# Sticky  Car Audio Tech Support Thread



## Brahma Brian

This thread will be HEAVILY moderated and is intended ONLY for topics that can help the members of Lay It Low with common car audio needs, so they do not have to be asked over and over again...

If you feel like you have found something that will be of use to other members, by all means post it here... 
Please provide an accurate description of what you are posting, along with any necessary links to go along with it...

If we find a post that we feel will help other members, we will move it to this topic...

No B/S or random meaningless posts will be tolerated what so ever!
No comments are needed in this thread, they WILL be deleted...
If your post gets deleted or edited, DO NOT whine about it, you have been forewarned...

I hope everyone gains from this thread, enjoy...


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## Chronic needs a new name

Basic Car Audio Electronics

*This site will help you to understand basic electronics and some electronic devices. 
It will, of course, also touch on car audio acoustics and car audio equipment. 
To make the lessons as painless as possible, you'll find hundreds of diagrams and pictures, 
.wav files and more than 50 javascript calculators on the 125+ individual web pages. 
If you make even a modest effort, you'll learn more about car audio electronics than you ever thought possible.*


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## 1ofaknd

*DataSheet4U is a free electronic engineering tool that enables you to locate product datasheets from hundreds of electronic component manufacturers worldwide.*

http://www.datasheet4u.com


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## 1ofaknd

*
<a href=\'http://www.darkscience.com.au/caraudiohowto/slotcalc/\' target=\'_blank\'>PORTED BOX CALCULATOR</a>*


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## lanman31337

Here's from a sticky I wrote up on another forum:

*"Frequently Asked Car Audio Questions"*

http://www.j-body.org/forums/read.php?f=4&i=118462&t=118462


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## CarShowDisplays

*Cadillac Fleetwood Tutorial - Big Body, 93-95ish H/U install with factory remote mounted tuner / amp in the trunk*

A lot of people ask about this type of Cadi, and I finally got one in and did a step by step on how to install a head unit and what you need to look out for. It has been a popular car, and the head unit can be tricky if you have never worked on one. I know its long but you can link to this when someone asks about this car. 

Here is the stock radio. There is no harness that will plug into this radios harness behing the dash. There is also no antenna behind the dash. 









There is a remote tuner/amp on the back passenger quarter panel next to the power antenna. this is where you will find front and rear speakers, 12v, acc, dimmer, and power antenna. Here you can use a Metra 70-1858, or best Kits BHA-1858 or what ever brand of 88-up Gm harness. 
What I did is take 9-conductor wire, for the speakers, and 3 conductor for the power. also an 18ft antenna extension and antenna adaptor., and hooked it to the 1858 harness and ran it to the back. 









A Major problem on these cars is the amount of depth that is available for a new radio. there is a metal brace running behind this plastic plate. if you are doing a basic cd player you may not have a problem. If you are doing anything that is deeper like a kenwood mask type deck or an indash flip out screen you may not have enough depth and may have to do some major work to get a radio mounted. 
I will make a new topic on how to modify the dash to get a deep radio to fit. 









This kit will fit. It is a Best Kits BKGM420, a newer version that has some extra tabs on the top and bottom. 









take the brackets off the stock radio and bolt them into the 420kit. 









break off all tabs on the 420, the stock brackets will mount the kit to the car.









here is the kit in the car.









and here is the problem with the depth.









if you were to cut the plastic you will gain a little bit. be carefull on cutting this becuse of the factory wiring that is running behind it.









I have some more pics of rebuilding the dash bezel to fit a panasonic monitor, and I will try an post them soon. 
any questions feel free to ask.
DC


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## SWITCHCRAFT

Found this on the net......

*"This thread is one to view if your are experiencing noise in your sound system."*

http://forum.sounddomain.com/forum/ultimat...f=5;t=008251;p=


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## junbug27

*Install Doctor : Install it yourself*

http://www.installdr.com/InstallYourself.html


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## Crenshaw's Finest

VERY good link....

*"Technical Information for Mobile Electronics Installers"*

http://www.the12volt.com/


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## Brahma Brian

*Stereo System Test & Analysis Tones*

ALL FILES CREATED BY RON "NINO" BATISTA - 2005 - 
FEEL FREE TO DOWNLOAD, BURN AND DISTRIBUTE.

http://www.ronelmm.com/tones/

Everyone have fun with these, just don't blow your equipment up...


