Rockville dBcomp Series User manual

OWNER’S MANUAL for dBcomp4 and dBcomp5
CLASS D 1-OHM COMPETITION AMPLIFIERS
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Thank you for purchasing this Rockville dBcomp Series amplier. Over the years, the technology used to create audio ampliers has grown by
leaps and bounds. Our competition is satised with just continuing to build the same units year after year without thought for improvement, but
not Rockville. We consider it our mission to use our expertise in developing the latest technologies and to bring you the absolute best sounding
ampliers on the market and of course at a reasonable price. You will be amazed at the quality and power that these new amps offer.
We have spared no expense in designing these ampliers, creating the most rugged, reliable, powerful and best performing ampliers. In fact we
are so sure of the quality, that we backup every dBcomp Series amplier with one year warranty which exemplies our commitment to the end
user. (See enclosed warranty card for details.)
Please read this installation guide carefully for proper use of your dBcomp Series amplier. Read this entire guide fully before attempting your
installation. Should you need technical assistance, please call our technical help line at 1-646-758-0144, Monday through Friday, 9am to 5pm
EST.
WARNING: BE AWARE! Use of this amplifier at extreme high volumes for extended periods of time may cause hearing loss and or
hearing damage. During periods of prolonged high volume levels it is recommended that you use ear safety devices. Your ability to hear
necessary traffic sounds will be impaired. While driving always keep your sound volume at reasonable levels. We at Rockville want you
listening for many years to come.
• When installing the amplier, secure it tightly. An unmounted amplier in your car can cause serious injury to passengers and damage to your
vehicle if it is set in motion by an abrupt driving maneuver or short stop.
• To reduce risk of electric shock, never open the unit. There are no user serviceable parts, refer service to an authorized Rockville service center.
• Do not expose this unit to any kind of moisture.
• Please ensure that the unit is situated in a properly ventilated area.
Introduction
IMPORTANT SAFETY INSTRUCTIONS

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Installation
Installation Basics
Before you begin your installation, disconnect the NEGATIVE(-) terminal from your car’s battery. This safety precaution will avoid possible short circuits while wiring your amplier.
Rockville ampliers operate on 12-volt negative ground systems only. It is recommended that you layout your sound system design on paper rst. This will help you during the
installation so that you will have a wiring ow chart and not miss-wire any of your components.
Mount the amplier in the trunk or hatch area of your vehicle. Never install an amplier in the engine compartment or on the rewall. Please be sure to leave breathing room around the
amplier heat sink so that it can dissipate the heat it produces efciently. The amplier can be installed either horizontally or vertically.
When mounting the amplier on the trunk oor, be sure to watch for your gas tank, gas lines and electrical lines. Do not drill or mount any screws where they might penetrate the gas
tank of your car.
Mounting The Amplifier
The dBcomp Series ampliers feature four mounting tabs located at the ampliers four corners. Choose a convenient mounting location with unobstructed airow. Lay down the
amplier and mark the location of the mounting holes. Remove the amplier and drill pilot holes for the screws. Place the amplier and secure it to the mounting surface using the
supplied screws.
DO NOT OVER TIGHTEN THE SCREWS.

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1. Make sure to disconnect the NEGATIVE (-) terminal from your car’s battery.
2. Attach an 8 gauge or heavier wire to the amplier screw terminal marked GND.Connect the other end to the boat’s house battery. The connection should be as close to the amp as
possible (20 feet or less). For runs of 20 feet or more, you will need 4 gauge or heavier wire. When connecting the ground wire make sure that there is no paint or other insulator blocking
a good ground connection. When installing multiple ampliers, mount them in close proximity so that they can all share the same ground point.
3. Connect the remote terminal to the head unit’s remote output using 18 gauge or heavier wire. This connection is responsible for turning the amplier on and off with the rest of the
system. If there is no dedicated remote output, make this connection to the power antenna lead. Should your head unit not have any turn on leads, you can wire the remote terminal to an
accessory lead, which turns the amplier on with your car’s ignition.
4. Use 0 gauge or heavier wire to connect the screw terminal marked +12V to the car battery’s POSITIVE (+) terminal. In order to protect the battery and electrical systems of your
vehicle, add an in-line fuse holder within 18˝ of the car battery. This in-line fuse offers protection against damage from short circuits. The power wire should terminate in a large ring
terminal connected directly to the POSITIVE (+) terminal. An optional second fuse can be installed closer to the amplier for additional protection to the amplier itself. If installing multiple
ampliers, install a distribution block near their location and, using a 4 gauge wire, connect the block to the in-line holder that is connected to the battery.
5. Insert fuse(s) into the in-line fuse holder(s) and check that all connections are properly secured.
6. Before powering up the system, set all of the amplier’s level controls to minimum, the crossover/setting switches to the desired postion, and the head unit’s volume to 75%.
We have received ampliers back to our service department with melted power/ground terminals caused by a bad ground connection. When there is a lack of good ground, heat builds up
at the contact screws of the amplier terminal. Over time the heat generated will begin to melt the terminal. It is a good practice to feel the power and ground wires near the amplier after
using the amp for a while. If the wires feel hot to the touch you probably have a bad or loose connection. If after adjusting your connections the wires still feel hot, you should upgrade to
next heaviest gauge wire. As connections can work loose due to vehicle vibrations we recommend periodically tightening all power and ground connections.
All dBcomp Series amplifers are supplied with external fuses. Never replace the supplied external fuse with one of a larger value.
Wiring
BATTERY FUSE
GROUND
HEAD UNIT or VEHICLE’S ACCESORY LEAD.
DO NOT CONNECT WHEN USING HIGH LEVEL INPUTS.

