Mackie LM-3204 Stereo Line Mixer Owner's Manual

Introduction

The Mackie LM-3204 is a 32-input, 2+2 Bus line level sound mixer designed for applications requiring control of multiple stereo/mono line level sources. It offers exceptional audio performance in a compact, rack-mountable unit, making it suitable for project studios, stage use, sound reinforcement, audio-visual setups, and post-production suites.

Each of its 16 stereo input modules features gain, balance, EQ, and auxiliary send controls. The mixer also includes microphone preamplifiers, insert points, and comprehensive monitoring options.

Safety Instructions

[WARNING SYMBOL] RISK OF ELECTRIC SHOCK. DO NOT OPEN.

[WARNING SYMBOL] RISQUE DE CHOC ELECTRIQUE. NE PAS OUVRIR.

CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER (OR BACK). NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.

ATTENTION: POUR EVITER LES RISQUES DE CHOC ELECTRIQUE, NE PAS ENLEVER LE COUVERCLE. AUCUN ENTRETIEN DE PIECES INTERIEURES PAR L'USAGER. CONFIER L'ENTRETIEN AU PERSONNEL QUALIFIE.

[WARNING SYMBOL] AVIS: POUR EVITER LES RISQUES D'INCENDIE OU D'ELECTROCUTION, N'EXPOSEZ PAS CET ARTICLE A LA PLUIE OU A L'HUMIDITE.

The lightning flash with arrowhead symbol within an equilateral triangle is intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure, that may be of sufficient magnitude to constitute a risk of electric shock to persons.

Le symbole éclair avec point de flèche à l'intérieur d'un triangle équilatéral est utilisé pour alerter l'utilisateur de la présence à l'intérieur du coffret de "voltage dangereux" non isolé d'ampleur suffisante pour constituer un risque d'éléctrocution.

The exclamation point within an equilateral triangle is intended to alert the user of the presence of important operating and maintenance (servicing) instructions in the literature accompanying the appliance.

Le point d'exclamation à l'intérieur d'un triangle équilatéral est employé pour alerter les utilisateurs de la présence d'instructions importantes pour le fonctionnement et l'entretien (service) dans le livret d'instruction accompagnant l'appareil.

1. Read Instructions: Read all the safety and operation instructions before operating the LM-3204 Console.

2. Retain Instructions: Keep the safety and operating instructions for future reference.

3. Heed Warnings: Follow all warnings on the LM-3204 Console and in these operating instructions.

4. Follow Instructions: Follow all operating and other instructions.

5. Water and Moisture: Do not use the LM-3204 Console near water (e.g., bathtub, washbowl, kitchen sink, laundry tub, wet basement, swimming pool).

6. Heat: Locate the LM-3204 Console away from heat sources like radiators or devices that produce heat.

7. Power Sources: Connect the LM-3204 Console only to a power supply described in these instructions or marked on the unit.

8. Power Cord Protection: Route power supply cords to prevent them from being walked on or pinched, paying attention to plugs and where cords exit the unit.

9. Object and Liquid Entry: Do not drop objects or spill liquids into the LM-3204 Console.

10. Damage Requiring Service: Service the LM-3204 Console by qualified personnel if the power-supply cord/plug is damaged, objects have fallen/liquid spilled, it has been exposed to rain, it does not operate correctly, or its chassis is damaged.

11. Servicing: Do not attempt to service the LM-3204 beyond what is described in this manual. Refer all other servicing to the Mackie Tech Support Department.

13. To prevent electric shock: Do not use the LM-3204 Console polarized plug with an extension cord, receptacle, or other outlet unless the blades can be fully inserted to prevent blade exposure.

14. Grounding or Polarization: Do not defeat the grounding or polarization of the LM-3204 Console.

This apparatus does not exceed Class A/Class B limits for radio noise emissions from digital apparatus as set out in Canadian Department of Communications regulations.

WARNING: To reduce the risk of fire or electric shock, do not expose this appliance to rain or moisture.

Panel Layout & Function

The LM-3204 front panel is divided into two main sections: the 16 stereo line level input modules (channel strips) on the left, and the Master Output section on the right.

