Apogee APL-220 User manual

APL-220, APL-500, & APL-800
SELF-POWERED FULL-RANGE
SPEAKER SYSTEM MANUAL
© 2001 Apogee Sound International
Specifications subject to change without notice.
55-0048-01D 0711

2
Notice
Every effort was made to ensure that the information in this guide was complete and accurate at the time of
printing. However, information is subject to change.
IMPORTANT SAFETY INFORMATION
WARNING: To Reduce The Risk of Fire Or Electric Shock, Do Not Expose This Apparatus To Rain Or
Moisture.
Always follow these basic safety precautions when installing and using the unit:
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with dry cloth.
7. DO NOT block any ventilation openings. Install in accordance with the manufacturer's instructions.
8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus
(including amplifiers) that produce heat.
9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two
blades with one wider than the other. A grounding-type plug has two blades and a third grounding
prong.The wide blade, or the third prong, are provided for your safety. If the provided plug does not
fit into your outlet, consult an electrician for replacement of the obsolete outlet.
10. Protect the power cord from being walked on or pinched, particularly at plugs, convenience
receptacles, and the point where they exit from the apparatus.
11. Only use attachments/accessories specified by the manufacturer.
12. Unplug this apparatus during lightning storms or when unused for long periods of time.
13. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been
damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects
have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate
normally, or has been dropped.
CAUTION: TO PREVENT THE RISK OF ELECTRIC
SHOCK, DO NOT REMOVE COVER (OR BACK). NO
USER-SERVICEABLE PARTS INSIDE. REFER SERVICING
TO QUALIFIED PERSONNEL.
The exclamation point within an equilateral triangle is intended to
alert the user to the presence of important operating and mainte-
nance (servicing) instructions.
The lightning flash with arrowhead symbol, within an equilateral tri-
angle, is intended to alert the user to the presence of uninsulated
"dangerous voltage" within the product's enclosure that may be of
sufficient magnitude to constitute a risk of electric shock to persons.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN

Table of Contents Precautions & Safety Notes . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
The Concept of Integration. . . . . . . . . . . . . . . . . . . . . . . . . . . 7
AC Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Audio Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Signal Processing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Using the APL-220, -500, and -800 . . . . . . . . . . . . . . . . . . . . 23
Troubleshooting & Field Repairs . . . . . . . . . . . . . . . . . . . . . . 32
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Troubleshooting Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Amplifier Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Line Drawings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Warranty Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3

English
• To reduce the risk of electric shock, disconnect the AC mains power cable
before installing audio cable. Reconnect the power cord only after making all
signal connections.
• Connect the loudspeaker only to a three-pole, three-wire grounding mains
receptacle. The receptacle must be connected to a fuse or circuit breaker.
Connection to any other type of receptacle poses a shock hazard and may
violate local electrical codes.
• Do not install the speaker in wet or humid locations without using weath-
er protection equipment from Apogee Sound International.
• Do not allow water or any foreign object to get inside the loudspeaker. Do
not put objects containing liquid on, or near, the unit.
• To reduce the risk of overheating the loudspeaker, avoid exposing it to
direct sunlight. Do not install the unit near heat-emitting devices or appli-
ances, such as a room heater or stove.
•The loudspeaker contains potentially hazardous voltages.Do not attempt to
disassemble the unit. The unit contains no user-serviceable parts. Repairs
should be performed only by factory trained service personnel.
Francais
• Pour réduire le risqué d’électrocution, débrancher la prose principale de
l’haut-parleur, avant d’installer le cable d’interface allant à l’audio. Ne
rebrancher le bloc d’alimentation qu’après avoir effectué toutes les connec-
tions.
• Branchez l’haut-parleur dans une prise de courant à 3 dérivations (deux
pôles et la terre). Cette prose doit être munie d’une protection adéquate
(fusible ou coupe-circuit). Le branchement dans tout autre genre de prose
pourrait entraîner un risqué d’électrocution et peut constituer une infraction
à la réglementation locale concernant les installations électriques.
• Ne pas installer l’haut-parleur dans un endroit où il y a de l’eau humidité
excessive.
• Ne pas laisser de l’eau ou tout objet pénétrer dans l’haut-parleur. Ne pas
placer decipients contenant un liquide sur cet appareil, ni à proximité de
celuici.
• Pour éviter une surchauffe de l’haut-parleur, conserver-la à l’abri du soleil.
Ne pas installer à proximité d’appareils dégageant de la chaleur tells que radi-
ateurs ou appareils de chauffage.
Precautions &
Safety Notes
4

