in sound great and it's a shame that you can't get the full enjoyment from yours.
Jim
06-19-2003, 09:52 AM
#4
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Something is grounded improperly. I've had this on a couple stereo installs before. Noise suppressors work, but its a band aid on a fixable problem.
On a couple cars I ran multiple grounds for each amp and the head unit. This usually works. I'm no expert, but from what I remember that type of whine is feedback from the alternator.
I would start with just the head unit and a pair of speakers. Eliminate the whine there and start adding components. If the whine is in the head unit, the amps are only going to make it worse by amplifying the whine.
I agree with Jim, a good shop should have no problem figuring this out. It can be a pain and lot of people don't notice. I've had friends with terrible noise like yours and they never noticed it.
If you decide to go with the noise suppressor route, find one that plugs into the RCA/Phono jacks that go to the amp as well as a line filter for the power source for the head unit.
Good Luck.
On a couple cars I ran multiple grounds for each amp and the head unit. This usually works. I'm no expert, but from what I remember that type of whine is feedback from the alternator.
I would start with just the head unit and a pair of speakers. Eliminate the whine there and start adding components. If the whine is in the head unit, the amps are only going to make it worse by amplifying the whine.
I agree with Jim, a good shop should have no problem figuring this out. It can be a pain and lot of people don't notice. I've had friends with terrible noise like yours and they never noticed it.
If you decide to go with the noise suppressor route, find one that plugs into the RCA/Phono jacks that go to the amp as well as a line filter for the power source for the head unit.
Good Luck.
06-19-2003, 10:17 AM
#6
Racer
Join Date: May 2002
Location: Hackberry AZ
Posts: 336
Likes: 0
Received 0 Likes
on
0 Posts
Jay Msot units wheaher amps. headunits. or powered crossovers have ground supressors built in. When they go out and they do. Ithe induce some ugly whine into a system. It only takes one unit to go bad and the whole system will whine.
I use a walkman as a test unit when looking for whine like yours. I will plug it into the amp whit the car running and play it If no whine then move up the line. Plug it in at the rca behind your deck. No whine? then you more then likely have a bad deck or a ground problem there.
I cant count the times I have had new rca whine on me. Either bad out of the box or ran just to close to a power source like the computers in are cars. If those rca's are within 9 inches of those they may whine like a dog with a yard dart in its *&**. Hope that helps or gives you some amo to take to the installers.
Thurston.
85 Iris Blue Auto 928
I use a walkman as a test unit when looking for whine like yours. I will plug it into the amp whit the car running and play it If no whine then move up the line. Plug it in at the rca behind your deck. No whine? then you more then likely have a bad deck or a ground problem there.
I cant count the times I have had new rca whine on me. Either bad out of the box or ran just to close to a power source like the computers in are cars. If those rca's are within 9 inches of those they may whine like a dog with a yard dart in its *&**. Hope that helps or gives you some amo to take to the installers.
Thurston.
85 Iris Blue Auto 928
06-19-2003, 10:22 AM
#7
Addict
Rennlist Member
Rennlist Member
Thurston,
good points and the Walkman would make an excellent source..have to remember that. Jay's crossovers are all passive so it's unlikely that those are the source of his problems.
Jim
good points and the Walkman would make an excellent source..have to remember that. Jay's crossovers are all passive so it's unlikely that those are the source of his problems.
Jim
Trending Topics
06-19-2003, 12:40 PM
#9
Addict
Rennlist Member
Rennlist
Site Sponsor
Rennlist Member
Rennlist
Site Sponsor
As gone over in the above replies,
I installed a new Blaupunkt head unit, all new component speakers front and rear, 2 subwoofers, crossovers, 2 amps and all new wiring. And of course had the whine.
The culprits were the ground and a power wire run next to a speaker wire. To fix it; I ran the ground for all the components to a single ground point near the battery ground strap and separated the speaker wires from all other wires.
With a common ground, there was still a slight whine. Separating the wires took it all out.
I installed a new Blaupunkt head unit, all new component speakers front and rear, 2 subwoofers, crossovers, 2 amps and all new wiring. And of course had the whine.
The culprits were the ground and a power wire run next to a speaker wire. To fix it; I ran the ground for all the components to a single ground point near the battery ground strap and separated the speaker wires from all other wires.
With a common ground, there was still a slight whine. Separating the wires took it all out.
06-19-2003, 12:55 PM
#10
Intermediate
Thread Starter
Join Date: May 2001
Location: Goodyear, AZ
Posts: 47
Likes: 0
Received 0 Likes
on
0 Posts
This is so frustrating! I'm going to switch the crossovers now and see if the other side makes the noise still. I guess I'll bring the car back again and have them try to fix it again. I do remember them saying that one of the amps was grounded where the battery grounding strap was attached in the back of the hatch area (I think), and they said the other amp was grounded somewhere else. Wouldn't a shop know they are supposed to be grounded at the same spot? Once again, I wish I could do more of this stuff myself and save some hassle and money. Ugh!! Thanks for all the replies so quick. This board is great! Keep the replies coming. I think I'll print it all out and bring it to the stereo shop with me. I know they will be pissed to see me again, and may just say it's something wrong with the car (which they mentioned it may being spark plug wires or needing special plugs).
Wish me luck.
Jay in Az.
PS: As soon as I'm done messing with what I can with the stereo, I'll be back on the computer to become a member. I feel guilty for not contributing now.
Wish me luck.
Jay in Az.
PS: As soon as I'm done messing with what I can with the stereo, I'll be back on the computer to become a member. I feel guilty for not contributing now.
