COMMON SENSE
ALWAYS DISCONNECT THE NEGATIVE TERMINAL OF THE BATTERY WHEN
WORKING ON YOUR SYSTEM.(This is not a rule, it is a LAW and should
only be broken by God's and anyone who thinks that dying is an acceptable outcome!!!!)
HEADUNITS
Always buy
the best Head unit you can afford and choose a well known "car audio" brand(not
someone who makes microwaves, hair dryers, and camcorders, etc). A couple of hundred
dollars more on a high quality head unit may mean you get great results from a fairly
moderate system. Remember if your source signal isn't nice and clean, then the best amps,
speakers, or filters, etc, in the world won't make poor sound better.
If you plan on using Power
Amplifiers to increase your system output (Volume), then a head unit with a High
Voltage(4volts or more) pre-out's is recommended. These types of head units allow you to
run your amps with the gain settings at the minimum posistion which has the benefit of
reducing or eliminating background hiss, as well as allowing you to produce full rated
power from the amp without clipping(distortion).
Inbuilt
sublevel controllers are better than having no control at all, because you need some way
to adjust the level, as the amount of sub-bass on different CD's varies dramatically.
Personally I have found that an outboard or independent control is the best option. It
allows you to adjust the level without having to go thru a series of buttons presses to
access the level control, which can be a very urgent adjustment if your subs are
"letting go" when a surprise bass note catches you pushing things a little bit
too hard.
A remote
control, to many people often sounds like a stupid idea, because its not often that you
will be in the backseat and cant reach the unit, but the whole point of a remote is that
you use it with your eyes on the road, not the radio. The remote often allows you to do the
most common functions ie change track/station/disc and volume by simply feeling for the
right button.
SUBWOOFER 'S
When
designing a system, it is a good idea to keep your subwoofer size within 2 sizes of your
midbass driver ie: in a 6" 4" 1" 3-way front system or 6" 1"
2-way front system then 10" subs would tend to blend in better than 12" or
15" but if you are running 8" 5" 1" 3-way system or 8" midbass
with horns (HLCD) then 12" subs would tend to blend better etc
If you
would never consider adding a subwoofer to your system, then please leave my site
immediately. You do not belong here :) .Attention to the Sub Bass end of the Music is what
separates the great systems from the other's. If you didn't have two octaves of the
midrange playing, you wouldn't expect great sound either.
Sealed
boxes tend to have a better low end extension than other designs. They tend to have
predictable performance, and are simple to design and construct but they are not very
efficient and typically require plenty of power to perform properly. They also have good
transient response (ie: tight Bass)
Bandpass
boxes (NB: I do not recommend this design) tend to have a significantly higher
output than other designs. But sacrifice low end extension to achieve this. They are also
very efficient, and so require very little amplifier power to achieve huge
output (volume),
but usually require very large boxes. It is also very hard to hear a speaker unload and so
blowing up speakers can be fairly easy. This type of design can easily produce listener
fatigue with anything but relatively short periods of listening at moderate
volumes. They
tend to have fairly low power handling ability but due to there efficiency this is not a
problem. They tend to need large boxes and suffer from high group delay
errors (ie: Lag in
timing or delay of the bass note compared to the sound from the full range speakers),
depending on how high the order of the box design is (ie: 4th or 6th order). They can
sound O.K.(?) with dance and techno.
Vented
boxes tend to have a slightly higher output than Sealed designs but need bigger boxes to
achieve it. The vented box also sacrifices some bottom end extension to create a higher
Output, but if designed correctly this is not a problem. Vented boxes have poor power
handling below the Tuned Frequency of the box.It is always a good idea to use subsonic
filters (to remove power stealing ultra low bass ) with this design so as to protect the
speaker, and to make sure all the power available is used for audible output. This design
can suffer from poor transient response and high order (ie: 4th & 6th) box designs
will have substantial Group delay errors.
Free-Air
(Infinite baffle) subs can sound fine if mounted on a very solid, well sealed baffle and
are capable of very high transient response (ie: tight bass with virtually no group delay
errors). But have low power handling capability.
