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Some basic tips and guidelines (1 Viewer)

Feb 14, 2007
Real Name
Because I find some fun in helping people, I want to just throw a few things out.
I have been a not-so-active member of this forum for a few months, and since I enjoy helping people out and this particular section of the forum is more my forte than anything else, allow me to share a few things.

-Head Units:
1. Make sure to list the features you absolutely MUST have.
2. Try and list things you can live without, or KNOW you will never use.
3. Provide a budget for the purchase.

1. Personal preference is a key factor in what sounds good and what doesn't.
2. Listening to some speakers will always be a better way to chose, than simply asking the people "in the know", what brand or model THEY would chose.
3. Make sure to list the vehicle so we know what kind of space constraints there are.
4. Provide a budget for the purchase.
5. It couldn't hurt to let us know how much custom work you are capable of and want to do.
6. Make sure to pair speakers and amps power by looking mainly at the RMS power handling and power output of the products, max power is not something to go by, there is no industry standard on measuring this rating. In some cases it is an inflated number for marketing reasons.

1. Please list what type of vehicle this is for.
2. List what amp you either have or plan to have running the sub(s).
3. List how many of the subs you plan to be running off said amp.
4. List the vehicle so we know what kind of space constraints there are.
5. What is the main reason for you buying subs?(i.e. you want to compete in SPL comps, you just want booming bass, or you actualy do want to pick up the low end of your frequency range smoothly and clearly as to hear the music as it was meant to be heard, etc...)
6. Provide a budget for the purchase.
7. Make sure to pair subs and amps power by looking mainly at the RMS power handling and power output of the products, max power is not something to go by, there is no industry standard on measuring this rating. In some cases it is an inflated number for marketing reasons.


1. Please list what you have or plan to have that the amp is going to power.
2. Links to said speakers or subs would be nice so we can see the specs.
3. If you can't get links, Model numbers are always helpful.
4. Please list coil configuration.(number of coils, and impendance rating. Ex: Dual 4ohm coils, Single 2ohm coil etc...)
5. Provide a budget for the purchase.
6. Make sure to pair subs/speakers and amps power by looking mainly at the RMS power handling and power output of the products, max power is not something to go by, there is no industry standard on measuring this rating. In some cases it is an inflated number for marketing reasons.

-Sound Deadener:
1. What all are you dampening?
2. Provide a budget for the purchase.
3. Visit SecondSkinAudio.com (I am in no way affiliated, but as far as R&D, Customer Service, Product functionality, and Product Quality, I have yet to find any company capable of doing dampening better than them)

Ok, that about takes care of some tips and guidelines for asking recomendations. Another thing I want to throw out is just some very basic general knowledge. Nothing deep and technical, just things the average Joe might want to know, and should know before embarking on a car audio/electrical install.

1. Speaker power ratings:
One thing that gets misunderstood the most by new people is power ratings.
I have even seen misunderstandings as extreme as people reading the max power handling of each driver in their car, and the max power output of each amp(including the head unit amp), and adding them all up to make statements such as "my system puts out 5000 watts."
Now, In no way would I ever bash someone for doing so. If they are entirely out of the know on this subject, that is not their fault. So lets clear this up real quickly here....

1. Max power rating is next to useless when chosing equipment. Alow me to copy and paste a certain statement again: "Make sure to pair subs/speakers and amps power by looking mainly at the RMS power handling and power output of the products, max power is not something to go by, there is no industry standard on measuring this rating. In some cases it is an inflated number for marketing reasons." I mean this!

2. When talking about power handling and power output, there are ways to hurt your equipment on both the high AND the low end. Here are some examples:
-You have an amp putting out 50 watts RMS per channel to your speakers. You have speakers that are rated to handle 150 watts RMS each. You are 100 watts less than their full listed handling. Now a lot of people say "I'm not pushing them with too much power, I can't hurt them". This is a very very very false statement!
If you are not completely up to snuff on how to set an amp properly, and expect your speakers to be louder than your amp can make them, you can definately destroy your speakers. Basicaly what happens is this: You install them, hook the amp up, and listen.. "man these arent that loud" so you turn the volume up. When the volume doesn't cut it, you turn the gain knob up on your amp. Now you are forcing the amp to try to put out more power than it can. By doing this you are clipping the signal. Sending a dirty, or clipped signal damages your speakers. Thus, too little power destroying them because you tried to do more with less power.

