DLS SOUND HANDBOOK User manual

Hints and advices for car sound builders using
DLS amplifiers and speakers
DLS Svenska AB
P.O. Box 13029, SE-402 51 Göteborg, Sweden
Tel. [phone]
Fax [phone]
E-mail: [email protected]
www.dls.se
CONTENTS:
Page
1 Introduction
2 - 3 Formulas and facts
4 - 5 Amplifier facts
6 - 8 Passive crossover filters
9 Cabling
10 - 13 Installation
14 - 20 Building speaker boxes
21 Enclosure examples
22 Some useful tables
SOUND HANDBOOK

INTRODUCTION
We have made this handbook as a small help for
thoose who want to do a first class car sound instal-
lation.
This book advices the reader in matters concerning
amplifier and speaker installation and wiring, passive
crossovers, cable choice and different bass box
constructions. Information about DLS products can
also be found on our Internet WEB-site www.dls.se
DLS SOUND PHILOSOPHY
DLS sound philosophy is based upon providing
equipment that will accurately and faithfully reproduce
all kinds of music without distortion and colouration.
The sound reproduction must be natural, the
soundstage well imaged and stable even when the
tweeters are mounted apart from the bass/midrange
elements.
If you close your eyes the sound should be as close
as possible to the real. You should be able to
experience the sound as it is in the concert hall or on
a rock concert. Every instrument and singer should
be on it´s correct place on the stage. To achieve this
you need a good front stage image and to do such
an installation is not easy. DLS amplifiers and spea-
ker systems will help you to achive a sound as good
as possible, but you also have to do a correct instal-
lation if you want a perfect result. This book will give
you hints about doing a good installation.
1
Depending upon the construction, amplifiers are
divided into different classes, there are class A, AB,
B or C. The characteristic mark for a class A amplifier
is the lack of switching noise distortion, which the
other types have. The class A amplifier also has a
higher idle current, but instead it creates a much bet-
ter resoulution and dynamics. For home use the class
A amplifiers are not very common, many people think
they are only for sound connoisseurs and Hi-Fi
entusiasts.Powers from 2x15 up to 2x50 Watts are
common on these types, no high power, but instead
real good AC/DC-converters with reliable power
resources.
The most common amplifier type is class AB.
Now you can also find class "D" amplifiers. Class D
amplifiers process the signal in a digital way and this
gives the amplifier a high efficiency. A normal class
AB amplifier has an efficiency of around 50%. This
means that a 500 watt amplifier will take up to a 1000
watts from the battery and 50% of it will be transfor-
med to heat. The power transistors must work very
hard and will get very hot. A class D amplifier has an
efficiency of 80-90%. and the heat dissipation is much
lower. The power consumption is also much lower.
The disadvantage of a class D amplifier is the higher
distorsion and it is also difficult to make it work over
the entire audiable frequency range. Class D
amplifiers are normally used only as subwoofer
amplifiers with limited frequency range.
AMPLIFIER CLASSES
DLS lay a great job in developing and refining the
different products in order to give the market the best
Car-Hi-Fi products possible to the worlds most
demanding listeners.
A wellknown french sound philosopher, Jean Hiraga,
said regarding home Hi-Fi: A good sound starts in
the mains plug and then through the AC/DC-
converter, which must be oversized.
The same is valid for Car Hi-Fi, the amplifier must at
all occasions have enough power to make a good
job. Remember to use well oversized cables from
the battery to the amplifier. It is also essential that
the DC/DC-converter is well oversized to make it
distribute enough power to the amplifiers final stage
when it´s needed, otherwise both the dynamics and
the good sound will be lost. The amplifier will sound
"tired" and the sound will be strained. The bass will
lack the real "bass-kick" and the treble becomes sharp
instead of soft and airy.
The built-in amplifers in most CD:s and stereo casette
players can´t stand up to these demands. To achieve
a good sound it´s necessary to install an external
high quality amplifier.
DLS AMPLIFIER PHILOSOPHY
DLS SOUND HANDBOOK - INTRODUCTION
DLS AMPLIFIERS 2007:
DLS amplifiers in ULTIMATE series work in class
AB. In order to minimize the transient distorsion the
final stage uses accurately matched transistor
These are the ULTIMATE-series models:
A2 - The Mid Stereo
A3 - The Twin Mono
A4 - The Big Four
A5 - The Big Five
A6 - The Mono Amp
A7 - The Big Five
TA2 - Tube amplifier
The Reference amplifiers are also working in class
AB.
These are the Reference-series models:
RA10, RA20, RA25, RA30, RA40 & RA50.
These are the Performance-series models:
CA12, CA22, CA23, CA31, CA41, CA51, CAD11 &
CAD15.
CAT31-24 is a CA31 for 24 Volt use.

FORMULAS
It's easier to understand some parts in this book if
you know some of the formulas on this page. They
are also useful at many other occasions.
Box volumes (V):
When caculating the volume of a box you simply
multiply the width (W) x heigth (H) x depth (D).
Use measures in dm and you will get the answer in
liters.
A trapezoid box is calulated as below:
Volume =
width (W) x heigth (H) x ((upper depth + lower depth)/2)
W
H
UD
LD
OHMS LAW:
R = resistance in ohm, U = voltage in Volt
I = current in Ampere, P = power in Watt
Volume (V) of a pipe:
D = depth (length) r = radius
V = r2x 3,14 x D
2
r
MEASURE CONVERSION
The following relation between some units are
useful to know of.
1 yard (yd) = 3 ft = 36 in = 0,9144 m
1 foot (ft) = 0,3048 m
1 inch (in) = 2,54 cm
1 square yard (yd2) = 9 ft2 = 1296 in2 = 0,8361 m2
1 square foot (ft2) = 144 in2= 9,290 dm2
1 square inch (in2) = 6,452 cm2
1 cubic yard (yd3) = 27 ft3= 0,7646 m3
1 cubic foot (ft3) = 1728 in3= 28,32 dm3
1 cubic inch (in3) = 16,39 cm3
1 pound (lb) = 16 oz = 0,4536 kg
1 ounce (oz) = 28,35 gram
CONVERSION GAUGE - mm2
Gauge (ga) is an American measure for cable
areas, also called AWG (American Wire Gauge).
1 AWG = 42 mm29 AWG = 6,8 mm2
2 AWG = 33 mm210 AWG = 5,3 mm2
3 AWG = 27 mm211 AWG = 4,2 mm2
4 AWG = 21 mm212 AWG = 3 mm2
5 AWG = 16 mm213 AWG = 2,7 mm2
6 AWG = 13 mm214 AWG = 2 mm2
7 AWG = 10 mm215 AWG = 1,65 mm2
8 AWG = 8 mm216 AWG = 1,3 mm2
SPEAKER TERMS
It´s useful to know what the most common speaker
data terms stands for.
Fs = speaker resonant frequency in Hz
Fc = box resonant frequency in Hz
F3 = approximative lower frequency for vented
boxes in Hz. Often called F-3 dB point = the point
where the power is half.
Qes = the speakers electrical Q-value
Qms = the speakers mechanical Q-value
Qts = the speakers total Q-value
Vas = Eqvivalent air volume. The air volume having
the same aqoustic compliance as the speaker
suspension.
X-max = voice coil length - 2 x thickness of the
inner pole plate.
Sd = the speakers effective cone area
Vb = net volyme of the box
SPL = sound pressure level in dB
Sens. = speaker sensitivity in dB at 1Watt / 1 mtr
Re = speaker DC resistance in ohms
Mms (Mmd) = moving mass
Le (Lbm) = Voice coil inductance
RMS = AC average power value
BL = The flux density factor in the magnetic gap in
the speaker * the wire length of the voice coil
GEOMETHRY:
Circel:
r = radius O = periphery
d= diameter A = area
Radius (r) = O Diameter (d) = O
2π π
Periphery (O) = 2π x r Area (A) = πx r2
To get the net volume use the inner measures of
the box.
Use measures in dm
and you will get the
answer in liters.
DLS SOUND HANDBOOK - FORMULAS AND FACTS

