Speakers - How They Work and What They Do

After the response from the power capacitor article,Subwoofers come in a variety of sizes usually 8, 10, 12,
there have been many requests for an article on15 and 18 inches. They are used to produce the low
speakers and which ones are the best to have as wellfrequencies. Almost all subwoofers are amplified due
as how to choose the speakers for your ideal carto their demand for high power; however a few head
audio system. So if you want to know the basicsunits and subwoofers from pioneer are able to work
behind creating a car audio system so great that ittogether without the use of an amplifier. Some
almost feels as if Linkin Park are rocking out in yoursubwoofers require an enclosure, this may be a sealed
back seats while Jay Z is sitting next to you telling youor vented enclosure with some subwoofers being
about his 99 problems, then you'll want to give this afree-to-air, i.e. they will work without the use of an
read... just my 2 cents...enclosure, and however these subwoofers on
Speakersaverage require more power than a subwoofer of
Speakers (drivers) are a vital part of car audioequivalent sound output that requires the use of an
systems. They take charge of reproducing the soundenclosure. Free-to-air subs have also been
from electrical to audible. They work by vibrating thecommented on by many people who say that they
air around the speaker when an electrical current isfind that type of bass that is produced is not of the
passed through them. This is why it is important tosame standard or quality even though they are rated
choose the best speakers that your budget will allow.at the same power. There are also active bass boxes
This will give you end impression that you would feelwhere the amp, subwoofer and the enclosure are all
that you were in a live concert hall; with the artist nextbuilt into one unit however they, on average tend to
to you actually singing live!have a lower power output than say a separate sub
Types of speakeramp combination. This is why many people will choose
There are usually four types of speaker used in caran enclosure type subwoofer. The presence of a port
audio set ups. For the low end of the sound spectrum,will adapt the type of bass produced. With a port,
subwoofers and mid-bass drivers are used; the middlemany people find that there is more bass produced
of the sound spectrum is taken care of by the(as the subwoofer is moving the air through a tuned
mid-range drivers while the high end is reproduced byport, however there is less definition in terms of the
tweeters. There are also speakers such as 6x9's thatsound. With a sealed enclosure however, the bass
are able to produce a broader spectrum of soundproduced can be described as more of a tighter
than a standard midrange driver on its own forsounding bass as the air is moved inside the box,
example and also the design of the speaker varieshowever the use of a sealed enclosure will also put
depending on the intended use.more strain on the subwoofer, due to the pressure
Tweeterslevels built up inside of the enclosure.
Tweeters are used to play the high end of the soundWhile doing some research for my enclosure, I found
spectrum. Due to the nature of the speaker, either anthat the size of the enclosure makes a massive
inline capacitor or a crossover is used to filter thedifference. After choosing the Kicker L7, I had two
sound out to ensure that only the frequencies that theoptions for my enclosure, to either use a sealed box
tweeter is designed to play are sent to the tweeter.that would be very small (the benefit would also be to
The crossover may also aid in reducing damage tosave space) or if I wanted to use a ported box, then
the tweeter, as well as increasing efficiency of thethe size would be much larger and the effect of the
speaker. With my car, I chose to install a separate pairbass would be different as greater pressure levels
of JBL GTO-18T tweeters that are running directly ofcould be built up inside the car with a slot ported box,
the head unit. This is purely to aid my pursuit towhich is why I chose the ported box.
