NUX NAI-24 Desktop USB Audio Interface User Manual

1. Introduction

The NUX NAI-24 is a compact 2-input, 4-output USB audio interface designed for personal studios. It features high-quality audio transformers and a pure Class A discrete transistor microphone preamp with up to 71dB of gain. Inspired by the classic 76 compressor, it includes an easy-to-use pure analog compressor. The NAI-24 supports a sampling rate of 32-bit/192kHz and offers two audio interface modes to suit various recording and monitoring environments.

This manual provides detailed instructions for the proper setup, operation, maintenance, and troubleshooting of your NAI-24 audio interface to ensure optimal performance and longevity.

2. Setup

Follow these steps to connect your NAI-24 audio interface to your computer and other audio equipment.

2.1 Package Contents

NUX NAI-24 USB Audio Interface
USB Cable (Type-C to Type-A)
User Manual (this document)

2.2 Connecting to Your Computer

The NAI-24 connects to your computer via a USB-C port. Ensure your computer meets the minimum system requirements (Windows, macOS, Android, iOS compatible).

Connect one end of the provided USB cable to the USB-C port on the rear panel of the NAI-24.
Connect the other end of the USB cable to an available USB port on your computer.
The NAI-24 will draw power from the USB connection. No external power adapter is typically required.
Your operating system should automatically detect the NAI-24 as an audio device. Install any necessary drivers if prompted by your system or if experiencing issues (drivers can usually be found on the official NUX website).

2.3 Connecting Audio Devices

The NAI-24 offers various input and output options for microphones, instruments, and monitoring systems.

Rear panel of NUX NAI-24 showing inputs and outputs

Figure 1: Rear Panel Connections. This image displays the rear panel of the NAI-24, highlighting the USB-C port, balanced 1/4-inch outputs (1L, 2R, 3L, 4R), and combination XLR/TRS inputs for Channel 1 and Channel 2.

Microphones: Connect microphones to the XLR inputs on Channel 1 and Channel 2. For condenser microphones, activate the +48V phantom power on the front panel.
Instruments (e.g., Guitar, Bass): Connect instruments directly to the 1/4-inch TRS inputs on Channel 1 or Channel 2. Ensure the HI-Z button is engaged for high-impedance instruments on Channel 1.
Line-Level Devices: Connect line-level sources (e.g., synthesizers, drum machines) to the 1/4-inch TRS inputs. Ensure the LINE IN button is engaged for the respective channel.
Monitor Speakers: Connect your active monitor speakers to the 1L/2R (Main Output) and/or 3L/4R (Secondary Output) balanced 1/4-inch outputs on the rear panel.
Headphones: Connect headphones to the 1/4-inch headphone jacks on the front panel.

Figure 2: Typical Connection Diagram. This diagram illustrates a common setup for the NAI-24, showing connections from microphones and an external effect unit to the interface, and outputs routed to monitor speakers, headphones, and a computer via USB.

3. Operating the NAI-24

This section details the functions of the controls and features on your NAI-24 audio interface.

Figure 3: Front Panel Controls. This image provides a clear view of the NAI-24's front panel, detailing the gain knobs, +48V phantom power buttons, LINE IN buttons, 76 PRE buttons, input/USB mix knob, stereo mode button, loopback button, OUT 3/4 buttons, monitor mute button, main monitor knob, and dual headphone output controls.

3.1 Input Controls (Channels 1 & 2)

GAIN Knobs: Adjusts the input level for Channel 1 and Channel 2. Turn clockwise to increase gain.
+48V Button: Activates phantom power for condenser microphones connected to the XLR input. Press to engage, press again to disengage. An indicator light will illuminate when active.
LINE Button: Switches the 1/4-inch input between instrument (HI-Z for Channel 1) and line-level sensitivity. Press to engage line-level input.
HI-Z (IN 1): Specifically for Channel 1, this button optimizes the 1/4-inch input for high-impedance instruments like electric guitars and basses.
76 PRE Button: Engages the pure analog compressor, inspired by the classic 76 compressor, for the respective input channel. This adds character and dynamic control to your input signal.
Input Level Indicators: LED meters provide visual feedback on the input signal level (-27dB, -9dB, -6dB, -3dB, 0dB). Aim for levels that illuminate the green LEDs consistently, with occasional flashes of the yellow LEDs, avoiding the red 0dB LED to prevent clipping.