• Ce haut-parleur contient des circuits haute tension présentant un danger.
Ne jamais essayer de le démonter. Il n’y a aucun composant qui puisse être
réparé par l’utilisateur.Toutes les reparations doivent être effectuées par du
personnel qualifié et agree par le constructeur.
Deutsch
• Um die Gefahr eines slektrischen Schlages auf ein Minimum zu reduzieren,
den Lautsprecher vom Stromnetz trennen, bevor ggf. Ein Audio-
Schnittstellensignalkabel angeschlossen wird. Das Netzkabel erst nach
Herstellung aller Signalverbindungen wieder einstecken.
• Der Lautsprecher an eine geerdete zweipolige Dreiphasen-Netzsteckdose
anschließen. Die Steckdose muß mit einem geeigneten Abzweigschutz
(Sicherung oder Leistungsschalter) verbunden sein. Der Anschluß der unter-
brechungsfreien Stromversorgung an einen anderen Steckdosentyp kann zu
Stromschlägen führen und gegen die örtlichen Vorschriften verstoßen.
• Der Lautsprecher nict an einem Ort aufstellen, an dem sie mitWasser oder
übermäßig hoher Luftfeuchtigkeit in Berührung kommen könnte.
• Darauf achet, daß weder Wasser noch Fremdkörper in das Innere den
Lautsprecher eindringen. Keine Objekte, die Flüssigkeit enthalten, auf oder
neben die unterbrechungsfreie Stromversorgung stellen.
• Um ein Überhitzen dem Lautsprecher zu verhindern, das Gerät vor direk-
ter Sonneneinstrahlung fernhalten und nicht in der Nähe von wämeab-
strahlenden Haushaltsgeräten (z.B. Heizgerät oder Herd) aufstellen.
• Im Inneren diesem Lautsprecher herrschen potentiell gefährliche
Spannungen. Nicht versuchen, das Gerät zu öffnen. Es enthält keine vom
Benutzer reparierbaren Teile. Reparaturen dürfen nur von ausgebildetem
Kundenienstpersonal durchgeführt werden.
Español
• Para reducir el riesgo de descarga eléctrica, desconecte de la red el altopar-
lante antes de instalar el cable de señalización de interfaz de la segnale.Vuelva
a conectar el conductor flexible de alimentación solamente una vez efectu-
adas todas las interconexiones de señalizatción.
• Conecte el altoparlante a un tomacorriente bipolar y trifilar con neutro de
puesta a tierra. El tomacorriente debe estar conectado a la protección de
derivación apropiada (ya sea un fusible o un disyuntor). La conexión a
cualquier otro tipo de tomacorriente puede constituir peligro de descarga
eléctrica y violar los códigos eléctricos locales.
5

• No instale el altoparlante en lugares donde haya agua o humedad excesiva.
• No deje que en el altoparlante entre agua ni ningún objeto extraño. No
ponga objetos con líquidos encima de la unidad ni cerca de ella.
• Para reducir el riesgo de sobrecalentamiento, no exponga la inidad a los
rayos directos del sol ni la instale cerca de artefactos que emiten calor, como
estufas o cocinas.
• Este altoparlante contiene niveles de voltaje peligrosos en potencia. No
intente desarmar la unidad, pues no contiene piezas que puedan ser repar-
das por el usuario. Las reparaciones deben efectuarse únicamente por parte
del personal de mantenimiento capacitado en la fábrica.
6

The Concept
of Integration
Why a Powered Loudspeaker?
Apogee’s powered speaker systems further the company’s original concept
of processor-based loudspeakers. By combining advanced electronic signal
processing with precisely matched amplifiers, and integrating this package
into the speaker enclosure itself, a number of engineering improvements
result. Some of these are:
• The internal signal processor corrects driver and enclosure anomalies, and
provides required crossovers, time-domain alignment, and protection cir-
cuits.
• The amplifier’s power output, headroom, frequency response and dynamic
range are optimized for each model of loudspeaker system.
• The gain structure of the signal processor and amplifiers are always per-
fectly matched.
• An integrated speaker system is able to use voltage sensors to provide
information to the processor’s protection circuits.The result is more accu-
rate control of the drivers’ mechanical and thermal limits, and therefore
better protection under abusive conditions.
• The amplifier output cables are kept to very short lengths, thereby reduc-
ing cable losses to nearly zero.
Introduction Apogee Powered Loudspeaker Systems are highly-engineered products that
combine advanced-technology amplifiers, sophisticated signal processing, and
state-of-the-art drivers housed in rugged, roadworthy loudspeaker enclo-
sures. They are suitable for a wide variety of applications, ranging from
portable use for shows and events in all types of venues to permanent instal-
lations in auditoriums, churches, theaters, stadiums, meeting rooms, board-
rooms, and similar locations.
The APL-220, APL-500, and APL-800 are compact, bi-amplified speaker sys-
tems capable of providing clean, undistorted sound at very high output lev-
els. They easily form acoustically-correct arrays when used in multiples.
Although deceptively small in size, they are capable of fulfilling an astonish-
ingly wide range of professional sound reinforcement requirements due to
their wide-range response, predictable pattern control, excellent sonic qual-
ity, and easy arrayability.
Apogee powered products are exhaustively engineered and finely crafted.
They will provide years of trouble-free service if care is taken in their use and
maintenance. It is recommended that you read this manual and retain it in a
convenient location for future reference.
7

