ARTA 80
Technical Notes
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ABACUS ELECTRICS

ARTA 80 Audio Analyser - Specification

   
The ABACUS ELECTRICS ARTA 80 one-third-octave analyser is a compact, battery portable, precision instrument which displays the real-time intensity and spectral distribution of sounds. Accessories
Microphone
Pink Noise Generator
Reverberation Timer
 
Frequency Range
Audio band, 20Hz to 22kHz.
 

Frequency Resolution

The audio spectrum is divided into thirty one-third-octave bands, centered on ISO frequencies:-
25Hz, 31.5Hz, 40Hz, 50Hz, 63Hz, 80Hz, 100Hz, 125Hz, 160Hz, 200Hz, 250Hz, 315Hz, 400Hz, 500Hz, 630Hz, 800Hz, 1kHz, 1.25kHz, 1.6kHz, 2kHz, 2.5kHz, 3.15kHz, 4kHz, 5kHz, 6.3kHz, 8kHz, 10kHz, 12.5kHz, 16kHz, 20kHz.
 
Microphone Input
A sensitivity of 50dB to 120dB SPL for 0dB reading is provided in eight switched ranges. A calibrate control trims the microphone sensitivity for precise SPL readings.
Input is balanced, with 1 kohms input impedance and 12 volt phantom power on a Switchcraft TY3F connector.
 
Line Inputs
Two inputs, Left and Right.
A sensitivity of -60dB to +10dB for 0dB reading is provided in eight switched ranges.
Inputs are balanced, with 10 kohms input impedance, on a single Switchcraft TY5F connector.
The Left and Right signals may also be displayed in Sum or Difference form.
 
Noise Output
Noise is pink over the audio bandwidth.
Output level is adjustable between -10dBu and 0dBu.
Output is unbalanced, with 22 ohms output impedance, on Switchcraft TB3M connector.
 
Display
Ultra-bright LEDs are used for a clear display over a wide viewing angle.
Thirty columns, one for each frequency band, show the signal level at that frequency.
An additional column shows the wide-band level.
The display range is switchable; either 24dB with 2dB or 12dB with 1dB resolution.
The dynamics are switchable; either slow for noise or fast for program analysis.
The wide-band level detector may be "C" weighted if the microphone input is selected.
 
SPL Meter
The analyser may be set to numerically display "C" weighted Sound Pressure Level (SPL), auto-ranging between 50dBC and 129dBC SPL.
 
dBu Meter
The wide-band Left or Right line input signal level may be numerically displayed in dBu (0.775V reference), auto-ranging between -60dBu and +19dBu.
 
Spectral Memories
Thirty non-volatile memories permit the saving spectral data.
Any one memory may be viewed simultaneously with the "live" display for comparison.
A memory may be continuously up-dated with the peak level.
Memory 30 may be pre-set with the ISO2969 cinema equalisation house curve.
The contents of up to four memories may be automatically averaged, the result being placed in a fifth memory. The average frequency response of a number of positions in an auditorium may be found, simulating the operation of a microphone multiplexer.
Spectral data is saved, printed and down-loaded at finer resolution (0.125dB) than can be viewed on the analyser display.
 
Noise Criteria
To quantitatively measure background noise the ARTA 80 may display standard Noise Criteria (NC) curves for comparison with the measured acoustic background noise.
The curves from NC-15 to NC-65 are incorporated into the analyser.
If the acoustic noise is saved to memory and subsequently printed the NC curve will also be printed.
 
Dolby Cat 566 Function
The Dolby Cat 566 slit illumination test film simplifies the adjustment of film projector optics.
Six frequencies at the same level are recorded over the sound-track area.
The ARTA 80 can be set to display just the six frequencies used on the film.
 
Printer Port
The Centronics parallel printer port facilitates printing saved spectrum plots on a  LaserJet/Deskjet or Epson dot-matrix printer.
Beneath the graph additional information is printed:- memory number, ARTA 80 serial number, 0dB reference level, wide-band level, and a "user-name" if it was specified at the time of purchase.
Female 25 way "D" connector.
 
Serial Port
The RS232 serial port allows remote control of the ARTA 80 and transfer of memory data to and from personal computers.
Data format is eight data bits, one stop bit, and no parity, either 300 Baud or 1200 baud.
Male 25 way "D" connector.
 
Windows 95/98 Software
The A80W application supplied manages spectral library files and provides a simple but effective way of archiving and retrieving spectral data produced by the ARTA 80 audio analyser.
The program can directly control the ARTA 80 via a serial link and transfer spectral data in either direction.
Text comments may be entered, edited, printed and saved to disk with the spectral data.
Bitmap files may be generated and spectral data may be exported, via the clipboard, to other Windows applications.
 
Personalisation
If specified when purchased the ARTA 80 may be personalised. When switched on an optional personalised message scrolls across the screen. Typically this would be the name and address of the owner. This personalised sign-on message can not be removed by the user and so is a useful anti-theft feature.
A second, shorter message (user name) can also be incorporated to print out when spectral data is printed.
 
Power
Internal rechargeable battery; lamp indicates when battery needs charge.
Universal 120VAC/240VAC battery charger/power adapter type CH80.
 
Weight
1.5kg (3.5lb.)
 
Size
24 x 16 x 8 cms. (9.5 x 6.5 x 3 inches)
 

 

ARTA 80 Audio Analyser - Options/Accessories

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Instrumentation Microphone - M80C

The M80C is an instrumentation quality microphone designed for use with the ARTA 80 audio analyser. It utilises an electret capsule and each microphone is issued with its own frequency response plot.
The M80C will plug directly into the Switchcraft TY3F microphone input socket on the ARTA 80 allowing one handed "walk-about" operation of the analyser. Alternatively a microphone extension cable may be used to remote the microphone up to about forty metres (120 feet) from the analyser.
 
Powering
+12 volts phantom power, as provided by the ARTA 80 analyser.
 
Output Level
200 millivolts for 116dB SPL - (approx. 15 mV/Pa)
 
Impedance
300 ohms nominal source impedance; 900 ohm load expected.
 

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Battery Portable Pink Noise Generator - N80A

 
The N80A is a light-weight portable pink noise generator. Using a separate pink noise source permits "walk-about" operation of the ARTA 80 analyser.
 
Powering
A single alkaline PP3 type (9 volt) battery is used giving a typical battery life of over 50 hours.
 
Output Level
A variable control sets the output level up to a maximum of -6dB average.
Output on Switchcraft TB3M connector.
 
Impedance
22 ohms nominal source impedance; a 600 ohm load can be driven.
 
Weight
170 gms (6 ounces)
 
Size
12 x 7 x 3.5 cms (4.8 x 2.7 x 1.3 inches)
 

 

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 Reverberation Timer (RT60) Option - A80rv

The reverberation time of a room is an important and measurable parameter that affects the clarity of music and intelligibility of speech. The A80rv circuit board is an optional accessory that is factory-fitted inside the ARTA 80 analyser enabling the analyser to measure reverberation time.
 
Method
Gated band-limited (whole-octave) noise source; wide-band receive.
20dB decay measured, extrapolated for 60dB. Direct numeric read-out.
 
Range
200 milliseconds to 10 seconds
 
Resolution
10 milliseconds.
 
Frequencies
63Hz, 125Hz, 250Hz, 500Hz, 1kHz, 2kHz, 4kHz and 8kHz.

 
Contact Us
ABACUS ELECTRICS
10 Barley Mow Passage, Chiswick, London W4 4PH
Telephone: 020 8994 6477
Fax: 020 8994 1766