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Biamp Systems

Parlé-series microphones tips and tricks

Biamp's Parlé Series Beamtracking™ Microphones can be used in a wide variety of applications. We've developed some tips and tricks to ensure that the Parlé microphone is always performing at its best and that installations always go smoothly. This article is intended to provide some extended information pertaining to the installation and programming of these microphones.

Discovery and communications

The Parlé series microphones are Audio Expander-class devices. This means that they require a Server-class device (TesiraSERVER, TesiraSERVER-IO, or TesiraFORTÉ) to be present in order for them to be discoverable and manageable in Tesira software. Unlike other audio expander devices, Parlé microphones are not assigned an IP address for control communications. AVB's AVDECC (Audio Video Discovery, Enumeration, Connection management, and Control) protocol is utilized for this.

Parlé microphones still adhere to Tesira's discovery and communications rules that other audio expander devices require. This means that AVB devices must still be correctly configured to operate in either converged or separated mode

A common system design utilizing a Parlé microphone includes a single Server-class device, such as the TesiraFORTÉ VT4, with the microphone directly connected to the TesiraFORTÉ VT4's AVB port through a PoE+ injector. Since the AVB and Control networks are physically separated, this setup will require separated networks to be enabled on the Server-class device in order for it to discover and communicate with the microphone.

Please reference the essential rules for implementing separated networks to ensure success in configuring device discovery and communications. In separated network mode, the AVB and Control IP addresses must be in different subnets. If the microphone does not appear in Remote Devices, double-check to verify that the port IP addresses are not in conflict with these rules.

TCM-1A vs TCM-1A with TCM-EX in Device Maintenance.png

Device Count

The following device count limits apply to all Tesira systems running firmware version 3.5 or newer:

  • Each SERVER or SERVER-I/O can act as the proxy for up to 24 expander devices in systems that include the TCM-X, TCM-XA, TTM-X, TCM-1, TCM-1A, AMP-450P or EX-UBT. 
  • Each TesiraFORTÉ can act as the proxy for up to 12 expander devices in systems that include the TCM-X, TCM-XA, TTM-X, TCM-1, TCM-1A, AMP-450P or EX-UBT. 
  • Additional details on system device limits can be found in the System Limits section of Tesira Help.

NOTE: TCM-XEX, TTM-XEX, and TCM-1EX microphones do not count against the total expander device counts. For example, a TCM-1A with two TCM-1EX microphones connected should be considered one expander device (TCM-1A) when making device count considerations.

Custom Blocks

To simplify programming of a system containing Parlé microphones, custom DSP blocks are automatically included in the Processing Library when installing Tesira software. The Processing Library includes custom blocks for common microphone array counts from one to six:

Processing Library w annotation.png

Choose the appropriate custom block for the project needs. When the custom block is opened, all the blocks necessary to set up a system using Parlé microphones can be seen in its signal chain. These blocks are pre-configured with the optimal settings to get started. In larger or more customized systems, it may be necessary to modify the Custom Block or its components.

Custom Block.pnginside no combiner.png

Adding an Auto Mixer Combiner

In a divisible/combinable space, it may be desired to utilize the Auto Mixer Combiner. The Auto Mixer Combiner requires a direct connection to the Mix Out of the associated Auto Mixers. This connection allows NOM coordination between Auto Mixers. The following images show a modification of the custom block which passes the Mix Out to the Combiner output node. 

Custom Block with Combiner.pnginside with combiner.png                        

Duplicate the custom block as needed and then tie the multiple custom blocks to the Auto Mixer Combiner. Configure the Groups settings as needed.

Custom blocks combined.png    AMixerCombiner.png

Adjusting Gate Hold Time

Some room layouts will benefit from a faster transition between microphone arrays than others. This transition time can be fine-tuned by doing the following:

  • Expand the Custom Block, then double-click on the Beamtracking Auto Mixer.
  • Right-click on one of the blue "On" buttons and select "Edit Channel Settings."
  • Make sure the "Set All" button is active (blue).
  • Leave the "Off Attenuation" setting at -40, but edit the "Gate Hold Time (ms)" to a lower value. The default value is 1000 ms, but we've observed good results when this value is set between 400 and 600 ms. Please consider the number of microphone arrays and the intended use of the room/system when configuring this setting. If in doubt, contact Biamp Support while commissioning this setting.