These engineering advancements result in the following benefits:
• All aspects of the loudspeaker system’s performance are maximized. Sonic
quality, power output capability, flatness of response, distortion, and behav-
ior under abusive conditions meet remarkably high standards.
• Reliability is increased because the internal amplifiers deliver appropriate
power levels to the drivers, without danger of over-powering or under-
powering.
• Setup is quick and easy - all key circuitry is self-contained and factory-
interconnected.There is no longer a need for the time-consuming mount-
ing and wiring of processors and amplifiers in outboard rack enclosures.
• Powered speakers save valuable truck and stage space previously allocated
for amplifier racks. Load-ins and load-outs are quicker and easier than with
conventional systems.
• Powered speakers weigh less than equivalent non-powered speakers and
amp racks, resulting in easier handling and reduced shipping costs.
• Powered speakers cost less and offer higher value than the equivalent
non-powered speaker, processor, amplifier, and rack combination.
8

(1) AC Power Connector and Cable
The APL-220, -500, and -800 each use a PowerCon®3-pole AC mains con-
nector for their power inlet (see Figure #1). When joined to the mating
PowerCon connector supplied with the AC line cord, the connector pair
locks in place to prevent inadvertent disconnection. PowerCon connectors
are durable, inexpensive, and readily obtainable.
The AC PowerCon cable assembly provided with your APL-220, -500, or -800
is equipped with an AC mains plug compatible with the power service in the
country of sale. If you need to change this plug or to construct special pur-
pose power cables, the wiring must follow the convention shown in Figure #2.
9
AC Power
Requirements
Figure 2
Figure 1
Brown - Hot
Blue - Neutral
Yellow/Green - Earth Ground
Insertion
Removal

Max. Continuous Amperes
APL-220, -500, and -800
Typical Program Conditions
120V AC
6.0 ARMS
4.0 ARMS
3.0 ARMS
2.0 ARMS
240V AC
Chart
1
(2) Voltage Range
The APL-220, -500, and -800 use advanced, high efficiency, intelligent, power
supplies. A convenient external switch allows for easy conversion between
115V AC and 230V AC. In the 115V AC setting, the allowable line voltage
range is 90V AC to 132V AC and in the 230V AC setting, the allowable range
is 190V AC to 265V AC.
(3) Current Requirements
All power amplifiers require sufficient current for proper operation and the
amplifiers designed into Apogee powered loudspeakers are no exception.
Chart #1shows the required current for one APL-220, -500, and -800 at two
standard international working voltages (120 & 240V AC). Because current
drain is ultimately a function of the program source, Chart #1shows both
the theoretical maximum, and what can be expected under typical high-level
program conditions:
10
Figure 3
All AC power plugs must always be of the 3-pole grounding type.
Interior of PowerCon connector showing the wiring terminal
DO NOT DEFEAT THE GROUND CONNECTION BY USING
AN AC GROUND LIFT ADAPTER, OR BY CUTTING THE
GROUND PIN OF THE AC POWER PLUG.
Hot
Neutral
Ground

We recommend powering no more than 2 APL-220, -500, or -800s from a
single 15A, 120V AC circuit, and no more than 3 APL-220, -500, or -800s from
a single 20A, 120V AC circuit, thereby allowing a margin for low voltages.
The advanced design of the APL-220, -500, and -800 allow them to function
properly over a wide range of voltages.The power supplies are designed to
perfectly maintain the amplifier’s internal bus voltage throughout this range,
with no degradation in performance. However, it is important to be aware
that the unit will draw more current if the power line voltage decreases.
Under full-power conditions, one APL-220, -500, or -800 can draw as much
as 720 watts.At 90V AC, this equates to 8.0 Amperes whereas at 240V AC,
the current demand is only 3 Amperes, to produce the same amplifier power.
Power (Wattage) is simply voltage (RMS) times current (RMS) or:
P = V x I
You can easily calculate the power demand at any line voltage by using the
following formula:
P / V = I
For example: if the line voltage is 208V AC, a single APL-500 at maximum
power (720 Watts) will draw 3.46 Amperes (720 / 208 = 3.46). This calcula-
tion is useful for determining appropriate cables to use with your powered
speaker system.
To determine the total current requirement for a system of powered loud-
speakers, simply add their Maximum Continuous RMS Currents together,
then calculate a safety margin of 25% or greater.
If special length AC cables are required for your powered speakers, they
should be constructed of durable, high-quality portable cordage such as S,
SO, or SJO type.
11

