- How the Commercial Audio Technician Exam Is Organized
- What Comes Before Test Day
- Domain 1: Acoustics
- Domain 2: Microphones
- Domain 3: Speakers
- Domain 4: Sound & Measurements
- Domain 5: Wiring
- Domain 6: 70-Volt Systems
- Domain 7: Troubleshooting
- Domain 8: Safety, Codes and Standards
- Sequencing the Eight Domains in Your Prep
- Exam Format and Administration
- Frequently Asked Questions
- The Commercial Audio Technician (CAT) exam from ETA International covers eight competency categories, from Acoustics through Safety, Codes and Standards.
- ETA publishes no percentage weighting for the eight domains, so prepare for all of them rather than betting on one.
- CAT is not stand-alone: Associate CETa certification must be earned first.
- The exam has 100 questions, two hours, a 75% passing requirement, and costs $80 USD.
How the Commercial Audio Technician Exam Is Organized
The Commercial Audio Technician (CAT) credential from ETA International is a Journeyman-level specialty certification focused on the design, installation and troubleshooting of speech and music sound systems in commercial and institutional environments. Think conference rooms, school auditoriums, houses of worship, retail spaces and similar installations where intelligibility and reliability matter more than concert-scale spectacle.
ETA's scope document, Commercial Audio Technician - CAT: Categories Listing and Competencies Requirements, breaks the exam into eight major competency categories. This guide uses those exact category names as its domains. The linked competency document is a 14-page PDF bearing a 2013 copyright, so treat it as the official preparation outline rather than as evidence of a recent exam rewrite. If you are new to the credential itself, start with What Is CAT Certification? and come back here for the domain-level detail.
What Comes Before Test Day
The CAT-specific competency document states plainly that this is not a stand-alone credential. You must first earn the Associate Certified Electronics Technician (CETa) certification. That prerequisite shapes your timeline and your budget: the $80 CAT exam fee does not include the CETa exam, study materials, or later maintenance costs. For a full walkthrough of eligibility, see CAT Requirements 2026: Eligibility, Prerequisites & How to Qualify, and for the money side, CAT Certification Cost 2026: Complete Pricing Breakdown.
Because CETa covers general electronics fundamentals, the CAT exam can build on that foundation. That means the eight domains below lean toward audio-specific application: how sound behaves in rooms, how transducers work, how signal chains are measured, how cable and distributed-line systems are built, how faults are isolated, and how installations stay safe and compliant.
Domain 1: Acoustics
Acoustics is the physics layer underneath everything else. A technician who understands how sound propagates, reflects and decays in a space makes better decisions about speaker placement, microphone placement and equalization before touching any gear.
Acoustics: What Candidates Must Understand
Expect questions on the behavior of sound waves and how room characteristics change what listeners hear.
- Frequency, wavelength, amplitude and the relationship between them
- Reflection, absorption, diffusion and reverberation in commercial rooms
- How room dimensions and surfaces influence speech intelligibility
- The effect of distance on sound level, including the inverse-square idea
- Why hard, parallel surfaces create problems in lecture halls and gymnasiums
Practice reasoning about why a space sounds the way it does. Exam questions in this area tend to reward conceptual understanding: given a described room and a described complaint, which acoustic principle explains it?
Domain 2: Microphones
Microphones are the front end of most speech and music systems, and choosing or placing them badly causes problems no amount of downstream processing can fully repair.
Microphones: What Candidates Must Understand
Know the main transducer types, their pickup behavior, and where each belongs in a commercial installation.
- Dynamic versus condenser operation, and which needs phantom power
- Polar patterns such as omnidirectional, cardioid and their practical consequences
- Balanced versus unbalanced microphone connections and why balanced lines reject noise
- Placement principles that reduce feedback and improve gain before feedback
- Wireless microphone basics, including the practical concerns of interference and battery management
Feedback is a recurring theme across domains. A microphone's pattern, its distance from the talker and its position relative to loudspeakers all feed into the same question: how much usable gain can this system deliver before it rings?