DECIBEL - dB
Examples of fixed dB relations:
For voltage and current:
dB Amplification
0 dB 1 time
1 dB 1,1 times
3 db 1,4 times
6 dB 2 times (double)
10 dB 3,16 times
20 dB 10 times
The amplification increases logarithmic.
For power:
dB Amplification
0 dB 1 time
3 dB 2 times
6 dB 4 times
10 dB 10 times
20 dB 100 times
An attentuation of -6 dB is a half for voltage and
current and a quarter when talking about power.
CONNECTING RESISTORS
4 Ω6 Ω
8 Ω12 Ω
R tot = 4 + 6 + 8 + 12 = 30 Ω
IN PARALLEL:
When connecting in parallel the total resistance
always becomes lower, it is always lower than the
lowest resistor value in the connection.
Formula:1 = 1 + 1 + 1 + 1
R R1 R2 R3 R4
1 = 1 + 1 + 1 + 1
R4 4 8 8
CONNECTION OF CAPACITORS
4 Ω8 Ω
8 Ω
4 Ω
R = 1,33 Ω
Capacitors acts in the opposite way as resistors when
connected in series or parallel.
IN PARALLEL:
The total capacitance when connecting capacitors in
parallel is the sum of each capacitor.
C tot = C1 + C2 + C3 + C4 etc.
10 μF50 μF50 μF100 μF
C tot = 10 + 50 + 50 + 100 = 210 μF
When connecting only two resistors in parallel you
can use the formula below.
R1 x R2 4 x 8
R1 + R2 4 + 8
R = Ex. 32
12
== 2,66Ω
Formula: 1 = 1 + 1 + 1 + 1
C C1 C2 C3 C4
100 μF50 μF
50 μF
10 μF
1 = 1 + 1 + 1 + 1
C 10 50 50 100 C= 6,66 μF
1 μF = 0,000001 Farad (10-6)
1 nF = 0,000000001 Farad (10-9)
1 pF = 0,000000000001 Farad (10-12)
dB is a unit used to describe a realation. It´s used to
describe an amplification as well as an attentuation.
At an attentuation a minus sign is put before the figure.
An amplification is the relation between the input and
the output signal. In can be valid for voltage, current
or power.
When used for power amplification you must
remember that current x voltage = power. This means
that the relation becomes larger, see the table below.
The formualas below is valid when connecting
resistors and inductances in series or in parallel.
It can also be used for speakers.
IN SERIES:
The total resistance is equal to the sum of all
resistors in the connection.
R tot = R1 + R2 + R3 + R4 etc.
When connecting only two capacitors you can use
the same formula as in the example with two
resistors connected in parallel above.
3
IN SERIES:
When connecting capacitors in series you calculate
in the same way as for resistors connected in parallel.
DLS SOUND HANDBOOK - FORMULAS AND FACTS

4
DLS SOUND HANDBOOK - AMPLIFIER FACTS
DLS REFERENCE RA20 RA25 RA30 RA40 RA50
FILTER CONFIGURATION RA50
Ch. 1 & 2
High-pass 50 - 140 Hz*
Low-pass 250 - 700 Hz* (x 1 switch)
or 2,5 kHz - 7 kHz* (x 10 switch)
Ch. 3 & 4
High-pass 50 Hz - 140 Hz (x 1 switch)
or 250 Hz - 700 Hz (x 5 switch)
or 2,5 kHz - 7 kHz (x 50 switch)
Ch. 5
Low-pass 40 Hz - 125 Hz
Subsonic fixed 25 Hz*
*can be switched in/out
Number of channels 2 2 2 4 3 1 5 4
Power output in 4 ohm 2x45 W 2x85 W 2x150 W 4x85 W 2x85 W 1x500 W 4x60 W 4x40W
Power output in 2 ohm 2x80 W 2x145 W 2x270 W 4x145 W 2x100 W 1x870 W 4x100W 4x80 W
Power output in 1 ohm 2x120 W 2x220 W 2x425 W 2x220 W - 1x1200 W - -
Mono bridge mode 4 ohm 1x160 W 1x290 W 1x550 W 2x250 W - - - 2x165W
Mono bridge mode 2 ohm 1x240 W 1x450 W 1x870 W 2x400 W 2x220W
Mono bridge mode 1 ohm - - 1x1200 W -
Mono sub channel, nom. power 4 ohm - - - - 1x300 W - 1x300 W -
Mono sub channel, nom. power 2 ohm - - - - 1x500 W - 1x440 W -
Mono sub channel, nom. power 1 ohm 1x780 W 1x600 W
S / N ratio, A-weighted >100 dB >100 dB >100 dB >100 dB >100 dB >100 dB >100 dB >100 dB
Damping factor >200 >200 >200 >200 >200 >200 >200 >200
Input impedance >10 k >10 k >10 k >10 k >10 k >10 k >10 k >10 k
Input sensitivity 0,2-7V 0,2-7V 0,2-7V 0,2-7V 0,2-7V 0,2-7V 0,3-7V 0,5-5V
Filter highpass 20-200 Hz 20-200 Hz 20-200 Hz FRONT: LP: 50-125 Hz 50-150 Hz - FRONT: 80-400Hz / 1,6-8 kHz OFF/70/90 Hz
HP: 20-200 / 60-600 Hz REAR: 80-400 Hz
Filter lowpass OFF/70/90 Hz 50-125 Hz* 50-125 Hz* REAR: LP: 45-200 / 90-400 Hz 40-90 Hz 50-125 Hz REAR: 0,3-4 kHz / 3-40 kHz 50-125 Hz
HP: 20-200 Hz SUB CH: 50-125 Hz
*can be switched in/out SUBSONIC: 25 Hz
Subsonic filter 25 Hz/18 dB - - - - yes yes no -
Dual DC-inputs - - yes yes - yes - -
Phase shift button 0 / 180° - - yes - - - - -
Phase shift control continuous - - - - 0-180 degrees 0-180 degrees 0-180 degrees -
Fan output terminal - - yes yes yes yes yes -
Remote sub level control - - - - yes yes yes -
POWER CONSUMPTION
Idle 0,5 A 0,6 A 1,1 A 1,5 A 0,5 A 0,6 A 1,1 A 0,7 A
Maximum 32 A 60 A 140 A 95 A 90 A 140 A 120 A 50 A
Dimensions (mm) 205x240x73 265x240x73 410x240x73 465x940x73 410x240x73 410x240x73 605x240x73 350x240x73
Dimensions (inch) 8,07x9,45x2,87 10,43x9,45x2,87 16,15x9,45x2,87 18,30x9,45x2,87 16,15x9,45x2,87 16,15x9,45x2,87 23,82x9,45x2,87 13,78x9,45x2,87
Weight 2,8 kg (6,17 lb) 3,7 kg (8,16 lb) 6,2 kg (13,67 lb) 6,6 kg (14,55 lb) 5,9 kg (13 lb) 6,2 kg (13,67 lb) 8,1 kg (17,86 lb) 4,8 kg (10,6 lb)
DLS ULTIMATE AMPLIFIERS A1 A2 A3 A4 A5 A6 A7 A8
Number of channels 2 2 3 4 5
Power output in 4 ohm 2 x 130 W 2 x 70 W 2 x 70 W + 1 x 265 W 4 x 75 W 4 x 70 W + 1 x 265 W
Power output in 2 ohm 2 x 220 W 2 x 110 W 2 x 100 W + 1 x 365 W 4 x 110 W 4 x 110 W + 1 x 365 W
Power output 4 ohm bridged 1 x 440 W 1 x 220 W - 2 x 220 W 2 x 220 W
Signal to noise ratio, A-weighted >100 dB >100 dB >100 dB >100 dB >100 dB
Damping factor >200 >200 >200 >200 >200
Frequency response +/- 0,5 dB 10 Hz - 50 kHz 10 Hz - 50 kHz 10 Hz - 50 kHz 10 Hz - 50 kHz 10 Hz - 50 kHz
Input impedance, low level >10 kohms >10 kohms >10 kohms >10 kohms >10 kohm
Input impedance, high level 330 ohms 330 ohms 330 ohms 330 ohms 330 ohm
High level input with auto start yes yes yes yes yes
Input sensitivity 0,2 - 7 V 0,2 - 7 V 0,2 - 7 V 0,2 - 7 V 0,5 - 8 V
Bass boost adjustable gain @ 40 Hz 0 - +18 dB - 0 - +18 dB 0 - +18 dB 0 - +18 dB
Phase shift 0 - 180 degrees continuously yes - yes yes yes
Remote bass level and phase shift - - yes, on sub ch. - yes, on sub ch.
Filter highpass / fixed subsonic filter 20 - 150 Hz* 20 - 150 Hz* 45 - 125 Hz* / 25 Hz* 20 - 150 Hz on all ch. see spec.
Filter lowpass 40 - 125 Hz* - 40 - 125 Hz 40 - 125 Hz* see spec.
*can be switched in/out
POWER CONSUMPTION
Idle 0,6 A 0,6 A 0,9 A 0,9 A 1,2A
Maximum 50 A 25A 70 A 50 A 90 A
Fuses 2 x 25 A 1 x 25 A 2 x 35 A 2 x 25 A 3 x 30A
Dimensions (mm) 59 x 359 x 245 59 x 247 x 245 59 x 385 x 245 59 x 359 x 245 59 x 479 x 245 mm
Dimensions (inch) 2,33 x 14,1 x 9,65 2,33 x 9,72 x 9,65 2,33 x 15,15 x 9,65 2,33 x 14,1 x 9,65 2,33 x 18,85 x 9,65
Weight 3,8 kg / 8,4 lb 2,6 kg / 5,7 lb 4,4 kg /9,3 lb 4 kg / 8,8 lb 5,5 kg / 12,1 lb
R.M.S. Power output at 13,8 Volts, 20 Hz - 20 kHz, max 0,1% THD, all channels driven:
Number of channels 1
Amplifier class AB
Power output in 4 ohm (0,1% THD) 1 x 300 W
Power output in 2 ohm (0,1% THD) 1 x 500 W
Power output in 1 ohm (0,1% THD) 1 x 820 W
All power ratings at 13,8 Volt
Signal to noise ratio, A-weighted >100 dB
Damping factor >200
Frequency response 10 Hz - 125 Hz
Input impedance >10 kohms
Input impedance, high level 330 ohms
High level input with auto start Yes
Input sensitivity 0,5 - 8 V
Phase control continuous 0 - 180 degrees
Bass boost adjustable gain 0 - +18 dB
Filter subsonic, 18 dB slope 25 Hz fixed
Filter lowpass 12 dB slope 40 - 125 Hz
*can be switched in/out
Power consumption, idle 1,5 A
Fuse 3 x 40 A
Dimensions (mm) 59 x 359 x 245
Dimensions (inch) 2,33 x 14,1 x 9,65
Weight 5,4 kg / 11,9 lb
DLS REFERENCE RA10

