INTRODUCTION The Clarion APX400.4M is a full-featured four-channel amplifier. It comes with the following features: Full frequency response with low distortion and exceptional signal to noise performance Advanced circuit design features bridgeable and mixed mode operation for use in a variety of 4, 3 or 2 channel systems Independent front and rear, low-pass/high-pass electronic crossovers each with a 12dB per octave slope and full adjustment range (from 55Hz to 550Hz Front and 55Hz to 5.5kHz Rear) to aid in audio system design Variable bass boost circuit to reinforce low frequency signals that may be lost due to subwoofer box design Adjustable input level controls with ground loop isolation accepting a wide range of input signals Remote turn-on with soft start muting to prevent turn-on thump Pulse-Width Modulated (PWM) MOSFET power supply with low AM RFI and protection circuits for overheating and speaker shorts 2 ohm load capacity to drive a variety of speaker systems Gold-plated input/output connectors and an external automotive type fuse Aluminum heat sink for efficient heat dissipation Low profile, compact size for space limited installations ABOUT THE MANUAL AND W ARRANTY To start enjoying your new Clarion four-channel amplifier, please read the instructions listed in this manual. Keep all instructions for future reference. Please fill out and send in the enclosed warranty card to protect your purchase and aid in warranty service. Also, save your original sales receipt as proof of purchase. TABLE OF CONTENTS Description 1 Input Connections and Audio Controls 1 Connections for Power and Speakers 3 Applications 4 Installation 9 Mounting Precautions 9 Wiring Precautions 9 Setting the Gain 11 Setting the Crossover 11 Setting the Bass Boost 11 Final System Checks 12 Troubleshooting 12 Product Specs 13 Notes 13
DESCRIPTION The Clarion APX400.4M 4-channel marine amplifier is an excellent choice for creating a variety of multi-channel sound systems. It features built-in system design flexibility that allows you to create a 2, 3 or 4 channel amplifier with a flip of a switch. You can also configure the front or rear amplifier sections for a mixed mode operation to drive a set of satellite speakers and/or subwoofer. The built-in 12dB per octave electronic crossover lets you custom tailor the sound of the front and rear channels, using two independent filters with adjustable crossover frequencies for high-pass or low-pass filtering. The amplifier also uses an unregulated MOSFET power supply for superior control of output wattage. A toroid-coil transformer yields maximum power transfer with minimum heat loss. Careful circuit design keeps AM RFI at low levels, so you wont hear unwanted noise when the level is cranked up. Protection circuits safeguard the amplifier against overheating, speaker shorts, or improper load conditions that may occur. All connections and controls are on the end panels and are easy to understand. We use gold-plated RCA and barrier connectors to ensure the best electrical connection for your system. Included are external automotive type fuses that are easy to replace. INPUT CONNECTIONS AND AUDIO CONTROL The front panel of the APX400.4M contains connections for RCA Inputs and Audio Control as shown below. The Input Connections are gold-plated RCA Jacks and are labeled as FRONT Figure 1-
1. Front RCA Input Jacks 2. Rear RCA Input Jacks 3. Front Gain Control 4. Rear Gain Control 5. Bass Boost Control 6. Rear Channel Input Selector 7. Front Input Mode Switch
8. Rear Input Mode Switch 9. Speaker Level Inputs 10. Front Frequency Control 11. Front X-Over Mode Switch 12. Rear Frequency Control 13. Multiplier Switch 14. Rear X-Over Mode Switch
RIGHT, FRONT LEFT, REAR RIGHT and REAR LEFT. The Gain Controls provide a wide adjustment range to accommodate output levels from any brand of source unit. Gain Controls - Seperate Front and Rear Gain Controls allow you to set the nominal operating level of the amplifier. The amplifiers range, 250mV to 2.5V for RCA inputs or 500mV to 5V for speaker level inputs, can accommodate input levels from virtually any brand of source unit. Bass Boost Control - The amplifier also features a high-Q (i.e. narrow frequency band) Bass Boost circuit. It acts much like an equalizer, with adjustable gain (from 0 to +18dB) fixed at 45Hz. Use this feature to tune lowfrequency audio response to compensate for a less than ideal subwoofer enclosure design. The added boost produces rich, full bass tones that are normally difficult to reproduce in the car audio environment. Note: If Bass Boost is undesired, set Bass Boost to 0dB.

