Making the Connection
ACI's Guide for Hookup/Installation and Setup of Stereo and
We'll give it to you straight . . .
whatever you're thinking, the reality is it's probably easier and
simpler. Hooking up a stereo is not rocket science, but it can be a
bit confusing. Use this guide to have your system up and
running in no time:
Unsure of the meaning of certain terms? Use the ACI
Basic hookup is very simple. Speakers
require a connection to an amplifier. The amplifier might be a
separate component, or it might be built into a receiver or
integrated amplifier. All amplifiers have output terminals. For each
channel there will be a positive (red) and a negative (black)
terminal. A stereo amplifier will have a left and right set of
outputs. It may also have a second set often labeled "B".
The "B" output can be used to drive a second set of
speakers, for example, extension speakers in the kitchen.
Amplifier to speaker hookup is accomplished
with speaker wire, (see Cables and Connectors).
two channel speaker hookup
click on image to enlarge
Most important: Make sure that you connect
amplifier positive to positive at the speaker and amplifier negative
to negative at the speaker. If you are wiring a five or seven
channel home-theater system, the principles are exactly the same.
Speaker level signal has been amplified to
provide the voltage and current necessary to power the speaker. In a
basic stereo system there will be a left and right channel, each of
which will consist of a positive and negative connection. Many
receivers add a second set of outputs for extension speaker use. A
Dolby Pro-Logic Receiver has five speaker outputs for left, right,
center and two rear speakers. Newer multi-channel systems utilize
even more channels. 7.1 for example consists of left-center-right,
two sides and two rears plus subwoofer (LFE) channel.
Because the speaker cables are carrying an
amplified signal, they must be of sufficient thickness to carry the
signal without excessive resistance. The longer the cable run, the
more resistance. Cable thickness is measured in gauge, with the
lower numbers indicating thicker wire. 18gauge cable is the thinnest
that is recommended for speaker use. If the wire has too much
resistance, the amplifier will not have as tight a control over the
speaker, (the electrical damping is reduced).
wire gauges are as follows:
Under 15ft - - - 16awg
Under 30ft - - - 14awg
Over 30ft - - - 12awg
It never hurts to use a
thicker gauge wire!
Bi-wire speaker cables: Two speaker cables that
share the same terminals at the amplifier end but have separate
terminals at the speaker end. The separate terminals are for
attachment to separate woofer-tweeter terminals on the loudspeaker.
Shotgun speaker cables: Two speaker cables that are
"doubled up" to provide twice the amount of wire.
|Spring Loaded Push-In Cconnector
|Inexpensive. Easy to use
with bare wire, tinned wire or pin connectors.
May accept spade lugs if the spades are
spread apart with a pliers.
|Most are of relatively
low quality. The springs can break. Most do not easily accept
spades or banana plugs.
|5-Way Binding Post
||Accepts all the common wire
connectors. Electrical contact is very good if the wire
connector is good.
Many are gold-plated to eliminate
Good 5-ways have a large enough center
hole to accept heavy wire gauges.
|More costly than
spring-loaded push terminals.
Be careful with 5-ways that can be
torqued down with a wrench; it is possible to break the shaft!
Huge variation of quality and
Connectors can also contribute resistance and loss. The main
types of connections used for speaker hookup are:
|Least expensive, virtually
no contact resistance when new, easy to do.
||Frayed wires can cause
electrical shorts. Bare wire oxidizes causing excessive contact
resistance if not cleaned frequently.
|Just requires the addition
of solder. Correctly soldered ends won't fray. Wire won't
oxidize, very inexpensive and easy.
||Can corrode over time causing excessive
||Quick hookup and disconnect
from 5-way binding posts. Solid electrical contact. Won't
oxidize or corrode if gold-plated. Clean look.
||For the least oxidation, the
spade connector and the binding post it is used with should be
the same metal, preferably gold plated.
|Very fast hookup and
disconnect from 5-way binding posts. Good electrical contact IF
the plug has strong springs. Clean look.
||Some bananas have only three or four springs, and
those springs may not maintain enough tension to minimize
contact resistance. The gold-plated bananas with 9 springs are
usually of high-quality.
||Neat, quick connection with either spring loaded
terminals or 5-way posts.
||More contact resistance than spades/bananas/ bare
wires because of less contact area.
Line Level & Digital Connectors
level refers to a signal that is essentially unamplified. The
line-level signal may be from a Tape Deck, CD Player, DVD Player or
Pre-Amplifier. Most stereo systems use RCA jacks for line-level
input and output. The interconnect cable used is usually shielded to
prevent pickup of hum and noise. A properly shielded RCA
interconnect with good connections is usually quite immune from
noise pickup. Powered subwoofers often have line-level inputs as
well as speaker level inputs..
Some systems use balanced inputs and outputs which are terminated
with XLR connectors. Balanced systems are common in pro-sound
applications because the XLR connector is much more "secure"
than an RCA and balanced runs are almost completely immune to any kind
Digital connections are often made between a source such as a CD
transport and a matching DAC. These connections are usually AES/EBU (XLR)
or RCA ended.
Most subwoofers offer the choices of line-level hookup or speaker
level hookup. Here we'll deal with the methods to install the ACI
Titan and Force subwoofers. Other brands of subwoofers are likely to
have similar hookup capabilities, refer to your owner's manual for
Titan & Force
The Titan and Force utilize the same electronics package. The built
in powered amplifier has RCA line-level inputs for left, center and
right channels. Any combination of inputs may be used depending on
your system. The amplifier does not have speaker level
inputs. However, speaker level converters are supplied for the speaker
outputs of a receiver or integrated amp. There are a number of ways in
which these subs can be installed in any system. No matter which
hookup option you choose, it is important to note that no
power is drawn from the main system...
