# 2 12'' Help

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• 01-08-2012
elballz12
Re: 2 12'' Help
Yall are talking way over my head... I have no idea what your talking about. I want an amp that will give the sub its power but won't make it sound like crap.
• 01-08-2012
i2ain2thunder
Re: 2 12'' Help
basic operation of a subwoofer and amplifier. amplifiers take power from your electrical system and send it to your subwoofer. subwoofers are pretty much gaurenteed operation at a certain power level. Lets say your subs are made to handle 600 watts RMS (continuous power) This means the subwoofer should safely operate up to 600 watts. So say you have an amplifier rated to produce 600 watts. boom basic matching should work ok, thats all pretty basic stuff. Where we start to talk about clean and dirty power comes into play like this. Say your amplifier is made to produce 600watts cleanly if it is rated at that by the manufacturer (or should be able to anyway) However whether or not it actually does produce 600 watts cleanly depends on your electrical system or more specifically your Voltage and Amperage. If you think about electricity like water from a hose then Voltage is the amount of electrical force or in this example your water pressure. and Amperage is your electrical current and capacity or in this example how much water flow you have. A standard car battery stores energy and can release it at 13.7 Volts.(this is actually a bit more complicated than this but easy version) Your alternator is regulated to send power safely to your battery at a charge rate of 14.5 Volts. and electricity always flows from the source of highest voltage to the least voltage. So now if you check the voltage at your battery with the car running you will see 14.5 volts instead of the sitting voltage of 13.7. This is all important because amplifiers rely on a steady electrical force of 12volts or higher. I'll continue in my next post....
• 01-08-2012
i2ain2thunder
Re: 2 12'' Help
Now say you have a 2000 watt RMS amplifier and you have the gain on it set to output 2000 watts. Now you hooked up some subs that can handle that power and you are bumping to some rap. What happens everytime the subwoofers hit hard on those low bass notes it takes a toll on your electrical system. The amplifier is sending 2000watts of power to the subs clean for the first few notes but if you watch your voltage anywhere in the electrical circuit say at the battery you will notice as more bass gets played your voltage will likely drop from 14.5 volts lower and lower and lower, if you reach below say 12 volts now all of the sudden your amplifier is trying to make 2000 watts however it no longer has the voltage to do this properly...say it drops down to 10 volts. This is a very dangerous situation and this is in fact how most newbies to car audio end up blowing their first set of subwoofers. When an amplifier is no longer getting enough voltage to produce it's rated power it will try anyway and will fail to do so properly instead of the amp sending 2000 watts of a clean signal now it is sending what we call a dirty signal. This dirty signal forces your subwoofer to heat up at it's coil and not operated normally, if the coil gets hot enough you will start to smell a burning scent the very start of the smell is usually the glue on the coil getting very hot this is a bad sign, because next the coil will litterally get way hotter then it is made to handle and will the coil will literally fry and the sub will be what we call blown...or no longer operable.
• 01-08-2012
i2ain2thunder
Re: 2 12'' Help
How we in the car audio world tackle the problem of such a high electrical demand to run our high output subwoofer amplifiers is to have the proper things needed for correct operation installed in our electrical system. I.E. thick power wires, high output alternators, adding batteries and so on. We do this all to keep enough power available for our amplifier's particular needs. An amplifier's needs generally differs depending on it's rated output. Now with that in mind basic operation of a subwoofer: A subwoofer will get louder the more power it is being sent. If a subwoofer is being sent 600 watts rms it will be louder than if it was being sent 400 watts rms. For this reason we like to aim to have an amplifier that will have enough output to match (or exceed) our subwoofer's power handling. We know certain subwoofers like the SA can easily handle 1000 watts even though it is rated to only handle 600, the manufacturer is just being safe rating it that low. So many people will send them upwords of 1500 watts so that they can get very very loud. So long as the power is sufficient for the amplifier and the signal is clean the subwoofer should be able to handle much more than 600 watts is basically what we are saying.
• 01-08-2012
globalminds_ent
Re: 2 12'' Help
good post here ^^^
• 01-08-2012
globalminds_ent
Re: 2 12'' Help
this should be posted as the the newbie BIBLE!!
• 01-08-2012
globalminds_ent
Re: 2 12'' Help
Can we make this sticky!
• 01-08-2012
i2ain2thunder
Re: 2 12'' Help
The reason for a voltage drop stems from your cars specific electrical needs, remember amperage is your total electrical flow. Standard operating systems in a car including heaterfan, headlights dashlights radio and all electrical stuff is around 60amps. Now most alternators are rated in amps to tell you how much power you have to work with, stock ones are usually anywhere from 80-120 amps. So if your car has a 105 amp alternator stock it has roughly 45 amps extra to supply aftermarket electronics safely. Looking at our amplifiers electrical needs heres where we usually make a decision on how much amps we need our alternators to produce.
How to tell how much power your amplifier truly can do (a basic version)/will need. Basic electrical: Volts x Amps = Watts.
If you look at the fuses on your amplifier or (fuse rating) you will see say for example 4 30 amp fuses, or 120 fuse rating and it says it is rated for 1500 watts rms. Since we now know the amps and we know you want your amp normally operating at between 12-14 volts we can use the equation Volts x Amps = Watts, so 12 x 120 = 1440 (pretty close to the rating of 1500 watts when this happens its a good sign that the manufacturer is not over exaggerating the amplifier's rating)
Many people say fuse rating x 10 but honestly I don't understand that you never wanna send an amp 10 volts, but maybe theres something I don't know.
Anyway so your fuse rating is 120 thats how many amps this amplifier has the potential to pull from your electrical system (it is likely the amplifier will never pull this much juice unless you're just playing a flat 50hz tune on full tilt) So you want an alternator capable of powering your car's standard electrical systems (roughly 60 amps) plus your amplifier which is 120 amps, 60+120=180 so you want an alternator rated at 180 amps or above, in order to avoid dips in your voltage.
• 01-08-2012
i2ain2thunder
Re: 2 12'' Help
^^^this is all the safe proper approach to an aftermarket sound system installation. Honestly there are ways to get by without all this stuff but this is the safe way. Extra batteries can help stem problems in voltage drop, since music is not constantly using the amplifier's power it is possible to get by with a stock alternator and extra batteries sometimes it all really depends, watching your voltage as your system is running is usually the best way to tell if your vehicle's electrical system can handle your car audio setup.
• 01-08-2012
i2ain2thunder
Re: 2 12'' Help
People so often come into this forum and ask what amp and subs and speakers are the "best"
All of us who know the audio field well enough just have to chuckle at the statement, because there are so many variables in how a speaker will sound in a given environment, things come into play like air space (volume) enclosure, speaker placement and angle, the construction of the vehicle itself what the doors windows seats dash everything are made of sound waves will bounce off them differently. The equation and algorithms are so complex that most of us wouldn't logically be able to tell people what the "Best" setup will be, it is also why we all experiment constantly to see how new speakers and placements sound.
If someone wants the truly "Best" setup really God only knows that or an advanced mathematician and audio engineer.
The only thing we are capable of doing is giving people a good place to start, speakers that perform well amps that do rated or better power easily and have good sound quality, subs that are well built and made for different aplications SPL (sound pressure level), SQ (sound quality and accuracy), SQL a mix of the two.