Domain 3: Speakers
The Speakers domain covers the output end of the chain: how loudspeakers convert electrical energy to sound, how they are specified, and how they are matched to amplifiers and rooms.
Speakers: What Candidates Must Understand
Be comfortable with both the electrical and the acoustic behavior of loudspeakers.
- Driver types, enclosures and crossover networks
- Impedance, power handling and sensitivity ratings, and how they interact with amplifier output
- Series and parallel speaker wiring and the resulting load impedance
- Coverage patterns and why speaker choice differs for a low ceiling versus a tall atrium
- Phase and polarity relationships between multiple loudspeakers
Load calculations are the classic exam-style task here. Practice working out the total impedance of several speakers wired in series, parallel and series-parallel combinations until it is automatic, since it connects directly to the 70-volt material later in this guide.
Domain 4: Sound & Measurements
This domain deals with quantifying audio: levels, ratios and the instruments used to verify that a system performs as designed. Decibel math is the heart of it, and it is where many otherwise strong candidates lose easy points.
Sound & Measurements: What Candidates Must Understand
Know the units, the logarithmic scale, and how to interpret measurement results.
- Decibel concepts for power, voltage and sound pressure, and why the formulas differ
- Reference levels and the meaning of common dB-based notations
- Using meters and test equipment to verify signal levels and system gain structure
- Gain staging across mixers, processors and amplifiers to balance noise and headroom
- Interpreting frequency response and understanding what equalization can and cannot fix
Because ETA permits a nonprogrammable scientific calculator, build fluency with logarithms before exam day. Know by heart that doubling power adds a fixed number of decibels, and be ready to reason about what that means for perceived loudness versus measured level.
Domain 5: Wiring
Wiring covers the physical layer that connects every component: cable types, connectors, grounding practices and the habits that keep systems quiet and dependable.
Wiring: What Candidates Must Understand
Cable and connector choices are design decisions, not afterthoughts.
- Balanced versus unbalanced cabling and the connectors associated with each
- Shielding, twisted-pair construction and how they reduce interference
- Cable gauge selection for loudspeaker runs and the effect of resistance over distance
- Grounding concepts, ground loops and the hum they produce
- Separating low-level signal cabling from power cabling and other noise sources
- Termination, labeling and documentation practices for installed systems
Wiring questions often shade into troubleshooting. A described symptom such as hum, buzz or intermittent dropout may be answerable purely from wiring knowledge, so study this domain together with Domain 7.
Domain 6: 70-Volt Systems
Distributed-line, constant-voltage audio is a defining skill for commercial sound, and it gets its own domain. These systems let one amplifier feed many loudspeakers over long cable runs with manageable current, which is why you meet them in schools, warehouses, stores and campuses.
70-Volt Systems: What Candidates Must Understand
Master the logic of line transformers, taps and power budgeting.
- The purpose of a constant-voltage distribution line compared with a low-impedance line
- Line transformers on each speaker and how taps select the power drawn by that speaker
- Adding up tap settings to find total load and sizing the amplifier with sensible headroom
- Why cable losses matter less on a distributed line than on a low-impedance run
- Wiring speakers in parallel across the line and recognizing common installation errors
Typical problems ask you to total the wattage of several taps and decide whether an amplifier is adequate. Work these step by step until the arithmetic and the reasoning are routine.
Domain 7: Troubleshooting
Troubleshooting is where the other domains converge. The exam wants to know whether you can isolate a fault methodically instead of guessing.
Troubleshooting: What Candidates Must Understand
Think in signal flow: start at the source, move toward the output, and divide the chain to localize the problem.
- Following the signal path and testing at defined points to find where the signal degrades or disappears
- Recognizing symptom patterns: hum, hiss, distortion, low output, intermittent sound and feedback
- Linking each symptom to likely causes in gain structure, grounding, connections or components
- Using basic test instruments safely and interpreting what the readings imply
- Deciding whether a problem is electrical, acoustic or operator-related before replacing parts
Expect scenario-style prompts: a system produces a specific symptom, and you must choose the most probable cause or the best next diagnostic step. The strongest preparation is to rehearse a consistent method, not to memorize isolated fixes.
