NVX XDSP28 Bluetooth Digital Signal Processor User Manual

Thank You for Choosing NVX

Thank you for purchasing the NVX XDSP28. Please read this manual to fully understand how to get the best results from this product, ensure proper care, and follow safety precautions. We hope you enjoy using the product.

The NVX XDSP28 is a digital audio processor offering a wide variety of high-accuracy settings and configurations to improve your audio system's performance. The DSP provides real-time equalizing, filtering, balancing, gain, phase inversion, limiting, and digital output and input routing, among other features.

Before mounting and installing your new DSP, please read the entire user manual. For any questions regarding your DSP or other NVX products, contact your nearest NVX dealer/distributor.

What's in the Box

• Digital Signal Processor
• Remote level controller
• Level remote cable 5M
• Screws (6pcs)
• Allen keys (2pcs)
• User manual

Safety & Warranty

Warranty

All NVX products carry a full warranty depending on the country where sold. The warranty is valid from the original receipt date. Contact your NVX dealer or distributor for specific warranty procedures in your country.

What is Not Covered

• Damage due to improper installation.
• Subsequent damage to other components.
• Damage caused by moisture, excessive heat, chemical cleaners, or UV radiation.
• Damage through negligence, misuse, accident, or abuse.
• Costs related to removal and/or reinstallation.
• Damage caused by amplifier clipping or distortion.
• Items repaired or modified by unauthorized facilities.
• Return shipping on non-defective items.
• Products returned without a return authorization number.
• Damage due to use of sealant.

International Technical Inquiries

For international technical support, please contact the dealer/distribution agent for your country.

Instructions

Installation Experience

Installation of the NVX XDSP28 may require various mechanical procedures, including cable wiring and drilling. This manual provides general installation and operation instructions. If you have reservations about your installation skills, contact your local authorized NVX dealer.

Choosing DSP Mounting Locations

Choose a mounting location where the DSP will not be damaged and is not covered. Mount the DSP where it remains dry; never mount it outside the vehicle or in the engine compartment. If installed in an enclosed space, ensure sufficient air circulation for cooling. When mounting under a seat, ensure it is clear of moving parts and does not affect seat functionality. Mount securely using nuts, bolts, or screws.

Installation Precautions

• Always wear protective eye-wear when using tools.
• Turn off all stereo and other electrical devices before starting.
• Disconnect the negative (-) lead from your vehicle's battery.
• Keep the DSP in its package until final installation, and always rest it upwards.
• Never use force when installing a DSP.
• Locate all fuel lines, brake lines, oil lines, and electrical cables when planning your installation.
• Check clearances on both sides of the planned mounting surface before drilling any holes or fixing screws.
• When routing cables, keep input-signal cables away from power cables and speaker wires.
• When making connections, ensure all cables are secure and properly insulated.

Power Connections

For optimal performance, follow these instructions carefully:

Ground Connection (GND)

Connect the DSP Ground (GND) terminal to a solid point on the vehicle's metal chassis, as close to the DSP as possible. Scrape away any paint from this location and use a star-type lock washer to secure the connection.

Ground wire recommendation: 16 AWG

Battery Connection (+BAT)

Connect a wire directly to the vehicle's 12V positive battery terminal. Install an appropriate fuse and holder within 30cm/12" from the battery terminal. Keep the fuse uninstalled while routing and connecting the power wire. Use grommets when routing wires through the firewall or other metal parts. Once routing/connecting is done, install the fuse into the holder.

+12V wire recommendation: 16 AWG (Min. 1A fuse)

Remote Connection (REM IN)

Connect the DSP Remote (REM IN) terminal to the source unit's Remote turn-on lead using a minimum of 18 AWG. If your source unit lacks a turn-on connection, connect the DSP (REM IN) terminal through a power switch button that can provide a +12V signal.

Control Panel

Navigation and control of the NVX XDSP28 are managed via the “MAIN CONTROL” knob and the “OUTPUT SELECTS” hotkeys.