Cliff notes: to answer your question of you want an amplifier that won't make your subs sound like crap...the more accurate statement is you want an amplifier that can adequately power your subwoofer from your electrical setup in your vehicle.
• 01-08-2012
i2ain2thunder
Re: 2 12'' Help
more notes and tips:
Ground connections are very important to do properly. Make sure all grounds are very secure and directly contacting a solid metal surface, that means sanding paint away. Many issues with electrical setups stem from poor grounding at any one spot in the circuit.
Wire selection is important,OFC=Oxygen free copper: Highest quality copper, CCA=Copper Clad Aluminum: most wire is this, this was invented as a cheap effective alternative to pure copper, it is very effective and generally a lot cheaper than pure copper. Size does matter with wire, the thicker the actual copper area the better, many companies claim 4 gauge or 0 gauge wire, but just fill the space with the rubber surround, ends up being more surround rubber than actual copper strands look out for this!
Fuse rating, generally people misconstrue fusing wire as a means to protect the equipment. Fusing is actually meant to prevent wire fires from extreme power surges/heat. However it isn't exactly unpractical to fuse wire close to the fuse ratings on your amplifiers as it will add some extra protection for them on top of their own protection and fuse circuitry. Always fuse any power run, I.E. fuse alternator to batt + terminal for Big 3, fuse Power leads from Battery 1 to Battery 2 and so on, fuse power lead from Battery to Amplifier.
Batteries: make sure "resting voltage" (voltage reading while vehicle is off) is at or very close to 13.7 this is a sign of a good battery, look for any bulges in the casing as that is a sign of a battery gone bad. Any time you are connecting multiple batteries, make sure their resting voltage is a match otherwise problems can stem from what we call parasitic draining, remember current always flows from highest voltage to lowest, meaning if 2 batteries are connected and have differing resting voltage IE. ones is good 13.7 the other is going bad 12.4 the lower voltage battery will constantly drain from the 13.7 battery shortening the life of the good battery.
• 01-08-2012
elballz12
Re: 2 12'' Help
Wow thank you a lot you just helped me out way more that i thought you could. Yes i know its not all about your subs and amp. The box,airspace,wires,batteries, grounds, and many other things. I will be using Kicker 1/0 AWG wires for big 3, Power, and ect. Fuse holders and distribution blocks are necessary as well. As for a second battery and the HO Alternator I have no idea what to get. Have heard good things about XS Power and Kinetic just don't know what battery i need exactly. I just want to do everything the right way the first time and not have to worry about upgrading wires or putting a new battery in later on. Want everything the best way the first time
• 01-09-2012
i2ain2thunder
Re: 2 12'' Help
There are many many posts on high output alternators and batteries if you use the search navigation in this forum you can read up on people's opinions. I'll give my opinion and general layout.

