Audio Precision APx1701
Transducer Test Interface

APx1701 Transducer Test Interface

Low Noise, Low Distortion and Flat Response for Loudspeaker, Headphone and Microphone Measurement

SKU: 1664 Categories: , ,

The APx1701 Transducer Test Interface is an APx accessory device that integrates instrument-grade amplifiers and microphone power supplies for designers and production test engineers seeking clear insight into the behavior of their electro-acoustic devices.

Primarily designed for electro-acoustic testing, the system drives loudspeakers and headphones with dedicated power amplifiers, enables impedance measurements, and provides power to measurement microphones and microphones under test. Its functions are integrated with the APx500 audio measurement software and a connected APx analyzer.

It requires an APx500 Series analyzer and is supported by APx500 audio measurement software version 4.3 or later.

Audio Precision APx1701 Transducer Test Interface

Audio Precision APx1701<br>Transducer Test Interface datasheet


APx1701 accessory cable kit (CAB-1701)
This kit provides additional cables to support additional test scenarios. Includes:

  • 2 BNC-BNC cables (14 in; 36 cm)
  • 1 XLRF to XLRM cable – blue (2 ft; 61 cm)
  • 1 XLRF to XLRM cable – red (2 ft; 61 cm)
  • 1 SpeakON to BNC loopback cable with 100 Ohm to ground (2 ft; 61 cm)

APx1701 self-test fixture kit (SLFT-KIT-1701)
Provides load box and cabling to support performance self-testing of APx1701. Includes:

  • Load box with 2 x 5 W, 8 ohm loads
  • 1 SpeakON-SpeakON cable (3 ft; 91 cm)
  • 2 BNC-BNC cables (3 ft; 91 cm)
  • 2 BNC-BNC cables (14 in; 36 cm)
  • 2 XLRF to XLRM cables – blue (2 ft; 61 cm), 2 XLRF to XLRM cables – red (2 ft; 61 cm)
  • Instructions


Listed below are APx500 software options related to electroacoustic and perceptual audio testing. These are options intended for B Series, or Legacy, APx analyzers (not the APx1701).

For B Series APx analyzers, and Legacy APx analyzers running version 5.0 software, software option licenses are electronically activated and are tied to a specific analyzer via serial number. For Legacy APx analyzers running APx software version 4.6 or earlier, software option licenses are enabled by one “iButtons” that mount on the rear of the instrument.

Electro-Acoustic Production Test (SW-SPK-PT)
The SW-SPK-PT option enables high-speed production test of electro-acoustic devices, providing key loudspeaker measurements in a single one-second sweep. Results include Rub & Buzz detection, essential Thiele-Small parameters, and impedance magnitude and phase. A proprietary modulated noise measurement is also provided to aid in detecting enclosure air leaks.

Electro-Acoustic R&D (SW-SPK-RD)
The SW-SPK-RD option delivers a complete suite of measurements and results tailored to the needs of designers and engineers developing electro-acoustic audio products. It includes key measurements and results such as complete Thiele-Small characterization; time-gated, quasi-anechoic Acoustic Response; Impedance analysis; plus the Loudspeaker Production Test measurements.

Perceptual Audio Test: POLQA (SW-POLQA-2)
Perceptual audio measurement returns a subjective assessment of speech quality using the next-generation POLQA algorithm for wide-band speech devices or devices with acoustic coupling. (Successor to PESQ with support for HD Voice, 3G, 4G/LTE and VoIP technologies)

Perceptual Audio Test: PESQ (SW-PESQ)
Widely-used, enhanced perceptual measurement for subjective assessment of speech quality on low-bandwidth devices. (PESQ algorithm)

Speech Intelligibility: ABC-MRT Measurement (SW-ABC-MRT)
The APx ABC-MRT plugin is a software option for APx500 audio measurement software that provides speech intelligibility measurement based upon the ABC-MRT speech processing algorithm developed by the Institute for Telecommunication Sciences (ITS) of the United States National Telecommunications and Information Administration (NTIA).

Speech Intelligibility: Speech Transmission Index (SW-STI)
SW-STI is a plug-in for conducting Speech Transmission Index (STI) measurements using the STIPA method.

Power Ratings
100 W (1 channel into 8 Ω)
60 W (1 channel into 4 Ω)
30 Vrms (2 channels into ≥15 Ω)

Frequency Range
DC to 100 kHz

Frequency Response
±0.08 dB (10 Hz to 20 kHz, DC-coupled)
±0.30 dB (20 kHz to 50 kHz)
±0.80 dB (50 kHz to 100 kHz)

Voltage Gain
20.0 dB [x10]

Residual Noise
≤7.5 µVrms (22 kHz BW)
≤13 µVrms (80 kHz BW)

Signal-to-Noise Ratio
≈134 dB (ref 30 Vrms output)

Output Impedance
≈0.13 Ω (0.1 Ω current sense resistor in series with the – output terminal)

Residual THD+N
≤ –100 dB, 10 Hz to 20 kHz (80 kHz BW)


Balanced and Unbalanced (2 each)

Balanced Mic Inputs
2 female XLR
Switchable +48 V phantom power

Unbalanced Mic Inputs
Switchable CCP (4 mA, +24 V)

Maximum Input
10 Vpk Balanced
5 Vpk Unbalanced

Residual Noise
Determined by analyzer; inputs passively switched

Input Crosstalk
≤ –80 dB + 1 µV to 20 kHz