The guidelines and recommendations described in this article cover the key concepts and best practices for Dolby Atmos music studios. They can be viewed as the industry expectation for commercial studios and reference environments and can be used as guidance for private mix rooms.

For more detailed information on studio design, see our Technical Guidelines. For details about inclusion in the Dolby Atmos music studio directory, see our Process and Guidelines.

 

Speaker Configuration

The minimum speaker layout for a Dolby Atmos music studio is 7.1.4, i.e. 7 ear-level speakers, 1 LFE channel, and 4 overhead speakers. 9.1.4 or 9.1.6 configurations, which utilize “wide” speakers are preferred and considered our standard reference design.

 

Figure 1: A 9.1.4 speaker layout, i.e. 9 ear-level speakers, 1 LFE channel, and 4 overhead speakers. To create a 9.1.6 layout, a pair of overhead speakers are added above the mix position between the front and rear overhead pairs.

For more information about room design and speaker placement, refer to our Technical Guidelines.

 

Speaker Layout Dimensions

While we do not specify minimum room dimensions, it is recommended to maintain the minimum distances between speakers to create an accurate monitoring environment.

 

Minimum distance between the side surround speakers (measured speaker baffle to speaker baffle)	3.0 Meters (approx. 10ft)
Minimum distance between center speaker and line of rear-surrounds (measured speaker baffle to speaker baffle)	3.5 Meters (approx. 11.5ft)
Minimum distance from the floor to the lowest overhead speaker (measured floor to speaker baffle)	2.4 Meters (approx. 8ft)

 

Figure 1: Minimum recommended distances between speakers

Speaker height (when measured from floor to acoustic center) should be at ear-level for a seated mixer; approximately 1.2 m or 3.94 ft. The front and side speakers can be elevated up to 20 degrees, and the rears up to 25 degrees to avoid impediments as long as proper separation is maintained between the ear-level and top surround speakers.

 

Figure 2: Ear-level speakers elevated up to 20 degrees

In smaller rooms where the recommended speaker layout dimensions cannot be achieved, a quality mix environment is still possible through careful speaker positioning and aiming. Obstructions such as live room windows, patch bays, console bridges, and other obstacles may be avoided if proper angular separation is maintained as defined in the Technical Guidelines.

 

Monitoring Level

Dolby Atmos music masters should be reviewed on a speaker system that can achieve +20 dB of headroom over a calibrated monitoring level of 85 dB C-weighted SPL (Sound Pressure Level). A calibrated monitoring level of 79-82 dBC SPL may be appropriate for small/single operator mix rooms. Levels lower than 79 dBC SPL can be considered for writing, production, and personal-use spaces that do not wish to be considered for the Dolby Atmos Music Studio Directory.  

All measurements are based on the use of pink noise generated by the Dolby Atmos Renderer. Using other signal generators, pink noise should be set to approximately -20 dBFS (RMS).

You should monitor your mix at a level that allows you to work comfortably while meeting the required loudness delivery specifications.

 

Frequency Response

The frequency response specification for each speaker (i.e. the published data) should extend from 40 Hz to 18 kHz with no greater variation than +/-3 dB. We recommend matching the capabilities of your speakers at all locations to enable full-range frequency response throughout the room. Smaller, non-full-range speakers may be used for ear-level surrounds and/or overheads when supplemented with bass management. 

The subwoofer(s) should have a minimum frequency response range of 31.5 Hz to 150 Hz.

 

The Low Frequency Effects (LFE) Channel

The LFE channel’s acoustic output is required to be 10 dB higher across its frequency range compared to the center speaker (sometimes called +10dB in-band gain).

Figure 3: LFE channel reflects +10 dB of in-band gain (compared to the main channel) for the frequency range it covers.

When calibrating the LFE channel in a room with a 85 dBC monitoring level, the LFE channel should measure between 89 – 91.5 dBC on an SPL meter, and be capable of at least 23 dB above this level to prevent distortion and allow additional headroom for equalization. Multiple subwoofer cabinets may be required to achieve this.

 

Bass Management

Smaller speakers with a more limited frequency response should be supplemented with bass management to achieve consistent performance across the system. Bass management is necessary when the speaker of choice at any given position does not extend down to 40 Hz.

Figure 4: Bass management is utilized to supplement the main channel’s frequency response with a crossover of 100 Hz.

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 where strong modal behavior is experienced (i.e., large variations in measured output across the room), the cabinets can instead be spaced across the front wall so to temper room mode dominance.

We recommend dedicated bass management subwoofers in larger, commercial studios so that they may be placed near the speaker(s) they are managing.

 

Acoustics and Calibration

Dolby does not dictate the acoustics for Dolby Atmos music mix rooms. Well established international standards, such as ITU-R BS-1116-1 cover a number of relevant topics for the ideal acoustic performance of a critical listening environment. It is best to consult a professional acoustician who can evaluate the room’s acoustic performance and recommend appropriate treatment.

Room calibration is about providing consistency and confidence in material that is mixed/mastered in a Dolby Atmos music studio. Calibration is the process of optimizing room configuration and speaker placement and then applying adjustments to level, equalization, and delay so the measured acoustic response of the speakers meet a defined target.

When completing this work, professional analysis equipment should be used, and changes should be made as a result of multiple measurements in and around the mix position. For more information about acoustics and room calibration, refer to our Music Room Calibration FAQs.

The target curve for Dolby Atmos Music is shown below. The curve was developed in partnership with studios and music labels who required confidence in translation across multiple monitoring and playback environments.  If you are mixing in a room that is substantially larger or smaller than the recommended dimensions, you may wish to apply a steeper or shallower roll-off.

 

Figure 5: The Dolby Atmos music curve is flat from 160 Hz to 1.6 kHz, -1.5 dB per octave from 1.6 kHz to 10 kHz, with a final downward deflection above 10 kHz to –3.0 dB per octave. In this nearfield environment, a +1.0 dB rise below 160 Hz is also utilized.