-You have an amp that will put out 200 watts RMS per channel, and your speakers are rated at 100 watts RMS. This means that it only takes 100 watts of clean power to push them to their maximum output, basicaly. Now, you install them and set everything and just turn things up to get loud... the power is still clean and unclipped, but you are pushing them far harder than they need to be pushed and end up blowing your speakers.

You could basicaly look at the relationship between Drivers and Amplifiers as being similar to the relationship between the Internal parts of an engine and a Turbocharger.
If you have a high compression engine(low power speakers) built to run fast without forced induction(high powered amp), once you put the boost to it, bad things will happen.
If you have a low compression engine(high power rated speakers) built to run fast WITH forced unduction(low power amp in this case), once you try and push that boost too far, the engine is going to fail.
This is not a DIRECT relation, but a roundabout way to describe it.

Moving on, lets talk about some basic electrical terms and specs in car audio
1. RMS Power Output: This is the ammount of power, measured in Watts, that an amplifier can put out cleanly and consistantly.
2. RMS Power Handling: This is the ammount of power, measured in Watts, that said driver can handle constantly to reach it's full potential, without being fatal to the driver.
3. Pre-Amp Outputs and their Voltage ratings: Pre-Amp outputs are the places in the back of the head unit that send the signal to external amplifiers.
Some head units have dedicated Subwoofer outputs, so you can utilize the Head Unit's on board bass control and EQ settings.
The voltage output is directly related to your amplifiers GAIN knob(that I will explain soon). If your Head Unit puts out a good clean 5 Volts, your gain knob will not need to be turned up as far as if it had 2 Volts, to get the amp to efficiently put out more power. Basicaly, the gain and pre-out voltages are going to move in opposite directions voltage wise. You could almost think of voltage ratings on the gain knob as "how much extra amplification do I need to give the input signal to make it give my speakers the most power".
4. Impendance(measured in ohms): Alright. Every driver, heck, every single load you put on an electrical circuit, has some sort of electrical resistance.
The ohm's rating on a driver is going to tell you a general idea of what kind of resistance load it puts on the electrical current. The higher the load(higher ohms measurement), the less output it is going to have given the power source is the same.
EXAMPLE: You have an amp that says it will put out 100 watts at 4 ohms. When you hook a 2 ohm speaker up to that same circuit you have now halved the resistance in the electrical flow, and in escence, doubled the power (IF YOUR AMP IS STABLE AT THAT RESISTANCE LOAD).
5. Impendance handling on amps: Now, some amps are stable at different impendances and they will list this and also list what their power output is at each resistance. (remember what I said though, pay attention to the RMS rating, not the MAX ratings!)
Now, This part is pretty simple: If your speaker is 4ohms, and you have an amp that puts out 100 watts at 4ohms, then the speaker is going to see 100 watts.
6. Amp parts:
-Gain knob: controls the ammount you amplify the signal that you will, in turn, be sending to your speakers. Turning it up amplifies the signal, sending more power(remember not to force the amp to put out too much, or you will clip it and hurt your speakers), turning it down takes off amplification on the signal.
-Hi-pass and Low-pass: These will filter out frequencies you do not want your speaker to play.
If you put the high-pass filter on, whatever frequency you set it to, your speakers will not play BELOW (hi-pass at 100hz and your speakers will play from 100HZ on up).
If you put the low-pass filter on, whatever frequency range you set it to, your speakers will not play ABOVE (low-pass at 100hz and your speakers will play from 100HZ on down)
The "all pass" or usualy center choice between high and low pass disables the amps crossover all together allowing all frequencies to go to your speakers.
-B+ terminal: This is where you have a power wire from the batter to the amp. Make sure there is a fuse no more than 6 inches from the connection at the battery with a rating sufficient for the current flow based on wire gauge.
-NEG terminal: This is where you have a ground wire from the amplifier to a BARE METAL PART OF THE CARS CHASSIS. This should be as close to the amp as possible. the shorter the ground and cleaner the connection, the better.
-REM terminal: this is a small gauge signal wire that is usualy light blue. It goes from the amp to the back of the head unit(most aftermarket head units have the Remote power wire labeled, and is almost always light blue with a white stripe)
-Speaker terminals: well... come on now... don't tell me I need to explain what gets hooked up here :P
Signal imput terminals: This is where you run the RCA Interconnects to the amp, from your head units pre-amp outputs.
Pass-Through: some amps allow you to "daisy-chain" amplifiers. this means you run your Interconnects from the head unit to the first amp(sometimes called the master), then you simply run a second set of Interconnects from the Pass-Through on the master, to the Input of the slave(second amp).