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## junbug27

*Enclosure Building & Tech tips:*

http://www.rockfordfosgate.com/rftech/encl...osure_v2002.pdf


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## IDINIEILIL

*Pre-Designed Ported Box Plans by cubic feet and port tuning.*

http://www.caraudio.com/forum/showthread.php?t=137804

*EDIT: Some of the images are not working now.*


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## junbug27

*Upgrading Your Electrical System: Amps, Alternators, and Batteries*

http://www.termpro.com/articles/electsys.html

I'm seeing alot of Alt. questions, so hope this helped some.


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## IDINIEILIL

*Official CarAudio.com Upgrading The Big 3 Thread*

http://www.caraudio.com/forum/showthread.php?t=152355

*R.O.E. "Big 3" Thread*

http://forum.realmofexcursion.com/showthread.php?t=924


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## Brahma Brian

Not sure how accurate this is, but it may be useful...










http://www.reaudio.com/speaker_box/LPort_Box_Calc.html


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## S10laynframe

BORROWED FROM ANOTHER FORUM!
*"What matters" with regard to speaker specs, T/S specs, for the layman"*
--------------------------------------------------------------------------------
If you are looking to "get your feet wet", with understanding what the heck all these specs, figures, and numbers mean - my best advice is to NOT worry about the textbook definition of "what they mean" literally - there's really not much practical value in that for most enthusiasts.
Let's take a look instead at "what can I use these specs for, to understand this subwoofer better?" 
...and you may be surprised that with many of these specs, comparing them from one manufacturer to another is like compariing apples to oranges. 
So it pays to understand what questions to ask when you are looking at them, also. 
*Qms -*
A mechanical / pneumatic "quality" number that truthfully doesn't lend a great deal of insight to helping you choose a subwoofer for most applications.
It is affected by physical properties that you can look at more accurately (IMO) through other specs, such as moving mass (look at Mms), suspension compliance (look at Vas, or a Cms curve), etc.
*Qes -*
An electrical "quality" number... think of it instead as a good indicator of motor strength. Do you need a subwoofer with a strong motor? You might be surprised to learn that high strength isn't always a good thing. (hint: Look at EBP... or check out Qts. ) 
The smaller the number, the stronger the motor.
(also, the smaller the number, the smaller the enclosure, quite often - but it is just one factor in that equation )
*Qts -*
A calculated number, using Qes and Qms - for a "total quality" number. I sort of downplayed Qms's importance earlier... and even in this calculation, Qes so far outweighs Qms in this calculation, that Qts actually ends up quite close in value to Qes - and small adjustments to Qes affect Qts much more than even large adjustments to Qms would have. 
Anyway - this is an important one. One of the "main 3" you need to calculate enclosure size/type/performance. (along with Fs and Vas). 
Qts mainly can tell you what sort of application your subwoofer is compatible in:
High Qts value? Very compatible in a sealed enclosure.
Low Qts value? Very compatible in a vented enclosure.
Qts around 0.45 (middle of the road)? Design compromise to work OK in either, rather than outstanding in one and bad in the other.
It's very helpful that way.
*Fs - *
Resonant frequency. This is the frequency the subwoofer most easily resonates at - and in free air, has the highest impedence (actual resistance with a subwoofer varies both with frequency and enclosure - it's not just "4 ohms" or whatever - it may rise up over 40 ohms, in fact, at points!) at that frequency.
What it's useful for looking at is in judging how low a subwoofer can play.
A low Fs means the subwoofer will be able to play lower...
...but means it won't be as efficient in the higher frequencies either. 
So maybe not always a good thing - or rather, something you need to compromise with realistically, to target your own personal tastes... loud? Or low? Or a little of both? 
*EBP -*
EBP stands for "efficiency bandwidth product", and it's just a helpful calculation, to expand on what Qts tells you with regard to the "what box is it good with?" question.
EBP = Fs / Qes. Simple calculation.
It includes Fs in the equation, because in a sealed box, the subwoofer needs a low Fs in order to play low frequencies.
In a vented box however, you can design the enclosure so that it helps extend the low frequencies farther than a sealed box, so Fs isn't as important for that.
