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Old 09-27-2004, 11:57 PM   #1
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Default Audio Question? Look Here First!

can somebody set up a sticky with a buying guide for beginers? include subs and amps. not whats good and whats not but what we should be looking for when we buy. i still dont understand ohms, or any of that. i know it would be a big task, but if somebody couold do a write up on subwoofer and amp specs i think it would clear up alot of repeated questions in this forum.
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Old 09-28-2004, 12:06 AM   #2
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I'm editing your topic. And I'll create the sticky. Use this topic to assemble a future techinfo article. You must have general consensus, so keep it general. No bitching, fighting, kicking, or biting.
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Old 09-28-2004, 12:44 AM   #3
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Before buying speakers, subs, or amps, consider what you want. Do you want deafing sound levels and quality, or just a little bit better than stock stereos.

A.-if you want a little bit better sound, go for speakers with less ohms. This will mean you will lose less power/watts between the amp/head unit and the speakers. Also means better sound quality. Also consider what watts you will run the speakers at. It would be a waste of money IMO to buy speakers with high watt ratings, and not power them very high. You could also add a cheap aftermarket head unit for a little gain. If you only want a little bit better sound, you might want to stay cheap. Its up to you.

B.-If you want a stereo with deafing power, go for really low ohms, high watts, and good brand name speakers and subs. You should get a good aftermarket head unit, and a good amp. Match the amp according to your number of speakers/subs, and the speaker/sub watt ratings. You cant be afraid to spend lots of money for this.

C.Speakers-I would say go for 2 or 3 way speakers. Get watt, ohm, and speaker quality according to what you want.

D.Subwoofers(Subs)-Remember this-bigger is not always better in this case IMO. Buy according to what will be the best for you, there quality of sound, there watt rating, and there ohm rating.

E.Amps-You should get amps according to what kind of watts you want to send to the speakers or subs. If you are going to get an amp for subs, you might want to make sure it has a low-frequency mode.

F.Head Units-This is pretty much about looks and what you will use it for. If you want to hook up more speakers/subs/or amps, get a head unit with rca cable preouts. Also consider how many watts the built in amp sends to each speaker. Then, it is all about what fits in your car, and its looks.

G.-Good Brands IMO-Rocford Fosgate, Sony, Poineer, Kenwood, Audiovox, and Lightining Audio. I have actually seen and heard all these brands.

H.-Some one help me out on Capacitors, and anything i missed or got wrong.
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Old 09-28-2004, 03:56 AM   #4
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Can't forget about the caps.

1 Farad Cap per 1,000 watts.

Also, when purchasing an amp, you will want High/Low Pass Filters. That way you aren't sending bass to the tweeters, and highs to the subs. You can always get the filters which go inline with the wiring, in case your amp does not have this, but most new amps of good quality will have it. You may also want to consider a "mono-amp" to power your subs. These are linked to giviing more power, according to Crutchfield'* article on setting up your system. Do a little searching there also, they have TONS of info, I learned a lot of what I know, there.

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Old 09-28-2004, 01:57 PM   #5
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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

Fs 30hz
Q .4
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
14 134
13 169
12 213
11 269
10 339
9 427
8 537
7 677
6 853
5 1075
4 1355
3 1707
2 2151
1 2710
0 3414

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

Fuse guide

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
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Old 09-28-2004, 04:48 PM   #6
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Great general resources here...
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Old 09-30-2004, 06:58 PM   #7
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Head Units
Additional Inputs: to connect a music keg or other systems (iPod - PC whatever)
Low-Level Outputs: for sending clean signal to an Amp or other reinforcement gear
12v remote turn on lead and power antenna lead ('tho the 2k has no power antenna)

Other notables: Easy to handle controls - a variety of format support (wma mp3 etc)
power output (especially if the HU powers the front speakers as opposed to amplified)
SatRadio - when we gonna get integrated tuners!

Otherwise the HU world is purely a personal (and pocketbook) pick.

What you'll NEED: - Help me out here folks!
(provide some link'* and verify the accessories that are needed and really work)

Mounting Kit with faceplate (contingent upon HU) (metra)
Remote steering wheel control unit (SoundGate)
Factory Chime Unit
Wiring Harness / OnStar compatability
SIR issues?

The Kenwood units I've installed (6999'*) have all of nearly 1/8" and likely closer,
between the drivers side torsion bar and the magnet, way closer to the magnet
than I realized! Carefull consideration for magnet size and basket depth should
have been more scrutinized. Use the kenwood 6999'* spec'* as a maximum
magnet diameter or physical driver size!

Spend a little more on a high end 2ways and you will not be disapointed.

The sensitivity (Spl) of the driver is what determines where on the power curve
it really hit'* the "sweet spot" and where the driver is functioning at design load.
This is the measurement I use to compare drivers... the old 1watt1meter spec.


Consider what the eventual system will comprise. Going for a Sub? Either
you'll power it seperately (Look at Mono or bridged mono spec'*) or share
an amp with the rear drivers (Look for 3 way or Tri-mode amps).

What to look for:
High and Low level inputs - Provides wiring flexibility, tie into the stock harness for
speaker connections with factory heads and still have the low level capability with
aftermarket HU'* that can be added later.

