This article serves as a help guide for the Dolby Atmos Room Design Tool (DARDT), and provides key information about the following features:

Monitoring Level Selection

Speaker Layout Selection

Speaker Position Entry 

Speaker and Amplifier Selection

Speaker Performance Estimates

Speaker Delay Calculation

 

For more details about DARDT features and workflows, including in-depth articles and video walkthroughs, see the Room Design Tools Knowledge Base.

If you need further assistance, visit the Room Design and Calibration Forum.

 

Selecting Your Monitoring Level

Monitoring level refers to the sound pressure level (SPL) measured at the mix position when pink noise is generated through a single loudspeaker in the renderer software. This value is also known as the reference level.

The selected monitoring level is used to determine the loudspeaker and amplifier output required to achieve full dynamic‑range playback. These requirements are then compared with the performance capabilities of the chosen equipment.

Results are displayed in the Estimated Headroom Above Target SPL and Estimated Max. Cont. SPL at Mix Position fields.

 

Choosing Your Speaker Layout

Dolby Atmos speaker layouts are referred to in the form x.y.z, where x is the number of ear-level speakers, y represents the Low Frequency Effects (LFE) channel, and z is the number of top surround (overhead) speakers.

Note that the LFE channel is always represented as ".1" in the speaker configuration (regardless of how many subwoofers are used), and dedicated bass management subwoofers are not represented in the x.y.z schema.

For additional information about selecting your speaker layout, consult the following article: What is the difference between 5.1.2, 7.1.4, and other speaker configurations?

 

Speaker Position Entry

Speaker positions can be entered using either a coordinate-based system or angular positioning. Both methods define the location of the acoustic center of the speaker. In a standard 2-way loudspeaker design, this point is often midway between the low and high frequency drivers.

In the coordinate system, X, Y, and Z represent width, length, and height. The origin point (0, 0, 0) is located at the front center line of the working space.

 

• X (width): The horizontal distance left or right from the center line of the working space to the speaker. Because designs are assumed to be symmetrical, both left and right directions are treated as positive values.
• Y (length): The distance from the front of the working space to the speaker
• Z (height): The distance from the floor to the speaker

 

When the working space dimensions and mix position are entered, the DARDT automatically populates the XYZ and angle fields using recommended values. These appear in gray text, while user-modified values appear in black text.

Angle-based positioning can be enabled by selecting Switch to Angle Entry in the Design Creation sheet. In this mode, speaker positions are defined relative to the mix position using angular values.

 

Speaker and Amplifier Selection

The speaker model dropdown displays all available loudspeakers in the DARDT database and can be filtered by manufacturer. Start typing a manufacturer’s name to narrow the results or click the dropdown arrow to browse the full list.

An asterisk (*) indicates the manufacturer has reported the model as out of production. 

Models with ‘80Hz BM’ appended use performance data based on an 80Hz high-pass filter and require a bass management solution. High-pass filtering may reduce low frequency driver load and, for some models, increase available SPL in the operating range. 

Speaker models are listed alphabetically. If a required model is not available, custom data can be entered in the Alternate Speaker and Amp Entry sheet. User-defined entries appear in alphabetical order for speakers and subwoofers, and at the bottom of the list for amplifiers.

For a step‑by‑step walkthrough of the Alternate Speaker and Amp Entry sheet, see the following article: Entering Custom Speakers and Amps

 

Speaker Performance Estimates

The DARDT relies on loudspeaker and amplifier specification data provided by equipment manufacturers, and makes several assumptions about speaker mounting, room acoustics, and typical listening conditions.

All performance results generated by the DARDT are estimates, and actual in‑room performance may differ. Always confirm equipment suitability with the manufacturer or an authorized reseller.

Active Speaker Max Peak SPL: This column displays the maximum peak sound pressure level (SPL) a speaker can produce at 1 meter in free-field conditions. This value is provided by the manufacturer.

Estimated Max. Continuous SPL at Mix Position: This column displays the estimated maximum continuous SPL at the mix position. This value is derived by:

 

• Converting peak SPL to continuous SPL using a –6 dB adjustment
• Adding +2 dB to account for acoustic loading
• Applying the inverse square law based on distance to the mix position

 

Estimated Headroom Above Target SPL: This column shows the differerence between a loudspeaker's estimated maximum continuous SPL and the maximum SPL needed to reproduce the full dynamic range at the selected monitoring level, both measured at the mix position. The required levels are defined as:

 

• Left, Center, Right: Monitoring level + 20 dB
• Surrounds and Overheads: Monitoring level + 17 dB
• LFE: Monitoring level + 30 dB

 

This value indicates whether the selected loudspeaker and amplifier combination meets Dolby Atmos playback requirements.

 

Speaker Delay Calculation

If speakers are placed at different distances from the mix position, delays must be applied to closer speakers to achieve time alignment.

In the Design Creation sheet, delay values are automatically calculated based on speaker position and time of flight to the mix position.

The Commissioning sheet, available in Advanced and Music – Advanced modes, includes a delay calculator for entering measured system propagation delays. This calculation accounts for:

 

• Monitor processing latency
• Minor inaccuracies in speaker placement

 

For additional information on time alignment and delay configuration, consult the following article: What is time alignment of Dolby Atmos speakers and how do I do it?