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Settings
Adjusting The System
1. Once the system is operational, set all crossover points to approximate settings. In the case of the basic sub woofer system, set the Low Pass lter crossover at 100Hz or so. Set the
bass equalizer controls to 0 dB. Turn the controls using a small at head screwdriver. Do not apply any pressure while turning as this might break the control unit.
2. Now set the amplier’s Input Sensitivity adjustment. The control(s) accessible on the side of the amplier marked LEVEL or INPUT LEVEL adjusts the input sensitivity. Turn it counter
clock wise to the MIN position. Adjust your head unit’s volume level to the maximum it can go before signal distorts or to the loudest level which is usually about 75-85% on most head
units (you can also use an oscilloscope,or if you have a friend who has an oscilloscope, to see at what level your head unit distorts.). When you begin to hear distortion in the sound, back
down one notch and your amp is set. It is helpful to have a second person to help you set the gain. When setting up a multi-amp system, set each amplier’s level controls separately.
Start off with the bass amplier, then adjust the highs amplier’s level control to match. Please note that the level control of any car amplier should not be mistaken for a volume control.
It is a sophisticated device designed to match the output level of your source unit to the input level of the amplier. Do not adjust the amplier level to maximum unless your input level
requires it. Your system can also be extremely sensitive to noise when the LEVEL is set to maximum and does not match your input signal. These adjustments need to be made only once
when rst setting up the system.
3. Once you are satised with the level control settings, use any equalizer controls to adjust the system tonal level for personal preference. Keep in mind that after equalizing, you may
have to go back and reset the amplier’s level controls.

If your unit has been professionally installed please do not change the gain settings set by the installer, he is the professional!
Audio Preamp Input
The dBcomp Series ampliers feature RCA pre amp inputs. Run RCA cables from your sound source to the amplier inputs. We suggest you use high quality, shielded RCA patch cords to help
reduce and eliminate unwanted electrical noise to your system. Use good quality RCA interconnect cables. Cheaper cables usually have poor shielding that can cause interference pickup.
Be sure to run the RCA cables on the side of the vehicle opposite to the side used to carry the power and ground leads of the amplier.
Using The Built-In Low Pass Electronic Crossover
All dBcomp Series ampliers feature 24dB per octave fully adjustable crossovers with differential circuitry.
The knob marked LOW PASS will control the low pass frequencies from 50Hz – 250Hz. A frequent error made is setting the low pass frequency too low, especially when using vented sub
woofer enclosures. We recommend that for most installations you set the frequency knob between 80 – 150Hz depending on your preference and the rest of your audio system.
Using The Subsonic High Pass Filter
Subsonic frequencies are very low and can cause damage to your subwoofers. The Subsonic HPF is a high pass lter which will allow you to attenuate any frequencies below the set limit.
Sealed Enclosures: Sealed boxes are tuned by enclosure volume; larger enclosures tune lower, smaller enclosures tune higher. Subsonic frequencies can cause damage to your woofer
as they cause it to play below the enclosure’s tuning, forcing it to the limits of its excursion and making it expend a lot of energy. To avoid damage to your woofer set the Subsonic HPF
to 25 – 35Hz.