High-pass/Low-pass Filter Controls
Freq (Hz) Controls - The front crossover frequency is fully adjustable between 55Hz and 550Hz. The rear crossover frequency is fully adjustable between 55Hz and 5500Hz (via the Rear Crossover Frequency Multiplier) for a wide range of crossover points. Use this feature, along with your speaker manufacturers recommended crossover frequencies, to quickly design a more advanced system (see Applications on page 6.) NOTE: If either of the X-Over Mode Switches is set to OFF, varying the Freq (Hz) Control will produce no effect. Rear X-Over Frequency Multiplier Switch - When engaged, this switch increases the crossover frequency of the rear channels by a factor of 10. Example: If the Freq (Hz) dial is set for 240Hz, pushing in the multiplier Switch changes the setting to 2400Hz. X-Over Mode Switches - These switches are equipped with 12dB per octave electronic filters for precise frequency attenuation with minimal phase distortion. The steep crossover slopes keep midrange tones out of the subwoofer and thereby eliminating an unnatural nasal tone quality in the audio system. Each filter is activated by sliding the X-Over Mode Switch to either LP or HP. Input Mode Switches - These switches allow you to set the input mode for front and rear channels. Stereo input allows full left and right stereo operation. Right (bridged) input allows single channel input for bridged operation. This is especially useful in high-powered systems when using the APX400.4M as a bridged 2 channel amplifier. L + R (sum mono) allows a stereo input to be summed into a mono output.
Rear Channel Input Select - This switch allows you to use a 2 channel input to drive all 4 channels of this amplifier. Speaker Level Inputs - These provide connections for a high-level stereo source. In addition, these connections are provided for installations where the source units RCAoutputs are unavailable. WARNING: When using the speaker (high-level) inputs, the Black wire must be grounded at the Radio. Failure to do this will result in noise and improper operation. CONNECTIONS FOR POWER AND SPEAKERS The rear panel of the APX400.4M contains power and speaker connections as shown below. Figure 2-
1. Left Front Speaker Output 2. Right Front Speaker Output 3. Remote Turn-on Input 4. Ground Input
5. Battery + 12V Input 6. 40 Amp Fuse 7. Left Rear Speaker Output 8. Right Rear Speaker Output
APPLICATIONS The Clarion APX400.4M 4-channel marine amplifier can be used in a variety of system applications. Weve enclosed some example systems to help plan your own installation.
4-Channel Full-Range Stereo System
Figure 3 - In this application, the APX400.4M is used as a 4-channel amplifier to drive four full-range speakers in stereo.
4-Channel Stereo System 2-Channels High-Pass, 2-Channels Low-Pass
Figure 4 - In this 4-channel system, the APX400.4M drives a pair of stereo satellites for the front and a pair of stereo subwoofers for the rear. Note the filter settings.

2-Channel Stereo System with Low-Pass Bridged Mono Channel
Figure 5 - The APX400.4M can also be used to drive a pair of stereo satellites for the front and a single mono subwoofer for the rear. Note the filter settings.
2-Channel High Power Systems (Satellite or Subwoofer)
Figure 6 - The APX400.4M can be set up as a 2-channel high-power amplifier to drive a pair of satellites (or subwoofers).
Mixed-Mode System On Rear; Full-Range Speakers On Front

FREQ (hz)

L (mH)

C (uF)