AWG# 86°F (30°C) 104°F (40°C)
14
12
10
8
15 A
20 A
25 A
35 A
12.3 A
16.4 A
20.5 A
28.7 A
6.9 A
8.7 A
14.5 A
20.3 A
Ambient Temperature
As you can readily see from Chart 2, the maximum permissible current rat-
ings decrease rapidly as the ambient temperature rises. Carefully consider
the ambient temperature in which the equipment will be used when deter-
mining appropriate wire gauge size.
12
122°F (50°C)
Chart 2
(4) Voltage Drop
Another important consideration in determining appropriate wire gauge is
the voltage drop that occurs across the cable’s resistance.This is a function
of the gauge and the length of the conductors, the current drawn by the load,
and the starting AC mains voltage. Generally, the permissible voltage drop
should not exceed 2.5% of the working voltage for audio loads. Although the
APL-220, -500, and -800 power supplies automatically compensate for volt-
age drops down to 90V AC in the 115V AC setting and 190V AC in the 230V
AC setting, it’s important to provide adequate power to the powered loud-
speaker by choosing appropriate cable sizes. A drop in voltage across the
power cable will cause the intelligent power supplies to draw more current
thereby causing the voltage to decrease even more. If the voltage drops
below 90V AC or 190V AC, damage may occur to the unit.
Chart 3 shows voltage drop as a percentage of the nominal working voltage
for typical lengths of cables at 120V AC and 240VAC.The shaded areas show
cable lengths and loads that result in 2.5% or less of voltage drop.
(NOTE:AWG stands for American Wire Gauge.)
Chart 2 provides the basic guidelines of The National Electric Code for four
common gauges of copper wire related to permissible load in amperes.
Chart 2 applies to three-conductor portable cordage of the types S, SO, SP,
SPT, SJ, and SJO, which are typically rated at a maximum operating tempera-
ture of 140°F (60° C). (NOTE: Operating temperature is the heat generat-
ed within the cable from the voltage drop added to the ambient tempera-
ture.) Chart 2 covers ambient temperatures of 86°F (30°C), 104°F (40°C),
& 122°F (50°C).
For safety reasons, the maximum ratings in the table below should never
be exceeded.