Qes is important because in a vented enclosure, you have higher pressure forces at work - so you need a stronger motor to contend with them. In a sealed box, that stronger motor will drive up the system resonance (a box/sub combination version of Fs), making for bad sealed performance.
The actual EBP number tells you whether it's good in sealed or vented...
EBP at 50 or below, sub is best suited to sealed.
EBP higher than about 80, sub is best suited to vented boxes.
EBP in between, sub is OK in either sealed or vented.
*Vas -*
Suspension compliance. This number represents the "volume of air" that provides the same "spring" force as the suspension system on the subwoofer.
What it means to you, is that a smaller Vas makes for smaller enclosures.
What it also means, is that a smaller Vas makes for lower efficiency, and a higher system resonance as well. 
*Mms -*
Moving mass. The cone and coil, and surround and spider even have a mass associated with them. The higher the moving mass, the lower the efficiency of the speaker - but the lower the Fs as well. A designer adjusts these when deciding how thick of a cone (of course a thick cone may be rigid too, which is a good thing), or what cone material to use.
This is one reason why "high output" SPL subs are actually much less efficient than cheapo subs. Cheapo subs can be louder than SPL subs? Yes, unless you have the wattage to make that SPL sub scream, and that cheapo sub melt. 
*Xmax -*
Here's a good one... represents the linear excursion of the subwoofer, from the "at rest" position, moving in one direction, until the measurement limit is met.
AT least that's how SOME manufacturers list Xmax. 
Others list it as "peak to peak" - which obviously doubles the value.
Others list Xmax when they really mean Xmech (like Polk, for example). 
Some perform a calculation of voice coil winding length compared to the thickness of the top plate - that's the traditional method, and it's not horrible, it's just also not "apples to apples".
So you have to know what you are looking at, when comparing. 
(and by "linear" - that means that the motor strength spec doesn't change, and suspension compliance spec doesn't change, as excursion changes. When it does begin to change, that marks the end of "linear" excursion)
*Xmech -*
This is essentially excursion without regard to how "linear" excursion is. This is how far the cone assembly can physically move, before it crashes into something and something breaks - coil smacks the back plate, cone crashes on the spider mount ring, tinsel leads rip out of the cone - needless to say, it's a limit you don't want to find the hard way! 
*Xsus -*
This is the suspension component of "Xmax". Subwoofers may be "suspension limited", having a suspension that has a smaller range of linear excursion capability than the motor has. Xmax is always the smaller of the two values.
*Xmag -*
This is the motor strength component of "Xmax". Subwoofers may be "motor limited", having a motor that has a smaller range of linear excursion capability than the suspension has. Xmax is always the smaller of the two values.
*BL curve -*
This is an actual plot of motor strength with respect to excursion - simple plot really - motor strength on the Y-axis, excursion shown on the X-axis (and generally shows both positive and negative excursion - so traditional subwoofers with traditional architectures can look quite a bit like parabolas on these plots).
Very helpful for understanding visually exactly HOW LINEAR a motor can be - and even how gradually it rolls off after that limit. 
*Cms curve -*
The same thing as the BL curve, but shows suspension compliance with respect to excursion... so you can see exactly how linear the suspension is, and what it's limits are, where they are reached, and even how graduallly it rolls off after that limit.
*Re -*
This is just the DC resistance measurement of the coil. It's always a bit less than the "nominal impedence", and really doesn't tell you too much, other than "this is the lowest the impedence will ever dip to, on the impedence curve". (at some frequencies, impedence may rise up very high - a 4 ohm speaker might hit 50 ohms at Fs!)
*Le -*
Inductance is potentially an important thing to look at.
a voice coil is a coil of wire - and so resembles an inductor.
What does an inductor do? It resists changes in current direction and flow.
What does a speaker do? It changes direction and frequency as quickly as the music throws those changes at it.
So - basically you want your inductance to be as low as possible.
Also... an inductor is a 6dB/octave low pass crossover - so at some point, inductance could be high enough that it prevents the speaker from playing frequencies higher than a certain point - the speaker itself prevents it - the lower the inductance, the higher the speaker is capable of playing.