8.0 6.4 5.1 4.2 3.2
NOTE: Chart values based on 4 ohm speakers. Figure 7 - The amplifier can be configured for a mixed-mode operation on either channels 1/2 or 3/4 amplifier sections. The table provides component values to create a 6dB per octave crossover at specified frequencies. Use components that have a + 5% tolerance and capacitors rated at 100V. NOTE: Choose the same frequency for both LP and HP crossovers. Do not overlap frequencies, as this may damage the amplifier.
INSTALLATION This section lists Mounting and Wiring Precautions for installing the Clarion APX400.4M. Combined with the experience of a professional installer, these safeguards provide enough detail to successfully complete an installation. If you do not have the necessary skills, do not install the amplifier yourself. Instead, see your authorized Clarion dealer for installation recommendations. MOUNTING PRECAUTIONS Although the Clarion APX400.4M incorporates heat sinks and protection circuits, mounting the amplifier in a tight space without any air movement can still damage internal circuitry over time. Choose a site that provides adequate ventilation and is isolated from the marine environment. For easy system setup, mount the amplifier so the front panel controls will be accessible after installation. In addition, observe the following precautions: 1. For the most efficient cooling, mount the amplifier so cool air runs along the length of the fins rather than across them. Remember, any moving air will dissipate heat. 2. Mount the amplifier on a rigid surface. Avoid mounting to subwoofer enclosures or areas prone to vibration. 3. Prior to drilling, make sure proposed mounting holes will not cut into the fuel tank, fuel lines, brake lines (under chassis), or electrical wiring. WIRING PRECAUTIONS Read all wiring precautions. If you are not sure of the connections, contact your authorized Clarion dealer. 1. Before installation, make sure the source unit Power switch is in the OFF position. 2. Disconnect the negative (-) lead of the battery before making any power connections. 3. When making connections, be sure that each connection is clean and secure. Insulate final connections with electrical tape or shrink tubing. Failure to do so may damage your equipment. 4. A secure clean ground connection is critical to the performance of your Clarion amplifier. Use the shortest ground wire possible and securely connect to the vessel battery to minimize resistance and avoid noise problems. 5. Add an external fuse on the amplifiers positive (+) power lead and connect it as close as possible to the vessels (+) battery terminal. Use a rating that equals the total current consumption at full output of all amplifiers in the system. Adding an external fuse will protect the electrical system from short circuits that can cause a fire.

6. Refer to the Figure 8 when making electrical connections. Connect the amplifiers positive (+) lead via a fuse directly to the positive (+) terminal on the battery. Do not connect this wire to the vessels fuse panel. Use redinsulated 10-gauge (or larger) wire for the amplifiers positive (+) power lead and the same-gauge black insulated wire for the ground. 7. When replacing the amplifier s fuse, always use one having the same current rating. Substituting a higher-rated fuse or a slow-blow type can result in serious damage to the amplifier. 8. Make sure that your vehicles electrical system (alternator, battery, etc.) is capable of handling the additional load. If you are planning a multi-amplifier system, you may need to add a second battery and possibly upgrade the alternator with a higher-output rated model. Consult your authorized Clarion dealer for recommendations. 9. To avoid noise problems, run the amplifiers positive (+) power lead along one side of the vessel to the battery. Run the remote turn-on wire and RCA audio cables down the center, and route the speaker wires along the remaining side. If wires must cross, run them perpendicular to each other. 10. When creating passage holes for the power wire, use grommets to eliminate any sharp edges created during drilling. This will protect the wire from being nicked and causing a short circuit. 11. Extra cable can cause signal loss and act as an antenna for noise. Use only high-quality RCA cables that are no longer than necessary to make a direct connection with the source unit or equalizer.
Figure 8 - Electrical connections for the APX400.4M
SETTING THE GAIN After completing the installation, follow these steps to set the Gain Control and then perform the Final System Checks. 1. Turn the Gain Control all the way counter-clockwise. 2. Turn the vehicles Ignition Switch to the ON position. Then turn the ON/OFF Switch on the source units to the ON position. Set all Tone or Equalization Controls to flat positions and turn Loudness off. 3. Play a CD or Tape and set the Volume Control at 75% of full level. Note: If the system uses an equalizer, set its frequency controls to flat positions. 4. Slowly increase the Gain Control. Stop when you hear a slight distortion of audio. SETTING THE CROSSOVER The Clarion APX400.4M features fully adjustable front and rear crossovers. To set the crossovers, follow these steps. 1. Using the X-Over Mode Switch, select the desired mode - LP for Low Pass, HP for High Pass and OFF for Full Range. 2. Using the Freq (Hz) Selection Control, select the desired frequency. If the desired frequency exceeds the range of the Freq (Hz) Selection Control, press the Crossover Frequency Multiplier Switch to increase the value by a multiplier of 10. For example, 55Hz x 10 = 550Hz or 550Hz x 10 = 5.5kHz. 3. Repeat steps 1 and 2 for both the front and rear crossovers. SETTING THE BASS BOOST 1. Initially set the Bass Boost control to its full left position (i.e. 0dB). 2. Listen to a variety of music styles (e.g. Rock, Rap, etc.) and slowly increase the Bass Boost control until a noticeable increase in low bass response is perceived. 3. Slowly adjust the Bass Boost control (up or down) to realize the best bass response. CAUTION: If you hear a pop (due to speaker over-excursion), lower the Bass Boost to prevent speaker damage. If the system sounds muddy and distorted (due to amplifier clipping), lower Bass Boost to avoid shutdown from overheating.