produce a special sound in the car as opposed to justPower ratings
sound coming directly from the speakers.Power ratings determine what power each
Midrange speakercomponent is able to handle at continuous and at
The midrange is a vital part of a car audio system. It ismaximum. For example, a speaker may have a rating
in theory possible to run a car audio system solely ofof 45w RMS and 135w MAX. The RMS indicated is
midrange speakers however for someone wishing tothe maximum amount of continuous power that can
recreate sound at a high level, it is unheard of. Therun through without bringing about damage to the
midrange speakers come in a variety of sizes to fitcomponent and the max is how much power the
the different door panels. Unlike subwoofers forcomponent can handle for a short period of time this is
example, midrange speakers are able to run directlywhy it is important to ensure that the components are
off the head unit however it is common to see that ifnot supplied with too much power. Most head units are
the head unit is turned too high, then distortion can becapable of producing 50Wx4 max on average
heard (clipping). This is why many people choose tohowever some amplifiers are able to produce 50Wx4
add an amplifier to amplify the signal sent to theRMS and upwards. For my set-up I went for a system
midrange speakers so that at high volumes, a cleanerwhat would be able to output 50Wx4 rms. I felt that
signal is being sent to the speakers. Again some willthis would result in a small enough amplifier as well as
choose to use a crossover system to limit certaingiving me the midrange punch that I desired.
frequencies to be reproduced by the midrangeOther speakers
speaker. There are two types of midrange speaker,Traditionally speakers come in round shapes. However
component and coaxial. The difference betweenthere are speakers that come in different shapes and
component and coaxial is design. With a pair ofsizes. For example, recently, companies such as Kicker
component speakers, the tweeter is separate to theand Sony have released subwoofers that are
main driver whereas with a coaxial speaker, the designdifferent in size to the traditional round subwoofer.
is of an all-in-one nature. The difference is in the typeThere are also oblong shaped speakers such as the
of sound produced. As coaxial speakers are all in one,popular 6x9's, as well as 4x6, 5x7 and 6x8.
the sound comes from one location, however withThere are tweeters known as super-tweeters. They
component speakers, the tweeter is separate thus it isare similar to tweeters in the sense that they produce
able to achieve a more spatial sound. Due to thethe high end frequencies however they able to
benefits offered with a set of component speakers, inproduce frequencies that are beyond that of
my car, I have chosen to use one pair of JBLconventional tweeters. Bullet tweeters are a type of
component speakers to act as the 'front speakers' assuper tweeter. They are called bullet tweeters due to
well as a pair of JBL coaxial speakers as 'reartheir name. They usually work by having an inline
speakers' even though they both have been installed incapacitor when connected to a signal. Some people
the door. The reason for this is that my car, out of thechoose to use piezo electric tweeters in their cars in
factory only has 2 speakers, one in each door. Thisaddition to conventional tweeters. The piezo electric
left me with the problem of how I was going totweeters, like the bullet tweeters are known as
achieve a spatial sound. To go about this, ideally Isuper-tweeters and are chosen due to their high
needed to have another pair of speakers acting aspower rating and their durability. The piezo tweeters do
the 'rear' speakers. This is why I had chosen to use anot require anything to limit the frequencies that are
set of coaxial speakers for the rear speakers and adelivered to the component due to the way they are
set of component speakers for the 'front' speakers.manufactured, their high impedance acts as a filter.
The idea of this would be to achieve a surround soundSome people however find that the sound they
from the system while inside the car, and given theproduce is not of very high quality however I'm yet to
conditions I had to work with, I'm pretty happy with thetest out a pair of piezo tweeter in my system, but it is
turnout of the overall system.one of the next additions I am looking to install.
Mid bassConclusion
Mid bass drivers produce frequencies between theAt the end of the day, it is important to keep in mind
subwoofer and the midrange speakers. Some peoplethat if you're looking for that full bodied sound that you
argue that they are not a vital part of a system whileensure that your system is able to reproduce the
others swear by them. For some simple systems, thewhole sound spectrum, this will include a subwoofer of
mid bass driver can be a vital tool if someone is aimingsome sort for the bass, usually many people bypass
to achieve clarity over loudness, as again, it would bethe mid-bass drivers and will use midrange drivers as
separating the sound spectrum even more to each ofwell as tweeters and this will be enough to produce a
the components so that fidelity will be increased. Forfull sound. I personally have a pair of coaxial and
my project, I had decided against the use of mid basscomponent midrange speakers, a pair of bullet
drivers purely dude to space confinements of mytweeters and a Kicker L7 to the end result being
project car.enough to bring a smile to my face every time!
SubwoofersHope this was helpful.