Large UC conference room, two Parlé tabletop mics, four speakers, Bluetooth/USB
This system design template shows a Tesira solution in a typical large UC conference room installation. Traditionally, this approximately 4.5 meter x 8.5 meter (15' x 28') room includes a conference table of about 5' x 15' to support around 11-18 people. Local meetings can be hosted using in-room presentation capabilities, and a dedicated UC room solution (or sometimes a PC-based soft codec or a BYOD option like a phone or a tablet) is used to bring in participants from remote locations.
In this example, two Parlé TTM Tabletop beamtracking microphones are used, automatically tracking the speech of the participants around the table. Parlé TTM microphones have a capacitive touch button feature (w/red and green LED indicators) allowing the user to mute & unmute at the microphone if they wish. A Tesira EX-UBT, offers USB audio extension over Ethernet (100 meters) and allows bidirectional mute sync between the TTM's LEDs and the actual muting of the transmit audio in both Microsoft Teams Room & Google Hangouts Meet systems. Additionally, these UC solutions will offload Acoustic Echo Cancellation duties, allowing Tesira's AEC to take over. Desono C-IC6 ceiling speakers are located at suitable positions to evenly cover the room. Amplification for the speakers is achieved with the PoE+ AMP-450BP amp. All wiring between Biamp device is CAT 5e or greater (even the speaker cable), streamlining installation.
Room design
Room Functionality Scope:
- 2 table microphones with beamtracking technology
- 1 USB connection to the Microsoft Teams Room (or other UC or BYOD system)
- 1 Bluetooth connection point for mobiles, tablets or PCs
- 4 low impedance ceiling speakers for distribution of voice signals (soft codec, USB)
Equipment list
Below is the list of Biamp equipment used in this project:
- 1 - TesiraFORTÉ AVB VT4 4 mic/line level inputs with AEC; 4 mic/line level outputs with integrated VoIP, POTS, and USB audio
- 1 - Tesira TTM-X AVB beamtracking table microphone
- 1 - Tesira TTM-XEX AVB beamtracking table microphone extension
- 1 - EX-UBT Up to 8 channels of configurable USB audio in both directions, with support for Bluetooth wireless technology, mute sync and AEC offloading w/MS Teams Rooms & Google Hangouts Meet systems
- 1 - TesiraCONNECT Up to 5 Tesira devices connected, no configuration required, 4 PoE+ ports
- 1 - Tesira AMP-450BP 4-CH PoE+ backpack amplifier providing 4x 50 Watts burst power with RJ45 speaker outputs designed for use with Desono C-IC6 speakers
- 4 - Desono C-IC6 Wide coverage ceiling speakers (dispersion angle of 130°) optimized for voice reproduction
System configuration
The example file for this system design template is set up with all the 
audio I/O, processing, and control points commonly required, and is ready to load to the hardware and begin setting up the room gain structure and EQing. In the file, the matrix routing is already in place to support the room design requirements. Two AEC processing channels on the TesiraFORTÉ AVB VT4 will be occupied by the TTM-X microphone and the TTM-XEX extension microphone. No analog outputs will be required in this setup, as the speakers are being connected to the PoE+ AMP-450BP amplifier, represented by the 4-channel Parlé Amp output block.
To support the conferencing needs of the space, the microphone signal is routed to the USB and Bluetooth outputs. USB initialization in the file has been setup to support a 1x1 audio configuration with computer AEC disabled for the connection to the MTR (or other AEC offload compliant UC) system. All AEC references have been made in the matrix mixer for proper echo cancelation of conferencing sources. The file's Equipment Table is populated with proper hardware to match the layout, but will need to have serial numbers and proxy host assignments added before being sent to actual hardware.
Note that you can customize the Bluetooth SSID. Moreover the amplifier block has been configured to 8 ohm impedance. If you want to connect two 8-ohm Desono I-CI6 ceiling speakers in parallel to each output channel of the amplifier then set it to 4 ohms.
The .zip file below contains the example Tesira configuration files for this conference room application.
System Design Template - Medium Conference Room with 2 TCM-X Mics & Bluetooth.zip
Networking details
This conference room application will make use of TesiraCONNECT to interface the TesiraFORTÉ DSP, TTM-X base unit, AMP-450BP, and EX-UBT. A Cat5e (or better) peer-to-peer connection between the devices will carry audio, control, and power altogether. TesiraCONNECT provides PoE+. Regarding cable types and lengths, the common rules of Ethernet apply. As per factory default settings, the devices will look out for a DHCP server on the network or, in its absence, will self-assign a Zeroconf address (169.254.xxx.xxx). A static IP address may be assigned if desired, but the only Tesira devices that make use of IP address in this system are the VT4 DSP and TesiraCONNECT. When assigning static addresses, make sure to change the remote devices first and then your PC afterward. For a more detailed guide on how to implement in a larger range of network applications, it would be helpful to reference our Tesira Network Infrastructure article.
