PRESONUS Blue Max - User Manual

The PreSonus Blue Max is a smart compressor/limiter designed to provide dynamic range control for various audio applications. It aims to offer both ease of use for beginners and advanced control for experienced engineers, featuring built-in compression presets alongside a manual mode.

Function Description

The core function of the Blue Max is dynamic range compression and limiting. Audio signals often have a wide dynamic range, meaning a significant difference between their loudest and softest levels. This can lead to issues like signal overload and distortion during recording or reproduction, or make certain elements in a mix difficult to control. The Blue Max addresses this by acting as a type of amplifier where its gain is dependent on the signal level passing through it. Users can set a maximum level that the compressor/limiter allows to pass, resulting in automatic gain reduction above a predetermined signal level, known as the threshold.

Compression, specifically, reduces the output level of an audio signal by a fixed ratio relative to the input. This is beneficial for lowering the dynamic range of instruments or vocals, making them easier to record without distorting the recorder and assisting in the mixing process by reducing level changes. For instance, it can help stabilize the level of a vocalist who moves around a microphone, or make a kick drum "punch" through a dense mix.

Limiting is a more extreme form of compression where the signal is restrained from going any louder at the output, often referred to as a "brick wall" effect. The severity of compression is determined by the compression ratio and threshold. A ratio of 2:1 or less is considered mild compression, while ratios above 10:1 are considered hard limiting. The input signal level at which output reduction begins is set by the compression threshold; lowering the threshold means more of the input signal will be compressed.

The Blue Max also incorporates a sidechain insert on each channel. This feature allows external processing of the signal that the compressor uses to determine gain reduction. For example, an equalizer can be inserted into the sidechain to reduce sibilance (de-essing) in a vocal track. Another application is "ducking," where an external signal (like a narrator's voice) can automatically reduce the level of the main audio passing through the compressor.

Usage Features

The Blue Max is designed with a user-friendly interface, featuring both preset and manual control options.

• Presets: A standout feature of the Blue Max is its 15 studio-proven presets. These settings are categorized for various applications, including voice, percussion, fretted instruments, keyboards, stereo processing, and effects. These presets are designed to provide instant professional results and offer valuable insight into compression techniques, even for novice users. The presets digitally switch attack, release, ratio, and threshold parameters simultaneously, simplifying setup.

  • Vocal Presets: Include "SOFT" for easy, wide dynamic range compression suitable for ballads and live use; "MEDIUM" for more limiting and a narrower dynamic range, bringing vocals forward in the mix; and "SCREAMER" for hard compression on loud vocals, making them "in your face."
  • Percussion Presets: "SNARE/KICK" allows the initial transient through before compressing the rest of the signal for a hard snap; "L/R (Stereo) OVERHEAD" provides a low ratio and threshold to "fatten" drum overheads, increasing low end and presence.
  • Fretted Instrument Presets: "ELECTRIC BASS" offers fast attack and slow release for a tight, consistent bass level; "ACOUSTIC GUITAR" accentuates attack and maintains an even signal level; "ELECTRIC GUITAR" provides a slow attack for "crunch" rhythm guitar, adding punch.
  • Keyboard Presets: "PIANO" is a special setting for an even level across the acoustic piano, ensuring both hands are heard; "SYNTH" features fast attack and release for horn stabs and bass lines.
  • Stereo Presets: "STEREO LIMITER" acts as a hard limiter for controlling levels to a 2-track mixdown deck or stereo output; "CONTOUR" is a contoured setting to "fatten up" the stereo mix.
  • Effects Presets: "SQUEEZE" provides dynamic compression for solo electric guitar, creating a "glassy tele/strat" sound; "PUMP" creates a desirable "pumping" effect, good for snare drums to increase transient length.

• Manual Mode: For those who prefer granular control, the Blue Max offers a manual mode where users have full control over ratio, attack, and release parameters. In this mode, the threshold is fixed to -10dB. This allows for experimentation and fine-tuning beyond the presets.

• Variable Input Control: The input control allows for a wide range of gain adjustment, from -20dB to +40dB. This extensive range is crucial for amplifying low-level signals, such as direct outputs from electric guitars and basses, effectively acting as a pre-amp. This control is always active, even in manual mode.

• Ratio Control: In manual mode, the ratio knob sets the compression slope, determining how much the output level is reduced relative to the input above the threshold. It ranges from 1:1 (no compression) to 20:1 (hard limiting).

• Attack and Release Controls: Also active in manual mode, these controls dictate the speed at which the compressor reacts to the input signal. Attack sets how quickly the compressor "acts" (from 0.01mS to 100mS). A fast attack immediately subjects the signal to compression, while a slow attack allows initial transients to pass through uncompressed. Release sets the time it takes for the gain reduction to return to zero (from 10mS to 500mS). Short release times can create a choppy sound, while long times can lead to an "over compressed" or "squashed" sound.

• Full Metering: The unit provides comprehensive metering for both input and output levels, as well as separate meters for gain reduction. The input/output meter can be switched to display either the input signal level (before processing) or the output signal level (after compression). The gain reduction meter indicates the amount of gain being reduced in dB.

• Variable Output Control: This control, often referred to as "gain makeup," allows users to adjust the final output level of the Blue Max from -20dB to +20dB. This is essential for restoring the overall signal level after gain reduction has occurred.

• Process In/Out Button: This acts as a bypass button, but with a key difference: when pushed out, the Blue Max stops compressing the signal, but the input gain setting remains active. This allows for easy A/B comparison of the compressed versus uncompressed signal at a consistent input level.

• +4dBu or -10dBV Operation Switch: An internal switch allows users to match the Blue Max's operating levels to other gear in their system. +4dBu is for professional line levels (e.g., consoles), while -10dBV is for consumer levels or instruments. In -10dBV mode, the signal is internally raised to process at a lower noise floor and then lowered on the way out to match the connected gear.

• Mono and Stereo Operation: The Blue Max operates in a linked stereo mode at all times, meaning both channels contribute to the gain reduction amount, ensuring proper stereo imaging. It also features a high-gain mono input, allowing it to function as a pre-amp for instruments like guitars and basses.

Maintenance Features

While the manual does not explicitly detail maintenance features, several aspects imply a robust and user-friendly design:

• Internal Power Supply: The inclusion of an internal power supply eliminates the need for an external "wall wart," contributing to a cleaner setup and potentially greater reliability compared to external power bricks.
• Durable Construction: The device is built with "state of the art components to deliver crystal clear compression for an infinite period of time," suggesting a focus on longevity and consistent performance.
• Warranty: PreSonus offers a one-year limited warranty covering defects in material and workmanship, indicating confidence in the product's quality and providing recourse for users in case of manufacturing issues. Proper registration and adherence to warranty procedures are outlined for service.
• Customer Support: PreSonus encourages users to contact them with comments and suggestions, implying a commitment to product improvement and user satisfaction. They also advise users to refer to local distributors for warranty information in other countries, ensuring support globally.
• Connection Diagrams: The manual emphasizes the importance of proper grounding and provides connection diagrams to ensure optimum operation and prevent noise problems, which is a common issue in audio setups. This guidance helps users maintain a clean signal path.