Speech Intelligibility (STIPA) & Voice Alarm Testing: Turnkey Measurement Systems to IEC 60268-16
Measuring speech intelligibility has become an indispensable standard procedure that is normatively and legally mandated across numerous applications—most notably for Voice Alarm Systems (PAVA / SAA). The governing standard is DIN EN IEC 60268-16, with the efficient STIPA method having established itself as the primary procedure in practice. At the same time, speech intelligibility forms an important interface to classical room acoustics, such as in conference rooms, lecture halls, and public buildings.
In this category, we have bundled all relevant information and matching measurement equipment for STI and STIPA: Our portfolio ranges from compact, handheld instruments for rapid on-site verification to powerful, PC-based analysis systems such as Akulap for in-depth room acoustic evaluations.
How Do You Inject the STIPA Test Signal? (When Do I Need a TalkBox?)
Systems Without Live Paging Mic (Line-In / Aux / USB Injection)
If evacuation messages are stored digitally, the STIPA test signal (supplied as WAV on the SM50) is fed electrically into the rack line input. No TalkBox required.
End-to-End Test Including Paging Microphone (with Bedrock TalkBox)
Whenever live announcements are made via a firefighter microphone, the mic capsule and limiter must be included in the test chain using the calibrated Bedrock TalkBox (±1 dB from 125 Hz–8 kHz, with alignment laser).
3 Pre-Configured PAVA Test Kits (Click to Load into Configurator):
PAVA Basic Kit (SM50 + Mic Adapter + Center 326 Class 2)
For electrical STIPA injection at the 19" PA rack: Includes SM50 in case, 1/2" CNC adapter, and regulated Center 326 Class 2 calibrator.
PAVA Full Acceptance Kit (SM50 + TalkBox BTB65 + Center 326)
Complete end-to-end PAVA testing including the firefighter microphone via the calibrated Bedrock TalkBox (with laser) + Center 326 calibrator.
Class 1 Expert Kit (SM90 Class 1 + TalkBox PLUS + 1/2" Adapter)
For accredited inspectors requiring Class 1 precision: Bedrock SM90 (IEC Class 1) paired with the BTB115 TalkBox PLUS (with laser rangefinder) and our 1/2" CNC adapter for your existing Class 1 sound calibrator (e.g., B&K 4231).
→ Select matching Class 1 calibrator (B&K 4231 / PTB)1. Select Bedrock Base Unit (Click to Switch):
🟢 Lab-verified in Dresden before shippingBedrock SM50 STIPA (Demo New without Case)
Mint condition demo unit without rugged case, incl. BAM20 measurement microphone, 3.5" color touchscreen, WAV test signals, and all unlocked modules (STIPA, Full STI, RT60, FFT, RTA).
Bedrock SM50 STIPA Complete Kit in Case
Brand-new complete instrument in waterproof rugged case incl. microphone, XLR pre-amplifier, PCBcalibration certificate, STIPA WAV test signals, and 100% of all software licenses.
Bedrock SM90 STIPA (IEC Class 1)
When clients or building codes strictly require a Class 1 precision instrument. Includes Class 1 microphone and rugged case.
Bedrock AM100 (Class 1 High-End Analyzer)
The flagship from Embedded Acoustics: Capacitive HD touch display, 32 GB storage, WiFi/Bluetooth control, 2nd input channel, built-in signal generator, and Class 1 microphone.
Which sound calibrator fits your measurement task?
Why open-loop budget calibrators drift up to 1.3 dB with 1/4" adapters, when Class 1 (PTB) is mandatory, and why the closed-loop Center 326 is our installer bestseller.
🎛️ Live STIPA Simulator: Understand Reverb, Ambient Noise & Level Masking
Per EN 50849, average STI across 90% of each Acoustically Different Area (ADA) must be ≥ 0.50 (minimum ≥ 0.45). Click the 4 typical field scenarios below:
Bedrock SM50 STIPA Complete Kit in Case
- ✓ STIPA (18–20s) per IEC 60268-16 Ed. 4.0 & Ed. 5.0
- ✓ Full STI (65s) + CIS + Ambient Noise Correction
- ✓ Reverb Time RT60 (T20, T30, EDT in 1/3-oct) & Building Acoustics
- ✓ FFT Analyzer, 1/3-Oct RTA, LAeq/LCpeak & uncompressed .wav
All prices in EUR Net excl. VAT and Gross incl. VAT plus shipping costs (FCA Dresden). B2B offer for commercial, government & professional users.
PAVA & STIPA Field Compendium: Click Any Topic to Open the Full Engineering Dossier
Why do loud PA systems still fail STI acceptance? How do you apply octave background noise correction (-15 to +15 dB SNR)? Explore our 6 illustrated dossiers:
EN 50849 & IEC 60268-16 Standards
STI ≥ 0.50 (min 0.45) in Acoustically Different Areas (ADA) & why RASTI is obsolete.
STIPA in 18s vs. Full STI (5 Min.)
