Using the M‑Audio BX4 Monitors

The M‑Audio BX4 Monitors are compact, active 2-way nearfield reference speakers with a 4.5″ Kevlar woofer and 1″ silk-dome tweeter that deliver up to 120 W of peak power and a wide frequency response. The BX4 are powered monitors, meaning each speaker has a built-in amplifier. You don’t need an external amp. 

What you're working with

1. Rear Port: Enhances the bass produced by the woofer by increasing low-frequency response. Ensure the port is not obstructed, as blockage will negatively affect bass performance.

2. RCA Inputs: Use the included audio cable or other RCA cables (sold separately) to connect external audio sources.

3. 1/4" (6.35 mm) TRS Inputs: Use 1/4" (6.35 mm) TRS audio cables (sold separately) to connect external audio sources.

4. 1/8" (3.5 mm) TS Output to Passive Speaker: Provides the audio connection from the active speaker to the passive speaker. Use the included 1/8" (3.5 mm) TS interconnection cable.

5. 1/8" (3.5 mm) TS Input from Active Speaker: Connects the passive speaker to the active speaker using the included 1/8" (3.5 mm) TS interconnection cable.

6. Active Speaker Position: Adjusts the stereo position of the active speaker, allowing placement on either the left or right side based on your setup and connection preferences.

7. High EQ: Adjusts high-frequency output to boost or cut treble response.

8. Low EQ: Adjusts low-frequency output to boost or cut bass response.

9. Power Connector: Connect the included 2-prong IEC power cable here.

1. Tweeter: Outputs high-frequency audio.

2. Woofer: Outputs low-frequency audio.

3. 1/8" (3.5 mm) TRS Aux Input: A stereo 1/8" (3.5 mm) input for connecting a CD player, MP3 player, or other external audio source.

4. Headphone Output: Connect 1/8" (3.5 mm) headphones to monitor audio privately. When headphones are connected, speaker output is muted until the headphones are disconnected.

5. Volume/Power Knob: Controls speaker power and volume. Turn the knob clockwise to power on the speakers; you will feel a click and the LED will illuminate. To power off, turn the knob fully counterclockwise until the LED turns off.

Wired connections

The BX4 has multiple inputs so you can connect many sources:

• RCA - common on mixers, DJ gear, TVs
• ¼″ TRS - balanced input from interfaces or pro gear
• ⅛″ 3.5 mm AUX - from phones, laptops, tablets

Step-by-step wired setup

1. Power off speakers (volume/Power knob all the way down).

2. Choose the appropriate cable for your source:

   • Audio interface → ¼″ TRS

• • Phone or laptop → ⅛″ aux

• • Mixer or DJ controller → RCA

1. Connect your left output on your source to the input on the active (left) monitor using the right cable.

2. Connect the active monitor to the passive (right) monitor using the included ⅛″ interconnect cable.

3. Plug in power and turn speakers on.

Note: Balanced vs unbalanced: Use TRS balanced cables where possible for less noise — especially for longer runs. For short desktop setups, standard aux/RCA works fine.

Controls and sound tuning

Front Panel (see also Diagram 2)

• Volume/Power knob - adjust listening level.

Rear Panel (see also Diagram 1)

• High-EQ & Low-EQ switches - boost or cut high and low frequencies to tailor the sound to your room.
• Left/Right Active Speaker switch - choose which speaker has the volume knob on the front (handy positioning).

Basic listening tips

• Start at a low volume and gradually raise to a comfortable level.
• If using a DAW, keep your interface output at a moderate level and adjust speaker volume as needed.
• Reference familiar tracks: play music you know well to judge balance and clarity.

Common practical notes

• Standby mode: If no audio plays for a bit, the BX4 may enter standby and need audio input to wake up again.
• Avoid obstructions: Don’t block the rear ports - it can negatively affect bass response.
• Desk reflections: If the speakers are directly on a desk, reflections can muddy the sound - isolation pads help.