The MR-PRO is a powerful, hand-held instrument, aimed at professional applications. Based on the Minirator MR2, it offers, in addition, cable testing, phantom power, balance, impedance and phase measurements and apparent power and phase tests for 70V/100V distributed loudspeaker systems. The output circuitry is balanced, with a lower source impedance and higher maximum level. User waveforms may be loaded via USB into the internal flash memory.
Functions
- It generates pure sinusoidal waveforms with freely-selectable frequencies from 10Hz to 20kHz in 1 digit steps, accuracy 0.01% and a level range from -80 to +18dBu, +/- 0.2 dB. In sweep mode, the start frequency, stop frequency and a step resolution as fine as 1/12th of an octave can be adjusted. Analyzers like the NTI Audio Minilyzer automatically trigger to this signal and record the frequency response of a device under test. Sweep speed: 0.5 to 5 seconds.
- The chirp signal is a sine-wave with defined start and stop frequency and continuous frequency increase over time. It may be used in the recording of frequency responses, the measurement of impulse responses and the acoustic assessment of rooms. The frequency range may be selected freely, incrementing linearly or logarithmically. Cycle: 1-99 seconds.
- The delay test signal is the designated reference signal to measure the acoustics propagation delay time from speaker to speaker in areas such as churches or auditoriums. Testing is carried out in combination with an NTI Audio AL1 Acoustilyzer. Output level: -80 to +16dBu.
- Pink or white noise is synthesised with high spectral density, normal amplitude distribution and with infinite cycle duration. An automated on-off cycle mode for RT60 measurements with the AL1 Acoustilyzer is included. Output level: -80dBu to +8/+10dBu, pink/white.
- The saw-tooth waveform of the polarity test signal is a stimulus with only moderate stress to speakers. The NTI Audio ML1 Minilyzer and AL1 Acoustilyzer take advantage of this and analyze correctly the polarity of the incoming signal. Output level: -80 to +16dBu.
- A number of user test signals may be stored as uncompressed WAV-files in memory. The selected file is looped seamlessly. Data exchange is via the USB port. Format: 48kHz, 16-bit, (mono or stereo files, replayed in mono), 0dBFS=18dBu. Flash memory: 512MB for wave files and configurations.
- While in generator mode, balance, load impedance and phantom power voltage measurements provide a detailed view of the connected load, for rapid fault finding. Impedance measurement: 4ohms - 50kohms balanced, 2ohms-25kohms unbalanced. Phantom power measurement: 0-54V, +/- 3% or 0.5V.
- The built-in cable tester measures any cable connected between the XLR output and the built-in XLR input. It detects all common XLR wiring faults with a precise description to the user, such as '2-3 Crossed' or 'Pin 2 open'. In addition, an optional Cable Test Plug may be used for single ended testing.
- The impedance test supports the checking of 70/100V line loudspeaker installations and shows detailed information of the impedance and phase, or apparent power and phase of the connected load. This test requires the use of the optional protective adapter, see below.
- Up to ten complete instrument configurations can be stored in the internal flash memory and reloaded for repetitive tasks. The saved settings may also be transferred to other MR-PRO instruments.
The upper face has an LCD display and the controls. A rotary wheel with a central enter button is used to set the value of a setting. Four surrounding push buttons offer escape, wave mode, frequency of the output and level in dBu, dBV, volts, dBFS, %. Three further buttons are used for power on/off, mute and sensitivity steps for the frequency and level settings.
The ends have unbalanced RCA (phono) and balanced XLR output connectors and an XLR input for the cable test mode. A coaxial inlet for DC power and a mini-B, 5-pin USB connector are mounted on the two sides. A battery cover on the base may be removed to fit the three AA batteries.
Technical Specification
| Output: |
12.5 ohms, balanced, 10mA maximum. |
| Response: |
+/-0.2dB, 600 ohms load. |
| Distortion and noise: |
-96dB, 1kHz, +18dBu, 22Hz -22kHz, average. |
| Noise floor: |
15uV typical. |
| Power source: |
Either optional AC adapter or 3 x AA Alkaline dry cells or rechargeable equivalents. |
| Battery life: |
8 hours typical, 0dBu, no load. |
| Dimensions: |
152 x 81 x 43(l x w x h)mm, including protective shock jacket. |
| Weight: |
310g. |
Included accessories: Protective shock jacket, operating manual, USB cable, hand strap.
Optional accessories: Where both ends of a cable can not be brought to the MR-PRO, a 25-603 cable test plug may be connected at the far end so that the cable can be tested. The 25-604 -40dB adapter can be used to produce a better quality microphone signal, by operating the generator at a higher level. The 25-605 protective adapter has two test leads with probes and clips, and protects the instrument against excessive voltages when measuring 70/100V line systems. A soft pouch with belt clip and a moulded system case are offered to protect the MR-PRO; the latter will accept two NTI Audio Mininstruments and has room for adapters and test leads. AC plug top adapters may be used for extended testing.
Ordering Note
Unless otherwise stated, all products are exclusive of calibration certificate(s). NTi MR-PRO calibration certificates can be purchased optionally along with the product. Please ensure you add multiple calibration certificates if the system you are purchasing includes multiple products.