13
#14 AWG, 120V AC #14 AWG, 240V AC
Length in Feet 5A 10A 15A 20A Length in Feet 5A 10A 15A 20A
25' 0.6% 1.2% 1.8% 2.4% 25' 0.3% 0.6% 0.9% 1.2%
50' 1.2% 2.4% 3.6% 4.9% 50' 0.6% 1.2% 1.8% 2.4%
75' 1.8% 3.6% 5.5% 7.3% 75' 0.9% 1.8% 2.7% 3.6%
100' 2.4% 4.9% 7.3% 9.7% 100' 1.2% 2.4% 3.6% 4.9%
125' 3.0% 6.1% 9.1% 12.2% 125' 1.5% 3.0% 4.6% 6.1%
150' 3.6% 7.3% 10.9% 14.6% 150' 1.8% 3.6% 5.5% 7.3%
175' 4.3% 8.5% 12.8% 17.0% 175' 2.1% 4.3% 6.4% 8.5%
200' 4.9% 9.7% 14.6% 19.5% 200' 2.4% 4.9% 7.3% 9.7%
225' 5.5% 10.9% 16.4% 21.9% 225' 2.7% 5.5% 8.2% 10.9%
250' 6.1% 12.2% 18.2% 24.3% 250' 3.0% 6.1% 9.1% 12.2%
275' 6.7% 13.4% 20.1% 26.8% 275' 3.3% 6.7% 10.0% 13.4%
300' 7.3% 14.6% 21.9% 29.2% 300' 3.6% 7.3% 10.9% 14.6%
#12 AWG, 120V AC #12 AWG, 240V AC
Length in Feet 5A 10A 15A 20A Length in Feet 5A 10A 15A 20A
25' 0.4% 0.8% 1.1% 1.5% 25' 0.2% 0.4% 0.6% 0.8%
50' 0.8% 1.5% 2.3% 3.1% 50' 0.4% 0.8% 1.1% 1.5%
75' 1.1% 2.3% 3.4% 4.6% 75' 0.6% 1.1% 1.7% 2.3%
100' 1.5% 3.1% 4.6% 6.1% 100' 0.8% 1.5% 2.3% 3.1%
125' 1.9% 3.8% 5.7% 7.7% 125' 1.0% 1.9% 2.9% 3.8%
150' 2.3% 4.6% 6.9% 9.2% 150' 1.1% 2.3% 3.4% 4.6%
175' 2.7% 5.4% 8.0% 10.7% 175' 1.3% 2.7% 4.0% 5.4%
200' 3.1% 6.1% 9.2% 12.3% 200' 1.5% 3.1% 4.6% 6.1%
225' 3.4% 6.9% 10.3% 13.8% 225' 1.7% 3.4% 5.2% 6.9%
250' 3.8% 7.7% 11.5% 15.3% 250' 1.9% 3.8% 5.7% 7.7%
275' 4.2% 8.4% 12.6% 16.8% 275' 2.1% 4.2% 6.3% 8.4%
300' 4.6% 9.2% 13.8% 18.4% 300' 2.3% 4.6% 6.9% 9.2%
#10 AWG, 120V AC #10 AWG, 240V AC
Length in Feet 5A 10A 15A 20A Length in Feet 5A 10A 15A 20A
25' 0.2% 0.5% 0.7% 1.0% 25' 0.1% 0.2% 0.4% 0.5%
50' 0.5% 1.0% 1.4% 1.9% 50' 0.2% 0.5% 0.7% 1.0%
75' 0.7% 1.4% 2.2% 2.9% 75' 0.4% 0.7% 1.1% 1.4%
100' 1.0% 1.9% 2.9% 3.8% 100' 0.5% 1.0% 1.4% 1.9%
125' 1.2% 2.4% 3.6% 4.8% 125' 0.6% 1.2% 1.8% 2.4%
150' 1.4% 2.9% 4.3% 5.8% 150' 0.7% 1.4% 2.2% 2.9%
175' 1.7% 3.4% 5.0% 6.7% 175' 0.8% 1.7% 2.5% 3.4%
200' 1.9% 3.8% 5.8% 7.7% 200' 1.0% 1.9% 2.9% 3.8%
225' 2.2% 4.3% 6.5% 8.7% 225' 1.1% 2.2% 3.2% 4.3%
250' 2.4% 4.8% 7.2% 9.6% 250' 1.2% 2.4% 3.6% 4.8%
275' 2.6% 5.3% 7.9% 10.6% 275' 1.3% 2.6% 4.0% 5.3%
300' 2.9% 5.8% 8.7% 11.5% 300' 1.4% 2.9% 4.3% 5.8%
#8 AWG, 120V AC #8 AWG, 240V AC
Length in Feet 5A 10A 15A 20A Length in Feet 5A 10A 15A 20A
25' 0.2% 0.3% 0.5% 0.6% 25' 0.1% 0.2% 0.2% 0.3%
50' 0.3% 0.6% 0.9% 1.2% 50' 0.2% 0.3% 0.5% 0.6%
75' 0.5% 0.9% 1.4% 1.8% 75' 0.2% 0.5% 0.7% 0.9%
100' 0.6% 1.2% 1.8% 2.4% 100' 0.3% 0.6% 0.9% 1.2%
125' 0.8% 1.5% 2.3% 3.0% 125' 0.4% 0.8% 1.1% 1.5%
150' 0.9% 1.8% 2.7% 3.6% 150' 0.5% 0.9% 1.4% 1.8%
175' 1.1% 2.1% 3.2% 4.2% 175' 0.5% 1.1% 1.6% 2.1%
200' 1.2% 2.4% 3.6% 4.8% 200' 0.6% 1.2% 1.8% 2.4%
225' 1.4% 2.7% 4.1% 5.5% 225' 0.7% 1.4% 2.0% 2.7%
250' 1.5% 3.0% 4.5% 6.1% 250' 0.8% 1.5% 2.3% 3.0%
275' 1.7% 3.3% 5.0% 6.7% 275' 0.8% 1.7% 2.5% 3.3%
300' 1.8% 3.6% 5.5% 7.3% 300' 0.9% 1.8% 2.7% 3.6%
POWER CABLE VOLTAGE DROP (IN PERCENTAGE OF NOMINAL VOLTAGE)
Chart 3