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Ported Enclosures: The enclosure’s port should be tuned to a certain frequency so that the enclosure is capable of playing all frequencies above that tuning. The enclosure can play below
that frequency, but only half and octave before the cone starts to over-extend. Hence, set the Subsonic HPF to 1/2 an octave below the tuned frequency.
Here is a simple formula to help you gure out the proper Subsonic HPF setting for your particular ported enclosure. Keep in mind that one octave up is double the frequency and one
octave down is half the frequency:
1. Divide the tuning frequency of your port by two. This is one octave lower than your tuning frequency.
2. Divide the quotient (answer) of step 1 by two: This is half an octave lower.
3. Now subtract the quotient (answer) of step 2 from the port’s tuning frequency.
Example:
Port tuning frequency is 46Hz
1. 46Hz ÷ 2 = 23Hz (one octave lower)
2. 23Hz ÷ 2 = 11.5Hz (half an octave lower)
3. 46 - 11.5 = 34.5Hz (round up to 35Hz)
So, you would set your Subsonic HPF to 35Hz.
Please note: The subsonic lter is NOT a cut-off. It has a roll-off slope that will attenuate the frequency it is set to. Attenuation will increase as the frequencies get lower, meaning the
power to the woofer decreases at the ltered frequencies which reduces excursion and the potential for damage.
Subsonic lters have steep slopes such as 3rd or 4th order (18 or 24dB/Oct) so it can be set as close to your ½ octave frequency as possible, or 25 – 35Hz sealed, without losing power
in the surrounding frequencies.

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Class D Monoblock Amp Input
Connect your head unit’s RCA outputs to the ampliers Left and Right RCA input jacks. All dB series monoblock ampliers feature RCA pre-amp line outputs for feeding of a pass-through signal
to a secondary full-range amplier in a multi-amp system.
Class D Monoblock 1 Ohm Amp Configurations
L
R
SOURCE

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The dBcomp4 and dBcomp5 are 1 ohm stable monoblock ampliers. No matter how many woofers you choose to wire up to these models, the nal impedance should not fall below 1 ohm.
Please see page 16 and 17 for various speaker impedance congurations.
The dual positive and negative terminals are connected in parallel inside the amplier. Connecting two speakers, each to one set of positive and negative terminals, will result in a parallel speaker
connection. If only connecting one pair of speaker wires, it is not necessary to use both sets of connections.
2 OHM DVC SUBWOOFER
4 OHM DVC SUBWOOFER
4 OHM DVC SUBWOOFER
1 OHM MINIMUM
LOAD @ AMPLIFIER
1 OHM MINIMUM
LOAD @ AMPLIFIER

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Both dBcomp ampliers can be bridged together for double the power output into a single 2-ohm load. Remember, when bridging ampliers
you must bridge them to a 2-ohm load.
Input the head unit signal into the MASTER amplier and set the Bridged Mode switch to Output Master. Use a MONO RCA to RCA cable
to send the fully processed signal from the MASTER amplier to the secondary SLAVE amplier and set the Bridged Mode switch to Input
Slave. Do not input any RCA signals into the Slave amplier left and right inputs. All crossover controls, Bass Drive, frequency settings,
and subsonic lter settings will be controlled by the Master Amplier including input gain levels. There is no need to gain match the two
ampliers, it will occur automatically. The remote dash bass control should be plugged in to the Master amplier and it will control both
ampliers.
This same input/control system can be utilized when daisy chaining two ampliers to two independent 1 ohm woofers as long as you don’t
bridge the two ampliers outputs together.
You can only bridge 2 of the same amplifiers together. DO NOT bridge different models together.
When bridging two ampliers together, the nal impedance load of the bridged ampliers should be no lower than 2-ohms. Double power
will occur at 2-ohms. Master ampliers positive (+) speaker terminal should be wired to the positive terminal of the subwoofer.
Slave ampliers positive (+) speaker terminal should be wired to negative terminal of the subwoofer. Connect a heavy gauge wire (12 Gauge)
between the negative (-) terminal of the Master amplier and the Negative (-) terminal of the Slave amplier.
When daisy chaining two ampliers for independent woofers, wire up the woofers as you would typically wire them when installing individual
systems, even down to 1-ohm. By using the Master/Slave input conguration you gain the advantage of having one amplier’s preamp
section control both ampliers, eliminating the need to gain match and crossover match your system between ampliers.
Twin Amp Bridging