Batteries: A good battery is an AGM Or a Dry Cell battery. AGM's are typically cheaper than Dry Cell's and usually need to be larger to perform the same capacity job as a Dry Cell battery. I believe Dry Cell batteries are supposed to be better for car audio purposes because they release their power quicker and charge quicker than an AGM but don't quote me on that.
In my experience most all batteries are created equal performance wise, they are rated based on how much power they can store total and by how fast they can release that power. Others may dissagree and say one battery is superior to another I'm just saying in my experience I just look at those 2 stats, then check price (value) and customer reviews and warrenties. Batteries Known to be well built for car audio applications: Optima Yellow top or blue top, Odyssey, Kinetic, XS, Shuiriken(think I spelled that wrong), Deka, Batcap.

High Output alternators: What you want out of an alternator, Ratings on alternators should be pretty close to actual operating parameters for just about all alternator companies. You want an alternator that gives you full rating somewhere within your engine's typical driving range, alternators produce more power the higher the RPMs. Most driving RPMs are around 1.8-2.4k RPMs Idle is typically around .9 RPMs so you want an alternator that is rated at full rating at around 1.8k RPM and they are usually around half rating at Idle. Some Well known highly used companies for car audio include: DC Power, Mechman, EA (Excessive Amperage), Nations Auto Electric....theres some others but I forget.

Oh and you are welcome :) glad I could help. I think you are going about things the right way trying to do everything right the first time. I'd suggest looking into some sound deadner at the very least for help with rattles/vibrations, they also improve midbass response, road noise, vehicle insulation all that good stuff. I've never known someone to purchase sound deadner and regret it. I don't have enough experience to tell you exactly what size batteries you need for your application, but I think if you have even just a stock one up front and a decent one in the rear run in parallel it should be just fine with a high output alternator, without a high output alternator I don't know what to recommend to get by but if you go that route at least do the big 3 and get 2 big good batteries.
• 01-09-2012
THATpurpleKUSH
Re: 2 12'' Help
Quote:

Originally Posted by i2ain2thunder
Many people say fuse rating x 10 but honestly I don't understand that you never wanna send an amp 10 volts, but maybe theres something I don't know.

This method takes into account the amp's efficiency. Its not the acutal volts the amp is getting, just a place holder for efficiency. No amp is 100% efficient so they will never output the full power that they consume so the rest comes out in heat. AB class amps are usually around 50-60% and D class amps are 75-85% efficient. For AB amps I like to multiply onboard fusing x 7 (assuming 50% efficiency or 7/14.4) and fusing x 10 (low estimate assuming ~70% efficiency or 10/14.4) for D class amps. This usually gives a pretty accurate figure for 14.4v output at lowest rated impedance- though it is still a rough estimation. My Alpine 4ch has 50a of fuses, is an AB class, and is rated for 75w x 4 and my Rockford Fosgate D class mono has a 140a internal fuse and is rated for 1000 but has a birthsheet of 1399rms. My old Crunch p1500.1 (AB class) had 120a of fuses and was rated for 750wrms, not cea2006 compliant but did close to rated power (I estimate around 700wrms).
• 01-09-2012
i2ain2thunder
Re: 2 12'' Help
Hey thanks bro I got to learn something in here too! Yeah I'm only a novice with the more advanced concepts of electrical theory as it applys to car audio and other things. I'm like an expert in the basics haha, but knowing the basics really helps everything make sense and provides good starting points in building your own system, and probably most important, knowing the basics will help protect your equipment from user error....which is both very common and very costly in this hobby.
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