This article explains how to design a Dolby Atmos mix room with a focus on determining optimal speaker positions. It is applicable to studios mixing music, non-theatrical post-production, gaming, and podcast content. For guidelines for studios mixing cinema content, contact CSGStudios@dolby.com.

The guide should be reviewed alongside the Microsoft Excel-based Dolby Atmos Room Design Tool HE+Music (DARDT HE+Music). The DARDT can streamline several design steps while offering real-time feedback on room size, speaker placement, and equipment power output. When ideal speaker positioning or full adherence to the design guidelines is not feasible due to practical constraints, intelligent compromises can often be made to ensure a high-quality mix environment.

For additional room design, DARDT, or room calibration assistance, visit the Room Design & Calibration Forum or contact your local equipment reseller. A list of Dolby Atmos Certified Service Partners can be found here.

 

7 Steps to Design a Dolby Atmos Mix Room

Dolby Atmos mix rooms can be designed in seven easy sequential steps:

1. Define the room dimensions
2. Define the mix position
3. Position the ear-level speakers
4. Position the overhead speakers
5. Position the subwoofer(s) and consider bass-management options
6. Choose speaker models
7. Choose audio interface(s) and consider speaker management requirements

 

Step 1: Defining the Room Dimensions

The first step is to determine the dimensions of the space where the speakers will be placed. In Dolby Atmos mix room designs, this is referred to as the Working Space, defined by its length, width and height to form a 3D rectangle.

In standard rectangular rooms, the Working Space dimensions will match the room dimensions, measured from wall-to-wall and floor-to-ceiling.  For irregularly shaped rooms, the Working Space is a 3D rectangular approximation of the room.

 

 

Figure 1: Working space dimensions

 

When considering a room or space, it is key to ensure speakers can be placed at an adequate distance from the mixer to ensure a stable and spatially balanced sound field.  This can be achieved by meeting or exceeding our recommended minimum distance between speakers as shown in the diagram and table below.

 

Figure 2: Minimum recommended distances between speakers

 

Minimum distance between the Side Surround speakers (measured speaker baffle to speaker baffle)	3 meters (approx. 10 feet)
Minimum distance between the Center speaker and center line of the Rear Surrounds (measured speaker baffle to speaker baffle)	3.5 meters (approx. 11.5 feet)
Minimum distance from the floor to the lowest overhead speaker (measured floor to speaker baffle)	2.4 meters (approx. 8 feet)

 

Design Tips:

• Note that the minimum distances are measured from speaker baffle to speaker baffle (or floor to speaker baffle). Therefore, the Working Space may need to be extended in each direction to account for the depth of the speaker cabinet and mounting brackets. Example: if the depth of an overhead speaker bracket and cabinet is 0.3 meters, a Working Space height of 2.7 meters would be required to meet the recommended minimum distance of 2.4 meters from the floor to the speaker baffle.
• If the Working Space is small, recessing speakers into the ceiling and/or using low-profile speakers and brackets should be considered to optimize the available space.

 

Step 2: Defining the Mix Position

The mix position (i.e. the position of the mixer's ears while working) is the reference point for all speaker placements, and hence it is key to establish accurately. Typically, this is located between the edge of the console and 30 cm (approximately 12 inches) behind it.

To accurately assess the balance of a Dolby Atmos mix, it is recommended that the mix position be situated between 30% and 70% of the distance from the center speaker baffle to the line of the Rear Surround speakers. Since the exact speaker positions have not yet been determined, the initial mix position percentage can be an estimate. This estimate should be reviewed and adjusted once speaker placements are confirmed.

 

Figure 3: Mix position and recommended range

 

Design Tips:

• If converting a stereo mix room to Dolby Atmos, the existing mix position might be too far forward (i.e. closer to the center speaker than the recommended 30%). If this is the case, moving the mix position back by just 20-30 cm (approximately 8-12 inches) can help achieve a more balanced Dolby Atmos sound field.
• Different content industries may prefer different mix positions. For example, post-production studios often favor a rear-heavy room layout with client seating at the front, while music studios typically prefer front-heavy setups.