FRONT SPEAKERS
Front
Speakers usually work better if High passed filter at 80-100 Hz or above but if you run
8" speakers up front you will be able to go lower and conversely if you run 4"
speakers you will have to high pass at a higher frequency ie: 150 - 200Hz or more
Front
Speakers should Ideally have their tweeters mounted below glass level to stop them being
overly bright and to stop separation of bass and treble, if your tweeter is more than a
hand span or so away from your mid bass drivers you may perceive separation.
Speakers
mounted below dash height can still sound like they are actually at dash height, if
mounted correctly and the rear speakers are at the right level (volume), suitably
bandpassed(400Hz-7000Hz) and ideally in mono.
The front
speakers are critical for good sound quality so taking the time to listen for the right
ones is very important, it will also allow you to save for the money that good speakers
cost or to get the ones you want when reduced at a Sale. Dont worry about price, as you
will Know how much to spend when you hear the right speakers. You dont need "golden
ears " to hear good sound quality but you do need patience and a healthy budget never
hurts.
You should
choose the biggest speaker's you can fit up front like a 6" or even better 8".
The bigger you can fit the more midbass you will get. If you have a strong source of
midbass upfront, then your subs will tend to sound like they are up front as well. A very
desirable outcome.
You
should not mount an 8 " speaker in a door as it will be almost
impossible to stop door vibrating excessively. A a custom box in kick
panels or floor is the best method as box will be tiny, as speaker only has
to get into Midbass range and not to sub bass range
REAR SPEAKERS (optional &
not recommended)
Rear
Speakers (except subwoofers) should be band passed from at least 400Hz
(ideally1500Hz) to 7000hz and ideally,
be in mono. They or it (one rear centre speaker in mono instead of the traditional pair,
can help improve stage height up front) should also be low powered.
A cheap way
to get a band passed rear speaker/s set-up, is using a cheap 2 way co-axial speaker/s
(factory fronts maybe???? Just kidding, no one should be that cheap:) and simply cutting
one of the leads going to the tweeter/s (ie: the 2 leads between the front of the big
speaker and the smaller speaker in the centre). To filter out the sub-bass and mid-bass
from the speaker, use a capacitor between the positive terminal of the speaker and the
positive lead (I'm not sure what value capacitor you use for a 1500hz high-pass filter but
your local car audio shop should be able to tell you exactly). You should be able to do
this for well under AUS $100 , which could allow you to spend more money some where more
important in the system ie: your front speakers.
ACTIVE vs PASSIVE
Active
systems RULE . An active system is one with amplifiers dedicated to separate parts of the
audio spectrum ie one amp for bass, one for midrange, and one for high frequency.
One of the main
benefits, is that if you get distortion in the bass amp (for example) it is unlikely to
affect the other amps and vice versa.
Active
systems can be more flexible as to crossover points, level etc. So can be adjusted more
specifically for the individual car and components being used.
CABLE & WIRING
What ever
gauge positive power cable you use to an amp or from the battery, match or exceed it on
the negative cable
Ground all
amps/components/processors/etc at one spot.
Keep all
ground leads as short as possible.
Always use
good quality (twisted pair) RCA leads. They may reject noise better and may
also help with
frequency response and separation.
Don't cut
corners when it comes to connectors, the cheap ones look like the quality connectors but
use cheap materials and plating. If you've spent good money on your equipment, why start
trying to save a few bucks on connectors that may limit the potential of your
system, or
worse, be a fire hazard.
6" X 9" SPEAKERS (YUK!!!!)
Never ever
use 6"x9" speakers! unless they are up front in the kick panels, or at worst
,the doors but never the rear parcel shelf. Subwoofers produce subbass, 6"x9"
speakers produce midbass, midbass belongs up front. Subbass has no direction, and can
therefore be mounted in any part of the car, making the rear O.K. . 4" or 5.25"
speakers usually make the best rear fill speakers because of there lack of midbass. If
your midbass comes from up front ,your ears will assume the subbass comes from there as
well, but if you have strong midbass in the rear , your ears will hear the subbass coming
from the rear (never desirable).
SOUND DEADENER
Sound
deadener is always a good idea. If you reduce outside noise, and reduce vibrations , you
end up needing less power to do the same job, or you get increased volume.
You will also
get improved sound quality out of your components.
SURROUND SOUND