5
FILTER CONFIGURATION CA 41& CA 51
Ch. A & B
High-pass 15 - 500 Hz*
Low-pass 50(500) - 500(5k) Hz*
(x 10 switch)
Ch. C & D
High-pass 15(150) Hz - 500(5k) Hz*
(x 10 switch)
Ch. E (only CA51)
Low-pass 60 Hz - 120 Hz
Subsonic 25 Hz*
*can be switched in/out
DLS SOUND HANDBOOK - AMPLIFIER FACTS
Number of channels 1 1 1
Amplifier class D (digital) D (digital) AB
Power output in 4 ohm (0,2% THD) 1 x 400 W 1 x 550 W 1 x 220 W
Power output in 2 ohm (0,2% THD) 1 x 750 W 1 x 900 W 1 x 400 W
Power output in 1 ohm (0,5% THD) 1 x 1050 W 1 x 1600 W 1 x 500 W
All power ratings at 13,8 Volt
Signal to noise ratio, A-weighted >100 dB >100 dB >100 dB
Damping factor >100 >100 >100
Frequency response 15 Hz - 160 Hz 15 Hz - 160 Hz 10 Hz - 35 kHz
Input impedance 10 kohms 10 kohms 10 kohms
Input impedance, high level 100 ohms 100 ohms 100 ohms
High level input with auto start Yes Yes Yes
Input sensitivity 0,15 - 5 V 0,15 - 5 V 0,25 - 5 V
Phase control continuous 0 - 180 degrees 0 - 180 degrees 0 - 180 degrees
Remote bass level control yes Yes No
Bass boost adjustable gain @ 45 Hz 0 - +18 dB 0 - +18 dB -
Filter subsonic, 24 dB slope 15-50 Hz variable 15-50 Hz variable 15 - 150 Hz variable
Filter lowpass 24 dB slope 15 - 150 Hz variable 15 - 150 Hz variable 50 - 500 Hz variable
Bridge mode master/slave selector Yes Yes No
Built-in fan cooling Yes Yes Yes
Power consumption, idle / max 1,5 A / 120 A 2 A / 160 A 0,8 A / 60 A
Fuse 4 x 30 A 4 x 40 A 2 x 30 A
Dimensions (mm) 70 x 444 x 268 70 x 473 x 268 70 x 312 x 268
Dimensions (inch) 2,92 x 17,48 x 10,55 2,92 x 18,6 x 10,55 2,92 x 12,28 x 10,55
Weight 5,8 kg / 12,79 lb 6,4 kg / 14,33 lb 3,8 kg / 8,4 lb
DLS Performance CAD 11 CAD15 CA12
Number of channels 2 2 3 3 4 5
Power output in 4 ohm (0,1% THD) 2 x 60 W 2 x 135 W 2 x 65 W + 1 x 170 W 2 x 75 W + 1 x 170 W 4 x 70 W 4 x 50 W + 1 x 170 W
Power output in 2 ohm (0,2% THD) 2 x 100 W 2 x 200 W 2 x 90 W + 1 x 280 W 2 x 145 W + 1 x 280 W 4 x 125 W 4 x 80 W + 1 x 225 W
Power output in 1 ohm (0,5% THD) 2 x 210 W + N/A
Power output 4 ohm bridged 1 x 200 W 1 x 400 W 1 x 170 W 1 x 280 W 2 x 200 W 2 x 150 W
Signal to noise ratio, A-weighted >100 dB >100 dB >100 dB >90 dB >100 dB >100dB
Damping factor >100 >100 >100 >100 >100 >100
Frequency response 10 Hz - 35 kHz 10 Hz - 35 kHz 10 Hz - 35 kHz 10 Hz - 35 kHz 10 Hz - 35 kHz
Input impedance, low level >10 kohms >10 kohms >10 kohms 10 Hz - 35 kHz >10 kohms >10 kohms
Input impedance, high level 100 ohms 100 ohms 100 ohms 100 ohms 100 ohms 100 ohms
High level input with auto start yes yes yes yes yes yes
Low output yes yes no no yes No
Input sensitivity 0,25 - 5 V 0,25 - 5 V 0,25 - 5 V 0,25 - 5 V 0,25 - 5 V 0,25 - 5 V
Gramd bass adjustable frequency - 25 Hz - 80 Hz no no 25 Hz - 80 Hz no
Grand bass adjustable gain - 0 - 18 dB no no 0 - 18 dB no
Phase control continous no no 0-180 degrees 0-180 degrees no 0-180 degrees
Filter highpass / subsonic 15 - 500 Hz* 15 - 150 Hz* 15 - 150 Hz* / Yes, 25 Hz* 50 - 150 Hz* / Yes, 25 Hz* see spec. see spec.
Filter lowpass 50 - 500 Hz* 50 - 500 Hz* 50 - 120 Hz 50- 120 Hz, 24 dB slope see spec. see spec.
*can be switched in/out NOTE! For 24 volt use
POWER CONSUMPTION
Idle / max 0,5 A / 25 A 0,7 A / 60 A 1,0 A / 60 A 0,7 A / 40 A 0,7 A / 60 A 1,0 / 90 A
fuses 1 x 25 A 2 x 30 A 2 x 30 A 2 x 20 A 2 x 30 A 3 x 30 A
Dimensions (mm) 70 x 230 x 268 70 x 312 x 268 70 x 357 x 268 70 x 357 x 268 70 x 372 x 268 70 x 437 x 268
Dimensions (inch) 2,92 x 9,06 x 10,55 2,92 x 12,28 x 10,55 2,92 x 14,06 x 10,55 2,92 x 14,06 x 10,55 2,92 x 14,65 x 10,55 2,92 x 17,2 x 10,55
Weight 2,7 kg / 6,2 lb 3,6 kg / 7,9 lb 4 kg /9,2 lb 4 kg / 9,2 lb 4,2 kg / 9,3 lb 5 kg / 11 lb
DLS Performance CA 22 CA 23 CA 31 CAT 31 CA 41 CA 51
R.M.S. Power output at 13,8 Volts, 20 Hz - 20 kHz, all channels driven:

