Posts like a Corvette
Join Date: Sep 2003
Location: springfield il
The first thing you want to do when considering a car stereo setup is to figure out your goals and how much you are willing to spend to achieve them. Obvously price is the most important factor because you dont want to go out and buy the most expensive sub and not be able to afford an amp for it or an HU. IF you wanna know how a speaker is gunna act, then you can look at the theile small peramiters. These arent always a sure thing but they are a good starting point. Box size and location also have a lot to do with it.. I cant give you all of them but i can give you some of the more common and simple ones such as:
Spl: AN efficiency rating meant to tell you how the output of a particular speaker at 1 watt and 1 meter away from the speaker. Expressed in db
X-max: how far the speaker moves in a straight line in one direction before the cone flexes and causes distortion.
Fs: the frequency at which the speaker will perform the best. remember, box size and other factors also affect the overall fs of the system, there is a difference between the fs of the speaker alone and the system fs.
Qts: the amplification of the resonant freaquency of a given driver. The higher the q of a the driver, the louder it will be at Fs. Ported boxes often take advanage of this quality and this is how they are able to get so loud.
Vas:The volume of air that offers the same resistance on the cone,* movement as the cone'* suspension
With some of these numbers you can calculate the response curve and the spl of any given box, and here its how its done in a closed box system. The first thing you need to do is determine what kind of a Q you want the system to have. Typical Q values range from .7 to about 1.5 with .06 having the flattest response curve, meaning it would be the most musically accurate, and 1.5 having the loudest bass response; Anything in between would be just a trade off between the 2. In an example ill give you to kinda help you along, im aiming for a system q of 1.2 . The speaker has the following peramiters
Vas 10 cubic ft.
When all of this has been established find the ratio of closed bosx Q to the free air Q, which in this instance is
Qcb/Q= 1.2/.4 = 3
The ratio is also the same as your closed box resonance to free air resonance which would give you a system resonance of 90 hz.
Speakers: Remember that size is a very important factor when choosing any speaker, Any size speaker can sound just as good as the next if it is crossed over right and the proper box size is applied. 15s are usually the biggest you want to go, because they can usually go low enough to drop out of your hearing range, which is 20 to 20k hz. 10s and 12s are more common because there is usually more music at higher bass freaquencies. A very low percentage of music below 40 hz is actually on most common songs when compared to how much is played above that number. Which brand you choose is very important as well. You should only pay attention to the rms power rating, the peak ratings really dont matter. Look for a company that has a good reputation about being honest about the speakers specification, and most mainstream brands arent, they are built more on good marketing than good speakers. A few good affordable brands are elemental designs, adire audio, infinity, power acoustiks; kicker and rockford fosgate have some affordable equipment in their lower lines as well.
What you will need to install it: speaker wire and maybe some crimp connectors, and a few screws
[b]Sound deadening:[b/] There are more than enough sound deadening options out there, and obviously some are more expensive than others, however, the main difference between brands is how well they stick. There is also a way to make home made sound deadening using peel and seal insulation and maybe some spray glue if needed. When applying the sound deadening, the most effective way get rid of trunk noise is to sound deaden EVERYTHING this includes parts of the car that you might not be able to see, but can still rub together, such as removing the trunk lid and sound deadening the bars that the trunk itself bolts to. Make sure that you also sound deaden all visible surfaces and make sure that it is complete. If you want to go all out, then sound deaden the entire trunk lid all the way to the edge, chop off the large excess peieces and then shut the trunk lid, and go around it with a razor knife and cut off what you can see in the gap. sometimes also aiming the speakers in a way that will relieve preasure in the trunk could also help to eliminate rattles, such as aiming them through the blowthrough in the back seats or maybe remove the rear 6by9s and point the speakers up through the holes, however beware that some of these techniqes can add to your overall spl and some can take away, experiment and find out what is best for you
Head Unit When your choosing an hu, look for something with high voltage preouts. 2 volt rms will usually give you pretty good soung quality, but if you can, aim for something with 4 volts rms. Also look for something that has DACs and high tolerance parts. And if your going to buy something with a motorized face, you want to get sometihing from a good brand, not a less expensive one that will wear out quickly.
IN most instances, features are what determine pricing, you might see the same cd player cost 50 or 100 bux extra because it can play mp3s and has a fancier face. If your going to buy something with a motorized face, you want to get sometihing from a good brand, not a less expensive one that will wear out quickly. The most important feature, you can get in a deck is time delay, this allows the sound coming from the speakers to arrive at your ears at the same time, which is key to sound quality.
Nakamitchi and eclipse are the best brands, everyone else comes in second.
What you will need to install it: an installation kit, a wiring harness for your specific year and trim level, and maybe a harness for the steering wheel controls if you want it
Amps: When it comes to amps, consider the honesty of the brand. Yes your 2000 watt may be able to push 2000 watts, but it can only do it at 17 volts for a millionth of a second before it blows up or catches on fire. Be sure to pay attention to rms power ratings, the peak ratings dont really mean as much because an amplifier can only put out that much power for a very small ammount of time before it is damaged or blown. Dont only look at power ratings, but also look at impedence, which is very important, because if you run your 1000 wat amp that is rated at 2 ohms, in 4 ohms, it will only be putting out half of its power potential. Also look for crossover slope, 18 db/octave is usually good, but if you can, get something with a 24 db slope to be sure. IF your looking for sound quality, then look at the THD rating, which stands for total harmonic distortion. Try to select something with a THD rating of .1 or less because you cant hear anything below that level. Despite some people'* belief, wieght doesnt always mean anything, because some manufaturers design amps to have small and cheap circuitry housed in a beefy looking heavy heat sink. There are several different classes of amps but most of them either fall into one of these classes or are close variations of one of these 2 kinds of amps. The most common is a class D amp, which are always single channel amps and in most instances, they sacrifice clarity for efficiency, however in most instances, you wont be able to tell very much of a difference if any between a class D and a class AB amp. THis brings us to the second kind, which is a class AB. They are geared more towards sound quality, however they are extremely ineffecient, they usually have very little distortion but they also tend to heat up a lot and should be put in an area that is well ventalated or maybe even fanned. There are numerous good amp brands out there, such as jbl, elemental designs, ...............