Main Control

• Rotation: NAVIGATION/INCREASE/DECREASE
• Quick Press: ENTER/SELECT
• Hold: RETURN

Output Selects

• Quick press: SELECT CHANNEL
• Hold: OUTPUT ON / OFF

Menu Navigation

The menu structure is as follows:

• Main Menu
  • Audio Processing
    • Audio Inputs - Graphic EQ
    • Audio Inputs - Input Param. EQ
    • Audio Out - Output Param. EQ
    • Audio Out - Routing
    • Audio Out - Crossover
    • Audio Out - Phase
    • Audio Out - Delay
    • Audio Out - Limiter
    • Audio Out - Gain
    • Audio Out - Mute
  • Graph EQ Preset
  • Xover Preset
  • Save
  • Load
  • Copy Channel
  • Security
    • Lock/Unlock
    • Change Password
  • Tools
    • Tone Generator
    • Frequency Sweep
    • Pink Noise
  • Screensaver
  • Language
  • Sequencer

Connect Bluetooth

When "BT" is flashing on the display, the unit is ready for pairing. Connect to Bluetooth by finding "XDSP28" in your mobile device's Bluetooth list. Bluetooth audio will override RCA input audio. Unpair Bluetooth connections using the “Load default” settings. Turning off Bluetooth mode on the mobile device re-enables RCA input. Ensure the source level connected to the A & B input is lowered before turning off Bluetooth to avoid system damage.

Audio Processing

Audio Inputs - Graphic EQ

The input graphic equalizer has 15 bands: 25Hz, 40Hz, 63Hz, 100Hz, 160Hz, 250Hz, 400Hz, 630Hz, 1kHz, 1.6kHz, 2.5kHz, 4kHz, 6.3kHz, 10kHz, 16kHz. Each band offers a variation of ±12 dB with a 0.1 dB pitch. The graphic equalizer affects both inputs simultaneously.

Example Display: GRAPHIC EQ f: 63 Hz +2.6 dB

Audio Input - Input Param. EQ

The parametric equalizer allows selection of gain/attenuation at a specific frequency and the bandwidth via the Q factor. A smaller Q results in a wider bandwidth, affecting neighboring frequencies more. The NVX XDSP28 has 1 parametric equalizer for the inputs.

Example Display: PARAMETRIC EQ freq.: 214 Hz, gain: +3.2 dB, Q: 1.4

Visual Description: Multiple bell curves are shown, representing different Q factor settings, with the highest curve indicating a higher gain at the specified frequency.

Audio Out - Output Param. EQ

The parametric equalizer allows selection of gain/attenuation at a specific frequency and the bandwidth via the Q factor. A smaller Q results in a wider bandwidth, affecting neighboring frequencies more. The NVX XDSP28 has 8 parametric equalizers for the outputs (1 for each output).

Example Display: PARAMETRIC EQ freq.: 214 Hz, gain: +3.2 dB, Q: 1.4

Visual Description: Similar to the input parametric EQ, showing multiple bell curves for different Q factor settings.

To change the output channel, press the “OUTPUT SELECT” button.

Outputs: OUT1, OUT2, OUT3, OUT4, OUT5, OUT6, OUT7, OUT8

Audio Out - Routing

The routing option allows selection of audio source A, B, or A + B (sum) for each output. Turning the “MAIN CONTROL” dial moves the audio source to the selected route. To select another channel, quickly press the corresponding “OUTPUT SELECT”.

Example:

• Selecting A for OUT1, OUT2, OUT3 and B for OUT4, OUT5, OUT6 enables a 3-way setup.
• Selecting A for OUT1, OUT3 and B for OUT2, OUT4 enables a front and back setup.
• Selecting A+B for OUT7 & OUT8 enables a subwoofer setup.

Visual Description: ROUTING IN A+B ---> OUT1

Audio Out - Crossover

The crossover function allows precise definition of cutoff frequencies for high-pass and low-pass filters, along with filter attenuations and topology individually per output. Available filters and attenuators:

• HPF: Butterworth 12/24/36/48 dB/Oct, Linkwitz-Riley 12/24/36/48 dB/Oct
• LPF: Butterworth 12/24/36 dB/Oct, Linkwitz-Riley 12/24/36 dB/Oct

Example Display: HPF OUT1 f:12 Hz LR48, LPF OUT1 f:107 Hz BT12

Visual Description: A graph showing frequency response curves for HPF and LPF filters, illustrating cutoff points and slopes.

In the “CROSSOVER” menu, the “MAIN CONTROL” setting changes parameters like output, filter type, frequency, and attenuation/topology. To select another output channel for editing, quickly press the corresponding “OUTPUT SELECT”.