CROSSOVERS
The ideal speaker, able to reproduce all frequencies
from lowest bass to highest treble, is not yet invented.
Instead we have to use two or more speakers where
each speaker is reproducing a part of the frequency
range.
To make this work the input signal to each speaker
driver must contain only the frequencies it´s desig-
ned for. For this purpose we need crossover filters.
ACTIVE CROSSOVERS
Crossovers can be ACTIVE or PASSIVE. An active
filter is connected before the amplifier line input. You
need one amplifier for each speaker pair which will
become rather expensive.
But the advantages are that it´s possible to mix
speakers with different impedance or sensitivity and
still be able to balance the system.
Most amplifiers are equipped with built-in active
crossovers that can be adjusted in frequency and also
switched in-out.
All DLS amplifiers have built-in active crossovers.
PASSIVE CROSSOVERS
Passive crossover consists of coils and capacitors,
and sometimes resistors for impedance adaption. A
passive filter is connected between the amplifier and
the speaker and is of LC-type, (coil and capacitor).
A coil stops the higher frequencies while the low pas-
ses through, a capacitor works in the opposite way.
By changing the component values, different cross-
over frequencies are obtained. The coils must be of
high quality with a large wire area to avoid losses
and distortion. Air coils without iron core are the best
but they can be rather big for high values. For high
values we often use coils with an iron core. The best
capacitors are of polyester type. For large
capacitance values bipolar electrolytic capacitors are
used.
Resistors are used in a filter for impedance adap-
tion. Read the part about conjugate compensation.
A passive filter steals more power than an active.
CROSSOVER EXAMPLES:
(without conjugate compensation)
3-WAY SYSTEM:
4-WAY SYSTEM:
123
1
2
3
1
2
3
123
12
12
12
12
12
12
12
Sub-bass Mid-range Tweeter
0-80 Hz80 Hz - 5 kHz 5 kHz -
10 mH
10 mH
300 μF
300 μF5,6 μF
0,18
mH
+
-
12 dB filter slope
+
-
12 dB filter slope
123
1
2
3
1
2
3
123
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
The systems above are shown without impedance
compensation. Read below about conjugate links.
10 mH
10 mH
300 μF
1,75 mH
1,75 mH
0,18 mH
50 μF
300 μF
Sub-bass Mid-bass Mid-range Tweeter
0-80 Hz80 - 520 Hz 520 - 5 kHz 5 kHz -
50 μF
5,6 μF
PHASE SHIFT IN PASSIVE CROSSOVERS
All passive crossovers will phase shift the signal.
A 6 dB filter shifts 90 degrees and a 12 dB 180
degrees. Because of this you should always try to
phase reverse the tweeter in a system to see what
phase is creating the best sound. In a 3-way system
it´s normal to phase reverse the tweeter. All tweeters
used in a system must have the same polarity
(phase). Also subwoofers with a 12 dB crossover
should you try to phase reverse. If the subwoofer cone
is moving but you don´t achieve any good bass you
can try to phase reverse. If two subwoofers are
connected with different polarity (phase), the sound
from each speaker will kill the sound from the other,
resulting in a poor bass reproduction.
CONJUGATE COMPENSATION:
Conjugate compensation is a way to equal the spea-
ker load over the whole frequency range. A 4 ohm
speaker can have an impedance peak up to 25 times
the normal at the resonant frequency (Fs). To make
the calculated crossover filter to match, you can
connect a conjugate link in parallel with the speaker.
It´s normally made of a capacitor and a resistor. If
you cant calculate the exact component values for
the conjugate link you can use a 33 μF capacitor in
series with a 3,9 ohm resistor to most 4", 5,25" and
6,5" speakers.
DLS SOUND HANDBOOK - PASSIVE X-OVER FILTERS
CROSSOVER FREQUENCIES:
In a two-way system with separate tweeter a cross-
over frequency from 3 - 8 kHz is normal.
In a three-way system it´s normal to split the sub at 200-
400 Hz and the tweeter at 3 - 8 kHz.
In a four-way system the x-over frequencies can be
as follows. To the subwoofer 80-130 Hz, mid-bass 400-
600 Hz and the tweeter 3 - 8 kHz.
This is a just a recommendation. Depending upon the
speaker data and where the different elements are
mounted in the car, other x-over frequencies could be
better.
6

7
PASSIVE 6 dB LOW-PASS PASSIVE 6 dB HIGH-PASS
A 6 dB x-over filter has a 6 dB slope / octave. The
output from an amplifier is only a quarter after falling
with 6 dB. A 6dB filter is also called 1:st order filter.
A common use for a 6 dB low-pass filter is for a
subwoofer to stop frequencies over, as for example,
100 Hz.
A 6 dB low-pass filter consists of a coil. The x-over
frequency is decided by the inductance value
measured in the unit Henry (H) and parts of a Henry.
For speakers we normally use coils with the unit mH.
1 H = 1000 mH.
123456
1
2345
6
123456
+
-
CALCULATION FORMULA:
L (mH) = 160 x Z
Fc
Z = speaker impedance in Ω
Fc = x-over frequency in Hz
L= Coil inductance in mH
Speaker impedance
X-over fq. 2Ω4Ω8Ω
Hz L (mH) L (mH) L (mH)
65 5 10 20
80 4 8 16
100 3,2 6,4 12,8
130 2,5 5 10
200 1,6 3,2 6,4
360 0,9 1,75 3,5
500 0,65 1,3 2,6
800 0,4 0,8 1,6
1000 0,32 0,64 1,28
X-over frequencies at given values:
10 mH 6,3 mH 1,75 mH
2Ω32 Hz 50 Hz 183 Hz
4Ω64 Hz 101 Hz 365 Hz
8Ω128 Hz 203 Hz 730 Hz
Inductance values for different x-over frequencies:
A 6 dB high-pass x-over filter consists of a capacitor.
The crossover frequency varies with the capacitor
value that is measured in the unit Farad and parts of
Farad. Normally we use μF values for speakers.,
1 F = 1000 000 μF
Capacitor values from approx. 10 μF and up are
normally of bipolar electrolytic type. For lower values
we often use polyester capacitors. A capacitor as in
the drawing below let the high frequencies pass and
stops the lower.
+
-
C (μF) = 160000
Fc x Z
1:st order 6 dB low-pass filter: 1:st order 6 dB high-pass filter:
C
L
CALCULATION FORMULA:
Z = speaker impedance in Ω
Fc = x-over frequency in Hz
C = Capacitor value in μF
Capacitor values for different x-over frequencies:
Speaker impedance
X-over fq. 2Ω4Ω8Ω
Hz C (μF) C (μF) C (μF)
80 1000 500 250
100 800 400 200
130 600 300 150
200 400 200 100
500 160 80 40
800 100 50 25
1000 80 40 20
2000 40 20 10
5000 16 8 4
X-over frequencies at given values:
300 μF 200 μF 150 μF 50 μF 6,8 μF
2Ω266 Hz 400 Hz 533 Hz 1,6 kHz 11,7 kHz
4Ω133 Hz 200 Hz 266 Hz 800 Hz 5,85 kHz
8Ω67 Hz 100 Hz 133 Hz 400 Hz 2,92 kHz
Treble
Bass
=
When connecting coils in series the values are
added.
Use this formula when connecting in parallel:
1 1 + 1 + 1
L L L L =
When connecting capacitors in parallel the values
are added. Use this formula when connecting in
series.
1 1 + 1 + 1
C C C C
DLS SOUND HANDBOOK - PASSIVE X-OVER FILTERS

PASSIVE 12 dB LOW-PASS PASSIVE 12 dB HIGH-PASS
A 12 dB x-over filter has a 12 dB slope / octave.
A 12 dB filter is a combination of a coil and a
capacitor. It is also called 2:nd order filter. 12 dB
low-pass filters are often used for subwoofers in or-
der to stop frequencies over the x-over frequency,
for example 100 Hz. A combination of a low- and high-
pass filter is called a band-pass filter.
The difference between the passive 12 dB high-pass
x-over filter and the low-pass filter is that the coil and
capacitor change place. For a certain x-over
frequency the component values are the same for
both high- and low-pass filters. A high-pass filter let
high frequencies pass, and stops the lower.
2:nd order 12 dB low-pass filter: 2:nd order 12 dB high-pass filter:
123
1
2
3
1
2
3
123
L
C
123456
123456
C
L
CALCULATION FORMULA:
L (mH) = 225 x Z C (μF) = 112500
Fc Fc x Z
CALCULATION FORMULA:
Z = speaker impedance in Ω
Fc = x-over frequency in Hz
L = coil inductance in mH
C = capacitor capacitance in μF
L (mH) = 225 x Z C (μF) = 112500
Fc Fc x Z
When connecting coils in series the values are added.
Use this formula when connecting in parallel:
1 1 + 1 + 1
L L L L
When connecting capacitors in parallel the values are
added. Use this formula when connecting in series.
1 1 + 1 + 1
C C C C
=
=
COMPONENT VALUES FOR 12 dB PASSIVE CROSSOVERS
X-over freq. 2 ΩΩ
ΩΩ
Ω4 ΩΩ
ΩΩ
Ω8ΩΩ
ΩΩ
Ω
in Hz C (μμ
μμ
μF) L (mH) C (μμ
μμ
μF) L (mH) C (μμ
μμ
μF) L (mH)
62,5 900 7,2 450 14,4 225 28,8
95 600 5 300 10 150 20
140 400 3,2 200 6,4 100 12,8
190 300 2,35 150 4,7 75 9,5
375 150 1,2 75 2,4 38 4,8
520 108 0,87 54 1,75 27 3,5
800 70 0,56 35 1,12 18 2,25
3500 16 0,12 8 0,25 4 0,5
5000 11 0,09 5,6 0,18 2,8 0,36
8
IMPORTANT WHEN CONNECTING FILTERS!
When connecting a 12 dB low-pass x-over to a
subwoofer it´s suitable to solder the capacitor directly
on the sub terminals between + and -.
If the sub is disconnected without disconnecting the
capacitor at the same time the amplifier can be
damaged.
A 12 dB filter connected without a speaker will
overload the amplier (if it´s turned on) and damage
the output circuits.
The same component values are used for both high-
and low-pass filters, but they change place.
Use coils with low resistance, air coils are the best.
Coils with iron core must be able to handle high
current or the iron core magnetic saturation becomes
to high causing distortion.
Capacitors must be of bipolar type, 50 - 100 Volt.
Z = speaker impedance in Ω
Fc = x-over frequency in Hz
L = coil inductance in mH
C = capacitor capacitance in μF
DLS SOUND HANDBOOK - PASSIVE X-OVER FILTERS