Input Module (Channel Strip)

Each of the 16 input modules is identical and handles stereo signals, meaning each control affects both the left and right channels simultaneously.

• Gain Control: A white knob with a "U" detent for Unity Gain. It provides a wide range of gain, from off to +30dB, accommodating various line level inputs (+4dBu down to -10dBV).
• -20 LED: A green LED that lights when a signal level of -20dBu or above is present at the input jacks. It indicates signal activity.
• OL LED: A red LED that lights when the input signal is too high, causing overload or clipping in the circuit. This should be avoided.
• EQ Controls: Three sections: Lo (shelving, ±15dB at 80Hz), Mid (peaking, ±12dB at 2.5kHz with a 2-octave bandwidth), and Hi (shelving, ±15dB at 12kHz). All are ganged for stereo operation. The "U" detent bypasses the EQ section.
• Balance Control: Acts as a stereo pan control, adjusting the balance between the left and right channels. A "U" detent sets an even balance. When a mono signal is patched into the Left input, this control acts as a standard pan.
• Mute/Alt 3-4 Switch: Mutes the channel strip. When engaged, the signal is removed from the main L/R buses and any selected Aux buses. It also routes the signal to the Alt 3-4 outputs, effectively turning the mixer into a 4-bus system.
• Solo Switch: Allows listening to a specific channel or combination of channels without affecting the main outputs. When a channel is soloed, the -20 and OL LEDs light steadily. The Solo control in the Master Output section adjusts the solo monitoring level.
• Aux Sends: Four sets of auxiliary sends (1-4) per module. A Shift switch selects between sends 1&3 (stereo) and 2&4 (mono). These are post-Gain, post-EQ, post-Mute.

Master Output Section

Located on the right side of the panel, this section includes:

• Left and Right Master Faders: Control the overall mix level for the main L/R buses.
• Left and Right Meters: 13-segment peak averaging meters to monitor signal levels. They reference 0dB to 0dBu. Red LEDs indicate imminent clipping at +20dBu.
• Control Room Level: Controls the output level for monitor speakers.
• Phones Level: Controls the output level for headphones.
• Tape Monitor Switch: Selects the source for the monitor circuits and meters (main L/R buses or Tape Inputs).
• AUX Returns: Four stereo AUX returns with ganged level controls and EQ, allowing effects returns to be mixed back into the main buses.

Rear Panel Connections

The rear panel houses all input and output jacks:

• Line Inputs: 32 line inputs (16 stereo pairs) for connecting line-level sources. Accepts balanced or unbalanced signals.
• Mono Patching: Plugging into the Left (MONO) jack of a stereo pair applies the signal to both left and right circuits.
• Inserts (Channels 1-4 Only): 1/4" TRS jacks for inserting external processing equipment before the Gain and EQ circuits. Can be used for direct out or send/return.
• Mic Preamps: Two standard XLR inputs with trim controls and +48V phantom power for microphones.
• Outputs: Control Room Outputs, Main/Tape Outputs (balanced/unbalanced), Alt 3-4 Outputs (unbalanced).
• AUX Sends: 1/4" TS jacks for sending signals to external effects or monitor mixes.
• AUX Returns: 1/4" TS jacks for receiving signals from effects units.
• Expander In: For connecting an optional LM-3204E Expander.
• Phones Out: 1/4" TRS stereo jack for headphones.

Connection Diagrams: The manual includes various diagrams illustrating typical connection setups for different applications, such as live 2-track recording, multi-track recording, DJ setups, and studio submixing. These diagrams show how to connect instruments, effects processors, tape decks, and other audio gear to the LM-3204.

Using the LM-3204

The LM-3204 is versatile and can be used in many audio scenarios:

• Musical Instrument Submixer (Stage/Studio): Ideal for submixing multiple instruments, synthesizers, drum machines, and other electronic sources, providing stereo imaging, EQ, and effects routing.
• Effects Submixer: Can provide up to 16 stereo returns with EQ for external effects units.
• Main Studio Mixer: Can serve as the primary mixer for tracking and mixing, offering Mackie's sound quality.
• Club Sound Reinforcement Mixer: Suitable for small acts with electronic instruments and vocals, offering a compact and affordable solution.
• DJ Mixer: Features stereo gain, mutes, and EQ for balancing multiple music sources.
• Multi-Image/Multimedia Mixer: Perfect for combining numerous audio sources in corporate, educational, or presentation environments.