FINAL SYSTEM CHECKS 1. Start the engine and turn on the source unit. After a two-second delay, slowly increase the Volume Control and listen to the audio. If you hear any noise, static, distortion or no sound at all, check the connections, and also refer to Troubleshooting. Depending on your system design, the levels may become quite loud even at low Volume Control settings. Until you get an audio feel of the systems power, use care when adjusting controls. 2. Turn the Balance Controls to their extreme positions and listen to the results. Audio output should match control settings (audio from the left speaker when balance is left). 3. Increase the volume and verify that the amplifier reproduces audio (at full frequencies) without distortion. If you hear distortion, check the connections and verify that the Gain Control is set correctly. Another possibility is damaged speakers or under-powered speakers. Once again refer to Troubleshooting for additional help. TROUBLESHOOTING Problem No Audio. Solution Low or no remote turn-on voltage. Check remote connections at amplifier and source unit. Blown amplifier fuse. Replace with new fast-blow fuse (same rating). Power wires not connected. Check battery and ground wiring at amplifier; also check battery connections. Speaker leads shorted. Check speaker continuity to ground, it should not show a common ground. Speakers not connected or are blown. Check speaker connections at amplifier, measure coil impedance. Problem Audio cycles on and off. Solution Thermal protection circuits are shutting amplifier off. Check location for adequate ventilation; consult an authorized Clarion Audio Dealer Problem Distorted audio. Solution Gain is not set properly, or damaged speaker cones. Review Setting Gain; inspect each speaker cone for signs of damage (i.e. frozen cone, burning smell, etc.)
Problem Audio lacks punch. Solution Speakers wired incorrectly, which causes cancellation of bass frequencies. Check polarity of wires from amplifier to each speaker as defined by the system design. Problem Amplifier fuse keeps blowing. Solution Incorrect wiring or short circuit. Review Installation and check all wiring connections. Problem Whining or ticking noise in the audio with engine on. Solution Amplifier is picking up alternator noise or radiated noise. Turn down input gain; move audio cables away from power wires. Check power and ground connections on amplifier; install an in-line noise filter on source units power wire; check alternator and/or voltage regulator; test for weak battery or add water to battery PRODUCT SPECS APX400.4M

INTRODUCTION The Clarion APX400.2M is a full-featured two-channel amplifier incorporating the following features: Full frequency response with low distrotion and exceptional signal to noise performance Advanced circuit design that features bridgeable and mixed mode operation for use in various systems, including those with satellite speakers and/or subwoofers Variable high-pass/low-pass electronic crossover with a 12dB per octave slope and full adjustable range (from 55Hz to 5.5kHz) to aid in audio system design Variable bass boost circuit to reinforce low frequency signals that may be lost due to subwoofer box design Adjustable input level controls with ground loop isolation accepting a wide range of input signals Remote turn-on with soft start muting to prevent turn-on thump Pulse-Width Modulated (PWM) MOSFET power supply with low AM RFI and protection circuits for overheating and speaker shorts 2-ohm load capability to drive a variety of speaker systems Gold-plated input/output connectors and an extenal automotive type fuse Aluminum heat sink for efficient heat dissipation Low profile, compact size for space limited installations ABOUT THE MANUAL AND W ARRANTY To start enjoying your new Clarion two-channel amplifier, please read the instructions listed in this manual. Keep all instructions for future reference. Please fill out and send in the enclosed warranty card to protect your purchase and aid in warranty service. Also, save your original sales receipt as proof of purchase. TABLE OF CONTENTS Description Input Connections and Audio Controls Connections for Power and Speakers Applications Installation Mounting Precautions Wiring Precautions Setting the Gain Setting the Crossover Setting the Bass Boost Final System Checks Troubleshooting Product Specs Notes 12 13
DESCRIPTION The Clarion APX400.2M two-channel amplifier provides 2x70 watts of power into a 4 ohm load and 2x110 watts of power into a 2 ohm load. This full featured model is an excellent choice for a variety of marine audio sound system configurations. The APX400.2M uses an unregulated MOSFET power supply for superior control of output wattage. A toroid-coil transformer yields maximum power transfer with minimum heat loss. Careful attention to circuit design keeps AM RFI at low levels, so you wont hear unwanted noise when the level is cranked up. Protection circuits safeguard the amplifier when overheating and speaker shorts or improper load conditions occur. All connections and controls of the APX400.2M are on the end panels and are easy to understand. We use gold-plated RCA and barrier connectors to ensure the best electrical connection for your system. Included is an external automotive type fuse that is easy to replace. INPUT CONNECTIONS AND AUDIO CONTROLS The front panel of the APX400.2M contains connections for RCAInputs, Speaker Level Inputs and Audio Controls as shown below. The RCAInput Connections are gold-plated RCA Jacks and are labeled as RIGHT and LEFT.