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Twin Amp Bridging
MASTER
SLAVE
SWITCH SET TO
OUTPUT MASTER
SWITCH SET TO
INPUT SLAVE
REMOTE SUBWOOFER
LEVEL CONTROL
L
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IMPORTANT NOTE:
CONNECT THE TWO SPEAKER NEGATIVE SPEAKER TOGETHER WITH A
#12 WIRE STRAP. IF THIS STRAP IS NOT INSTALLED, THE AMPLIFIERS
COULD BE DAMAGED!
SUBWOOFER MINIMUM
IMPEDANCE 2 OHM
Twin Amp Bridging

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Bass Equalization Circuitry
A narrow “Q” peaking equalization circuit is included in the ampliers. The equalization system is preset at 45Hz. The equalizer control allows you to add up to 12dB of bass boost.
Utilize the bass equalizer to tailor your bass response to your systems needs. Make sure your speakers can handle the extra power output! It would be foolish to add 12dB of gain to
low excursion 8˝ and 10˝ Sub woofers or mid ranges and tweeters. It’s a sure way to blow your speakers.
Audio Output Section
The audio output sections of the Class D dBcomp Series ampliers feature rugged, fast switching MOSFETs.
Power And Protection Circuitry
dBcomp Series ampliers feature our unique IC controlled protection circuitry. This sophisticated circuit constantly monitors the heat sink internal temperature and various voltages,
adjusting the amp automatically and protecting it from dangerous conditions. The 2 LED’s located on the side of the amplier provide indication of the amplier status, the Power LED
will light when the amplier is receiving proper power, ground and remote voltages and the IC monitoring sequence indicates the amp is functional. In case the amplier encounters a
diagnostic condition as listed below, the second LED will light indicating a Diagnostic condition. When a diagnostic condition is sensed the amplier will then turn into a self preservation
mode and if the cause of the diagnostic condition is not corrected will eventually shut down. There are certain critical diagnostic conditions which will turn the amplier off immediately.
Thermal Protection: When the amplier reaches an unsafe operating temperature of 80 degrees Celsius the amplier will turn off.
Once the amplier cools down to a safe temperature, it will automatically turn on again.
If you live in a hot climate we suggest installing additional cooling fans in your trunk to exhaust the hot air which can build up in the trunk this will help keep the ambient temperature in
the trunk as low as possible so that your amps work awlessly and without any musical interruption.
Speaker Short Circuit Protection: Should your speakers short circuit due to voice coil burn out, or should the amplier sense an impedance too low to handle, the Protection LED will light, indicating
a diagnostic condition. Turn off your system, disconnect one speaker at a time and try to determine which speaker might be faulty. Correct the condition and restart the amplier. You must reset the
amplier by turning it OFF and then ON again by the Remote power connection after correcting a diagnostic condition. (Turn your radio off and then on again.)
Clipping or total shutdown may also be a result of a bad ground connection or loose ground. If you nd that your speakers and speaker wires are not shorted, please check
your ground and power connections.
Input Overload Protection: This circuit will either shutdown the amplier completely or make the amplier spurt on and off indicating that it is in a diagnostic condition. Turn the system
off and reduce the gain on the amplier or volume from your head unit, this should result in a corrected condition.
DC Offset Protection: Should any DC voltage try to enter the amplier via the speaker terminals it will cause the amplier to shut down and not operate until this condition is remedied.
This circuit will also protect damaging high DC voltages from reaching your speakers should your amplier ever malfunction.
You must reset amplier by turning it OFF and then ON again after correcting a diagnostic condition (turn your radio off and then on again). If the amplier stays in protection after a
reset, it is most likely faulty.
To reset the amplifier, you must first diagnose what caused the problem, correct the fault and restart the system.
Features

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Features
Limiter Circuit
The dBcomp series features a built-in limiter circuit with an On/Off switch. When the circuit is turned on, it will automatically limit input signals that may cause clipping, thus preventing
damage to your subs. For competition purposes, the limiter circuit can be turned off so as to allow you to “burp” your sub. The term burping refers to playing a specic frequency
through your sub for 3 to 4 seconds. This allows for maximum wattage without damage to your amp or sub.
Please note: Clipping occurs when an amplier is not able to generate enough voltage to reproduce the input signal. Continous or long-term clipping can cause serious damage to your
amp and subwoofers. If you are experiencing clipping, it is recommended that you adjust your gain settings and your head unit’s volume levels. Refer to “Adjusting the System” in the
Settings section on page 6 for detailed instructions on how to properly set your dBcomp amplier’s gain levels.
Mute Circuit
This is an anti-thump, mute and delay circuit that eliminates irritating speaker damaging turn-on and turn-off transients normally experienced with less expensive ampliers.
Bass Remote
The dash-mounted bass remote allows you to control the amplier’s bass level from the comfort of the driver’s seat. It features power, protect, and clipping indicator LEDs.
• The power LED indicates the unit is receiving power and operating nominally.
• The protect LED will light up when the amp enters protection mode. Refer to “Power and Protection Circuitry” on page 13 for detailed information.
• The clipping LED will light up if the limiter circuit is turned on and limiting is taking place. If the circuit is off, the LED will light when clipping occurs. Please see “Limiter Circuit”
section above for more information.
Battery Voltage
Rockville dBcomp Series ampliers feature a convenient LED readout which displays the current voltage input while the amp is in use. The amp will go into protect mode when the
voltage goes below 10 volts or above 16 volts.