(1) Input Impedance and Level
The APL-220, -500, and -800 were designed to receive a balanced-line signal
on their 3-pin female XLR type connector.They are also equipped with a 3-
pin Male XLR output connector, labeled “loop-through,” intended for the
purpose of daisy-chaining multiple powered speakers together on a common
signal feed.These input and output connectors are hard-wired in parallel; that
is to say, no active or passive buffer exists between the two connectors, they
are simply wired in parallel.This means that the loop-through connector will
always remain functional, even if AC power is interrupted to a speaker
“upstream” of other speaker(s) on the same feed circuit.
The input impedance is 35k-ohm, active balanced, and is intended to receive
a nominal +3 dBv input level (+3 dBv = full power). Because it’s common
practice to loop quite a few powered speakers together on a shared feeder
circuit, care must be taken to insure that the signal source is capable of driv-
ing the group of powered loudspeakers. For example, ten APL-500 speakers
present a 1k-ohm load to the signal source.This is well within the capability
of most line-level output drivers, but depending on the output impedance of
the source, some loss in level may occur. The formula to calculate such
loss is:
For example, let’s say you’re driving ten APL-500 speakers with a 100-ohm
source impedance.The formula to calculate loss would then be:
NOTE: It is important to be aware of the potential losses that may occur
from combining multiple powered speakers on the same feed circuit.This is
particularly important when attempting to adjust audio levels among a large
system that employs multiple feed circuits with different numbers of pow-
ered speakers on each feed.
Audio Signals
14
VS
RS
RIx VI
Voltage Loss (dB) = 20 *Log [ ]
RIx
RIx RS
+
()
Where: RS= Source Equipment Output Impedance
RIx =Combined Input Impedance of all APL Speakers
Note: VS=Unloaded Source Equipment Signal Voltage
VI= Loaded Signal Input Voltage to APL Speakers
Voltage Loss (dB) = 20 *Log [ ] = – 0.83 dB
1000+100
1000
( )

(2) Input and Output Connectors
The input and output connectors are wired as follows:
XLR Pin # Function
Pin 1Earth & Chassis Ground
Pin 2 Signal + DIFFERENTIAL INPUT
Pin 3 Signal - DIFFERENTIAL INPUT
Connector Case Earth & Chassis Ground
A positive signal applied to pin 2 of the XLR will result in a positive acoustic
pressure wave (excursion) appearing at the front of the drivers in the speak-
er system. Conversely, a positive signal appearing at pin 3 of the XLR will
result in a negative acoustic pressure wave (recursion) appearing at the front
of the speaker system’s drivers.
Overview
The internal amplification package consists of dual, fully-independent power
supplies and dual, fully-independent 500-watt RMS, 1600-watt peak, digital
amplifiers. One channel is utilized for the low frequency driver and the other
channel is used for the high frequency driver, hence the term "bi-amped."
These amplifiers and power supplies use numerous, proprietary design fea-
tures that result in extremely low distortion, high reliability, and a very low
heat by-product. No fans are used or needed, eliminating the risk of a
mechanical device becoming noisy during a quiet performance due to bear-
ing wear or contamination.The absence of fans also greatly simplifies main-
tenance, by eliminating the need to regularly check and clean air intake filters.
Unlike some competing designs, the amplifiers used inApogee powered loud-
speakers are designed to drive normal 4- and 8-ohm loads. Due to an excep-
tionally high voltage swing, the Apogee design does not require unusually low
impedance drivers in order to develop full power.Very low impedance driv-
ers (1- or 2-ohm) have a low BL-product and typically exhibit poor damp-
ening and transient response, resulting in a loss of clarity.
15
Amplifiers

The power supplies are robust and reliable.They each provide 650 watts of
continuous power, giving the system considerable headroom above its nom-
inal 500 WRMS per channel rating. Each of the two amplifiers is capable of
delivering 500 WRMS, and as much as 1600 watts of instantaneous burst
power.
Why the large difference between WRMS and instantaneous power? WRMS
is a measurement that occurs over a long period of time and is limited by
many factors including thermal considerations. Instantaneous power is a sim-
ple function of the peak voltage supplied to the speaker driver and the
impedance of the driver. Apogee’s APL series' amplifiers use a 80-volt bus (V)
with a 4-ohm driver (R).The instantaneous power calculation is:
Pi = V2/R
or
802/4 = 1600W
An amplifier's ability to handle musical transients is a function of its instanta-
neous power capability.
When installing and using the APL-220, -500, or -800, some simple precau-
tions should be followed.These include:
(1) Maintain Proper Air Flow
The APL-220, -500, and -800 are convection-cooled devices. Convection
cooling is more dependable than forced air cooling because fans are often
unreliable and require high maintenance. Apogee's APL-220, -500, and -800
do not need filter changes to protect the circuitry from contamination by
dust and dirt.The aluminum heat sink mounted on the rear surfaces provides
primary cooling of the system. Care must be taken to locate the loudspeak-
er away from heat registers, heat-generating appliances, lighting equipment,
and any other apparatus that could raise the temperature of the nearby air.
The APL-220, -500,and -800 require unimpeded air circulation in order to
function properly (this is especially important when multiple units are used
in stacked and/or tight-pack configurations).The APL’s rear surface should be
located at least 12" away from walls and/or ceilings. Sunlight and artificial
lighting, especially of the high intensity or theatrical type, should never be
allowed to shine directly on the heat sink.
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Installation