Figure 1-

1. RCA Input Jacks 2. Gain Control 3. Bass Boost Control 4. Freq (Hz) Selection Control
5. Crossover Frequency Multiplier Switch 6. X-Over Mode Switch 7. Input Select Switch 8. Speaker Level Inputs
Gain Control - This allows you to set the nominal operating level of the amplifier. The amplifiers range, 250mV to 2.5V for RCA inputs or 500mV to 5V for speaker level inputs, can accommodate input levels from virtually any brand of source unit. Bass Boost Control- The amplifier also features a high-Q (i.e. narrow frequency band) Bass Boost circuit. It acts much like an equlaizer, with adjustable gain (from 0 to +18dB) fixed at 45Hz. Use this feature to tune lowfrequency audio response to compensate for a less than ideal subwoofer enclosure design. The added boost produces rich, full bass tones that are normally difficult to reproduce in the car audio environment. NOTE: If Bass Boost is undesired, set Bass Boost to 0dB.

High-pass/Low-pass Filter Controls
Frequency (Hz) Selection Control - The crossover frequency is fully adjustable between 55Hz and 5500Hz (via the Crossover Frequency Multiplier) for a wide range of crossover points. Use this feature, along with your speaker manufacturers recommended crossover frequencies, to quickly design a more advanced system (see Applications on page 5.) NOTE: If the X-Over Mode Switch is set to OFF, varying the Freq (Hz) Control will produce no effect. Crossover Frequency Multiplier Switch - When engaged, this switch increases the crossover frequency by a factor of 10. Example: If the Freq (Hz) dial is set for 240 Hz, pushing in the Multiplier Switch changes the setting to 2400 Hz. X-Over Mode Switch - This switch is equipped with a 12dB per octave electronic filter for precise frequency attenuation with minimal phase distortion. The steep crossover slope keeps midrange tones out of the subwoofer and thereby eliminates an unnatural nasal tone quality in the audio system. A filter is activated by sliding the X-Over Mode Switch to either LP or HP. Input Mode Switch - This switch allows you to set the input mode. Stereo input allows full left and right stereo operation. Right (bridged) input allows single channel input for bridged operation. This is especially useful in highpowered systems when using one amplifier for each subwoofer/speaker. L + R (sum mono) allows a stereo input to be summed into a mono output. Speaker Level Inputs - These provide connections for a high-level stereo source. In addition, these connections are provided for installations where the source units RCA outputs are unavailable. WARNING: When using the speaker (high-level) inputs, the Black wire must be grounded at the Radio. Failure to do this will result in noise and improper operation.
CONNECTIONS FOR POWER AND SPEAKERS The rear panel of the APX400.2M contains power and speaker connections as shown below. Figure 2-
1. Left Speaker Output 2. Right Speaker Output 3. Remote Turn-on Input
4. Ground Input 5. Battery + 12V Input 6. 25 Amp Fuse
APPLICATIONS The Clarion APX400.2M 2-channel marine audio amplifier can be used in a variety of system applications. Here are some examples to help plan your own installation.

