WinAudioMLS – PC Audio Analyzer for Lab, Service, Acoustics & Production
WinAudioMLS turns a Windows PC with a soundcard or measurement interface into a precise real-time signal and system analyzer. Because the DSP algorithms are completely independent of the sampling hardware, you can scale the exact same software from a quick repair bench check to room acoustics and 192 kHz / 24-bit distortion analysis.
When to choose WinAudioMLS – and when do you need Akulap or high-end analyzers like the APX555?
WinAudioMLS (The Universal Lab & Workshop Analyzer):
Ideal for electronics R&D, repair workshops, loudspeaker design, tape machine alignment (Wow & Flutter, RIAA), automated end-of-line quality tests (Pass/Fail), and university labs. You get direct access to oscilloscope, FFT windowing, 10-channel ASIO generators, vectorscope, and correlometer.
Akulap (For Commercial Room/Building Acoustics, STIPA & Psychoacoustics):
For commercial room and building acoustics test reports (ISO 3382, ISO 16283), speech intelligibility (STIPA per IEC 60268-16), psychoacoustics (Sone per DIN 45631/A1, tonality per DIN 45681), and low-frequency DIN 45680, please use our specialized Akulap platform. WinAudioMLS focuses on electrical system measurements, lab/QA testing, Wow & Flutter/RIAA, and non-commercial EDU packages.
Physical Limit of Soundcards for Ultra-Low Distortion (< -115 dB):
Modern 24-bit soundcards combined with our 64-bit FFT reach around -115 dB THD+N. If you need to measure ultra-linear amplifiers or DACs beyond ADC converter dynamics (down to -120 dB / 0.0001%), analog notch filters in front of the ADC are still required—or our reference lab with the Audio Precision APx555.
The 4 Base Editions: Light, PRO, PRO EX, and LAB
WinAudioMLS consists of two independent executables working together: the signal generator exciting the Device Under Test (DUT) and the analyzer. For single-channel tasks, PRO is sufficient; as soon as you measure phase responses, impedances, group delay, or transfer functions with live music, you need the dual-channel PRO EX or LAB.
light
1-channel FFT and MLS analyzer with fixed 44.1 kHz sample rate and max. 2048-point FFT size. Includes level calibration, sample rate pitch compensation, bar graph display, peak hold, and averaging.
Pro
1-channel analyzer up to 96 kHz sample rate and up to 1 million points FFT resolution. Adds THD+N measurement, frequency response compensation (reference curves), digital oscilloscope with trigger, and DC offset filter.
Pro EX
Full dual-channel FFT and MLS analyzer up to 96 kHz. Enables true 2-channel phase and time-delay measurement, harmonic tracking (THD with markers), intermodulation (IMD), impedance measurement, spectrogram, cross-correlation, and transfer function measurement using real music.
LAB
Our highest base edition up to 192 kHz sample rate. In addition to all PRO EX features, it includes distortion-immune Log-Sweep/Chirp correlation measurement (with selectable frequency limits and 3 dB/oct decay), Signal Generator PRO, and the USB hardware dongle for use across multiple PCs.
Technical Feature Matrix of the 4 Base Editions (per Manual Chap. 24)
| Measurement Feature / Parameter | Light (#1719) | PRO (#1720) | PRO EX (#1721) | LAB (#1722) |
|---|---|---|---|---|
| Max. Sample Rate (Base) | fixed 44.1 kHz | up to 96 kHz | up to 96 kHz | up to 192 kHz |
| Max. FFT Block Size | 2,048 points | up to 16M points | up to 16M points | up to 16M points |
| Measurement Channels (Base) | 1 channel | 1 channel | 2 channels (Dual) | 2 channels (Dual) |
| Level Calibration & Sample Rate Pitch | Yes | Yes | Yes | Yes |
| Frequency Response Compensation (Reference) | — | Yes | Yes | Yes |
| Total Harmonic Distortion + Noise (THD+N) | — | Yes | Yes | Yes |
| Selective Harmonic Tracking (THD + Markers) | — | — | Yes (k2..k20, even/odd) | Yes (k2..k20, even/odd) |
| Intermodulation Distortion (IMD Dual-Tone) | — | — | Yes | Yes |
| Impedance & Dual-Channel Time Delay | — | — | Yes (R-L / R÷L) | Yes (R-L / R÷L) |
| Transfer Function with Real Music Signal | — | — | Yes (Dual-Channel R/L) | Yes (Dual-Channel R/L) |
| Spectrogram & Cross-Correlation / Correlometer | — | — | Yes | Yes |
| MLS Correlation Measurement (Hadamard) | Yes | Yes | Yes | Yes |
| Log-Sweep / Chirp Correlation Measurement | — | — | — | Yes (Band-limitable) |
| Included Signal Generator & Copy Protection | Base / Host-ID (or Dongle) | Base / Host-ID (or Dongle) | Base / Host-ID (or Dongle) | PRO Generator + USB Dongle included |
FFT, MLS, Log-Chirp, or Stepped-Sine? Which Method for Which Measurement?