Titan and Force Hookup / Diagrams
Integrating the Sub(s) into your System
Integrating a sub(s) is a process that requires following
ordered steps. Some rooms/systems are easy, and some systems are very
time consuming. The key is to eliminate each variable one at a time.
It really helps to have a test CD with some pure sinewave tones. These
can be had for as little as $10 in the stores. Second best is a CD
with a very repetitious bass line. (Note: ACI includes a FREE setup CD
with the purchase any ACI subwoofer.)
1) Set crossover frequency at 100Hz and adjust level to be easily
audible. Using your test CD with a tone at about 100Hz or repetitious
bass adjust phase switch for maximum output at the listening position.
This is most easily accomplished with an extra person to throw the
switch or adjust the knob.
2) Turn frequency and output controls all the way down. As you play
music with a repetitious line, adjust the bass level upward until just
3) Turn frequency control up gradually until the bass seems full,
then back it off just a bit.
4) Sit back and listen with a variety of music, play with only the
level until it seems just right, you're just try to fill in the bottom
so most likely the level control will be just barely on.
5) IF the music seems to lack warmth, try adjusting the frequency
control up just a bit at a time. Too much, and the sub becomes easily
audible by itself.
You'll never get it perfect for all music because
the music isn't recorded consistently! If you try to use the sub to
adjust for recordings that lack bass you'll go nuts, adjust to well
recorded music and leave it alone.
IF your main speakers have ports (vents) try
stuffing them, this often improves the transition drastically.
IF you have a separate amplifier, use the passive
plug-in high-pass filters, they make major improvements.
The proper placement of speakers in your room has a major
impact on sound quality. Because all of our rooms and tastes are
different, it is impossible to specify a "correct"
placement. Instead, let us present you with some acoustical facts,
then you can optimize placement in your room.
It helps to visualize sound waves as behaving very much like water
waves. The sound we hear is made up of two types of waves. Direct
sound waves come directly from the speaker to our ears.
Reflected waves come to us after bouncing (diffracting) off the
speaker enclosure itself, or walls, ceiling, floor or furniture. If
you want to see how much these reflected waves affect the sound, move
your speakers outside and hear the difference!
Sound waves come in different lengths; the lower the note, the
longer the wave. Extreme low frequencies such as the lowest organ
pedal notes are over 60 feet long! The biggest problem with bass
notes is the phenomenon we call standing waves. In effect the waves
"pile up". This creates big peaks and dips in the bass
response. If you put a low frequency test tone through the speakers,
you can walk around the room and find places where it is very loud,
and places where you perceive virtually nothing.
Just as the room affects the bass response, so it affects the
mid-treble sound of the system. In the mid-treble range, the sound
waves are shorter and have peaks and dips, most of the affects (peaks
and dips) occur from enclosure edges, furniture, walls, or the floor.
The shorter wavelengths of the mids and highs are more easily absorbed
than the longer wavelengths of low frequencies. This is why a bare
room sounds so harsh compared to a room with a lot of stuffed
furniture, carpets, drapes, etc.
An ideal setup for sound would be achieved if you could:
- Choose a room with width, height and length dimensions that are
not multiples of each other. (A cube is the worst!) Good numbers
might be something like, height = 8 feet, width = 15 feet, and
length = 26 feet.
- Choose a room that has an irregular shape, non-parallel walls
cut down on standing waves.
- Place the speakers so that the woofer cones are at irregular
distances to the floor, walls and ceiling. This can be difficult.
Use a tape to measure the distance from the center of the woofer
to the room boundaries. Move the woofers around till you have cut
down on the number mathematic multiples. (You donít want
distances like 12 and 24", but more like 12 and 22").
- Use the distance from the woofer to the boundaries to increase
or decrease bass output. Sticking the speaker in the corner or
close to walls will give more bass output than putting the speaker
out into the room. You can use this to get the best balance
between bass output and upper range output. One of the advantages
of using separate subwoofers is that you can place them in corners
for best bass response, while keeping the main speakers out into
the room for best mid-treble response and imaging.
- Use absorbent materials to help smooth upper-range response and
improve transient response and clarity. Why? Letís take the
sound of a bell for example. First you will hear the direct sound
from the speaker. But some of that sound bounces from
wall-to-wall, ceiling-to-floor, off furniture, etc. before it
reaches your ears milliseconds later. Because the time difference
is short, you donít hear an echo, but the sound of the bell is
stretched out from something like a "ding" to a "ddiiinngg".
- Place speakers as far as possible from other furniture and room
boundaries. Keeping the mids and tweeters away from the floor is
particularly important. Many speakers sound best when placed
on sturdy stands to get the right listening height.
- Use padded furniture and drapery when possible to cut down on
reflections. Furniture has the added bonus of helping to break up
standing wave patterns in the bass.
- Use a symmetrical placement of the speakers in the room. Of
course the distance between the speakers is also important. In
general, the further back your listening position, the farther
apart should be your speakers. Think in terms of approximating an
- In most rooms you will want the main speakers placed between
five and eight feet apart. Experiment! Too much distance will
smear the image and it will seem like there is a hole in the
middle. Too small a distance will compress the image. Experiment
with facing the speakers straight into the room or toed in
slightly toward the listener. For video applications the left and
right speakers should be close to the edges of the screen.
Common causes of noise and intermittent problems:
- Dirty connections
- Poorly made terminals, inexpensive RCA jacks often fit poorly
enough to cause a buzz or hum.
- Poorly terminated connections. Cold solder joints, loose fitting
- Poorly shielded cables picking up noise from RF or house main
- Cables picking up noise from AC extension cords. Move cables or
cross at right angles
ACI, Sound that Satisfies...Since 1977