QRS model controls in Logic Pro for Mac

The QRS model remains a significant development in algorithmic reverb technology. It was one of the first digital reverberation units to use complex algorithms to accurately simulate the acoustic properties of various environments.

The QRS has three different features to create various reverb effects:

Reverb: This traditional reverb effect replicates the natural acoustics of a room, incorporating early reflections and a reverb tail, all controlled by eight parameters.
Freeze: This feature lets you capture a snapshot of the reverb tail and loop it for any length of time, giving the effect of the sound being trapped in the room. It’s ideal for creating ambient textures and soundscapes.
Enhance: Instead of creating a typical reverb tail, Enhance creates a dense cluster of reflections that improves the clarity and spatial quality of the source signal. This feature can also be used to transform mono signals into a stereo image or to produce a binaural effect.

QRS main parameters

Quantec logo: Click the logo to open the Quantec Room Simulator information window, which provides details about the inventor and the development of the QRS and YardStick reverbs.
Reverb model buttons: Select a reverb model: QRS or YardStick. The QRS is the original classic vintage unit, and the YardStick represents the evolution and modernization of Quantec’s reverb technology.
Reverb Time knob and field: Adjust the reverb duration in conjunction with the Room Size control. The ring around the knob displays the reverb time range based on the chosen room size.
Freeze button: Use Freeze to capture and sustain the reverb tail, an ideal way to create organic soundscapes. Once captured, the audio routes only through Freeze, bypassing the main reverb.
Add button: Click and hold to capture another portion of the reverb tail. How long you hold determines how much audio is captured and added to the existing freeze effect. Repeat to layer sounds.
Clear button: Click to clear the audio captured in the Freeze effect.
Enhance button: Turn the Enhance effect on/off for the QRS model. It replaces the reverb tail with a dense reflection cluster, adding spatial depth. Adjust the effect using the Room Size parameter. While Enhance is turned on, the reverb time parameters are dimmed and inaccessible.
In meter: Displays the level of the incoming audio signal sent to the reverb effect. This helps monitor signal strength and prevent distortion in the source signal feeding the reverb.
Out meter: Displays the combined output level of all signals within the plug-in.

QRS reverb time multiplier parameters

The multiplier curve is used to adjust and visualize the room’s reverb response across the frequency spectrum. This feature lets you create either brighter or darker reverbs, simulating rooms with more reflective or absorbent walls.

The graph shows reverb time on the y-axis. The right scale reflects the reverb time, which changes with the reverb time knob. Two control points adjust reverb time for low frequencies (below 500 Hz) and high frequencies (above 1 kHz) relative to the set reverb time. The left scale indicates this factor, ranging from a maximum increase of 10 x to a decrease of 0.1 x.

These multipliers offer control over the reverb tail’s frequency response, achieving a natural room reverb effect that can’t be replicated with EQ alone.

Figure. The QRS reverb time multiplier parameters.

Low control point and field: Set the multiplier for the reverb time to affect low frequencies. Adjust it by dragging the control point or by dragging up or down in the value field.
High control point and field: Set the multiplier for the reverb time to affect high frequencies. Adjust it by dragging the control point or by dragging up or down in the value field.

QRS primary parameters

Figure. The primary set of QRS parameters.

Primary button: Access frequently used reverb settings.
Room Size slider and field: Set the room dimensions in cubic meters, from 1 m³ to 1,000,000 m³. Changing this parameter also adjusts the range of the Reverb Time knob.
1st Reflection Delay slider and field: Adjust the time between the direct sound and the first reflection to influence the spatial perception of the room.
Reverb Delay slider and field: Increasing the Reverb Delay value introduces a delay between the source signal and the reverb onset. Use this parameter to add up to 200 ms of delay, affecting spatial perception and timing in the mix.
Dry Level slider and field: Set the level of the dry signal at the plug-in output independently from the first reflection and the reverb tail.
1st Reflection Level slider and field: Set the level of the first reflection at the plug-in output independently from the dry signal and the reverb tail. Raising the level adds intimacy and presence, and lowering it creates a more open, spacious feel, shaping the reverb’s depth.
Reverb Level slider and field: Set the level of the reverb tail at the plug-in output independently from the dry signal and the first reflection.

QRS secondary parameters

Figure. The secondary set of QRS parameters.

Secondary button: Access additional settings for detailed adjustments and fine-tuning options. Note that this button and its settings are unavailable when using the Quantec Room Simulator on a mono channel strip.
1st Reflection Source pop-up menu: Set the channel assignment for the output of the first reflection. Maintain the original order (L R) or swap the left and right channels (R L).

Download the guides:

Logic Pro User Guide: PDF

Logic Pro Instruments: PDF

Logic Pro Effects: PDF

Control Surfaces Support Guide: PDF

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Logic Pro User Guide for Mac

QRS model controls in Logic Pro for Mac

QRS main parameters

QRS reverb time multiplier parameters

QRS primary parameters

QRS secondary parameters