Bridged- Mono Subwoofer System
Set X-Over Mode to LP and adjust FREQ to speaker specifications.
Figure 3 - In this application the amplifier is bridged for mono operation to drive a subwoofer.
2-Channel Full-Range, Satellite, or Subwoofer Stereo System
(Set INPUT SELECT Switch to STEREO)
Set X-Over Mode as shown.
Set X-Over Mode as shown; adjust FREQ to speaker specifications.
Figure 4 - In this application, the amplifier is used in stereo and drives two full-range (or satellite or subwoofer) speakers. NOTE: A passive crossover must be used with satellite speakers.
Mixed-Mode Satellite and Subwoofer System

FREQ (hz) 200

L (mH) 8.0 6.4 5.1 4.2 3.2

C (uF) 199

Set X-Over Mode to OFF.
NOTE: Chart values based on 4 ohm speakers. Figure 5 - The amplifier can be configured for a mixed-mode operation. The table provides component values to create a 6dB per octave crossover at specified frequencies. Use components that have a + 5% tolerance and capacitors rated at 100V. NOTE: Choose the same frequency for both LP and HP crossovers. Do not overlap frequencies, as this may damage the amplifier.
INSTALLATION This section lists Mounting and Wiring Precautions for installing a Clarion APX400.2M marine amplifier. Combined with the experience of a professional installer, these safeguards provide enough detail to successfully complete an installation. If you do not have the necessary skills, do not install the amplifier yourself. Instead, see your authorized Clarion dealer for installation recommendations. MOUNTING PRECAUTIONS Although the Clarion APX400.2M incorporates heat sinks and protection circuits, mounting the amplifier in a tight space without any air movement can still damage internal circuitry over time. Choose a site that provides adequate ventilation and is isolated from the marine environment. For easy system setup, mount the amplifier so the front panel controls will be accessible after installation. In addition, observe the following precautions: 1. For the most efficient cooling, mount the amplifier so cool air runs along the length of the fins rather than across them. Remember, any moving air will dissipate heat. 2. Mount the amplifier on a rigid surface. Avoid mounting to subwoofer enclosures or areas prone to vibration. 3. Prior to drilling, make sure proposed mounting holes will not cut into the fuel tank, fuel lines, or electrical wiring. WIRING PRECAUTIONS Read all wiring precautions. If you are not sure of the connections, contact your authorized Clarion dealer. 1. Before installation, make sure the source unit Power switch is in the OFF position. 2. Disconnect the negative (-) lead of the battery before making any power connections. 3. When making connections, be sure that each connection is clean and secure. Insulate final connections with electrical tape or shrink tubing. Failure to do so may damage your equipment. 4. A secure clean ground connection is critical to the performance of your Clarion amplifier. Use the shortest ground wire possible and securely connect to the vessel battery to minimize resistance and avoid noise problems.

5. Add an external fuse on the amplifiers positive (+) power lead and connect it as close as possible to the vessels (+) battery terminal. Use a rating that equals the total current consumption at full output of all amplifiers in the system. Adding an external fuse will protect the electrical system from short circuits that can cause a fire. 6. Refer to Figure 6 when making electrical connections. Connect the amplifiers positive (+) lead via a fuse directly to the positive (+) terminal on the battery. Do not connect this wire to the vessels fuse panel. Use redinsulated 10-gauge (or larger) wire for the amplifiers positive (+) power lead and the same-gauge black-insulated wire for the ground. 7. When replacing the amplifier s fuse, always use one having the same current rating. Substituting a higher-rated fuse or a slow-blow type can result in serious damage to the amplifier. 8. Make sure that your vessels electrical system (alternator, battery, etc.) is capable of handling the additional load. If you are planning a multi-amplifier system, you may need to add a second battery and possibly upgrade the alternator with a higher-output rated model. Consult your authorized Clarion dealer for recommendations. 9. To avoid noise problems, run the amplifiers positive (+) power lead along one side of the vessel to the battery. Run the remote turn-on wire and RCA audio cables down the center, and route the speaker wires along the remaining side. If wires must cross, run them perpendicular to each other. 10. When creating passage holes for the power wire, use grommets to eliminate any sharp edges created during drilling. This will protect the wire from being nicked and causing a short circuit. 11. Extra cable can cause signal loss and act as an antenna for noise. Use only high-quality RCA cables that are no longer than necessary to make a direct connection with the source unit or equalizer.
Figure 6. - Electrical connections for the APX400.2M.
SETTING THE GAIN After completing the installation, follow these steps to set the Gain Control and then perform the Final System Checks. 1. Turn the Gain Control all the way counter-clockwise. 2. Turn the vessels Ignition Switch to the ON position. Then turn the ON/OFF Switch on the source units to the ON position. Set all Tone or Equalization Controls to flat positions and turn Loudness off. 3. Play a CD or Tape and set the Volume Control at 75% of full level. NOTE: If the system uses an equalizer, set its frequency controls to flat positions. 4. Slowly increase the Gain Control. Stop when you hear a slight distortion of audio. SETTING THE CROSSOVER The Clarion APX400.2M features a fully adjustable crossover. To set the crossover, follow these steps. 1. Using the X-Over Mode Switch, select the desired mode - LP for Low Pass, HP for High Pass and OFF for Full Range. 2. Using the Freq (Hz) Control, select the desired frequency. If the desired frequency exceeds the range of the Freq (Hz) Control, press the Crossover Frequency Multiplier Switch to increase the value by a multiplier of 10. For example, 55Hz x 10 = 550Hz or 550Hz x 10 = 5.5kHz. SETTING THE BASS BOOST 1. Initially set the Bass Boost control to its full left position (i.e. 0dB). 2. Listen to a variety of music styles (e.g. Rock, Rap, etc.) and slowly increase the Bass Boost control until a noticeable increase in low bass response is perceived. 3. Slowly adjust the Bass Boost control (up or down) to realize the best bass response. CAUTION: If you hear a pop (due to speaker over-excursion), lower the Bass Boost to prevent speaker damage. If the system sounds muddy and distorted (due to amplifier clipping), lower Bass Boost to avoid shutdown from overheating.

