The Audio Precision APx525 is a high-performance, two-channel audio analyzer designed for R&D, design validation, and production testing. It features versatile analog and standard digital I/O, combining extreme accuracy with the powerful APx500 measurement software.

Specifications

General

ParameterValue
InterfacesUSB 2.0 (PC connection), AUX Control, Trigger I/O, Reference Clock I/O
DisplayNone (PC software controlled)
Warm-up Time20 minutes

Physical

ParameterValue
Power Supply100 - 240 V AC, 50/60 Hz, 120 VA maximum
Operating Temperature5 to 45
Dimensions (W×H×D)432 x 146 x 451
Weight9.3

System Performance & Metrology

ParameterValue
System Bandwidth10 Hz to 90 kHz
Frequency Accuracy±3 ppm
System Residual THD+N≤ -105 dB + 1.4 µV (typically < -110 dB at 1 kHz, 2.5 V)
System Amplitude Flatness±0.008 dB (20 Hz to 20 kHz)
Input-to-Output Crosstalk≤ -120 dB (10 Hz to 20 kHz)
Sampling Rate Range (A/D & D/A)Up to 192 kHz

Analog Generator (Source) Specifications

ParameterValue
Generator Channels2
Output ConfigurationsBalanced (XLR), Unbalanced (BNC)
Output Impedance (Balanced)100 ̧, 150 ̧, or 600 ̧
Output Impedance (Unbalanced)50 ̧, 100 ̧, or 600 ̧
Maximum Output Amplitude (Balanced)21.21 Vrms (28.75 dBu)
Maximum Output Amplitude (Unbalanced)10.61 Vrms (22.73 dBu)
Amplitude Accuracy (Generator)±0.03 dB at 1 kHz
Amplitude Flatness (Generator)±0.008 dB (20 Hz to 20 kHz)
Frequency Range (Generator)0.1 Hz to 80.1 kHz
Frequency Resolution0.001 Hz
WaveformsSine, Sine+DC, Split Sine, Var Phase Sine, Dual Sine, Square, Noise, IMD
Residual THD+N (Generator)≤ -105 dB + 1.4 µV (at 1 kHz)
Inter-channel Crosstalk (Generator)≤ -120 dB (10 Hz to 20 kHz)
Output CouplingAC or DC

Analog Analyzer (Receiver) Specifications

ParameterValue
Analyzer Channels2
Input ConfigurationsBalanced (XLR), Unbalanced (BNC)
Input Impedance (Balanced)200 kΩ
Input Impedance (Unbalanced)100 kΩ
Maximum Rated Input Voltage160 Vrms (230 Vpk)
Frequency Range (Analyzer)10 Hz to 90 kHz
Amplitude Measurement Accuracy±0.03 dB at 1 kHz
Amplitude Flatness (Analyzer)±0.008 dB (20 Hz to 20 kHz)
Residual THD+N (Analyzer)≤ -105 dB + 1.4 µV
Residual Noise (Analyzer)≤ 1.4 µVrms (20 kHz BW)
Common Mode Rejection Ratio (CMRR)≥ 80 dB (10 Hz to 5 kHz)
Crosstalk (Inter-channel Analyzer)≤ -120 dB (10 Hz to 20 kHz)
Input CouplingAC or DC

Filters & Signal Conditioning

ParameterValue
Weighting FiltersA-weighting, C-weighting, CCIR, CCITT, ITU-R 468
User-defined FiltersSupported via custom coefficient upload

Digital Audio I/O Specifications

ParameterValue
Digital Interface FormatsAES3 (AES/EBU), S/PDIF (coaxial), TOSLINK (optical)
Digital Output Impedance (AES3)110 Ω
Digital Output Impedance (S/PDIF)75 Ω

Measurement Modes & Capabilities

ParameterValue
Measurement FunctionsTHD+N, THD, IMD, Frequency Response, Phase, Group Delay, FFT Spectrum
IMD StandardsSMPTE, MOD, DFD
FFT SizeUp to 1.2M points
FFT Windowing TypesHann, Blackman-Harris, Flat Top, Rife-Vincent, Hamming

Connectivity & Interfaces

ParameterValue
Analog Inputs2 x XLR Female
Analog Outputs2 x XLR Male
Digital Inputs1 x XLR (AES3), 1 x BNC (S/PDIF), 1 x TOSLINK
Digital Outputs1 x XLR (AES3), 1 x BNC (S/PDIF), 1 x TOSLINK
Reference I/OBNC (Ref In, Ref Out)
Trigger I/OBNC (Trigger In, Trigger Out)
Monitor Output1/4" (6.35 mm) headphone jack (front panel)

Software & Automation

ParameterValue
Control Software SuiteAPx500 Control Software
Automation APIsPython, LabVIEW, MATLAB, .NET

Physical, Power & Environmental

ParameterValue
CoolingForced air (internal fans)
Recommended Calibration Cycle1 Year

Hardware Options & Expansion

ParameterValue
Expansion Slots1 slot for optional hardware I/O modules
Supported I/O ModulesHDMI+ARC, Bluetooth, PDM, Digital Serial (I2S/TDM), Advanced Master Clock (AMC)

A/D & D/A Conversion

ParameterValue
A/D Converter Resolution24-bit
D/A Converter Resolution24-bit

Phase Measurement

ParameterValue
Phase Measurement Range±180°

Technology

Audio Test and Measurement

Applications

Audio R&D, Production Line Testing, Design Verification

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