THE CABLES - AN IMPORTANT LINK
No chain is stronger than it´s weakest link !
It´s not unusual that people buy expensive amplifiers
and speakers but forget the wiring. DLS have high
quality cables for both amateurs and professional
users.
Cables made of oxygen free copper (OFC).
Cables made of oxygen free copper will not oxidize
as normal copper do. The oxidation increases the
DC-resistance and as a result of this the voltage drop
in the cable. All DLS cables use oxygen free copper.
SKIN-EFFECT AND INDUCTANCE
In a conductor the higher frequencies moves on the
surface, while lower frequencies moves in the center
of the cable. To make the active resistance
( impedance and inductance) as low as possible for
each frequency some cables use different strand
sizes for different frequencies. Higher frequencies
prefer a cable with very thin strands while the lower
frequencies will find the lowest active resistance in a
thicker strand. To minimize the cable resistance
further the cable can be designed with a combination
of copper and silver plated strands.
One of the advantages with DLS speaker- and sig-
nal cables are the low inductance. Opposite an
ordinary DC-resistance the inductance is linear. It
means that higher frequencies will be more supres-
sed than the lower which can create a distored and
false sound reproduction. Inductance will occour
when an AC-current flows in an electromagnetic field.
These fields are causing eddy currents superposed
the normal current leading to an increase of
resistance. They also make the current flow to
decrease towards the center of the conductor (skin-
effect). A low inductance is to prefer. This is achieved
by using raw materials with high purity. A low
inductance will also be achieved by twisting the
strands in the conductor. When the current to the
speaker passes through the speaker coil, which is
an inductance, it creates eddy currents that goes back
to the amplifier called counter- Electro Motive Force
(EMF). The EMF is also reduced by a correct cable
construction with twisted strands.
DLS POWER CABLES.
SIGNAL CABLES:
The signal cables must be of good quality as well as
the speaker cables. The construction of the cable
must have the best possible reduction of inductance
and capacitance together with a low damping over
the whole frequency range.
The shielding is also important to avoid interference
noise from the electric system of the car.
DLS SL2PRO and SL5PRO are triple shielded but
without a remote wire. A remote wire included with
the signal cable may induce interference. These
cables are also quasi-balanced for maximum
performance.
Also use RCA phono connectors of highest quality
with good shielding and gold plated for minimum
contact resistance.
DLS ULTIMATE signal cables are of balanced type
and are often used by very critical listeners. The best
performance is achieved by the ULTIMATE silver
cables that uses silver plated strands.
DLS speaker cable design gives the following
advantages:
Maximum reduction of the EMF which causes
phase shift resulting in bad sound quality.
Lowest possible damping resistance on all
frequencies by using the skin effect.
Lowest possible power loss.
DLS SOUND HANDBOOK - THE CABLES
9
As we have said before the DC-feed to the amplifier
is of great importance. The amplifier must in all
occasions have enough current, otherwise both the
dynamics and good sound will be lost.
DLS power cables of oxygen free copper are made
of a lot of small cores to make it soft and flexible with
lowest DC-resistance. Use the table below to choose
the correct DC-feed.
In many installations the current capacity is improved
with extra batteries (OPTIMA) with low inner
resistance or large 1 Farad capacitors, DLS Power
Caps. If you don´t want to spend money on extra
batteries at least you shouldn´t save money on the
DC-feed.
Also the speaker feed must be of high quality. Use
cables with an area of at least 1,5 mm2.DLS speaker
cables are soft and flexible with a construction that
minimizes the loss over the whole frequency range.
DLS SC 4x1 and SC 4x1,5 are special speaker
cables with four leads. They are twisted and has a
powerful insulation protecting them from mechanical
agitation.
The four leads are connected in pairs as they have
different strand sizes using the skin effect to minimize
the resistance on all frequencies. The capacitance,
inductance and EMF are reduced by the twisted cores
in the cable. Two of the four leads have a strand size
of 0,1 mm2, and the two others have 0,2 mm2.
DLS SCP, SCK and SCKS are other types of cables
that offersthese advantages. The SCKS uses silver
plated aluminium strands and offers the best sound
quality for all purposes.
DLS SC 2x1,5, SC 2x2,5 and SC 2x4 are the stan-
dard two-lead speaker cables made of oxygen free
copper. They have twisted strands and are soft and
flexible for easy installations.
DLS SPEAKER CABLES.
Cable length: <1,5 m 1,5 - 5 m > 5 m
CA22/ CA23/CA12 10 mm216 mm221 mm2
CA31/CA41/CA51 16 mm221 mm233 mm2
CAD11, CAD 15 16 mm221 mm233 mm2
RA20/RA30/RA40 16 mm221 mm233 mm2
A1 / A2 /A8/RA25 10 mm216 mm221 mm2
A3 /A4 / A5 / A7 16 mm221 mm233 mm2
A6/RA10/RA50 21 mm2 33 mm250 mm2

INSTALLATION
THE HEAD UNIT
The heart in a car stereo installation is the car ste-
reo, often called head unit. Today it´s normally a tuner
with an external CD-changer or built-in CD-player.
The well-known brands are the best choice if you
want a high quality product.
One important detail is to buy a head unit with RCA
pre-outs which makes it easier when you want to do
a more sophisticated installation than standard. The
head unit is normally installed in the dash-boards ori-
ginal fitting, just make sure it´s fastened properly. If
possible use heavier DC-feeds than the originals used
in the car. If you use the internal amplifier to feed any
speaker pair this is important. The ground wire must
have the same area as the +-feed.
If you have interference noise from the alternator or
ignition its´often the ground connection that is wrong.
Try different places for the ground connection, the
best is close to a unit (the amplifier).
THE AMPLIFIER
An extra amplifier should be installed in a place where
it can be satisfactory cooled. Many amplifiers get very
hot and need a good cooling.
In some installations you might need one or two
external cooling fans.
First check if there are any cable mats or fuel pipes
behind the place where you plan to mount the
amplifier. Alternatively use an extra particle board or
the bass box when you mount the amplifier and you
will have a better ground insulation. To avoid
interference noise this can be to prefer.
Install the amplifier far away from your radio aerial.
Sometimes the amplifiers DC/DC-converter genera-
tes high frequency interference.
10
THE DC-FEED
Maximum fuse values of the main fuse for different
cable sizes.
6 mm2(9 AWG) :25 A 10 mm2 (7AWG) :40 A
16 mm2 (5AWG) :60 A 21 mm2(4AWG) :100 A
33 mm2(2AWG) :150 A 42 mm2 (1AWG) :200 A
To avoid damage to the amplifier or the electric sys-
tem of the car the DC-feed installation must be made
with care. A main fuse must be installed on the power
line close to the battery. This fuse protects the cable
from burning if a short circiut occours.
Use either glass fuses or automatic circuit breakers.
If the amplifiers are installed in the back of the car
it´s normal to install a separate fuse block from which
you distribute the power to the separate units. Each
unit will then be separately fuse protected.
THE CABLES
As we have said before the cables are very important.
In the table on page 5 you find recommended areas
for the DC-feed for different amplifiers. The ground
wire must have the same area as the +-wire. Connect
the ground wire as close as possible to the amplifier.
Connect all units in the system to the same ground
point to avoid interference.
Use high quality speaker cables with an area of at
least 1,5 mm2to the side systems and 2,5 mm2to the
subwoofers, (or more).
Signal cables must have good shielding, otherwise
they can pick up interference noise.
Avoid to place the power cables on the same side of
the car as the signal cables. Also try to avoid the
cars own cable mats to come close to the signal
cables.
Any extra cable must be laid out in zig-zag style and
definitely not coiled.
Don´t let the cables pass sharp edges that can hurt
the cable insulation causing short circuits or other
problems.
Battery
Main fuse
Fuse block
Amplifier Amplifier
Amplifier
Wiring diagram with 3 amplifiers,
main fuse and a fuse block with
a fuse for each unit.
The main fuse holders use either a glass fuse of AGU-
type (max 80A), or ANL-fuses with values up to 250
Amps. There are fuse blocks for 2, 3 or 4 AGU fuses.
Automatic circuit breakers is another good alternative
as main fuse. They also have a test button with which
you easily can switch off the power to all units.
The ground wires from all units can easily be
connected together with a power block like the PB1.
For best function with lowest possible DC-resistance
in all connection points, all the above products are
gold plated with 24 K gold. Besides of a good function
it´s also gives a good impression.
EXTRA BATTERY
In many exclusive installations, and most competition
cars, extra batteries are installed. Sometimes also
extra alternators for improved charging, or extra
capacitors of 0,5 or 1 Farad value.
The purpose of this is to make sure that the amplifiers
always gets enough current even at very high
volumes, otherwise the sound will be destroyed at
high volumes.
For a normal listener the ordinary car battery is
sufficient. Just make sure you have DC-feeds that´s
big enough. But if you plan to compete or just want to
get the most out of your equipment it´s always right
to install an extra battery or extra capacitors that
works as a current reservoir.
These extra batterys are of a special type with low
internal resistance that can handle large current flows.
DLS SOUND HANDBOOK - INSTALLATION