Some short fuse explanations: Why do amps have on-board fuses, but you still fuse the power wire going to the amp?
Simple! The fuse by the battery is only there to protect the WIRE, NOT THE AMP! If you get an amp that draws more current(amperage) than the power wire can carry, the wire heats, melts, causes a fire. If you have a fuse on the wire(6 inches from the battery or closer), that is rated slightly below the power wires thermal amperage handling, the fuse will pop before the car burns to the ground. The on-board fuses are there to protect the amp in the case of a short.

Some very simplified speaker explanation:
Tweeters: used to produce high frequency notes only. Most tweeters are crossed over anywhere from 1,000hz to 3,000hz. If you send them a signal below the frequency range they are designed to handle, you could damage them.
Midrange: a midrange speaker is used to produce mid-range frequencies(no duh, right?). They generaly are going to be crossed over to play the frequencies between the subwoofers range and the tweeters range(unless we are talking a setup with dedicated midbass, which will be discuss in a moment)
Midbass: this is a driver specificaly designed to pick up where your sub left off, but not go too high into the midrange frequencies, the most common midbass frequency range that I personaly see is somewhere around 60hz up to somewhere around 500hz.
Subwoofer: This is a drive specificaly designed to play the lower bass and subbass notes. A general frequency range that subs are deisnged to handle is 15hz(some argue anything below 20 is inaudible with regular music), up to 100hz.
Coaxial: A coaxial is a speaker with everything integrated and has no external crossover. The tweeter is built in and has very basic crossovers built in to filter out the lower notes. Same with the woofer part of the coaxial, except exactly opposite. It only plays the notes below what the tweeter is designed to play.

2-way components: A 2-way component set has a more complex crossover network. It is mounted externaly from the drivers. This is more desireable than a coaxial for many reasons.
1.The filtering is better.
2. The power handling, generaly is greater due to the extensive crossover network helping seperate the frequencies.
and 3. You can mount the midwoofers and the tweeters in different locations.(the higher the frequency the more directional... and you dont want your soundstage on the floor).

3-way component set: This is an even further seperation. This is also slightly harder for the newcomer to set up and stage properly. It consists of a Midbass driver(usualy 6.5 inches), a Midrange driver(usualy 3-4 inches), and a tweeter(usualy 3/4-1 inch).

I have covered quite a few things here, and hope it helps. If anyone wants me to clarify on one single point, post a reply stating such, and i will explain it, and edit the post if neccesary. Also, if there is a part of car audio I did not cover, that I might be able to explain or decifer for you, post a reply and ask. I will add it to the thread and answer you directly.
Again, I hope this helps someone and I'm glad to take some time to explain these things :)



May 20, 2007
Real Name
Thanks man, yeah I did read through this before I posted mine, but it didn't really go into the difference between wiring through the fuse box and straight to the battery. Anything I've ever read basically says the battery is the only way, no questions asked. But I'd like to understand why. There are avaliable spots in my fuse box... it's so tempting to just use those haha.

Kenny A

Stunt Coordinator
Oct 17, 2004
I just want to say a big thank you to Dustin (JLAudioCavalier). I am new to car audio and had some questions regarding a sound system for my daughters trailblazer. Dustin was a ton of help. He's honest and truely likes helping people. Don't be afraid to ask him what you think may be a stupid question. He is very professional and can explain his answer so you can easily understand. One thing that will help when talking to him is to know your budget. He is not one to push you into buying a high dollar system when you only have a couple of hundred dollars to spend.
Dustin, I ending up going with the Pioneer 5900 head unit.
Thanks again for all your help.
Feb 14, 2007
Real Name
awww thanks Kenny :)

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