3.2 Monitoring and Output Controls

INPUT / USB MIX Knob: Blends the direct input signal (INPUT) with the playback signal from your computer (USB). This allows for zero-latency direct monitoring of your input signal while recording.
STEREO Button: Switches the monitoring mode. When engaged, inputs are monitored in stereo. When disengaged, inputs are monitored in mono.
LOOPBACK Button: Activates the loopback function, allowing you to record your computer's audio output along with your live inputs. Useful for streaming or podcasting.
OUT 3/4 Button:
- Recording Mode: When using main outputs (1L/2R), pressing this button allows you to monitor the sound sent to the 3/4 channels. This is useful for a sound engineer to temporarily monitor tracks sent to recording musicians.
- A/B Mode: In this mode, you can connect active monitor speakers to both 1L/2R and 3L/4R outputs simultaneously. Pressing the OUT 3/4 button switches monitoring between these two sets of speakers.
MONITOR Knob: Controls the overall output level for the main monitor outputs (1L/2R) and headphone outputs.
MUTE Button: Mutes the main monitor outputs (1L/2R) and headphone outputs.
Headphone Level Knobs (1 & 2): Independently adjust the volume for each of the two headphone outputs.

3.3 Audio Interface Modes

The NAI-24 supports two distinct audio interface modes to accommodate different usage environments:

Standard Mode: Default operation for general recording and playback.
A/B Mode: Allows for switching between two sets of monitor speakers connected to outputs 1L/2R and 3L/4R.

Refer to the "OUT 3/4 Button" description above for details on how to utilize these modes.

4. Maintenance

Proper care and maintenance will ensure the longevity and optimal performance of your NUX NAI-24.

Cleaning: Use a soft, dry cloth to clean the exterior of the unit. Avoid abrasive cleaners, solvents, or waxes. Do not allow liquids to enter the unit.
Storage: When not in use, store the NAI-24 in a clean, dry environment away from extreme temperatures and direct sunlight.
Handling: Avoid dropping or subjecting the unit to strong impacts. Do not place heavy objects on top of the interface.
Ventilation: Ensure adequate airflow around the unit to prevent overheating. Do not block ventilation openings.
Cable Management: Use proper cable management to prevent strain on connectors and accidental disconnections.

5. Troubleshooting

If you encounter issues with your NAI-24, refer to the following common problems and solutions.

Problem	Possible Cause / Solution
No sound from outputs/headphones.	Check if the NAI-24 is selected as the default audio output device in your computer's sound settings. Ensure the MONITOR knob is turned up and the MUTE button is not engaged. Verify headphone volume knobs are turned up. Check all cable connections (USB, monitor speakers, headphones). Ensure your DAW or audio application is routing audio to the NAI-24.
No input signal detected.	Check input cable connections. Increase the GAIN knob for the respective channel. For condenser microphones, ensure +48V phantom power is engaged. For instruments, ensure the HI-Z button (Channel 1) or LINE button is correctly set. Verify the NAI-24 is selected as the input device in your computer's sound settings and DAW.
Audio crackling or dropouts.	Increase the buffer size in your DAW's audio settings. Ensure you are using a high-quality USB cable and connecting directly to a computer USB port (avoid unpowered USB hubs). Close unnecessary applications on your computer to free up CPU resources. Update NAI-24 drivers if available from the NUX website.
Ground loop hum.	Ensure all equipment is plugged into the same power outlet or power strip. Use balanced cables for connections to monitor speakers. The NAI-24's audio transformers at the main output are designed to help avoid ground loop interference. If hum persists, try isolating power sources or using a ground loop isolator.

6. Specifications

Detailed technical specifications for the NUX NAI-24 USB Audio Interface.

Feature	Detail
Model Number	NAI-24
Connectivity Technology	USB
Number of Channels	2 Input, 4 Output
Audio Input Types	XLR, 1/4 inch (TRS/TS Combo)
Maximum Sample Rate	192 KHz
Bit Depth	32-bit
Microphone Preamp Gain	Up to 71dB (Class A discrete transistor)
Latency	Ultra-low (3.17ms at 192kHz 32 sample buffer)
Operating System Compatibility	Android, Windows, iOS
Item Weight	1.32 Kilograms
Special Features	Audio Transformers, 76PRE Analog Compressor, Independent 48V Phantom Power, HI-Z Input, Dual Headphone Monitoring, Loopback, Stereo Mode Switching, A/B Monitor Switching

7. Warranty and Support

7.1 Warranty Information

The NUX NAI-24 USB Audio Interface comes with a one-year manufacturer warranty from the date of purchase. This warranty covers defects in materials and workmanship under normal use. It does not cover damage caused by misuse, accident, modification, unauthorized repair, or improper installation.

Please retain your proof of purchase for warranty claims.

7.2 Customer Support

For technical assistance, troubleshooting beyond this manual, or warranty service, please contact NUX customer support. You can typically find support contact information, driver downloads, and FAQs on the official NUX website:

Visit the Official NUX Website

When contacting support, please have your product model (NAI-24) and purchase information ready.

NUX NAI-24