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Specifications
• Digital Voltage Display on Amp
• High-Speed MOSFET Power Supply
• Optical Coupler Class “D” Technology
• Fully Adjustable 24dB/Octave Crossover with Differential Circuitry
• Low Pass Filter: 50Hz – 250Hz
• Subsonic Filter: 15Hz – 55Hz
• Fully Adjustable 12dB Bass Equalizer
• Phase Control Switch
• Limiter with ON/OFF Switch
• RCA Preamp Line Out
• Mute and Delay Soft Start System
• Full IC-Controlled Protection Circuitry
• Status Mode LED Indicator
• 8 Volt Preamp Circuitry
• Dashboard Mounted Subwoofer Remote Control with Status Mode LED Indicator
• Digital Voltage Display on Amp
• High-Speed MOSFET Power Supply
• Optical Coupler Class “D” Technology
• Fully Adjustable 24dB/Octave Crossover with Differential Circuitry
• Low Pass Filter: 50Hz – 250Hz
• Subsonic Filter: 15Hz – 55Hz
• Fully Adjustable 12dB Bass Equalizer
• Phase Control Switch
• Limiter with ON/OFF Switch
• RCA Preamp Line Out
• Mute and Delay Soft Start System
• Full IC-Controlled Protection Circuitry
• Status Mode LED Indicator
• 8 Volt Preamp Circuitry
• Dashboard Mounted Subwoofer Remote Control with Status Mode LED Indicator
CEA Compliant Power Output:
1 Ohm: 3000 Watts x 1 Channel <1% THD+N at 14.4 volts (93% efciency)
2 Ohm: 2000 Watts x 1 Channel <1% THD+N at 14.4 volts (88% efciency)
4 Ohm: 1100 Watts x 1 Channel <1% THD+N at 14.4 volts (83% efciency)
• Minimum THD at Rated Power: < 0.1%
• Frequency Response: 15Hz - 250Hz
• S / N Ratio: >90dB
• Damping Factor: > 150 @ 100Hz
• Under Voltage Protection at 10V
• Over Voltage Protection at 16V
• 400 Amp External Fuse
• Dimensions: ( W x H x L ) 9˝ x 2.4˝ x 21.8˝
dBcomp4
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• CEA Compliant Power Output:
1 Ohm: 3500 Watts x 1 Channel <1% THD+N at 14.4 volts (90% efciency)
2 Ohm: 2200 Watts x 1 Channel <1% THD+N at 14.4 volts (85% efciency)
4 Ohm: 1100 Watts x 1 Channel <1% THD+N at 14.4 volts (76% efciency)
• Minimum THD at Rated Power: < 0.1%
• Frequency Response: 15Hz - 250Hz
• S / N Ratio: >90dB
• Damping Factor: > 150 @ 100Hz
• Under Voltage Protection at 10V
• Over Voltage Protection at 16V
• 450 Amp External Fuse
• Dimensions: ( W x H x L ) 9˝ x 2.4˝ x 23.7˝
dBcomp5

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Woofer Wiring Configurations
Please note that the minimum impedance load for single dBcomp Series amps is 1 ohm. If 2 ampliers are bridged together then the combined output of both ampliers will be a minimum 2 ohm
load. Lower impedance loads will cause overheating and may damage the ampliers.
Dual Voice Coil subwoofers have multiple wiring options that are available to you. You can create a nal impedance load to match the nal impedance load of your amplier.
Do not mix dierent impedance speakers in series and /or parallel combinations, as unequal power sharing and acoustic outputs will result.

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©2019 ROCKVILLE // Features and specications are subject to change and or improvement without notice. Though we
tried our best to ensure that this manual is free and clear of errors please don’t hold us responsible for printing errors.