 

Step 3: Positioning the Ear-Level Speakers

Once the mix position is set, you can establish the positions of the ear-level speakers. In a 7.1.x layout, these include the Left, Center, Right, Left Surround, Right Surround, Left Rear Surround, and Right Rear Surround speakers. In a 9.1.x layout, the Left Wide and Right Wide speakers are added.

Using a plan view diagram as shown below, first mark the mix position. Next, place the ear-level speakers around it, staying within recommended angle ranges per speaker position and as close to the ideal angles as possible. Note all angles are relative to the center speaker, which is at 0° directly facing the listener.

While most speaker positions are specified as angle ranges, the Left and Right Wide speakers are positioned by taking the Left and Right speaker angle and adding 15 - 20°. In addition, it is important to ensure there is at least 30° of separation between the Left and Right Surrounds and the Left and Right Rear Surrounds.

Speaker pairs are symmetrically placed. For example, if the Left Side Surround speaker is at 100^o, then the Right Side Surround speaker should be placed at -100^o.

Once the speaker positions are determined, ensure speakers are rotated and aimed at the mix position. This includes both rotating them laterally and tilting them down as appropriate.

 

Figure 4: Recommended angles with tolerance ranges per speaker position

 

There are many mounting solutions on the market. In addition to traditional in-wall and on-wall options, stands can be purchased or custom-made for ear-level speakers. Creative use of trussing systems can also be employed to avoid mounting on existing surfaces such as walls and ceilings.

Regardless of the chosen solution, the final setup should adhere to the speaker placement, frequency response, and headroom requirements.

Design Tips: 

• Speakers can be placed against walls or in a circle around the mix position. Different distances from speakers can be compensated for with audio delays.
• The wide speakers (Left Wide and Right Wide) can be considered optional; however, they benefit panning resolution between the front and side surround speakers and are recommended for studios mixing Dolby Atmos music content.
• In smaller environments, it may be appropriate to use a single pair of surround speakers. This configuration is called 5.1.4. In this situation, the single surround pair should be placed at approximately 110°.
• After positioning the ear-level speakers, make sure the mix position is still between 30% and 70% of the distance between the baffle of the center speaker and the line of the rear-surround speakers.
• It is recommended to place the acoustic center (usually the mid-point between the drivers) of the ear-level speakers at ear height (1.2 to 1.3 meters).  Higher placement is possible, however, avoid going higher than 70% of the distance between the floor and the baffle of the overhead speakers as this will give a false impression of height to the mix audio.

 

Step 4: Positioning the Overhead Speakers

The optimal placement of the four overhead speakers will result in a square centered above the mix position. The distance from the mix position to the overhead speakers will depend on the height of the room. High ceilings will create a larger square around the mix position, while low ceilings will create a smaller square.

Figure 5: Overhead view of a mix room showing the relative position of the overhead speakers (shown in light blue). Left is a high ceiling room and right is a low ceiling room.

 

The overhead speakers should be positioned so that the vertical angle from the mix position to each overhead speaker is 45°. This is shown below in both the side-view (left) and rear-view (right) diagrams.

 

Figure 6: Side and rear-view diagrams showing the 45^o angles intersecting with the baffles of the overhead speakers.

 

To achieve the ideal 45° vertical angles, ensure that the distance between the front and rear overhead speakers is twice the vertical distance from ear height to the overhead speakers. The same concept can be used to determine the left and right placement of the overhead speakers.

 

Figure 7: Side and rear-view diagrams showing how the distance between the overhead speakers is calculated

 

For example, in a room where the baffle of the lowest overhead speaker is 2.5 meters, and the seated ear height of the mixer is 1.2 meters, the vertical distance from the mix position to the overhead speakers is 1.3 meters.