An important part of the installation is of course the
speakers.
How they are installed varies from car to car and
depends upon the possibilities in each type.
The factory pre-made installation holes are not always
ideal for other types of speakers than original. We
will give you some hints of what to think of when
installing speakers.
ORIGINAL INSTALLATION
The easiest way to install a speaker in a car is to use
the factory pre-made holes. If you use car specific
speakers, the installation job becomes very easy. But
the problem is that these type of speakers are usually
not of the highest quality and will not satisfy a
demanding listener.
The high quality speakers often have large magnets
making it necessary to first measure the space and
sometimes make changes in the door or dash-board
to make them fit. Especially the depth is important to
check so that the side windows goes clear from the
magnet.
Some car models requires special adaptors or
distances to make the speaker fit when you use other
speakers than the original.
If possible use some kind of baffle on the back of the
door panel. Make sure the baffle is fastened properly
and fasten the speaker in the baffle. This is easy to
make and will normally result in a better sound than
without baffle.
A speaker installation high up on the door-side is to
recommend, but if the pre-made hole is at the bot-
tom part of the door it´s difficult to change.
A 2/3-way system should be installed with the
elements close to each other to achieve the best
sound image. An alternative is to install the bass
element in the door and the tweeter on the dash-
board.
A door or dashboard installation is actually an "open-
air" installation since there is no limiting box.
SPEAKER INSTALLATION
Exemple of a door installation with new baffles.
11
DLS SOUND HANBOOK - INSTALLATION
NEW DOOR BAFFLES
If you want to improve your door installation you
should build a new door-side. This must be adapted
to the door side and is normally made of MDF or
particle board. The baffle is covered with cloth or vi-
nyl matching the car interior. Some car sound builders
changes the whole door-side to a new one. The spea-
ker element is directed to obtain the best sound
image. They are also fastened properly to avoid rattle.
They are normally mounted with a sealed speaker
box behind the elements. The volumes needed for a
4" or 5,25" element are only a few liters.
ORIGINAL MOUNTING:
ADVANTAGES:
- Fast, easy and simple
DISADVANTAGES:
- The speakers have no baffle = rattle.
- Bad power handling capacity.
- Bad sound image.
BAFFLE MOUNTING:
ADVANTAGES:
- The speakers are mounted in real baffles.
- A box construction that improves the sound
quality with less rattling.
- Higher power handling capacity.
- Better sound image (front stage).
DISADVANTAGES:
- More work and more expensive mounting.
- The cars original door sides are affected.
- The installation requires a lot of knowledge to
make the installation to look professional.

DLS SOUND HANDBOOK - INSTALLATION
CENTRE CHANNEL SPEAKER
A centre channel speaker can be used to improve
the sound image in installations where the speaker
mounting makes it difficult to achieve a correct sound
image.
On a DLS amplifier the centre speaker is connected
in bridge mode between Left and Right channel. The
speaker is now fed with the sum signal from left and
right channel. This will fill in what you can call the
gap in the soundstage of the earlier installation.
Your side system will hopefully be good 6,5 inch
coaxes or two-way systems or even better. A small
centre channel speaker of smaller size will have to
be feed at a lower level of volume.
123456
1
2345
6
123456
Centre channel speaker 4 ohm
1234
1
23
4
1
23
4
1
23
4
1
23
4
1234
DLS AMPLIFIER
L+
R-
20Ω
15W
0-20Ω
15W
0,15
mH
1,75
mH
In this example the signal is dampened with a 20 ohm
resistor. The level can then be adjusted with the
variable resistor. The component values can need
to be changed sometimes.
The frequency response in this example is between
550 - 6000 Hz. The component values can be
changed if you want another frequency response.
In amplifiers with built-in highpass and lowpass filt-
ers, you can use these instead of the passive band-
pass filter. A 5-channel amplifier like the CA51 is
suitable in this case.
Here is a description of a passive bandpass filter for
a 4 ohm speaker.
12
KICK-PANELS
Another installation alternative giving a good sound
image is the kick-panel. It´s placed down on the floor
in front of the door on both sides. It can contain the
whole system with bass, midrange and tweeter or a
bass and midrange with the tweeter installed on the
dashboard. The best places for the speakers must
be tested out in the respective car.
Kick-panels are normally made of MDF or particle
board and are build as sealed boxes or as membrane
boxes where the element is allowed to breath through
a membrane of foam rubber or similar.
Kick-panels are very popular in competition cars.
MOUNTING IN KICK-PANELS:
ADVANTAGES:
- Stable mounting without rattling.
- Superb sound image.
- Higher power handling capacity.
- Less affection on the cars interior.
DISADVANTAGES:
- More mounting work.
- Possibilites to damage the speaker if kicking on
them with the feets.
HIGH MOUNTED KICK-PANELS:
In some cars the kick-panel can be mounted invisible
up under the dashboard. Can create a good sound
image despite the strange mounting.
DASHBOARD MOUNTING
A mounting of the midrange and tweeter up on the
dashboard will result in an improved sound image. It
will be moved up on the dashboard. Some cars that
have suitable original dashboard mounting holes can
be used.
The tweeters should be mounted on the dashboard
or on the door poles. The woofer elements should be
mounted in a door-side or in a kick-panel. Suitable
for DLS C36, UR35i/UR36i, UP-35/UP-36 or Iridium
6.3 / 8.3.
REAR FILL
A well mounted front system is the most important in
a sound system. In some cases we also use rear
mounted speakers used as "rear fill". Rear fill
speakers will improve the front stage image by adding
a weak sound from the rear filling up the sound stage
and giving it a deep. As Rear fill speakers we can
use midrange elements in combination with a passive
or active bandpass filter, mounted in the rear. A
suitable frequency response can be from 500 - 6000
Hz. The level must be dampened easiest made with
a series resistor of 10 - 20 ohms in series with the +
lead. The rear fill speaker can also be connected in
multimode. In this case you use only one element
working as a center channel speaker.
50 μF
4,7 μF