FINAL SYSTEM CHECKS 1. Start the engine and turn on the source unit. After a two-second delay, slowly increase the Volume Control and listen to the audio. If you hear any noise, static, distortion or no sound at all, check the connections, and also refer to Troubleshooting. Depending on your system design, the levels may become quite loud even at low Volume Control settings. Until you get an audio feel of the systems power, use care when adjusting controls. 2. Turn the Balance Controls to their extreme positions and listen to the results. Audio imaging should match control settings (audio from the left speaker when balance is left). 3. Increase the volume and verify that the amplifier reproduces audio (at full frequencies) without distortion. If you hear distortion, check the connections and verify that the Gain Control is set correctly. Another possibility is damaged speakers or under-powered speakers. Once again refer to Troubleshooting for additional help. TROUBLESHOOTING Problem No Audio. Solution Low or no remote turn-on voltage. Check remote connections at amplifier and source unit. Blown amplifier fuse. Replace with new fast-blow fuse (same rating). Power wires not connected. Check battery and ground wiring at amplifier; also check battery connections. Speaker leads shorted. Check speaker continuity to ground, it should not show a common ground. Speakers not connected or are blown. Check speaker connections at amplifier, measure coil impedance. Problem Audio cycles on and off. Solution Thermal protection circuits are shutting amplifier off. Check location for adequate ventilation; consult an authorized Clarion Audio Dealer.
Problem Distorted audio. Solution Gain is not set properly, or damaged speaker cones. Review Setting Gain; inspect each speaker cone for signs of damage (i.e. frozen cone, burning smell, etc.) Problem Audio lacks punch. Solution Speakers wired incorrectly, which causes cancellation of bass frequencies. Check polarity of wires from amplifier to each speaker as defined by the system design. Problem Amplifier fuse keeps blowing. Solution Incorrect wiring or short circuit. Review Installation and check all wiring connections. Problem Whining or ticking noise in the audio with engine on. Solution Amplifier is picking up alternator noise or radiated noise. Turn down input gain; move audio cables away from power wires. Check power and ground connections on amplifier; install an in-line noise filter on source units power wire; check alternator and/or voltage regulator; test for weak battery or add water to battery PRODUCT SPECS APX400.2M

Frequency Response Signal Noise Ratio THD Input Sensitivity Low Level Input Sensitivity Speaker Level Max. Power Output Cont. Power Output 2-Ohm Stereo Output Bridged Power Dimensions Current Consumption at output @ max power 20Hz ~ 20kHz >98db.05% all channels driven 250mV ~ 2.5 V 500mV ~ 5V 380w (190 x 2) 200w (100w x 2) @.08% THD 190 x 2 @.05% THD 280 x 1 @.05% THD 2 1/8H x 8 1/4W x 12 L 43A @ 382 Watts
661 W. Redondo Beach Blvd. Gardena, CA 90247 1-800-GO-CLARION www.clarion-usa.com
APX400.2M-10 Rev.2 (05/00)