What you will need to install it: power, ground and remote wire
Crossovers: Really isnt much to them, the most common kinds are: 6db per octave through 18 db per octave. Rarely will you see a crossover that is greater than 18db per octave, but i have seen them as high as 36. In most cases, An 18 or 24db/octave curve is good as a low pass filter for most subs, while id sugguest setting a 12 db/octave curve for the high pass filters on most midranges/ midbasses, that way it will blend a little more with the subs. Remember to set the filter a little higher than the lowest octave the speaker can play so you wont damage your speaker with freaquencies it cant play
wires For the most part, wire selection is simple, the most important part of it is choosing the right size, because if you dont you can risk starting a fire and yes it has happened before, although it is rare. Below is a wire size selection guide. You also may want to choose oxygen free wires because they wont corode as quickly, although if you dont plan on having the stereo for more than a few years, this wont be important. I usually use the walmart wiring kits, because they are the best value, for the most part, the more expensive kits are just for looks
Wire size guide
Wire awg Max total power
IT is also important to note that this is only a guide for using power wire, it is not neccessary to use a lager wire for your speaker wires. This guide is for class D amps, if your running a class AB amp, you may want to step up one size larger to make up for the lack of efficiency
Charging system: A large percentage of aftermarket stereos will require anything more than a good battery. Most people choose optima red tops, but there are others, the most important thing is to make sure that you have a strong battery that can hold a charge. IF your going for a larger system, say over 800 watts rms, it might be a good idea to upgrade your alternator too. i think a 160 would be good most of the time, you dont want to constantly pump too much of a charge into your battery because you can ruin it like that. Capacitors are also an option on smaller stereos, but in my opinion, a better battery will usually do the job.
setup: The most important part of any stereo system is the setup. it can make or brake any system, and this is how i usually do it; Lets start with the head unit, in most instances, a head unit will usually have preset eq curves, and they are sometimes the best choice for novice begginers. Whatever you do, dont turn the bass and the treble all of the way up, and usually fading most of the sound to the front will help project a better musical image. Onto the wiring, you always want to run your rca cables and your power wire on opposite sides of the car, not doing so can cause innerferance and ground noise. There are a thousand different ways to hide it but what i usually do is runi it through a hole in the firewall on the driver'* side behind the strut towers and about 3 or 4 inches down, and then to get it into the back seat, the best way would be to remove the rear seat and run it through the holes for the trunk wiring, that way it wont snake alont the bottom of your trunk and it will be out of sight. Up next comes the most common mistake in all stereo setups, setting the gains on your amplifier, the gain is not a volume ***, it is simply meant to match the preout voltages when you have a setup with mulitple manufacturers, i usually set it a little above half way, but this isnt always the best case, because different equipement requiers different setups, The best thing to do is to turn the radio up a little bit above the volume level you will usually be listening to it at, then turn your gain **** all of the way down, then slowly turn it up until you hear distortion, then back it down a little. IF your amp has a bass boost, its best do the same, but set your gains first.
How to achieve good sound quality: The most important thing is to make sure your head unit is equiped with time delay and that your delays are set properly. What time delay does is it puts a delay on the sound coming from the closest speaker to you so that the sound from each speaker hits your ears at the same time. This can make a huge difference in the higher freaquency ranges where there are only fractions of a second between when the sound waves contract and expand, that time, by the way, determines freaquency. Also try to keep it as simple as possible, having too many devices that manipulate the signal can add too much nosie, however you dont want to go too far and not have everything you need, because in most instances, this wont make a huge difference. The same thing applies to speakers, you should never have multiple drivers playing the same freaquencies, aside from subwoofers, because you get too much phase variance. In some instances, however, it is best to have an extra set of tweeters somewhere up high, such as the pillars so that you avoid a rainbow affect in your imaging. In sometimes you will need that, in sometimes you wont, use your own best judgement. If you want to get into fabrication, you can try ur hand at some kick panels or maybe some other kind of setup that points the speakers at your ears. Despite popular belief, the midrange freaquencies are the most important because your ears are the most sensitive to midrage freaquencies, and having them off axis can change the tone of the sound and pointing the speaker at different parts of the car can alter the kind of sound that comes out of it, for instance whenver a sound wave hits different kinds of surfaces, it can actually switch polarity.
Box calculations: 1 x 0.7937 x 1.2599
93 green and gold ssei w/ all the options
Performance mods: 2.2" pulley, dp.com cai, lucas 42.bs/hr injectors, mini-afc 2.0, gatorback belts magnaflow high flow cat flowmaster 80 series muffler optima red top battery KYB GR-2 front struts
In the works: fiberglass trunk installation, 2 6.2 widescreen tvs in visors
Stereo: alpine 9831 cd player
ample audio exonic silk dome tweeters
Adire audio Koda 6 midbass
Pheonix gold Octane-R 5.0:4 amp
2 Elemental Designs 0v2 15s and ED 9.1 amp--
sitting in the closet--Nx express wet kit, autopage alarm 63 cam 200 amp alternator
Future: currently saving for transmission