Adjust Gate Hold.png

Parlé Series LEDs

The TCM-X, TCM-XA, TTM-X, TCM-1, and TCM-1A network boxes, as well as the microphone arrays themselves, have LEDs that provide the current status of the device(s). Below is a list of the various LED behaviors and what they indicate. 

Network Box Status LED Indicator
No Power Off
Booting/Self-Test Red Solid
Ready to receive configuration or updating firmware Yellow Solid
Configured and ready to participate in the system Green Solid
Unit is in Locate mode Green Flashing
Unit has a Major Alarm Red Flashing
Unit has a Minor Alarm Yellow Flashing
Unit has both a Major & Minor Alarm Red & Yellow Flashing


Amplifier (TCM-1A and TCM-XA only) Status LED Indicator
No Power Off
Powered Green Solid
Amplifier limiter is engaged Yellow Solid
Amplifier is in Locate mode Green Flashing
Unit has a Major Alarm Red Flashing
PoE+ power is not available or insufficient to power the amplifier - it has been turned off Red & Yellow Flashing


Microphone Array Status LED Indicator
No Power or Unit is not configured as part of a system Off*
Unit is configured and operating normally Green Solid*
Unit is in Locate mode Green Flashing
Microphone is Muted Red Solid*
Unit has a Major Alarm condition Red Flashing

* The microphone array LED behavior can be customized using logic in an active Tesira configuration file. In this case, certain LED indications may differ from the expected default. Additional information on customizing LED control can be found in the next section - Parlé Microphone Array Logic

Parlé Microphone Array Logic 

The Parlé input block provides a series of logic nodes in order to customize the muting and LED behavior of the microphone pendant. Logic is enabled from the Parlé Mic Initialization dialog. The following configuration within the Initialization Dialog on the left would produce the input block configuration on the right.

TCM-1 Single Channel Init.pngTCM-1 Single Channel Logic.pngAll logic nodes are provided on a per-array basis. The TCM-1 input block can support a maximum of 3 microphone arrays. The TCM-X and TTM-X input blocks each support up to 2 microphone arrays. The exception to this is the "M1" nodes (for mute control and status feedback logic). If selecting "Mute Mics as a group," only a single logic input/output will be added for mute control and this will affect all channels simultaneously.

The "LED1" logic input will drive the LEDs for the corresponding pendant. The LEDs will remain off while receiving a logic low signal (0) and will turn on when they receive a logic high signal (1). 

The "RG1" logic input will select the LED color. A logic low signal (0) will set the LED color to red and a logic high signal (1) will set the LED color to green. Please note that the LED will not illuminate until the "LED" Logic input is driven high (1).

The granularity provided by these controls allows for customized behavior to suit the LED needs for a variety of situations. One example of this is to enable the green LED only when a pendant is active (gated on), while also allowing for a privacy mute that sets all pendants' LEDs to red for the duration of the privacy mute. The diagram below shows how logic could be wired to accommodate this scenario in a dual-array system. This is accomplished by using the Mic Active logic output of the Parlé Custom Block (included in Tesira software versions 3.11 and above) in conjunction with a Logic State serving as the trigger for the privacy mute.

Parlé Active Mic + Privacy Mute.png

  • Logic State - Privacy Mute
    • When Logic State output is high, the following conditions are met:
      • TCM-X M1 Logic input is set high, muting both pendants.
      • OR Gate outputs are set high, activating the LEDs on each pendant.
      • NOT Gate output is driven low, setting the LED color to Red.
    • When Logic State output is low, the following conditions are met:
      • TCM-X M1 input is set low, unmuting both pendants.
      • OR Gate outputs are set low, deactivating the LEDs on each pendant.
      • NOT Gate output is driven high, which will set the LED color to Green.
  • Mic Active Logic from Custom Block
    • When a Mic Active logic output is high and the Logic State is low, the following conditions are met:
      • OR Gate output is set high, enabling the LED for the active pendant.
      • Since the Logic State is low, the NOT Gate output is driven high, which sets the activated LED color to green.