Low level output - hook-up that mono SUB amp later on!

Output modes - Mono or 2 channel and Tri-mode. Remember that tri-mode configurations
will require seperate crossovers (active or passive) since outputs may not allow LPF
options when running in three way mode.

Hi and Low pass filters - This is just built in crossover networks. Look for filters that are
adjustable with broad slopes. It was nice to enguage the HPF on the main speaker outs
and roll the adjustment to the minimum... Still get some bottom end to the drivers but not
the bottoming out of the drivers with no filter enabled at all.
(The sub rounded out my low end sound issues)

Note that enabeling filter modes generally places LESS work on the amp since full
ranges are no longer being sent to the output stages.

If your going to use the amp for pairs. Keep an eye on XX watts @ 4 Ohm per
channel which is a much better description of the power for this application. I see
many amplifiers sold as 1000w amps that output like 80 watts or so per channel at
4 Ohm. Tricky Tricky. Seems the more expensive amplifiers use this tactic so take
care to apply the actual use of the equipment and gather specifications from that
angle as opposed to total possible output.

I've taken a liking to the all in one units. Infinity & Kenwood both offer a nice
small amp & driver in a box with input sensitivity turn on features. Really nice
tack if your just after a simple solution. There is always the "free box with speaker"
options or build up your own affair. Not much else can be said except this: Size is
not about loud but about Low! Deep and boom'in or pounding and tight are
all about personal preference yes?

Noise Abatement
Short Length Grounds!
Clean and paint free ground contact points fastened with 'star' washers.
Isolate amplifiers from the chasis (fixed my quiet "hum") use rubber grommets where
fastners may contact the amplifier. Also use large rubber washers between the amp
and the chasis, isolate amplifier to chasis contact points. Especially if the amps are
mounted at a point other than the chasis ground point. Some folks use wood
(it'* a conductor!) not real pro-install tho'.

Hi-Level inputs are noisy by nature. Generally most amplifiers that provide Hi-In request
that only the positive lead be wired into the HiLevel harness.

Seperate the power from the source feed. In other words don't run sound and power
together. Usual practice is to power on one side of the car and source feed the other.

Rattle and buzz: Peel & Seal is really good stuff!

Power Re-inforcement
Take that C-Note your going to spend on that LED CAP and use it to install
a real alternator! As the demand on your electrical system increases the charging
system will need addressed. Cap'* have their place but only after the charging
system has been upgraded as required.
__________________________________________________ _______________

Disclaimer: I'm an old geezer and really into Home Theater/Audio
so much of my automotive audio experience is dated.
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Old 10-01-2004, 12:14 AM   #8
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dayum howy thats nuts. this is all great stuff guys, keep it comin! im building up the confidence to write abit myself.
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Old 10-01-2004, 11:33 AM   #9
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Default Wiring Pin-out Factory HU W/O Amp

2000 Bonneville Radio Pin-out W/O Amplifier

}- ( ) Antenna NCA
}- (A1) Computer Data Lines flat 1807 - PPL
}- (A2) Computer Data Lines flat 1807 - PPL
}- (A3) *Switched Power* flat 608 - Pink (w/amp)
}- (A4) FM Comp Signal flat 1488 - Red/White
}- (A5)
}- (A6)
}- (A7)
}- (A 8 )
}- (A9) Com Audio In - flat 372 -Blk/White
}- (A10) L Audio In - flat 367 -Brn/White
}- (A11) R Audio In - flat 368 -Dk Grn/White
}- (A12) Lr Speaker - flat 199 -BRN
}- (A13) Lr Speaker - flat 116 -Yel
}- (A14) Rf Speaker - flat 117 -Dk Grn
}- (A15) Rf Speaker - flat 200 -Lt Grn
}- (A16) Gnd - flat 551 -
}- (B1) Batt - flat 2240 -
}- (B2) Batt | flat 2240 -
}- (B3) Enable flat 1487 - White
}- (B4) Ill flat 1491 - Yel
}- (B5) gnd A pillar flat 450
}- (B6)Amp Sns flat 551 - *gnd*
}- (B7)
}- (B 8 )
}- (B9)
}- (B10)
}- (B11)
}- (B12) Lf Speaker flat 201 - Tan
}- (B13) Lf Speaker flat 118 - Grey
}- (B14) Rr Speaker flat 115 - Lt Blu
}- (B15) Rr Speakerflat 46 - Dk Blu
}- (B16) GND flat 551

Cd Changer
}- (1) L Audio Out 367 Brn/White
}- (2) R Audio Out 368 Dk Grn/White
}- (3) Audio Com 372 Blk/White
}- (4) Shield Gnd 1782 NCA
}- (5) Batt 2640 ORG
}- (6)
}- (7) Gnd 551 Blk/Wht
}- ( 8 )
}- (9) Serial Data 1807 Ppl
}- (10) Serial Data 1807 Ppl
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Old 10-01-2004, 01:33 PM   #10
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You pretty much have most of it covered there, good job, however, i think it could still use a few more specifics. Look on for more info on how electricity and speakers work and all of that
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