Sensitivity Adjustment Procedure

A critical step for optimal performance is tuning the input sensitivity for each channel:

1. Set all faders and solo controls to off.
2. Apply signal to the channel input (stereo line or mono line).
3. Set channel strip controls: Gain to "U", Solo down, Mute up, Balance to "U", EQ to "U", Aux controls counterclockwise.
4. Apply a representative audio signal.
5. Adjust the channel Gain control so that peak levels hit 0dB on the Left/Right meters for +4dBu signals, or turn clockwise for -10dBV signals. For mic inputs, use the Mic Trim pot on the rear.
6. (Optional) Adjust EQ to desired settings and repeat level adjustment.
7. Return the Solo button to the up position.
8. Repeat for each channel.
9. Adjust master faders for optimal mix level, with occasional peaks of 0dB.

Key Concepts

• Levels: Understanding microphone vs. line level signals and proper gain staging is crucial.
• Noise: All circuits produce noise; keep signals above the noise floor but below clipping.
• Headroom: The range between the operating level and the clipping point, allowing for loud peaks.
• Unity Gain: Setting controls to the "U" detent means signal level in equals signal level out.
• Metering: Use meters to monitor signal levels, aiming for the middle range with occasional peaks into the yellow (+10dBu). Avoid clipping (red OL LEDs).
• Buses: Internal signal paths used to combine multiple signals (e.g., main L/R buses, Alt 3-4 buses, Aux buses, Solo buses).
• Sends and Returns: Used for routing signals to external effects or monitor mixes, and returning processed signals to the mix.
• Solo: Allows isolated listening to channels or groups, affecting only the monitor path.
• EQ: Controls for adjusting the frequency response (Lo, Mid, Hi shelving/peaking).

Specifications

Detailed technical specifications are provided, including:

• Noise: Various noise figures for different configurations (e.g., -104.2dBu with master fader down, -84.0dBu with master fader and channel gains at unity).
• Total Harmonic Distortion: Typically very low (e.g., 0.0022% for input to output at 1KHz @ +14dBu).
• Crosstalk: Low crosstalk between channels (e.g., -73dBu for channel gain down, -81dBu for channel muted).
• Frequency Response: Wide frequency response (e.g., 20Hz to 50kHz at ±0dB/-1dB, 20Hz to 100kHz at ±0dB/-3dB).
• Maximum Levels: Mic preamp input (+14dBu), Other inputs/outputs (+22dBu).
• Impedances: Input and output impedances for various connections (e.g., Mic preamp input 5kΩ, Other inputs 10kΩ, All outputs 120Ω).
• Equalization: Lo EQ (Shelving, 80Hz, ±15dB), Mid EQ (Peak, 2kHz, ±12dB), Hi EQ (Shelving, 12kHz, ±15dB).
• Microphone Preamp: E.I.N. (-129dBm).
• Power Requirements: 120 VAC, 50/60Hz, 60 watts.
• Weight: LM-3204 console: 24 lbs.

Service & Troubleshooting

Troubleshooting: Basic steps include checking power connections, fuses, and switch positions. It's recommended to swap cables for intermittent signal problems. Contacting Mackie Product Support is advised if issues persist.

Service: Repairs should only be performed at Mackie's factory. Unauthorized service will void the warranty. To obtain factory service, contact Mackie Customer Service to get a Return Authorization Number (RA number). The unit must be packed securely in its original carton with a detailed description of the problem and proof of purchase.

Shipping Box: Users are strongly advised to save the original shipping box and foam for potential future service needs.

Options

LM-3204E Stereo Line Expander: An optional unit that adds another 16 stereo line inputs to the system, expanding the mixer's capacity.

Appendices

The appendices detail connector types (XLR, TRS, TS, RCA) and their applications, including balanced vs. unbalanced signals, and special Mackie connections for simplified patching.