No single excitation method is ideal for every device under test. In our manual (Chap. 14.5, 17.1, and 26.8), we compared all four methods on real test objects (filters, CD players with clock offset, doors in noisy rooms, and power amplifiers):
1. Dual-Channel FFT (Noise & Live Music)
Works with arbitrary broadband signals—in PRO EX even during a live concert using the music signal itself (Channel 1 = mixer output, Channel 2 = measurement mic, frequency-domain division).
Requires very long averaging times with noise (e.g., > 300 s for < 0.2 dB ripple); with music, accuracy is reduced in frequency bands with low musical energy.
2. Maximum Length Sequences (MLS)
Deterministic pseudo-noise with a flat ('white') spectrum. Delivers the full impulse response within 20–100 ms via fast Hadamard transform, including 20–30 dB correlation gain against background noise.
Sensitive to non-linear distortion (appears as elevated noise floor) and clock offsets. Also, 50% of the total power lies between 10 kHz and 20 kHz, which thermally stresses tweeters.
3. Log-Sweep / Chirp (WinAudioMLS LAB)
Energy decays at 3 dB/octave like pink noise (maximum energy at low frequencies). Immune to clock offsets (e.g., 20 ppm crystal offset on CD players) and immune to speaker distortion. Freely selectable start/stop frequencies.
Sounds more annoying at high levels than stationary noise; woofers can be mechanically overloaded at excessive levels (included in LAB edition).
4. Stepped-Sine / Tracking (#3001)
Focuses all generator power into a single discrete frequency (+30 dB SNR advantage over broadband MLS in our door attenuation test). Measures level, phase, THD+N, and individual harmonics (THD) in a single run.
Slowest method because the analyzer must wait for the DUT to settle at each frequency step (e.g., 12–30 s for 40–55 steps).
FFT Resolution, Noise Floor & Window Function Calculator
A classic pitfall in spectral analysis (see Manual Chap. 13.5.1 & 16.3): Many users read the visual noise floor of an FFT plot (e.g., -150 dB) directly as the Signal-to-Noise Ratio (SNR). Because the spectrum represents spectral density, doubling the FFT size lowers the visual noise floor by 3 dB (FFT process gain), while the true wideband RMS noise remains constant. Use this calculator to test the interaction between sample rate, FFT block size, 32-bit vs. 64-bit math, and windowing:
Why Standard Analyzers Often Fail at These 4 Measurement Tasks
Peak Interpolation: < 0.01 dB Instead of 3.5 dB Level Error
When a sine tone falls between two discrete FFT bins (scalloping loss), conventional spectrum analyzers show level variations of up to 3.5 dB (Rectangular) or 1.0 dB (Blackman) across 100 Hz to 1 kHz. Our peak interpolation compensates the windowing effect mathematically down to less than ±0.01 dB with a Blackman window.
64-Bit FFT Against Floating-Point Rounding Noise
A 32-bit floating-point number only has a 24-bit mantissa. In an 8192-point FFT, the signal passes through 13 sequential addition stages—the 32-bit FFT's own rounding noise degrades an ideal 16-bit sine from 96 dB down to 90 dB THD+N! Our 64-bit FFT plug-in (#3005) lowers mathematical noise by 144 dB, making true -120 dB SNR measurements possible.
Real-Time Sample Rate Pitch Correction Down to 0.001 Hz
When measuring a standalone CD player, its crystal oscillator often runs at e.g. 44,057.435 Hz instead of 44,100 Hz (20 ppm offset). In an MLS measurement, this tiny clock offset causes a high-frequency roll-off of up to 5 dB above 10 kHz. With our real-time Pitch slider, you continuously tune the effective sample rate on the fly until high-frequency response peaks.
Automated Quality Assurance & Production Testing (Pass/Fail)
For manufacturing QA, WinAudioMLS provides freely scalable Parameter Viewers, large green/red Pass/Fail indicators, dynamic tolerance masks (Dynamic Overlays that automatically track input level at 1 kHz), automated HTML test reports, and the WAremote.exe command-line interface for batch scripting.