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## Eric

*EDIT by Brahma Brian for NEWER model VM9312 is as follows...</span>

<span style=\'color:red\'>1: Go into AM/FM mode
2: Hit "setup" on the remote control
3: Enter 543210 on the remote, listening for the beep for each number entered
4: A new menu will appear. Touch the button that has the hammer/screwdriver on it in the upper left-hand part of the screen.
5: Select Brake bypass to "ON" and hit the "X" near the bottom of the screen.
6: Use the unit wisely and above all safely. A ticket is one thing, causing a fatal accident due to negligence is another.*


*By the way, this is for informational purposes only and I will not be responsible for anything bad/stupid/ignorant you do with your Jensen unit*


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## Brahma Brian

*Audio Terms Glossary

Find out what it means... A free service by ACI*

http://www.audioc.com/library1/glossary.htm


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## Crenshaw's Finest

*AMP REPAIR...
*
http://www.amprepaircenter.com/


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## Brahma Brian

*The Thiele-Small Loudspeaker Database*

http://www.thielesmall.com/

"The site is named after two Australian pioneers, A.N. Thiele and R.H. Small, who defined the Thiele-Small parameters, also known as TS parameters, around 1960-70. However, the site is by no means limited to Thiele-Small parameters; it also contains a lot of other information."


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## 727Lowrider

*BYPASS THE PARKING BRAKE SECURITY FEATURE ON DUAL INDASH PLAYERS*

These methods have worked on a variety of Dual DVD systems (mainly XDVD8181, also XDVD710), unsuprisingly, since Dual stated to me that most installations have the same codes. 

WARNING! It is usually ILLEGAL and most of all UNSAFE to drive while watching video. I only watch video while parked, and I suggest you do the same. This is for demonstration purposes only, if you use these codes, you do so at your own risk. 

STEP ONE. Ground the E-Brake wire. 
No matter which method you use, you must ground the brake detection wire. I suggest you tap it into the ground wire on your wiring harness (ensures a good ground). 

1. FACTORY RESET METHOD (Temporary) 
(This isn't the most effective, but it is the easiest to try, so it's worth a shot since it apparently works on some units.) 
** Go to the Menu 
** Get to the Settings Menu 
** Select <yes> to Reset to Factory Settings. 
Credit: DKA 

Have recently heard complaints of this method not being permanent, as this is needed everytime they want to watch a DVD. Also, radio and screen angle presets are lost. 

---------------- 

2. AUDIO CD METHOD (Permanent) 
** Insert Audio CD 
** Press PLAY 
** Press STOP twice on remote 
** Enter 26604 on remote 
** Press ENTER 
** Take out Audio CD and Insert a DVD 
Credit: Myself via a DUAL Tech 

---------------- 

3. DVD METHOD (Permanent) 
** Insert a DVD 
** Let it play until you hear sound 
** Press STOP twice on remote 
** Enter 26604 
** Press ENTER 
Credit: Adam P. 

The blue warning screen should immediately go away after pressing the last digit of "26604." Still press ENTER as a precaution.


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## MR. BUICK

I'm not too savvy with car audio, but I found this info online and thought I'd share it... 

*Speaker Fit Guide

Not sure what speakers fit your Lowrider.
Here is the easy car speaker guide you can follow. 
Finding the speakers you need: *

http://www.lowrider.com/information/speakerfit/


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## junbug29s

*Car Stereo Purchasing sites*


Acaraudio.com
Woofersetc.com
Audiocarplus.com
Etronics.com
Hookedontronics.com
Techronics.com
Onlinecarstereo.com
LightAV.com
Allcarstereo.com
SuperCrewSound.com
Garrett-SmartHome.com
SonicElectronix.com
TecBuyz.com
CarAudioImage.com
DimensionAudio.com
InfiniteCarAudio.com
USCarAudio.com
Discountjungle.net 
ebay.com
www.ficaraudio.com
www.audioque.com
www.soundsplinter.com
www.stereointegrity.com
www.ikesound.com
www.imagedynamicsstore.com
www.excessiveamperage.com
www.millionbuy.com
http://www.soundsolutionsaudio.com/shop/
http://store.realmofexcursion.com/
knukonceptz.com
circuitcity.com
bestbuy.com
crutchfield.com

*If you want to add more sites, post them in this thread and they will be edited into *this* post*

Make sure the links work before posting!


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## Crenshaw's Finest

*How to bench test a Head Unit:*

Power (red) and Ignition (Yellow) wires to + on battery and ground (Black) wire to - on battery. This will supply power to the unit. 