Audio Out - Phase

This function resolves problems caused by canceling frequencies. You can reverse the phase of all outputs individually. Turning the “MAIN CONTROL” dial changes the phase (0° or 180°) of the corresponding output. To select another channel, quickly press the corresponding “OUTPUT SELECT”.

Example Display: PHASE OUT1:180

Audio Out - Delay

The Delay function allows digital alignment of transducers via time correction performed by the DSP, ensuring sound from all speakers arrives at the listener with improved audio fidelity and avoiding frequency cancellations. See adjustment example below.

Example Display: DELAY 12.0cm 0.349ms

Visual Description: Two diagrams illustrate measuring distances from speaker coils to a reference coil for delay calculation. One shows a front panel view with a reference marked (R*), and the other shows side views with dimensions (8cm, 15cm).

1. Identify the coil farthest from the listener or box. This coil is the reference.
2. Measure the distance from other coils to the reference coil. These distances are used for configuring the delay of each output channel.

Audio Out - Limiter

To protect amplifiers and speakers, the XDSP28 features an integrated "Dynamic Attack-Release" system for each of the 8 outputs. This function attenuates and prevents damage from signal peaks.

• Threshold: (-24 to 0 dB) setting defines when the Limiter activates.
• Attack: (0.1 to 100 ms) defines how fast the Limiter reacts.
• Release: (1 to 1600 ms) controls the recovery time after the signal falls below the threshold.

The “AUTO” mode allows the “Dynamic Attack-Release” system to control Attack and Release parameters in real time for optimal sound fidelity.

Example Display: LIMITER THRES.: -9.5 dB, ATTACK: 0.1 ms, RELEASE: 500 ms, LIMITER OUT1 AUTO: ON

Visual Description: A graph shows an input signal (Entrada) and an output signal (Saída) over time (Tempo). The output signal is limited, demonstrating the effect of the limiter. Another diagram shows the gain (Ganho) over time, illustrating Attack and Release phases.

Audio Out - Gain

This menu allows adjustment of individual output gains from -45 to +15 dB and increases the NVX XDSP28 volume from 0 to 100%.

Example Display: MASTER LUL: 82%, OUT1 GAIN: +3 dB

Audio Out - Mute

Outputs can be switched on/off by holding the corresponding “OUTPUT SELECT”. The LED color indicates status: BLUE for ON, RED for OFF (MUTE).

In the “MUTE” screen, you can simultaneously mute/unmute all output channels using “ALL-ENTER” or “ALL-ENTER ON” via the “MAIN CONTROL”. You can also toggle the input graphic equalizer on or off.

Example Display: OUT1: ON, GRAPH EQ: ON; MUTE ALL [ENTER] GRAPH EQ: ON; ON ALL [ENTER] GRAPH EQ: ON

Functions

Graphic EQ Preset

The NVX XDSP28 offers 12 graphic equalization presets:

• FLAT
• LOUDNESS
• BASS BOOST
• MID BASS
• TREBLE BOOST
• POWERFUL
• ELECTRONIC
• ROCK
• HIP HOP
• POP
• VOCAL
• PANCADAO (Heavy beat)

Example Display: GRAPH EQ PRESETS Loudness

X-Over Presets

The NVX XDSP28 offers 11 crossover presets, selectable from "XOVER Preset" in the menu. Each preset can be used for all outputs. Use HOTKEYS for output selection.

Example Display: XOVER PRESETS OUT1 <- SWBW1

Available Crossover Presets:

Save / Load (factory reset)

The XDSP28 has four memory slots for saving personalized settings via the “SAVE” function. Saved settings can be named with titles up to 15 characters. There is also an auto-save feature. Settings are not lost if power is interrupted during configuration. Use the “LOAD” function to load previously saved settings or the “DEFAULT” memory for factory presets.

Example Buttons: SAVE MEMORY1, LOAD Default

Security

This function locks editing of XDSP28 settings, including save and load functions. Access via the “SECURITY” menu to lock/unlock and change the password. The default password is 1234.

Example Buttons: SECURITY Lock/Unlock, ENTER PASSWORD, SECURITY Charge Password, CHARGE PASSWORD Current PW:

Tools

The NVX XDSP28 includes tools to aid in sound system regulation: TONE GENERATOR, FREQUENCY SWEEP, and PINK NOISE GENERATOR. These are signal sources for all outputs.

Tone Generator

Used to generate a specific frequency with gain control. Parameters (frequency, gain, ON/OFF) can be edited via the “MAIN CONTROL”. Frequency and gain can be adjusted in real-time while the generator is active.