Domain 8: Safety, Codes and Standards
The final domain covers working safely and working legally. Commercial audio installations sit inside buildings governed by electrical and life-safety rules, so technicians must know the boundaries of their work.
Safety, Codes and Standards: What Candidates Must Understand
Safe practice and code awareness protect people, property and your professional standing.
- Electrical shock hazards, safe work practices and appropriate protective measures
- Awareness of electrical code requirements that affect audio cabling and equipment installation
- Safe mounting and rigging of loudspeakers and equipment overhead
- Considerations for plenum spaces, fire-rated penetrations and cable routing
- The role of recognized standards in system performance and documentation
Do not treat this as a throwaway section. Because the exam text does not publish weightings, you cannot assume safety is a minor slice, and the underlying concepts also reinforce your answers in Wiring and Troubleshooting.
Sequencing the Eight Domains in Your Prep
There is no official domain order, but the content has a natural dependency chain. One sensible approach is to build from physics outward to practice. Adapt the timing to your own schedule and experience, and see the CAT Study Guide 2026: How to Pass on Your First Attempt for broader planning guidance.
Acoustics and Microphones
- Learn sound behavior in rooms first; it supports every later topic
- Pair microphone patterns with feedback concepts
Speakers and Sound & Measurements
- Drill impedance and decibel calculations with your calculator
- Connect speaker ratings to amplifier matching
Wiring and 70-Volt Systems
- Study cabling and grounding, then apply it to distributed-line math
- Work tap-totaling problems until they feel routine
Troubleshooting, Safety, then Full Review
- Practice symptom-to-cause reasoning across all prior domains
- Finish with Safety, Codes and Standards and timed mixed practice
Troubleshooting sits late on purpose: it is easier once you have the vocabulary of the earlier six domains. Use the CAT practice tests to find weak domains, then revisit those areas rather than rereading everything evenly.
Exam Format and Administration
The mechanics are straightforward, and knowing them removes avoidable stress. The table below summarizes the key facts from ETA International.
| Item | CAT Detail |
|---|---|
| Governing body | ETA International |
| Classification | Journeyman |
| Exam fee | $80 USD |
| Questions | 100 |
| Time allowed | Two hours |
| Passing requirement | 75% |
| Hands-on assessment | Not required |
| Certification term | Four years |
| Retake | One free retake within one year of the first session |
| Prerequisite | Associate CETa certification first |
Testing is proctored through an ETA Certification Administrator, using either Trapeza online testing or paper and pencil. The standard Trapeza route requires an onsite administrator, and ETA also offers a distinct remote-proctoring route through ExamRoom.AI. Bring photo identification. Scratch paper and a nonprogrammable scientific calculator are permitted under ETA's general examination rules, and used scratch paper is surrendered afterward. For scheduling specifics, see CAT Exam Dates 2026: Testing Windows, Deadlines & Scheduling, and for the scoring threshold in detail, CAT Passing Score 2026: Exactly What You Need to Pass.
If you want to gauge how the exam feels before committing, read How Hard Is the CAT Exam? Complete Difficulty Guide 2026, and when you are ready to test yourself, take a timed run on the main practice test site.
Frequently Asked Questions
ETA International's competency document lists eight major categories: Acoustics, Microphones, Speakers, Sound & Measurements, Wiring, 70-Volt Systems, Troubleshooting, and Safety, Codes and Standards.
ETA does not publish a percentage allocation for the categories. You should not assume any single domain is the largest or that all are equal, so prepare broadly and use practice results to guide extra study.
Yes. The CAT competency document states that it is not a stand-alone credential, and Associate Certified Electronics Technician (CETa) certification must be earned first.
ETA offers one free retake within one year of your first examination session. Use your first attempt's weak areas to focus your review before sitting again.
No. CAT requires no hands-on assessment. It is a 100-question, two-hour exam with a 75% passing requirement, so knowing the concepts and calculations in all eight domains is what counts.