I'm not sure how to test RCA's, the advanced installers might want to edit this.


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## Crenshaw's Finest

*Installation tools and wiring....
*
http://installer.com/


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## Crenshaw's Finest

*How to Install a Car Stereo Inside a House*


1. Remove stereo from car or box, and connect. Make sure everything is connected except the 12v constant, 12v switched and ground wires to the stereo head unit.

2. Create a housing for the radio(this is optional). Make sure the housing has sufficient air space and dissipation of heat.

3. Prepare the power converter for installation. Remove packaging, attach required wires, etc. per its instructions. Or use a PC ATX power supply as an alternative.

4. Locate the the 12v constant (usually yellow wire) and 12v switched (usually red wire) from the head unit, twist them together and connect them to the 12v + positive output on the converter normally marked + and/or colored red, or connect them to any YELLOW wire from the PC power supply.

5. Connect the ground wire from the head unit,(usually black wire) to the negative jack (black) on the converter, Or any black wire from the PC power supply.

6. If using a PC Power supply, make sure it can provide sufficient current to power your stereo.

7. If operating from a PC Power supply that has been removed from a computer, you will need to join the GREEN wire of the power supply to any BLACK wire of the power supply otherwise it won't turn on

8. Cross fingers. Hold breath. Pray.

9. Plug in power converter / PC PSU into wall jack.

10. Turn on stereo.


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## Crenshaw's Finest

*Car Audio Manufacturer Stickers:
*
http://www.fastdecals.com/car_audio_stickers.htm


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## Crenshaw's Finest

*Probably the best place place to have amp repair done. I've seen many ++ feedbacks*

http://www.db-r.com/


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## Crenshaw's Finest

*High Output Alternators*

http://www.excessiveamperage.com/

http://www.ohiogen.com/index.html

http://www.alterstart.biz/


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## FlipFlopBox

POWER ACOUSTIK PTID 4006T BRAKE OVER RIDE


JUST GROUND OUT THE BRAKE WIRE!!!! ~~


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## trodder

> _Originally posted by Crenshaw's Finest_@Apr 23 2008, 05:58 PM~10487074
> *How to bench test a Head Unit:
> 
> Power (red) and Ignition (Yellow) wires to + on battery and ground (Black) wire to - on battery. This will supply power to the unit.
> 
> I'm not sure how to test RCA's, the advanced installers might want to edit this.
> *


FWIW I bench test RCAs by hooking them up to a home stereo receiver... to ensure i have signal output... I have one in the garage with RCAs hanging from it exclusively for this purpose.


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## streetlifer

Here a topic I made with some good info.  

http://www.layitlow.com/forums/index.php?showtopic=458890





I fixed your link.  

BB


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## Dysfunctional73

*MASSIVE WIRING DIAGRAMS *


http://www.modifiedlife.com/car-radio-and-...iring-diagrams/


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## OUTHOPU

I found two sites for calculating port dia. and length. You'll need to know what the volume of the enclosure will be with all displacement accounted for, as well as what HZ you want to tune it to. 

This one works but the math is a bit tricky

http://www.clubknowledge.com/Car_Audio_FAQ/?t16

This is much quicker for calculating round ports. Their numbers came up the same as when I calculated my port off the first link. 

http://www.psp-inc.com/tools.html


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## BIG DIRTY

PROBABLY ONE OF THE BETTER SPEAKER IMPENDENCE CALCULATORS

OHMS CALCULATOR


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## gizmo1

Got this from http://www.caraudiobook.com/car_audio_myth...audio_myths.htm
I didnt go through everything on this site but looks like it has alot of helpful info.

Favorite Car Audio Myths
Here's a list of my favorite car audio myths in no particular order. 

1. Amplifiers should be grounded at the battery

Generally the battery is the worst place to ground an amplifier. The battery is where all of the electrical noise from the vehicle's various parts ends up. Like a noise garbage disposal. Connecting your audio components to this noise hub is a bad idea.

2. Adding a second battery to the vehicle will ease the load on the alternator

A second battery will increase the load on the alternator, not decrease it. With the vehicle running the second battery becomes another load for the alternator to charge. Second batteries are only good for engine off listening time.