An example file including this logic can be downloaded here.

TTM-X Mute Button

The TTM-X microphone includes a capacitive touch ring surrounding the microphone array that functions as a mute button. This button will toggle the microphone array mute status as seen in the control dialog. The logic output node will send a low or high signal depending on the mute status, thus allowing other events to be triggered in Tesira from the mute button on the microphone array.

Parle TTM-X mute button.png

A typical example of how this might be utilized is to trigger presets based on the mute status through the use of a Preset Button block. The Preset Button block will trigger a preset on the rising edge of a logic input. In order to trigger a certain event when the microphone is muted and another event when it is unmuted, two presets will be used. The preset input directly connected to the logic output of the TTM-X block will be recalled when the mute button is activated. In order to recall a preset when the mute button is deactivated, it will need to be triggered on the falling edge of the TTM-X logic output. To do this, route the mute status logic signal through a NOT gate to invert the logic. Thus, when the microphone enters a mute state (falling edge) on the output node of the TTM-X block, the NOT gate will output a rising edge to the Preset Button.

If the mute is being controlled via a Logic State or Flip Flop gate, there will need to be corresponding presets to change the state of the logic blocks when the mute button is physically pressed. These presets will need to set the state of the Flip Flop or Logic State to match the state of the mute button.

Camera tracking

Integrated AV systems can utilize positional information provided by the Tesira audio DSP to coordinate positional functions such as camera tracking. The camera presets are typically driven by logic outputs on a Gating Automixer. When we apply this concept to the Parlé microphone arrays, the automixer gate logic provides information on which pendant is gated on/active. This bit of information allows camera presets to frame the coverage area of a specific pendant. If additional information is desired for a tighter camera shot, TTP offers two TCM-1 subscriptions that supplement the automixer gate logic:

  • TCM1Mic1 subscribe segmentsActive 1
  • TCM1Mic1 subscribe audioSources 1

The following examples were captured via PuTTY:

  TTP - segmentsActive.png  TTP - audioSources.png

NOTE: The TCM-1 will provide responses for three beams and the TCM-X and TTM-X will provide responses for four.


In Tesira v3.4, a Locate feature was added to assist with identifying physical Tesira devices on the network. This is particularly useful when attempting to identify expander devices in large distributed systems. The Locate feature can be found in several different places within the Tesira software:

  • Device Maintenance
  • Network toolbar
  • System > Network > Locate Device
  • Context menu for any DSP object (found by right-clicking on the object)


TCM-1A Locate.PNG

Parlé microphone array LEDs will repeatedly flash green to identify the microphone. If expander arrays are connected, a sequence of flashes followed by a pause is used to identify the connected array.

The "Power" LED on the network box will alternate between green and off when Locate is triggered from the Tesira software.

TCM-XA and TCM-1A devices will also flash the "Amp" LED on the network box alternately green and off when Locate is triggered from the Tesira software.

The TCM-XA and TCM-1A also include an audible locate function. Audible Locate runs concurrently with visual Locate, and will state the device model and channel being located. Locate messages will be played from the amplifier at the level selected in the Locate dialog, regardless of the level or mute status selected elsewhere in the software. A speaker must be connected properly to the respective amplifier output for this audio message to be heard.

The TCM-XA includes a Locate button that allows you to activate and deactivate the Locate function from the unit. This button acts as a toggle for the feature and will synchronize with the software, allowing you to turn it on from the software and then off at the unit, or vice versa. 