Setup Requirements:
- Connect the TesiraFORTÉ to the first port of the TesiraCONNECT, the TTM-X, the AMP-450BP and EX-UBT to any of the 4 PoE+ ports.
- Use a standard network cable (Cat.5 or higher) to connect the TTM-XEX unit to the TTM-X base unit.
- Do not exceed 33ft or 10m on this link
- This is a proprietary digital audio link, not compatible with Ethernet
- Make sure you've set the desired Bluetooth SSID in the EX-UBT block.
- Note that the TTM-X, AMP-450BP and EX-UBT use Layer 2 AVB for audio and control data, IP address setup is not required.
After these control and AVB network setup steps are complete, you will now be ready to send your compiled system configuration to the hardware.
Microphone and speaker placement
The room
Arguably the single most important element in a conference system is the room itself. A noisy and reverberant room will generally sound awful for conferencing. A properly designed room with controlled reverberation and low noise floor will generally sound good for conferencing.
The importance of creating a controlled acoustic environment cannot be overstated. It is important to make the room as quiet as possible (lower noise floor) and minimize reverberance (shorter RT60) in preparation for installing the conferencing system. When properly applied, soundproofing and acoustic treatments will yield dramatic improvements in performance for most rooms.
Microphone placement
Even though the TTM-X beamtracking microphone uses state of the art technology to track a
person's voice, while reducing unwanted background noise, the laws of physics cannot be ignored when deciding on the right placement of a microphone. A good signal-to-noise ratio is key in every part of the audio signal chain and for a typical microphone pickup scenario, this translates to avoiding large distances between the mic and the talker. The Parlé table microphone calculator will help to find the right mic distribution for the expected coverage area. Here are a few more tips to an ideal microphone placement:
- Place the mic in front of the talker.Keep the distance to the talker as short as possible.
- Keep the distance to the ceiling speakers as far as possible.
- Place the mic in front of the talker.
Speaker placement
Placing speakers in a room can be as equally critical as finding the right spot for a microphone. An ideal positioning of multiple ceiling speakers will achieve an even SPL coverage and a good speech intelligibility across the entire room. The Biamp Ceiling Loudspeaker Calculator tool is designed to help with this. Additionally, in order to get a better sense on how much SPL the speaker of choice is able to produce, our Amplifier Power Calculator will provide some answers. Finally, you may wish to utilize a speaker simulation software to predict the expected in-room STI values.
In this example, the speakers are not being used for voice-lift or similar live speech reinforcement, hence gain before feedback doesn't have to be considered. Still, avoiding short distances between the speakers (far-end audio) and the microphone will help to improve the AEC performance.
Audio setup
- Follow Gain Structure best practices to set input and output levels of microphones and sources. Input and output gain levels have been left at default settings for integration flexibility of the file. Input and Output metering has been added to assist with setting gain structure within the file. Additional meters can be added to the file as required to allow for additional detail at points along the signal path.
- Connect USB to the UC room system.
- Connect a mobile device using Bluetooth if required.
- Reference AEC best practices documentation and begin to do some test calls with the system. ERL values between 0dB and +15dB are optimal.
- Level and mute controls have been added to the file pre and post matrix mixer. These are added for flexibility to meet the design criteria and tastes of the client or integrator. These level controls have been left with their default maximum and minimum values in place, but can be adjusted to fit the needs of the space.
- Uber Filters have been added to all signal paths to allow for any additional equalization as needed to sources. It is recommended to use the advanced filters section of the AEC channel processing block for any high pass filtering needed on conference table microphone inputs. Additional filtering or dynamics blocks may be added or changed as needed to achieve the desired results in the file.
- Changes to matrix mixer can be made as needed to allow for appropriate sources to feed the speakers to fit the design application.
Control integration
The example Tesira configuration file for this application has been set up to allow third-party control systems to easily control the Tesira system. There are control points for Bluetooth, Level, Mute, and Mic Logic already in place to allow for you to use as it as-is, or add to as needed to suit the needs of the client. Control points within the file have been noted with an additional text box showing their default instance ID tag. These tags can be changed as needed to suit the programmer workflow or standardization.