3. Ground all of your audio components at the same place to eliminate noise 

Sometimes this works and sometimes it makes the problem worse. When you ground any current carrying component to the vehicle you create a circular field at that point. Poorly designed audio components could pick up this field and introduce it as noise into the system. When this is the case it's a good idea to separate your components by six inches or more. The higher the current (large amps), the more space I recommend.

4. Routing power cables on the opposite side of the signal cables will prevent noise

Maybe. It will prevent the signal cables from picking up noise inductively from the power cables. But it won't prevent them from picking up noise from the vehicle's chassis or from other electronic components along their path. It's a good practice but doesn't guarantee noise pickup.

5. A high output alternator will reduce the chance of noise

Actually it's the opposite. The larger the alternator the greater the noise output. The noise increases with the power output of the alternator.

6. Power capacitors should be fused

The purpose of a car audio capacitor is to deliver large amounts of current very quickly (faster than a battery is capable of). Adding a fuse, which is just a short length of very small wire, will slow down this current delivery. And because capacitors can discharge so quickly the fuse wouldn't blow before the capacitor has discharged.

7. Adding more speakers will increase the sound quality

Volume, maybe. Sound quality, no. The more speakers you add to a system the greater the problems you will have due to speaker interaction. Each speaker is a little wave producer and when the waves from one speaker meet those of another speaker the results are peaks and dips in the response. Generally less is more when looking for sound quality. Look to the car audio competition finals winners and you'll see that they use a small number of high quality speakers.

8. Turning up all of the frequencies on an equalizer will increase the system volume

The system volume is based on many factors including system power and speaker sensitivity. The purpose of an equalizer is to compensate for vehicle specific problems and not as a general volume control. Boosting all of the frequencies won't make your system louder, only more distorted.

9. Tweeters should be placed as high up as possible

Tweeters should be placed as near to the midrange/woofer as possible in most cases. The tweeter and the midrange/woofer are a matched pair and shouldn't be separated. Imagine an electric guitar which has a wide acoustical range. If the guitar is playing a riff in the frequency range of the woofer and then switches to a riff in the frequency range of the tweeter you'll likely notice the position of the guitar jump. Now if the tweeter is placed near the woofer the guitar position will remain in place. Better installers can make a tweeter that is separated sound correct but a much safer bet is to leave the set together. 

10. An amplifier's gain control should be set to maximum to get more volume

The purpose of the gain control is to match the output level of the component before it (head unit, equalizer, crossover, etc.) Since car audio manufacturers don't use a standard output level like home audio manufacturers do it is necessary to have an adjustable input. Adjusting the gain too high will only cause more distortion in the amplifier's output. Since our ears perceive distorted and painful sounds as louder this is a myth that has perpetuated.

Bottom line: Be careful who you listen to and what you believe (good advice for life too). There are plenty of folks inside and outside the car audio realm that will simply make something up if they don't know the answer (don't want to look stupid). Then there are those that have been told a lie, accepted it as truth, and passed it along. When in doubt, get a second opinion.


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## brian84corvette

hello all
I figured that we could maby start a thread here sharing tricks and knoledge that we have aquired - obviously since we are all individuals we will have diffrent oppinions of the best sounds and installs - where some people will like acurate reproduction thru the hz range and some people will like pure spl over acuracy -but its all good - so lets share



1 - sound for all intensive purposes has a hz rating.
the sound of your voice - the sound of a hammer hitting nails - a tree falling in the woods - all sounds are capable of being measured on the hz scale.

hz = hertz
hertz = how many sound waves there are per second.

1 to 20 hertz or hz are basicly concidered sub sonic - meaning you cant hear them - but I generaly feel like this is some what un true - as the 18" sub woofer I have in my car will play on 15hz tones and produce a condiderable amount of noise wethere its just the mechanical noise of the sub or me aduibly hearing what 15hz sounds like is arguable - but I tell you what - you get in a car with a big sub off a good amount of power and play 15hz tones you can REALLEY feel it.

sub bass is next up in the hz scale
what is concidered sub bass is also arguable - but is mostly from 20hz to 80 or 100 hz. anything above 100 hz is starting to get to mid terratory.

top of the line car audio amplifiers will amplify sound ranges from 10 or 20 hz up to 40 thousand or more hz. 