HAT-RACK MOUNTING
The best sound stage for front seat listeners is
achieved with door- or kick-panel mounting. In
competition cars the front system combined with rear
subwoofers are often the only speakers. Sometimes
they are combined with a pair of small 4" or 5,25"
speakers in the back used as "rear fill". These rear
fill speakers are connected with x-overs giving a
reproduction from 1-2 kHz and up. Tweeters are
normally not used in combination with rear fill.
The traditional hat-rack mounting with a speaker
component kit, 6x9" or 7x10" speakers requires some
installation work to create a good sound.
A new hat-rack made of particle board (22 mm) or
MDF-board (19 mm) must be produced. The original
hat-racks are normally not sufficient to use.
If you furthermore want the speakers to have a high
power handling capacity you need to make some kind
of speaker box (normally of sealed type) on the back
of the hat-rack, limiting the cone movement.
If you have a bass box in your trunk it´s necessary to
have a box for the hat-rack speakers. If not, the low
bass from the sub will have an influence on the spea-
ker cones and destroy the sound.
In many installations you must use passive filters to
the different speakers in your system. Later in this
book there are some wiring examples where passive
filters are used.
13
DLS IN MULTIMODE
All DLS amplifiers (except for A6, RA10 & CAD11)
can be used in multimode operation on the stereo
channels. Multimode means that you from one
amplifier can take three different signals, left channel,
right channel and the sum of right and left channel.
To the sum signal you can connect one or more
subwoofers through a passive low-pass crossover.
You can also connect a center-channel speaker in
multimode. (See example on page 18).
The stereo connected speakers can be either a 2/3-
way system or coaxial speakers. To this speakers
you must use passive high-pass filters that limits the
frequency response.
The advantages of multimode operation is that a
single amplifier can be used for all speakers in the
car. It´s easy to install, it needs less space and it´s
cheaper. The disadvantages is that you need passive
crossovers and it´s difficult to adjust the sound
balance between the front system and the subwoofer.
The load capacity of the amplifier limits the number
of speakers that you can use in the system.
DLS CLASSIC and Reference amplifiers are 2 ohm
stable, the minimum amplifier load is 2 ohms. The
DLS ULTIMATE amplifiers are 1 ohm stable, mini-
mum amplifier load is 1 ohm.
FRONT SYSTEM RIGHT CHANNEL
R- R+
1234
1
23
4
1
23
4
1
23
4
1234
10 mH
This connection can be used together with all DLS
amplifiers.
L+ L-
SUBWOOFER
300 μ F
STEREO
123
1
2
3
1
2
3
123
300 μ F
10 mH
12
12
12
12
10 mH
300 μ F
LP-filter
LP-filter
1234
1
23
4
1
23
4
1
23
4
1
23
4
1234
1234
1
23
4
1
23
4
1
23
4
1
23
4
1234
Tweeters
with filter
Tweeters
with filter
FRONT SYSTEM, LEFT CHANNEL
SUBWOOFER INSTALLATION
An "open air" subwoofer installation in the hat-rack
or towards the back seat calls for the same baffles of
particle board or MDF-board as described above.
DLS OA10D & OA12D are subwoofers designed to
use in open air installations.
But the best result is normally achieved using a
separate bass box of some type. Later in this book
we will describe different types of boxes and give
advices of how to build a box.
You will also find suitable box sizes for all DLS
subwoofers.
DLS SOUND HANDBOOK - INSTALLATION
DLS
AMPLIFIER
MULTIMODE OPERATION
This is an example of a typical multimode connetion
with a front system and a subwoofer. 12 dB passive
high- and low-pass filters are used in combination
with the original filters used for the front system.
All speakers have an impedance of 4 ohms.
The 10 mH coils
can be spared.
Change to 200
μF capacitors
instead of 300
μF.

WHY DO WE NEED SPEAKER BOXES?
A Hi-Fi speaker for home use is always mounted in a
box to reproduce the best possible sound.
Traditional mounting in cars are in a door side or in
the hat rack, this is a simple baffle mounting. You
can of course achieve a better sound in your car by
using suitable speaker boxes.
In a correct adapted box the sound is improved and
the power handling capacity increases.
If you have a subwoofer in your trunk and a pair of
"open air"- mounted speakers in the rear, the air
pumping from the sub will effect the rear speakers
and make the cones move a little, ruining the sound
from them. This is one of many good reasons to use
boxes in your car as well as at home.
Normally we use boxes for the subwoofer but also
the rest of the speakers sounds better mounted in a
suitable box. We will now describe the different types
of boxes normally used in a car.
SPEAKER BOXES, GENERAL
Build your box in a stable and air-tight material. The
best is MDF-board, 19 mm, or particle board, 22 mm.
Larger boxes must have braces inside to avoid
resonance. The box must be completely air-tight. Use
sealing compound in all joints, also in the conduit
entry. The size of the box is fixed by the speaker
data, but also the type of vehicle and music, have an
influence on the box size. Deep bass demands larger
boxes than disco music.
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VENTED BOXES
A speaker in a vented box has higher efficiency (3
dB) than in a sealed box. In a vented box the sound
from the speaker and the port work together creating
a higher sound level. The sound from the port must
come out in the same phase as from the speaker, or
the sound result is bad.
The size of the box is set by the speaker data just as
in the sealed box. Also the car type and music type
have an influence on the box size.
Often the size of the car decides the practical size of
the box. A smaller box has a higher resonant
frequency than the larger one. The size of the box
should not be so large that the speaker plays below
it´s own free air resonance (Fs), then the power hand-
ling capacity drops.
The port in a vented box should be installeded on the
same side of the box as the speaker. But sometimes
this is impossible. The port opening inside the box
must have a free area behind the port, to the wall
behind, of at least the port diameter.
If the port is very long you might have problems
with the install. You can make a trick and "fool"
the speaker. Cut the port approx. 2,5 cm (1") from
the rear wall inside the box. Then the speaker is
fooled to believe the port is longer than it actually
is. This is not a perfect method but it often works
good enough.
There must also be a free area in front of the port.
Don´t cover the port opening with cloth. A large sub
needs a larger port to avoid whistling sounds. Use
ports with conical openings to avoid this. The port
must also be fastened properly to avoid rattle.
3" or 4" PVC tubes are normally used for ports. In a
correct tuned box you should be able to feel the air
pumping out from the port. At high volumes the air
can blow out a burning match, if not the box and port
are mismatched.
The port does not have to be fully inside the box as
long as the area and length are correct. for example
you can mount the port through a hat-rack. In a small
box this can have an effect on the box tuning since
the volume changes.
Suitable port diameters for different speaker sizes:
8": 4 - 8 cm, 10": 6 - 10 cm
12": 8 - 15 cm, 15": 10 - 15 cm
Sometimes you need two or more ports in a box. You
can convert from one to two or more ports as long as
the total port area is the same.
Advantages:
- Less cone movement and lower distorsion at port
tuning.
- Higher sound level at port tuning.
- Improved "bass kick".
Disadvantages
- Less cone control below port tuning.
- Higher frequencies can "leak" through the port.
- The sound from the port can be out of phase
compared with the sound from the speaker cone. Can
give a trailing sub sound.
SEALED (CLOSED) BOXES
Sealed boxes are easy to build. The size is not critical,
but it can´t be too small. The speaker data such as
Fs, Qts, Vas and X-max decides the size of the box.
Large speakers need larger boxes. Two speakers
need a box of the double size etc. The box must be
completely air-tight. Sealed boxes are normally used
for door-panels or kick-panels. Most 4", 5,25" and
6,5" speakers can be used in sealed boxes.
A sealed box should be filled with acoustic wool up
to 75 - 100%. A sealed box has a lower efficiency
than vented boxes but they can handle high power
and are easy to build. A subwoofer in a sealed box
creates a tight bass suitable for the audiophiles list-
ening to classical music, jazz and soft rock.
Advantages:
- High power handling capacity
- Extended low frequency reproduction
- Excellent transient response
- Easy to build
- Not critical with the size
Disadvantage:
- Lower efficiency (needs more power)
If you use a 25-30 Hz subsonic highpass filter on the
line input of your amplifier you will achieve a tight
and well-defined bass in your bass-box. (All DLS
amplifiers have a built-in subsonic filter.)
DLS SOUND HANDBOOK - SPEAKER BOXES

BANDPASS BOXES
In all bandpass boxes the speakers are hidden
inside the box, all sound is coming out through the
ports. There are different types of bandpass boxes
and they have in common that they are a bit more
difficult to build.
BOX DESCRIPTION
Mechanical orders for speaker boxes:
1:th order
Speaker in free air. Not in practical use, the
speaker is acoustically shortened.
2:nd order
Speaker mounted on a baffle, normally called
"open air".
This is not a box, just a way of mounting the speaker. For
example in a hat-rack or behind the rear seat. Can create a
good sound with the correct speaker parameters. The speaker
should have a low resonant frequency.
3:rd order
Speaker mounted in a sealed box.
15
DLS SOUND HANDBOOK SPEAKER BOXES
SPEAKER CONSTRUCTION suspension
voice coil
pole plates
magnet
spider
chassie dust cap
speaker cone
A sealed box is easy to build and calculate. It also has a high
power handling capacity. On the other hand it has low
efficiency and the box must be rather big to create a deep bass.
With a rather small box and a 20-40 Hz subsonic filter you will
get a box suitable for hard rock with a fast attack in the bass.
4:th order
Speaker mounted in a vented box, often called
bass reflex box.
A vented box has a higher efficiency and a higher power
handling capacity than the sealed box - but only if it´s correctly
calculated with a suitable speaker element. Suitable for all
kinds of music. The power handling capacity below the F-3db
point is rather weak. It is important that the ports are correctly
tuned, they must not be too small, then whistling sounds can
occcour. With a wrong port the sound from the ports comes out
phase reversed and causes a blurred sound.
5:th order
Speaker mounted in a sealed box, playing into
a vented box.
This type of box can play one octave only, but it has a high
power capacity and gives a 3-5 dB raise at it´s tuned frequency.
Suitable for disco and hard-rock music. Difficult to build and
calculate and you can´t have speaker cloth in front of the ports.
6:th order
Speaker mounted in a vented box where both the
speaker and the port is playing into another
ported box.
This box is also difficult to calculate and build. Plays 2 octaves
and gives a natural cut-off for higher frequencis with 12 dB/oct.
which reduces the audible distortion. It has a high efficiency
and power handling capacity. Low F-3dB and a top at the tuned
frquencies. Small ports gives a whistling sound and you can´t
have speaker cloth in front of the port. Build as isobaric it
creates a powerful and distinct deep bass.

