NTI TalkBox

Description

NTI TalkBox greatly simplifies the acoustical feed of the STI-PA intelligibility test source signal into closed sound reinforcement systems. It presents the standardized voice-like acoustical signal emission simulating a human talker according to IEC 60268-16, combined with a TNO certified speech intelligibility signal at standardized levels.

NTI TalkBox features human head-like dimensions and is based on a Solid-State-Generator with CF-Card. It perfectly equalizes the STI-PA test signal and replays it at the precisely correct playback sampling rate, also minimizing systematic errors through the internal amplifier and internal precision loudspeaker. Due to the required overall accuracy of ±1 dB over the relevant frequency range, each TalkBox is individually equalized and calibrated for precision output. The radiation characteristic complies with the ITU-T P.51 in wide ranges. The built-in combination of solid state generator and DSP ensures highest playback accuracy and lowest sample frequency deviations with minimized jitter effects.

TalkBox Rear Panel View

Talkbox Electronics

NTI TalkBox Features

Individually Equalized
NTI TalkBox is equipped with a precision broadband loudspeaker. To guarantee perfect flatness and highest quality requirements, every TalkBox is individually equalized using advanced FIR filtering and DSP technology.

Adjusted output level
The IEC60268-16 standard specifies a sound pressure level for a speaker simulator of 60 dBA in 1 meter distance. TalkBox levels are calibrated to comply with this standard. To avoid operating failures the TalkBox has no volume control.

Lombard Effect
Human voice tends to be raised in emergency situations. In order to cope with this so called Lombard effect, all STI-PA related signals are alternatively offered with 10 dB increased level (70 dBA @ 1m).

Balanced Line Out
Using the balanced line out, the TalkBox operates as a signal generator. Sampling frequency deviations - dangerous trap when using portable CD players for STI-PA measurements - are completely eliminated.

Balanced Line In
Any external signal can be connected to the system using the balanced line input. The applied signal is transparently looped to the line output and processed in the internal DSP in real-time to appear equalized at the speaker.

Different Test Signals
Beside the STI-PA test signal the TalkBox is able to generate additional wave forms: White- and Pink-Noise, Sine wave and the Delay Time Measurement Chirp. Custom designed signals may be loaded onto the CF-Card externally and are seamlessly looped.

Mic Stand Mount
The exact positioning of the NTI TalkBox in front of a microphone (at the place where a real human speaker would be) is easy using a conventional mic stand. A universal mic stand mount is available at the bottom of the box.

Remote Mute
For measuring STI-PA in large buildings the remote mute functionality of the TalkBox may be of great help. Any external switching device may be connected to the mute input, allowing to build e.g. a cell phone controlled ON/OFF functionality.

Universal Power Supply
The TalkBox handles a wide DC power supply input voltage range. This allows its operation even from a battery pack (available as optional accessory). An external power supply for worldwide operation is supplied as standard.

Schematics

Talkbox Schematics