now something intresting - 
the power in your house - like what you plug your crap in to. its fed by ac current. ac means alternating current - and it generaly is suposed to be fed at around 55 to 60 hz in your house at 120volts
guess what your amps do ..... yep same thing - apply alternating power to your speakers / subs. 
60 hz just happens to fall in the upper range of sub bass frequencys
so if you have any old or crappy sub woofers laying around you could try this:

http://www.youtube.com/watch?v=-IxTrXjSoOE&feature=related
disclaimer - be safe when doing this - you could electrucute your self - think like what would happen when you stick a fork in the electrical socket.... same rules apply

the subwoofer that was being used in that vid was pretty beefy cause it played for a fiew minutes before melting down around the 3:10 minute mark.
most kicker and sony type subs will only last a short burp before burning up off of ac house hold power due to its current being so high at 120 volts.
volts times amps = watts so if you had a sub woofer hooked to a wall socket that was connected to your breaker box on a 20 amp switch - then you would have had 2400 rms watts running to the subwoofer wich can be manipulated a little by the ohm load that the sub woofer is wired to also but....... you get the point. 



next little intresting info bit ive got is this:
the fuze rating on the amp x10 = the full 100% out put capacity of the amp in watts.

sony xplode amp - says 1200w on the cover.
fuzed with two 20amp fuzes so its got 40 amps worth of power running thru it wich is capable of giving off 400 real watts of power before.
I dont care if it says 1200w on the cover its a flat out lie. - and 400w from is is completely absolutely the most it could make in ideal situations.

this or that amp has 90 amps of fuze on it....... - its capable of making 900w - thats it. - apply your fuze rating on the amp x10 = your max power in rms w.

there are also exeptions to this rule wich factor in things like efficency of the amp and also the ohm load you are putting to the amp.


what the heck is an ohm ?

ohms are like resistance on electricity.
the more ohms something is the harder time electricity will have flowing thru it.
it is arguable that our car stereo speakers sound cleaner and more acurate at higher ohm loads ( ie 4 ohms ) than they would running off lower ohm loads ( ie 2 ohms ) but again it is arguable on how much the diffrence will realley be capable of being noticed in the environment of a car with other noise going on also.

your amp will put off more power at lower ohm loads. 
if it does 100w at 4 ohms - then it might do 150 or 200w at 2 ohms
but
you have to check your amp to see its lowest ohm load that it can handel before going in to thermal melt down or protect mode - as running amps on low ohm loads tends to heat them up quick and they literly can catch on fire if you run impropper load rating to them.


this is the most handy tool ive ever used for anything car related. stereo / engine ..... it can be had for $25 basicly anywhere
its called a digital multi meter. or dmm for short. its amazing.








the weird setting in the green area on it that looks sorta like a pair of head phones measures ohms.
dc settings measure car battery voltage wich is direct current
ac settings measure alternating current like in your house - or coming out of your amp - wich you can also tune to play an exact amount of watts to your speakers by first hooking up the dmm to the amp and playing a tone - ajusting the gain knob on the amp until you reach your maximum ac voltage on the dmm. there is a huge huge involved process in wich you have to follow for this to work - but its not rocket science - and ill try and post up a link to it when I find it again. this is helpful to do if your running verry high power to your subs and dont want to over do it - like if you have a 2000w amp and a sub that will melt down on anything above 1500w you can set your amp to max out at 1500w with the dmm so that you will never send anything above 1500w to the sub and kill it.


lets go back to sound waves for a minute.... have a picture of them.









the blue line is the natural wave of sound.

the yellow peaks are mimal clipping
and the red peaks are dangerous clipping.

whats all this about clipping ? its what kills speakers - thats whats up.

a speaker will play a natural sound wave by fully entering and exiting the wave wich always will have a cone movment in every part of the wave.

the clipped wave will have a flat spot where the cone will stay stuck out for a brief period - wich will cause no air flow to pass over the voice coils so they will instantly start heating up. exesive heat buildup in the voice coil of the speaker/sub will cause it to destroy it self.

how does clipping happen ? by a number of things - but mostly its by turning up the gain / power leves beyond 75% on any piece of stereo equipment you have in the car. head unit / amps / line driver / eq - all of it counts for this.

some people actually have an ear for it - and can hear the clipped sound of the speakers / sub when its grossly distorted like it is in red in the sound wave pic.