Example Display: TONE GENERATOR freq: 100 Hz, gain: -45.0 dB, OFF [ON]

Visual Description: A graph shows a single frequency spike at a specific point on the frequency axis, with amplitude indicated.

Frequency Sweep

Performs a frequency scan, allowing selection of initial/final frequency, gain, and scanning speed. When activated, the sweep enters a continuous cycle. To stop, press any “OUTPUT SELECT” or move the “MAIN CONTROL”.

Example Display: FREQUENCY SWEEP start: 10 Hz, gain: -45.0 dB, end: 22000 Hz, Speed: medium, OFF [ON]

Visual Description: A graph shows multiple lines representing frequency sweeps at different speeds or gain levels across the frequency spectrum.

Pink Sweep

Generates a signal with constant magnitude across the entire frequency range, used for calibrating audio systems for flat response and alignment. Gain and ON/OFF can be adjusted via the “MAIN CONTROL”. Gain can be adjusted in real-time.

Example Display: PINK NOISE gain: -45.0 dB, OFF [ON]

Visual Description: A graph shows a relatively flat line across the frequency spectrum, indicating constant amplitude.

Specifications

Troubleshooting

Warranty

NVX warrants this product to the original retail purchaser against defective materials and workmanship for one (1) year from the purchase date, provided it is used and maintained properly. NVX will, at its discretion, repair or replace the product at no charge for parts or labor if it proves defective.

If the product model is unavailable for repair or replacement, NVX may replace it with a current model of equal or greater value. To obtain warranty service, return the product to the dealer first. You will need to submit a copy of the original receipt. Return shipping for exchanges/repairs is the responsibility of the original retail purchaser.

Limitations

• This limited warranty does not cover failure due to improper installation, misuse, abuse, accident, neglect, mishandling, or ordinary wear and tear or environmental deterioration.
• This limited warranty does not cover cosmetic damage, including paint damage, or consequential damage from ordinary use or environmental deterioration.
• This limited warranty is null and void for products with altered or missing serial numbers, or products not purchased from an authorized dealer.
• This limited warranty terminates if you sell or otherwise transfer the product to another party.
• This limited warranty is null and void for speakers or subwoofers damaged by overpowering, burnt voice coils, or mechanical failures like ripped spiders or surrounds.
• This limited warranty is null and void for products not used in accordance with NVX's instructions.

This warranty grants specific legal rights, and you may have other rights that vary by state, jurisdiction, or country. NVX's responsibility for hardware malfunctions and defects is limited to repair or replacement as stated in this warranty. Any implied warranties are limited in duration to the term of this warranty. Some jurisdictions do not allow limitations on implied warranties, so this limitation may not apply to you. NVX is not liable for special, indirect, consequential, or incidental damages. The maximum liability for which NVX may be responsible will not exceed the amount paid for the product.

Warranty Outside the U.S.: For warranty service outside the United States, contact the dealer from whom the product was purchased or the distributor that supplied the product.

What to Do If You Need Warranty or Service

Defective products should be returned to the place of purchase. Your authorized NVX dealer can assist with warranty claims. Assistance locating a dealer can be found at nvx.com or by contacting NVX directly.

Alternatively, to return defective products directly to NVX, follow these instructions:

• Receive your RA Number from NVX online at nvx.com/support.
• Package all defective components in the original packaging (if available) or in a package that will prevent shipping damage.
• Package the original packaging in an additional shipping container to avoid shipping damage and comply with courier requirements (e.g., UPS, FedEx).
• Insure your return shipment at the price paid, as NVX is not responsible for insurance losses or damages during shipment.
• Clearly mark the RA Number on the outside shipping container.
• Return only defective components; returning functioning items increases return freight charges. Non-defective returns or products not eligible for warranty service will be returned freight collect.
• Include a copy of the original receipt with the purchase date clearly visible, and a "proof-of-purchase" statement listing the customer's name, dealer's name, invoice number, and product purchased.
• Warranty expiration on items without proof-of-purchase will be determined from the type of sale and the manufacturing date code.
• Ship your package freight prepaid to the address below. Items sent freight collect or COD will be refused.

NVX Returns Address:
Attn: Returns
742 S. 11th st.
Louisville, KY 40210

Failure to follow these steps may void your warranty. For questions, contact NVX via email at cs@nvx.com or by mail at the address listed above.