Modular Plug-ins for High-Resolution Audio, Electronics & QA
All plug-ins can be added individually to an existing PRO, PRO EX, or LAB license—tailored for electrical measurements (192 kHz ASIO, RIAA, Sweep), Wow & Flutter, and automated QA testing. Filter the modules by engineering domain:
Plug-in ASIO 192kHz 24bits
Expand your measurement system to 24Bit and 192kHz Samplerate via ASIO
4 channels simultanously
4 channels simultanously
8 channels simultanously
8 channels simultanously
16 channels simultanously
16 channels simultanously
Plug-in Support for DataTranslation interfaces
Up to 64 channels /200kHz samplerate
Automatic measurement of Windows Mixer
Automatic measurement of Windows Mixer
Plug-in Freq.+Level Sweep
Measure Level Distortion, Level, etc vs. frequency and input level.
production test/ quality assurance
With this module you can run pre-defined tests as productions tests for quality assurance
script / batch processor remote control
script / batch processor
Plug-in Datalogger
Plug-in Datalogger
Plug-In 3D plot waterfall plots
Plug-In 3D plot waterfall plots / cumulative decay plot
Automatic polarplot with a turntable
Automatic polarplot with a turntable
Plug-in 1/3 1/1 Octave Analyzer
1/3 octave and 1/1 octave analyser according to DIN 61672 and IEC 1260
Plug-in TA-Lärm
Measurement of parameters according to TA-Lärm
Plug-in noise monitor PA/concerts
Monitor of noise level according to DIN15905-5
Wow and Flutter
Speed analysis tool plug-in (speedalyzer). This tool allows versatile analysis of rotating system.
Plug-in Filter-Designer
With this tool you can design flexible filters and process your signals in real-time.
Plug-in RIAA Filter
With this tool you can add the RIAA and inverse RIAA filter to both our analyzer and signal generator
Plug-in VST Host
Include thousands of 3rd party audio effects to your measurement chain
Plug-in audio recorder wav/mp3
With this module you can record the audio signal to directly to .wav files. This system is designed for longterm audio recording from days to months.
Automatic report from .wav or .mp3 files
Automatic report from .wav or mp3 files
Wow and Flutter
Speed analysis tool plug-in (speedalyzer). This tool allows versatile analysis of rotating system.
Complete Software Suites, USB Measurement Systems & EDU Licenses
For measurements on amplifiers, DACs, phono preamps, and crossovers, we recommend our Electrical System Measurement Suite (#1999) or the full-spec LAB edition (#1722). For universities, schools, and non-commercial users, we offer discounted EDU packages (#1101 to #1110).
Electrical Measurement Suites, USB System & Event Monitoring
This bundle is optimized for amplifier testing or general electrical testing We recommend it for the following group of devices: Pre-amplifiers, Radio transmissions Power-amplifiers, Soundcards AD/DA converter, Tube-amplifiers, Sound control devices, Filter
complete Audio measurement system including USB measurement microphone and software
Package for DIN 15905-5
Package for monitoring the Soundlevel
Lab Accessories & APx555 Reference Measurement
XLR attanuator
XLR attanuator
USB Key Dongle
USB Key Dongle
Measurements in our lab with Audio Precision APX555
We offer measurement services with our APX555 in our LAB for your devices
Educational & Non-Commercial Packages (EDU #1101–#1110)
Extended
2 channel and sweep measurements
Extended high resolution 192kHz/24bit for electrical measurements
Extended high resolution 192kHz/24bit with ASIO
Extended acoustic
Package for measuring room acoustics e.g. reverberation time according to DIN ISO 3382
Complete package all software module
Complete package with all software module
Related Laboratory Pages & Interactive Simulators
Test the correlation and evaluation methods used in WinAudioMLS directly online in your browser, or visit our specialized hardware pages:
Chirp / Log-Sweep Simulator
Why the LAB edition's Chirp measurement is immune to harmonic distortion and clock offset.
RT60 Reverberation Methods Lab
Compare Schroeder decay plots live using impulse, interrupted noise, and sweep excitation.
Loudness Measurement in Sone
Background on Zwicker loudness, low-noise microphones (< 20 dB(A)), and near-field distance correction.
Back to Disciplines Overview
Overview of all 6 main groups and 28 technical sub-domains (C01–C28).