(2) Ambient Temperature
The APL-220, -500,and -800 are designed to be used in ambient tempera-
tures ranging from 32°F - 113°F (0°C - 45°C).Higher or lower temperatures
could cause system shutdown or result in early component failure. When
used outdoors on a hot day, take precautions to avoid direct sunlight on the
rear heat sink. Direct, intense sunlight can raise the temperature of the heat
sink to a point where the amplifiers may automatically shutdown to avoid
permanent damage.
(3) Convection Cooling and use in Horizontal Position
The APL-220, -500,and -800 are convection-cooled.The heat generated by the
internal amplifiers and power supplies is conducted to the rear heat sink and
transferred to the air by means of natural convection. Convection occurs from the
change in density of air molecules as they are heated, creating a natural airflow
from the relatively cool bottom of the heat sink to the warmer top area. Air flows
through the cooling fins, increasing in temperature as it rises.
If the APL-220, -500,or -800 are used in a horizontal position, air will not
flow as readily through the fins. When placed horizontally, the fins act as
obstacles to the airflow, and cooling efficiency is reduced. In moderate ambi-
ent temperatures,this will not usually cause a problem. However, it is prudent
to test the system under maximum power conditions at the highest ambient
temperature that will be encountered, in order to verify if cooling is adequate
to prevent system shutdown. Since the temperature of the heat sink will
increase over time as the system is used, this test should be conducted for a
time period equivalent to the actual intended duration of use.
(4) More About Heating and Cooling
The APL-220, -500,and -800 have a relatively complex thermal dynamic sys-
tem. They contain several heat sources (amplifiers, power supplies, and driv-
ers) that generate significant heat but only when program material is being
reproduced. They are cooled primarily through convection; and secondarily,
by a small degree of air movement generated by the cone drivers.
Because the heat output of the system is directly proportional to the dura-
tion and nature of the program material, the system may not reach thermal
stability for several hours after it is activated. For this reason, it is important
to test the system under actual conditions of use if questionable conditions
are present. Questionable conditions include:
(a) ambient temperature at or above the maximum rating
(b) intense sunlight or artificial light shining on the heat sink
(c) program material that runs for many hours without pause
(d) combinations of the above
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Signal Processing
Here’s a hypothetical example of what to look out for. An APL-500
might be set up outdoors in 85°F (29°C) temperature with sunlight shining
partially on the rear panel. Let’s assume it is tested during a 30-minute sound
check and all is well. Later that day, the ambient temperature rises to 99°F
(37°C) and the sunlight is now shining directly on the rear of the loudspeak-
er.The show starts, featuring dance tracks with no pause between song titles.
Under such extreme conditions, it is entirely possible that after a period of
service, the loudspeaker will shut off to protect itself from excessive heat.
Problems, such as the one described above, can be avoided by shading the
heat sink from direct sunlight.
(1) Basic Concept
The APL-220, -500,and -800 use a highly-advanced signal processor con-
tained entirely within the unit. The processor provides the functions of an
eighth-order (48 dB/octave) electronic crossover, fixed equalization to com-
pensate for driver/enclosure anomalies, time delay to acoustically align the
low and high drivers, and advanced protective limiting circuits. It also provides
a low-frequency alignment circuit that acts synergistically with the enclosure’s
ports.This serves to extend the bass response well below that of a conven-
tional enclosure of a similar size. All circuits in the audio path utilize the high-
est quality, most up-to-date semi-conductor technologies available today.
The processor is the key to the extraordinary sound quality of the loud-
speaker system. Unlike generic crossovers, either digital or analog, the APL
processor was carefully designed in tandem with the amplifiers, the drivers,
and the enclosure to provide optimum performance.
(2) Functional Description of Integrated Design Philosophy
One example of integrated design is the deployment of the high-frequency
equalization circuit. Here’s how it works: The loudspeaker’s high-frequency
driver uses a composite diaphragm material that is capable of smoothly
reproducing the extreme high frequencies, but not with the same sensitivity
as that of the lower portion of the spectrum.This is because the material is
highly damped and exceptionally free from resonance, especially when com-
pared to the typical distortion-prone aluminum and titanium diaphragms
used by most manufacturers.This same property, however, causes the driver
to exhibit a linear fall-off in its high-frequency response.The driver would not
be very useful in a two-way, non-processor based system, because it would
require a very specific compensation filter, not available from most generic
equalizers, to restore its response to flat.
18