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## brian84corvette

something else ive recently found out :

your cars electrical system can only put out as much power as its designed to do.
?

my 72 plymouth valiant came stock with a 60amp alternator
and a normal starting battery with like 650cca ratings.

so its total output = 60amps x10 = 600watts

I put in a 600w stereo system - and fried my ignition coil 
why ? because I upgraded all the power wires running to my amps
and all the electricity that my car was making at that time was being sent to the amps and stereo - because electricity takes the path of least resistance - the ignition coil was being starved of its propper electrical supply causing it to run off of in suficent power / low voltage = its death.

this same thery of mine applys to you guys that get dimming of the headlights durring loud levels of music.

whats going on is this:
your cars alternator is generaly producing around 14.1 to 14.4 volts at what ever amp your alternator is rated at - wich is supplying your car battery with enough power to float charge it self - as car batterys generaly rest around 12.6 volts or so and the stereo is blasting loud now right - whell all the power that the alternator is making is now being fed to the stereo...... 
lets use some make believe #s here to get an idea of whats happening.....

your stereo is turned up so loud its asking for 160 amps of power from the car.
your car alternator is capable of filling 120 amps worth of electrical supply for that.
the car battery is capable of giving off 40 amps at a certan discharge rate ( diffrent for all batterys - and hard as hell to figure out ) but there is your 160 amps for the stereo - the catch is this...
since your alternator is maxed out giving its all to the stereo - and the battery is also giving off its power to the stereo at the same time - there is nothing giving float charge to the battery - so the volts to the system will drop down to below battery resting voltage...... wich is REALLEY BAD for everything.
your cars computers - they dont like operating at 10 volts
your amps are working extra hard to fight for all that power they are taking - and they are now running in eficently due to the low voltage situation.
your alternator is crying the entire time - and will eventually melt down.
and your car battery is being drained.



to properly fix the situation would require the instilation of a high output alternator - or a second alternator wired in correctly - and or a reserve battery bank ( wich is not as good as a good alt. is - but anything is better than nothing )
upgrading the wiring on the car ( the big 3 )


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## Brahma Brian

*How to Reset GM Theft lock Radio's*

Article Disclaimer: This article is meant to be used by Delco Radio owners to reset there radios. In no way is it meant to be used for any unethical or unlawful ways.

Purpose

The following instructions will allow you to reset any GM (General Motors), Cadillac, Oldsmobile, Buick, Pontiac theft lock radio.

Requirements

The theft lock radio must be in "LOC" mode.

Procedure:

1. Turn the ignition ON (The radio should display "LOC")

2. Hold down the Radio Presets 2 and 3 buttons for six seconds

3. The radio display changes from LOC to a three-digit number. Write this number down. You now have fifteen seconds to complete the next step.

4. Press the AM/FM button

5. The radio display changes to another three-digit number. Write this number to the right of the first one.

6. You now have a six-digit number, the first three digits are from STEP 03 and the last three digits are form STEP 05

7. Call 1-800-537-5140

8. Press 1 then # (pound). You'll hear "Invalid Code, try again"

9. Press 139010 or 106010 or 206010 or 202107 then # (pound). You will be asked to enter your four or six digit code followed by *

10. Enter the number from STEP 6 then *

11. Listen to the four-digit number and write it down. It will be repeated twice

12. Turn the ignition ON (The radio displays LOC)

13. Use the MN and HR buttons to enter the code from STEP 11

14. Press the AM/FM button. The radio display changes to "SEC". Your radio is now "un-locked" and usable.

Dealership Codes

* 139010
* 106010
* 206010
* 202107

Troubleshooting

If you fail to enter the correct code eight times, the radio goes into INOP mode. You have to wait an hour with the ignition on before the radio returns to LOC mode.

Read more: http://www.articlesbase.com/automotive-art...l#ixzz0wrwcOeRn
Under Creative Commons License: Attribution


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## Brahma Brian

*A simple GUI-interface box tuning calculator.*

I haven't tried this, perhaps it will be useful, try it out.

http://cid-1e28f7d3956a626f.office.live.co...0Calculator.exe


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## Jeff Rohrer

Free courses in basic electonics http://www.electronicstheory.com/


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## Jeff Rohrer

A really good how to channel on youtube for making panels, templates, trim pieces, vinyl wrapping and more.

https://www.youtube.com/channel/UC4FiN46mPTtkJxzRXJY21lQ


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