Cue output

When tuning any room for conferencing, it is important to know what is being sent to the far end. It can be helpful to set up a local output to assess changes made to microphone settings. This output can simply be one of the analog outputs of a Tesira with an adapter wired to headphones, or the USB output of a Forte or EX-UBT connected to a PC for headphone monitoring and recording samples of the audio. 

TCM cue source selector.PNGA Source Selector block with 4 or more inputs can be added to the layout. Connect the first input to the output of the Parlé microphone block (this is the raw output of the microphone array). Connect input 2 to the output of the AEC processing block (this reveals changes due to the AEC echo reduction, noise reduction, and high pass filter). Input 3 should be connected to the output of the Parlé custom library processing block (this contains a level boost, EQ curve, Gating Automixer, and AGC). If additional processing objects are added, then additional inputs should be defined for the Source Selector to incorporate these in the testing. The last input should be taken just prior to the transmit block (whether it is VoIP, POTS, USB, or analog out).

Wire the Source Selector to the appropriate output and update your hardware. Put on headphones and you should be able to choose the pick points in the mic signal chain where you'd like to compare performance. This allows the local technician an opportunity to tune the mic performance without hearing any effects of codecs on the signal. Once the local performance is verified then you can place a call and assess the transmit quality on the far end. 

Voice Lift / Mix-Minus

Attempting to do local reinforcement with Parlé microphones (or with any ceiling microphone) is not recommended. This is simply due to the physics of sound involved with respect to achieving acceptable reinforcement levels without feedback.

If local mix-minus reinforcement of talkers is desired, Biamp recommends the use of lavalier, handheld, or gooseneck microphones placed in close proximity to the talker's mouth. This will allow maximum gain before feedback. 

PAG-NAG.pngAchieving acceptable acoustic gain before feedback requires that the talker's mouth be located close to a microphone with respect to the reinforcement speakers. It is critical that the talker's reinforced voice coming from the loudspeakers be substantially less powerful at the microphone capsule than the actual talker's voice.

Ceiling microphones require relatively high input gain, as they must pick up the talker's voice at a greater distance than other microphones. In most local reinforcement applications, the reinforced audio from the loudspeaker may be equal to -- or even louder than -- the actual talker's voice at the ceiling microphone capsule. This will result in feedback if the ceiling microphone is routed to the speaker. Lowering the reinforcement level for the talker's voice to achieve acoustic stability typically results in the reinforced level being too quiet to be considered meaningful for reinforcement. 

Please see our article on calculating PAG and NAG for more information on reinforcement. Each Parlé microphone array can create 3 or 4 active lobes (depending on the microphone array model) at a time, but maintains NOM internally via gain sharing, so a NOM value of 1 per pendant should be used in calculations. 

The Parlé microphone array is an active beam tracking microphone, capable of tracking multiple talkers (or vocal sources) simultaneously in a 360-degree torus of coverage (more details on this can be found here). The lobes are constantly being repositioned for best coverage based on the talker's estimated position. There is no method for manually locking the lobe's coverage pattern.

In a mix-minus application, the dynamically adjusting azimuth and elevation angles of the beam tracking lobes may result in unpredictable gain before feedback behavior. Multiple arrays in a single space will further increase the complexity of calculating PAG-NAG and feedback stability, as coverage lobe patterns may intersect and overlap.

Parlé microphones are not able to distinguish between a voice emanating from a loudspeaker rather than a local talker. To prevent lobes tracking to loudspeakers in normal conferencing applications, the lobes are temporarily "frozen" when the far end speaks and the microphone channel's AEC reference receives input (more details on this can be found here). In a mix-minus application, one lobe may track to the talker and other lobes may track to the reinforcement loudspeakers, further complicating the gain-before-feedback behavior.

If mix-minus sources are also sent to microphone AEC references, the microphone's beamtracking will be inadvertently "frozen" during local speech and beamtracking will not function as expected. There is no method for pre-defining where the lobe be aimed when it freezes - it simply locks at the last active talker position. Tracking resumes ("unfreezes") when the signal to the AEC reference is no longer present.