Many product designers would summarily reject such a driver, because its fre-
quency response is not inherently flat, even though its response is excep-
tionally linear and its distortion extremely low.
Now the synergy of integrated design comes into play. The processor is
designed to correct the driver’s deviation from flatness with a proprietary
high-frequency filter circuit that flattens the driver’s response curve.
Simulating the effect of this particular circuit would be difficult, to say the
least, with a generic loudspeaker controller. In fact, if using a generic digital
controller, the required curve would most likely collide with the controller’s
anti-aliasing filter, making it impossible to duplicate. Does that mean this
unusual driver is not a good choice for a professional loudspeaker? Not at
all! On the contrary, when coupled with the processor’s compensation cir-
cuit, the driver exhibits a flat response and the lowest distortion of any high-
power, horn-loaded compression driver that we know of.The driver merely
required a properly designed compensation circuit to achieve its potential.It’s
that simple.
Here’s another way of looking at it.The compensation circuit is similar to the
pre-emphasis and de-emphasis circuits used for decades in analog tape
recorders. Only in the case of the HF driver, instead of reducing tape noise,
distortion is reduced. The de-emphasis side of the equation is really the
mechanical function of the driver's HF roll-off, and the pre-emphasis is the
EQ compensation circuit.The resultant reduction in distortion comes from
the highly damped nature of the diaphragm.A damped material is not prone
to resonance and, therefore, does not produce the harmonic distortion
products of a resonant material.
(3) Driver Protection
Apogee APL-Series speakers utilize a special, highly-evolved set of limiter
parameters and controls. Multiple limiters are used simultaneously with
attack, release, integration time, and slopes that have been carefully matched
to the individual speakers thermal and mechanical limits over time.
All of this occurs without compromising dynamic range or otherwise unnat-
urally compressing the program material. The protection circuits only act
when the drivers would otherwise be damaged and, therefore, are excep-
tionally transparent. They are effectively “out of circuit” when below the
threshold of engagement. The result is extremely clean sound quality, with
effective protection of potential damage to the drivers under abusive
conditions.
19

A clipping LED indicator is located on the rear panel.This LED will illuminate
when the speaker is several dB into limiting and indicates maximum operat-
ing level has been reached. It is not uncommon to see these LEDs illuminate
regularly, such as on downbeats and crescendos.
If the LEDs appear to be "on" more than "off " (i.e., if they are continuously
flashing or glowing at a steady state), the loudspeaker system is being pushed
too hard for its size and power output capability.To correct this, reduce the
drive level to the speaker system, or install additional speakers to achieve the
SPL (Sound Pressure Level) required for the application.
(4) A Word About Limiters
Properly designed protective limiters can do wonders to help prevent driver
damage and extend normal driver life, but they are by no means a panacea.
Apogee limiters do not exhibit “brick-wall” characteristics because such limiters
seriously degrade sound quality. Apogee’s intelligently engineered limiter circuits
provide an excellent measure of protection, while maintaining sonic purity.
Apogee's limiter circuits are capable of effectively reducing program levels
that would otherwise damage the system’s drivers.This takes place with little
or no loss of sonic quality or dynamic range, because the circuits are designed
so that they only engage when driver non-linearity or driver damage would
otherwise occur. However, when a limiter is pushed well past its threshold of
engagement to the point where it is continually “in circuit”, by nature it
increases the duty-cycle of the program material.This happens because, as the
limiter decreases peak amplitudes,RMS values increase, causing the drivers to
heat beyond normal. Additional circuits could be employed to reduce levels
and “clamp” the output of the system, but such circuits would represent a
high level of intervention and be very audible in their action.The proper solu-
tion is for the operator to recognize that the system is being pushed past its
capabilities and either reduce the operating level or add additional speaker
systems to provide the desired Sound Pressure Level (SPL).
(5) High-Pass Filter (HPF) Switch
The APL-220, -500,and -800 are equipped with a switchable High-Pass Filter.
The filter is of the 12 dB/octave type with a corner frequency of 80 Hz.The
High-Pass Switch is intended to be used when the speaker system is not
required to produce full-range output, such as in downfill, front fill, and other
band-limited applications. By using the High-Pass Filter Switch, the speaker
system can be driven approximately 6 dB harder before LF peak and LF RMS
limiters are engaged.The switch is located on the rear panel below the Input
XLR connector. It is recessed with only a small portion accessible, so that it
cannot easily be changed inadvertently.
20