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Ambisonics Sources

Ambisonic Stream sources are designed to receive audio encoded in a specific format. Unlike virtual sources, they do not represent a physical object in space; therefore they do not have any associated object in the Venue

Audio Parameters

All parameters are similar for all sources except for the parameters below.

Reverb

The Reverb level sends the W omnidirectional channel of the Ambisonic stream to the reverberation bus. There is no early and cluster simulation for Ambisonic sources.

A Format

A-Format sources allow to input in HOLOPHONIX the direct output stream of a 1st order Ambisonics microphone. Presets corresponding to the following microphones are available:

  • Sennheiser Ambeo,
  • SoundField ST250, ST450 and SPS200,
  • RØDE NT-SF1,
  • DPA-4
  • Oktava MK-4012.

The A-Format stream is the signal coming out directly of the microphone capsules. If you have allready transcoded that to a standard ambisonics stream using the manufacturer's software, use a B-Format source.

The A-Format stream will be automatically decoded to your loudspeaker layout by the chosen HOA bus.

info

A-Format sources can only be assigned to HOA 3D buses.

tip

For Higher Order microphones (i.e. with more than four microphone capsules), use the dedicated type of sources (Eigenmike®, Zylia®, and HOA Stream).

A-Format Parameters

Mic Type

Choose the model corresponding to you microphone within the available presets. If your microphone is not in the list, use the manufacturer or a generic B-Format transcoder, and a B-Format source. You can also contact our user support to create the preset corresponding to your 1st order ambisonics microphone.

Mic Radius

The radius of the microphone is set automatically when selecting a microphone model. However, this parameter can be adjusted manually if necessary. The radius cannot be changed when filtering is off.

Filtering

The Filtering option activates high-frequency filters to compensate for the non-coincidence of the microphone capsules, and enhance the Ambisonic signal.

Orientation

The orientation of the A-Format stream can be adjusted with Yaw, Pitch, Roll, to rotate the entire audio scene. See rotation angles.

B-Format

B-format sources allow inputting 1st order Ambisonics streams to HOLOPHONIX in virtually any formats. To input a Higher Order Ambisonic stream, use an HOA Stream source.

Configure the B-Format source to match the characteristics of the input stream with the B-Format section of the source inspector page.

B-Format Parameters

tip

For AmbiX B-Format streams, choose ACN sorting and SN3D normalization.

Sorting

Select the sorting (or "channels ordering") of your B-Format incoming stream, between the standards listed below. Choosing the wrong sorting will cause incoherent levels and localization.

  • ACN (wyzx)
  • FMH (wxyz)

Normalization

Select the normalization matching with your B-Format Stream from one of the standards listed below. Choosing the wrong normalization will cause incoherent levels, distorted localisation, and can result in signal saturation.

  • FuMa
  • MaxN
  • SN3D

Convention

The convention sets the orientation of the x-axis to the front or to the right. This adaptation equivalent to a 90° Yaw rotation.

  • Classic where x is in front, is the most common convention.
  • Spat where x on the right, is the convention used in Ircam's tools.

Orientation

The orientation of the B-Format stream can be adjusted with Yaw, Pitch, Roll, to rotate the entire audio scene. See rotation angles.

HOA Stream

Much like B-format sources, the HOA Stream sources allow inputting High Order Ambisonics streams to HOLOPHONIX in a large diversity of formats. When creating the source, select the order of your stream. The HOA Stream source will be automatically created with the right number of audio channels.

Configure the HOA Stream source to match the characteristics of the input stream with the HOA Stream settings.

HOA Stream Parameters

tip

For AmbiX HOA Streams, choose ACN sorting and SN3D normalization.

Sorting

Select the sorting (or "channels ordering") of your incoming HOA Stream, between the standards listed below. Choosing the wrong sorting will cause incoherent levels and localization.

  • ACN
  • SID
  • FMH

Normalization

Select the normalization matching with your HOA Stream from one of the standards listed below. Choosing the wrong normalization will cause incoherent levels, distorted localisation, and can result in signal saturation.

  • FuMa
  • MaxN
  • N3D
  • SN3D

Convention

The convention sets the orientation of the x-axis to the front or to the right. This adaptation equivalent to a 90° Yaw rotation.

  • Classic where x is in front, is the most common convention.
  • Spat where x on the right, is the convention used in Ircam's tools.

Orientation

The orientation of the B-Format stream can be adjusted with Yaw, Pitch, Roll, to rotate the entire audio scene. See rotation angles.

Eigenmike®

Eigenmike sources allow inputting to HOLOPHONIX the direct output stream of the HOA microphone "Eigenmike® EM-32" from MH Acoustics.

Check the section below for parameters explanation.

If you allready transcoded your Eigenmike recording to standard HOA stream, use an HOA Stream source to input the signal to HOLOPHONIX. Eigenmike sources are only intended to receive the 32-channel direct output of the microphone.

Eigenmike® Parameters

Method

Choose between the four HOA encoding methods. Each method corresponds to various techniques from the latest developments in scientific works concerning this specific task of transcoding audio signals coming from a microphone array, to a Higher Order Ambisonics stream.

We recommend using Method 3.

Regularization

The regularization parameter aims at adapting the dynamics of the filters used to encode the microphone array to HOA. Changing its value will have an effect on the ratio between, on one hand, the precision of the localization, and on the other hand, the tone and timber quality, as well as the signal-to-noise ratio.

When changing the value, new filters will be computed. It requires a small calculation time.

This setting is on only available for Method 1 and Method 3.

Orientation

The orientation of the B-Format stream can be adjusted with Yaw, Pitch, Roll, to rotate the entire audio scene. See rotation angles.

HOA Orders

Use HOA Order to decrease the contribution of the components of each order in the encoded HOA stream.

Zylia®

Zylia sources allow inputting to HOLOPHONIX the direct output stream of the HOA microphone "Zylia® ZM1". Check the section below for parameters explanation. If you allready transcoded your Zylia recording to standard HOA stream, use an HOA Stream source to input the signal to HOLOPHONIX. Zylia sources are only intended to receive the direct output of the microphone.

Zylia® Parameters

Method

Choose between the four HOA encoding methods. Each method corresponds to various techniques from the latest developments in scientific works concerning this specific task of transcoding audio signals coming from a microphone array, to a Higher Order Ambisonics stream.

We recommend using Method 1.

Method 3 and Method 4 are very CPU intensive.

Regularization

The 'REGULARIZATION' parameter aims at adapting the dynamics of the filters used to encode the microphone array to HOA. Changing its value will have an effect on the ratio between, on one hand, the precision of the localization, and on the other hand, the tone and timber quality, as well as the signal-to-noise ratio.

When changing the value, new filters will be computed. It requires a small calculation time.

This setting is on only available for Method 1.

Orientation

The orientation of the B-Format stream can be adjusted with Yaw, Pitch, Roll, to rotate the entire audio scene. See rotation angles.

HOA Orders

Use HOA Order to decrease the contribution of the components of each order in the encoded HOA stream.