7:th order bandpass box
Speaker mounted in a vented box playing into an-
other vented box. All ports going out.
What is valid for 6:th order boxes is also valid for 7:th order
boxes. The difference is that this box gives a 6 - 10 dB peak at
the tuned frequencies.
8:th order bandpass box
Speaker mounted in a vented box playing into
another vented box with all ports playing into a
third vented box.
This type of box becomes rather large but the port openings
can be covered with cloth. It has like the 6:th and 7:th order
boxes high efficiency and power handling capacity. It also gives
a 6 - 10 dB peak at the tuned frequencies.
3-chamber bandpass boxes
Both 5:th order boxes and 7:th order boxes can
be built as 3-chamber boxes with two speakers
playing into a ported chamber. The picture shows
a 5:th order 3-chamber box. In a 7:th order 3-
chamber box all chambers have ports.
ISOBARIC BOXES
Two speakers mounted on the same axis and
operating in the same phase and direction (push
and pull).
All box types can be built isobaric giving the following
advantages and disadvantages.
Advantages: Reduced box volume with the same F-3 dB
Higher efficiency
Lower distortion
Disadvantages: Difficult to build and calculate
The speaker specifications changes (Qts
and Vas)
Isobaric-connection:
Isobaric speakers are connected with the inner sub
in phase with the outer, but phase reversed as in the
drawing below.
If both are in boxes the one in the smallest box should
be phase reversed.
+
+
+
+
+
-
-
-
-
-
-
+
-
+
Speakers
in parallel
Speakers
in series
16
4:th order isobaric box
7:th order isobaric bandpass box
DLS SOUND HANDBOOK - SPEAKER BOXES
Use DLS BP-75 and BP-110 conical
ports to avoid port noise.

++
--
+
2 ohm
Two 4 ohm speakers in parallel
Two speakers in series.
8 ohm
+
+
+
---
We don´t recommend this connection.
Four speakers in series/parallel to 4 ohm.
4 ohm
+
+
-
+
-
-
+
-
+
-
Each
speaker
is 4 ohm
1,3
ohm -
-
+
+
+
-
+
Each
speaker
is 4
ohm
-
Three speakers in parallel
SPEAKER CONNECTION
Always use high quality speaker cables such as DLS
SC 2x1,5, SC 2x2,5 or SC 2x4. Subwoofer
connection requires 2 x 4 mm2cable.
Connect the speaker + (marked with + or a red dot)
to the amplifier + terminal, and the speaker - to the
amplifier -.
When fitting the cables to the amplifier terminals,
remove only 10 mm of the insulation. Twist the wire
strand together and insert the wire after loosening
the terminal screw. Do not over tighten as this can
cut the cable strands.
If you want an extra high class speaker cable choose
any of the DLS SCP, SCK, SCKS, SC 4x1 or SC
4x1,5 cables.
+
-
+
-
Batteri
1,5 Volt
NOTE! You can not test tweeters in this way.
17
SPEAKER POLARITY CHECK.
All speakers in a car audio system should be
connected in phase (the same polarity). All speaker
cones must move in the same direction. Out of phase
speakers will cause a lack of bass, and a poor stereo
soundstage.
Checking polarity:
Hold the - connection of the speaker wire to the -
terminal of a 1,5 Volt flashlight battery. Tap the + wire
on to the + terminal of the battery, and observe the
movement of the cone. The cone should move
outwards when the wire touches the battery, and
inwards when the battery is removed. If it is the other
way around, the speaker has been connected
backwards and it must be removed and connected
correctly.
If your system also has a subwoofer connected
through a passive 6 or 12 dB crossover, try to connect
this with various polarity and judge what sounds best.
The phase shift in passive crossovers sometimes
makes it necessary to change polarity.
SPEAKER LOADS
Most car audio speakers have a 4 ohm impedance.
DLS CLASSIC and Reference amplifiers can handle
loads down to 2 ohm on each stereo channel. DLS
ULTIMATE amplifiers can handle loads down to 1
ohm.
If you are using more than one driver they must be
connected in a way so the impedance still is 4 ohm
when connected to a CLASSIC amplifier in bridge
mode. To an ULTIMATE amplifier you can connect
speakers in bridge mode that has an impedance of
only 2 ohms. When you run the amplifier in mono
bridge mode it sees a 4 ohm load as 2 ohm, and a 2
ohm load as 1 ohm.
Below you find different speaker wiring examples.
DLS SOUND HANDBOOK - SPEAKER BOXES

DLS SOUND HANDBOOK - TROUBLE SHOOTING GUIDE
18
Installing car sound can sometimes cause
problems. If you are not satisfied with the sound
you could have made something wrong.
Some typical problems are described below with
hints for solving them.
1. Problem: Poor bass reproduction
despite of a correctly designed bass
box.
- Start with phase reversing the subwoofer to see if
this helps.
- If you are using more than one subwoofer make
sure they are connected in the same phase
(polarity), if not most bass sound disappears.
(The speaker cones are moving but will not create
bass sound).
- If the bass reproduction is improved when
opening the doors of your car the box is too large,
The F-3dB point is too low. Make the box smaller.
- Standing waves can "kill" some frequencies. Try
to change place for the box. You can also try to
make the bass port shorter, this will increase the
box resonant frequency.
In some cases the area under the dashboard can
work as a wave trap killing some low frequencies.
Try to fill this area and tighten it.
- Also check the signal cable. If yuor subwoofer is
connected in mono bridge mode and one of the
leads are broken in a signal cable the sound
becomes real bad.
- You must also have enough power, especially if
you have a small sealed enclosure the power
output should be at least 200 Watts RMS.
2. Problem: The real "kick" lacks in the
bass sound.
- The box is not correctly build, or the box is not air
tight.
- The sub amplifier does not get enough power, the
power cables are too small, the ground
connection bad, or some other things that is
causing voltage drop at high power outputs.
A cheap amplifier with unsufficient capacity in the
DC-converter can give the same result.
A good car battery with low inner resistance
(OPTIMA) or a Power Cap of 0,5
Farad or more connected to the power lead will
also improve the bass reproduction.
3. Problem: "Rumble" bass sound.
- The box tuning is too low, make the F-3dB higher
with a smaller box.
- Connect a subsonic high-pass filter, 30 - 50 Hz, in
series with the amplifier input.
- Use vented or sealed boxes. Avoid band-pass
boxes, they are more difficult to build, and if
theyare incorrectly designed they create a rumble
bass sound.
4. Problem: Poor bass reproduction in
a system without separate subwoofer.
- Is normally caused by incorrect speaker phasing.
Make sure all woofer elements in the system are
connected with the same polarity (phasing). Both
front and rear speakers.
This is easiest made with the use of a 1,5 Volt
battery. Connect the battery + to the speaker +
cable, and the - to the speaker - cable. All spea
ker cones must move outwards when the battery
is connected.
5. Problem: Interference sound from
the alternator in systems with a
separate amplifier.
- Is normally caused by incorrect grounding. Try to
connect all units to the same ground point. It
should be a place close to the amplifier where the
paint is removed from the metal surface.
- Poor shielding on the signal cables, or a
defective cable.
- The signal cable is placed close to the cars own
cable wiring inducing interference into the signal
cable.
- The input level control on your amplifier is set to
high, reduce the setting.
- Any extra cable must not be laid in a ring, shorten
the cable or lay it in zig-zag instead.

DLS SOUND HANDBOOK - SPEAKER BOXES
BASS BOXES IN DIFFERENT TYPES OF CARS
1. SMALL CARS LIKE VW GOLF AND SIMILAR
In this car type the bass box should be mounted with both speaker and port directed backwards.
Alternatively booth speaker and port can be directed upwards. This way of mounting is valid also for half-
combi car types.
2. SEDAN CARS
In this car type with the passanger compartment separated from the luggage compartment the bass box
should be mounted with booth speaker and port directed towards the rear seat. In some cars there is an
opening in the middle of the rear seat for loading skis etc. You can place the box behind this opening and
direct speaker or port through this opening. There must be some free space in front of the port, (between
the rear seat and the port opening)
Don´t put the port through the hat rack if the speaker is directed towards the rear seat, this will give a poor
sound. Alternatively you can mount both speakers and port in the hat rack with a box under it, but this
requires more changes of the car original interior.
3. LARGE CARS, STATION WAGONS.
In this type of cars the best sound is achieved with the bass box mounted behind the rear seat with booth
speaker and port directed backwards. Alternatively you can put the bass box on one side of the luggage
compartment.
19