7 octave bands, modulation loss & why excessive SPL (>80 dBA) degrades intelligibility.
Ambient Noise Correction (-15 to +15 dB SNR)
Why measuring an empty building isn't enough: 5-step octave SNR post-processing.
Bedrock TalkBox vs. ITU P.51 Mouth
Why firefighter paging microphones require a ±1 dB calibrated source with laser alignment.
Center 326 vs. AZ8930 & B&K 4231 Inside
Teardown: Why unregulated budget calibrators drift by 1.3 dB + our 1/2" CNC adapter.
Reverb Time (RT60) & Open-Plan Offices
Fixing hall reverb & why ISO 3382-3 open-plan offices require full STI + dodecahedron.
Master STIPA in 4 Videos — Powered by Our Akulap Cinematic DSP Engine
Watch our 4-part video series by Dr.-Ing. Frank Jordan. Every animation is mathematically rendered by our in-house Python DSP engine (privacy-friendly 2-click YouTube player):
Load STIPA Tutorial Video (GDPR 2-Click Protection)
Clicking below loads the video from YouTube (youtube-nocookie.com).
NTi Audio (XL2 / XL3) vs. Bedrock (SM50 / SM90): Key Differences in Field Practice
Why is STIPA often mistaken for a proprietary NTi format? Which software options (STIPA, Extended Acoustic Pack, microphone) are billed separately in modular systems—and how do touchscreen workflow and total system cost compare?
Rent from 199,00 € (236,81 € incl. 19% VAT) Net/Week for Your Next Job—100% Credited When You Buy!
Every rental instrument is inspected and calibrated on our APx555 in our Dresden lab prior to shipping. The 100% rental credit towards purchase applies exclusively to Bedrock analyzers, the Bedrock TalkBox, and calibrators. The NTi Audio XL2 systems are available solely as rental and comparison units from our laboratory stock—for new NTi device purchases, please contact your local NTi distributor directly.
Rental: Bedrock SM50 STIPA (Ed. 4 + Ed. 5)
Test the touchscreen SM50 for a week on your job site. 100% of the weekly rental fee is credited if you buy a new unit!
Rental: Calibrated Bedrock STIPA TalkBox
Calibrated acoustic source (artificial mouth with laser) for testing emergency and firefighter paging microphones. 100% credited towards purchase!
Rental: NTi Audio XL2 STIPA (Class 2)
Includes STIPA & Extended Acoustic Pack. Compare weekly rate and usability directly against the Bedrock SM50. Project rental only—for new NTi purchases please contact your local NTi distributor.
Rental: NTi Audio XL2 STIPA (Class 1 incl. Calibrator)
Complete Class 1 rental kit including sound level calibrator for official acceptance tests. Project rental only—for new NTi purchases please contact your local NTi distributor.
Frequently Asked Questions About STIPA, Standards & Test Kits
When do I need a TalkBox for STIPA measurement? ▾
A calibrated TalkBox (acoustic mouth simulator per ITU-T P.51) is required whenever the Voice Alarm System (PAVA) features an announcement microphone station, ensuring standardized acoustic signal injection. For systems using pre-recorded announcements, the test signal can be injected electrically via line-in.
Which standards mandate STIPA speech intelligibility? ▾
Measuring speech intelligibility via STIPA is standardized in IEC 60268-16 (Edition 5) and mandatory for Voice Alarm Systems (PAVA) under EN 50849, DIN VDE 0833-4, and DIN 14675.
Why is reverberation time (RT60) alone insufficient for speech intelligibility? ▾
Reverberation time (RT60) accounts neither for ambient background noise (SNR), distortion, late echoes, nor auditory masking effects. The Speech Transmission Index (STI, 0.00 to 1.00) integrates room acoustics and signal-to-noise ratio into an accurate single-number rating.
Which accuracy class is required for PAVA acceptance (Class 1 vs. Class 2)? ▾
For standard inspections per EN 50849, the Bedrock SM50 (Class 2) provides a fully compliant and cost-effective solution. For legal expert reports and precision class 1 sound level measurements per IEC 61672-1, a Class 1 meter such as the Bedrock SM90 is recommended.
Can I rent or test a Bedrock device before purchasing? ▾
Yes, we offer flexible rental options for all Bedrock systems (SM50, SM90, AM100, and TalkBox). If you decide to purchase, up to two weeks of rental fees are fully credited towards the purchase price.
Akulap STIPA & Impulse Response Kit (Art. 30002)
Supports both direct STIPA and indirect impulse-response STI (Chirp per ISO 18233)—mandatory for open-plan offices per ISO 3382-3!
Akulap Mobile & Building Acoustics (Art. 700300)
Our vendor-independent Building Acoustics software (ISO 16283 / ISO 717) controls the Bedrock SM30/SM50/SM90 directly via USB!
STIPA ED5.0 Engine & Conformance Report
100% in-house C++ code: View our official IEC 60268-16:2020 (Edition 5) conformance test report online.