Owen T. Heisler

Last updated 2019-10-08

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Introduction

This design has two goals which are often difficult to accomplish in combination: portability and flexibility. The system is designed to be portable while also being useful in a broad variety of scenarios, particularly regarding outputs. For example, the system has already been successfully used in the following ways:

The above scenarios do not require any additional equipment or accessories beyond what is pictured below and listed in the Building Guide. No system knowledge is necessary other than the willingness to carefully follow the instructions in the User Guide (though connecting to a separate system may require additional knowledge).

This design could also be used for permanent installation at a location. However, some steps and accessories could be skipped while building the system and during use, because no portability is required.

Features

This design provides the following features:

Portable
The main system is in a 6U rack case (about 22×22×14 inches) and weighs about 80 pounds. The case has a handle on each side and can be carried fairly easily by two people. The case can be fully enclosed, for transport and storage, with front and rear doors. Required accessories, such as cables and microphones, fit in a small rolling suitcase.
Two versatile room output channels
Each room output can be 70V, 8-ohm, line level, or microphone level; connectors can be speakON, 1/4 inch, XLR, or bare wire. This allows the system to be connected to and used with most pre-existing setups. A permanently installed in-house system only needs to have a microphone input, for example, and this system provides the accessories and instructions to correctly accommodate the signal levels. All necessary cables and adapters are included.
Supports up to 6 wireless inputs
Inputs are provided by a Revolabs wireless microphone system. Most standard dynamic microphones will work with the Revolabs wireless XLR adapter.
Automatic digital room correction
The mixer features TOA’s Acoustic Resonance Control (ARC), which will automatically measure the room response and generate a room correction curve. This can be used for up to two speaker zones.
Automatic feedback suppression
The TOA mixer provides automatic feedback suppression on each input.
Integration with conference calling
A XLR to TRRS cell phone interface allows any cell phone (with compatible audio input) to be used to share audio on a conference call.
Emergency signal path
A fully isolated emergency signal path uses a separate microphone-level input, a separate amplifier channel, and separate line level and 70V outputs. (The TOA DA-250FH has power-isolated amplifiers. If the UPS fails, the amplifier can be powered directly.)
Uninterruptible (battery backup) power supply
The UPS will provide power to the system in case of a power outage. The on-battery alarm (beeper) can be silenced (though the low-battery alarm cannot be silenced). The UPS will charge even when the system is powered off. Note that the UPS is not intended to power an in-room installed system that is being used via a line or microphone level link—in that case, it might be necessary to switch to a backup speaker.
Assistive listening output
An output, a transmitter, receivers, and headphones are provided for people with difficulty hearing.

Current status

Major components

Pictures

Packed
Packed
View from front, with no connections
View from front, with no connections
View from rear, with no connections
View from rear, with no connections
View from front, with microphone base connected
View from front, with microphone base connected
Microphones in charger base
Microphones in charger base
Front view of rack
Front view of rack
Labels on front
Labels on front
Rear view of rack
Rear view of rack
Labels on rear panel
Labels on rear panel
70V transformer/splitter box
70V transformer/splitter box
Output to two 8-ohm speakers on one channel, daisy-chained, with speakON, TS, or bare wire connections
Output to two 8-ohm speakers on one channel, daisy-chained, with speakON, TS, or bare wire connections
Output to secondary system, with microphone/XLR connection (omit attenuator for line level)
Output to secondary system, with microphone/XLR connection (omit attenuator for line level)
Output to two powered speakers on one channel, daisy-chained, with microphone/XLR connections (omit attenuator for line level)
Output to two powered speakers on one channel, daisy-chained, with microphone/XLR connections (omit attenuator for line level)
Output to secondary system, with microphone/TRS connection (omit attenuator for line level)
Output to secondary system, with microphone/TRS connection (omit attenuator for line level)
Output to assistive listening (headphones) transmitter
Output to assistive listening (headphones) transmitter
Output to cell phone for conference calling
Output to cell phone for conference calling
System with multiple connections: microphone/XLR output for room zone 1, one 8-ohm speaker for room zone 2, cell phone for conference call, assistive listening transmitter, and 70V for audio outside of the room
System with multiple connections: microphone/XLR output for room zone 1, one 8-ohm speaker for room zone 2, cell phone for conference call, assistive listening transmitter, and 70V for audio outside of the room
System with all its parts
System with all its parts
Emergency amplifier
Emergency amplifier
Emergency connections on rear panel
Emergency connections on rear panel
Extra power connections for transmitter and other accessories
Extra power connections for transmitter and other accessories
Inside the 70V transformer/splitter box
Inside the 70V transformer/splitter box