In this case, the ideal distance from the front overhead speakers to the rear overhead speakers is 2.6 meters (2 x 1.3 meters). The same calculation is also applied to give a distance of 2.6 meters from the left overhead speakers to the right overhead speakers.

A 2.6 meter x 2.6 meter square is then centered around the mix position, and the speaker mounting brackets are positioned accordingly. 

 

Figure 8: Side and rear-view diagrams showing how the distance between the overhead speakers is calculated

 

In an x.1.6 layout, two additional speakers are placed between the front and rear overhead speakers. 

Figure 9: Overhead view of an x.x.6 mix room showing the relative position of the overhead speakers. 

 

These speakers should be aligned with the existing front and rear overhead speakers, maintaining the same height and 45° vertical angle from the mix position, as shown in the rear-view diagram.

 

Figure 10: Rear-view diagram showing the the 45^o angles intersecting with the baffles of the overhead speakers.

 

The pair should be centered between the front and rear overhead speakers so that the angle to each is equal. 

Lastly, the overhead speakers are rotated and aimed at the mix position. 

Design Tips: 

• If the ear-level speakers are positioned higher than the mixer's ear height, the separation between them and the overhead speakers will be reduced. In this case, the overhead speaker array should be slightly smaller to maintain approximately 45° of separation between the ear-level and overhead speakers.
• The angles between the overhead speakers can be adjusted to accommodate any light fittings or air ducts. It is recommended to stay within the following ranges:
• • From a side view of the studio, the vertical angle to the front and rear overhead speakers should be between 30° and 55°.
  • From a rear view of the studio, the vertical angle to the left and right side overhead speakers should be between 45° and 55°.
• Considering the notes above, the overhead speakers may form a rectangle rather than a square. This will not affect the accuracy of the Dolby Atmos mix room, as the tolerance ranges account for this.

 

Step 5: Positioning the Subwoofer(s) and Considering Bass Management

There are no hard rules for subwoofer placement. It is recommended to consult an acoustician, and/or test where the subwoofer(s) performs best in the room. For subwoofer cabinets used for the LFE channel, a good starting point is typically at the front wall, positioned halfway between the center speaker and either the left or right speaker.

When multiple subwoofer cabinets are used, two approaches can be taken:

1. The cabinets can be mounted next to each other to optimize their acoustic summation and headroom.
2. In rooms with strong modal behavior (i.e., larger variations in measured output across the room), the cabinets can be spaced across the front wall to temper room mode dominance.

When multiple subwoofers are used solely for bass management, we recommend placing them near the speakers they are supporting (e.g. towards the rear of the room if they are managing the Rear Surround speakers).

 

Step 6: Selecting Speaker Models

To faithfully reproduce the audio from a Digital Audio Workstation (DAW), the speakers chosen must have adequate power output and headroom. In practice, this means choosing speakers that can produce 20dB above the chosen monitoring level at the mix position.

Using the DARDT, speaker models can be selected from a drop-down list for each speaker position and color-coded/numerical feedback will be provided on their suitability.

 

Step 7: Selecting Hardware and Considering Speaker Management

In addition to speaker positioning and suitability, the following functionality is typically required when designing a Dolby Atmos mix room:

• Audio interface: a PC or Mac audio interface with an appropriate number of outputs (e.g., 12 main outputs for a 7.1.4 speaker layout and an additional headphone output to monitor the binaural Dolby Atmos mix from the Renderer) 
• Monitoring control: Monitoring control functionality can be used to conveniently choose playback sources, select monitor levels, and utilize dim, mute, and solo
• Room equalization, speaker delay, and bass management: To make artistic decisions against an accurate technical monitoring reference and create mixes that translate to other environments, room EQ, speaker delays, and (when appropriate) bass management should be used

There are many suitable hardware and software devices on the market. Some will cover all of the above functions in one box, while others are more specialized.

For more information about room EQ, speaker delays, and bass management, refer to the Room Calibration FAQ.