AudioControl C550H (CM-550H) Review: Specifications, Uses and Comparisons
Quick summary: the buying decision
The C550H is a precision measurement microphone for users who need stable, repeatable readings: each one is individually calibrated and sensitivity-matched, and it covers 35 to 135 dB SPL. It needs phantom power from an analyser such as the DM-RTA or a measurement interface.
AudioControl C550H: what it is
The C550H (listed as CM-550H) is the Josephson C550H precision omnidirectional measurement microphone supplied by AudioControl. Made in California by Josephson Engineering, each microphone is thermally conditioned for stability, individually calibrated and sensitivity-matched, and its nose fits standard 1/2-inch calibrators.
AudioControl's DM-RTA analyser has a built-in calibration preset for the C550H.
Key features
Capacitive pressure transducer with a prepolarised backplate
20 Hz – 20 kHz (±2 dB) response and a 35 – 135 dB SPL dynamic range
Thermally conditioned for stable measurements; individually calibrated and sensitivity-matched
Phantom powered (15 – 50 V DC) through a 3-pin XLR connector
Calibration preset built into the AudioControl DM-RTA
Specifications explained
Frequency response 20 Hz – 20 kHz (±2 dB), omnidirectional polar pattern.
Dynamic range 35 – 135 dB SPL, impedance 50 ohm, phantom power 15 – 50 V DC, 3-pin XLR, pin 2 positive connector; it fits standard nominal 1/2-inch calibrators. Supplied with a bag and shock mount.
Full specifications as published by AudioControl:
Model: C550H
Type: Precision measurement microphone (capacitive pressure transducer, prepolarised backplate)
Maker: Josephson Engineering, made in California
Frequency response: 20 Hz – 20 kHz (±2 dB)
Dynamic range: 35 – 135 dB SPL
Polar pattern: Omnidirectional
Impedance: 50 ohm
Phantom power: 15 – 50 V DC
Connector: 3-pin XLR, pin 2 positive
Calibrator fit: Standard nominal 1/2-inch calibrators
In the box: C550H microphone, bag, shock mount
Connecting and using it
Use the C550H with a DM-RTA (select its preset) or any measurement interface that supplies 15 to 50 V phantom power; check the calibration with a 1/2-inch calibrator if you have one.
For in-car measurements, place the microphone at head height in the listening position, take several readings around the head position rather than one, and keep the doors and windows closed. Equalise broad trends rather than chasing narrow peaks and dips.
How it compares
Measurement microphones and analysers at VA3 Car Studio:
AudioControl CM-20: measurement microphone (back-electret condenser), ₹18,690
AudioControl SA-4100i: calibrated iOS measurement microphone, ₹50,990
AudioControl SA-4140i: calibrated iOS test and measurement microphone, ₹72,240
AudioControl DM-RTA: real-time analyser, oscilloscope and multi-test tool (analyser only), ₹1,44,490
Price and value in India
At the time of writing (October 2026), VA3 Car Studio lists the C550H at ₹93,490, 15% below the MRP of ₹1,09,990. A calibrated microphone is the foundation of a reliable tune; the right choice depends on how often and how precisely you measure. Prices can change, so the product page always shows the current price.
Verdict: who should shortlist the C550H
The C550H is for users who want precision and stability across sessions, for example competition tuning or studio-grade measurement in a car.
Real-world reviews and limitations
We have not yet published a VA3 installation report for the C550H. The figures in this review are AudioControl's published specifications, not our own measurements, and real-world results depend on how the measurements are taken and the tune. If you have used one, we would welcome your feedback.
Frequently asked questions
Who makes the C550H?
Josephson Engineering in California; AudioControl supplies it.
Is the C550H calibrated?
Yes. Each one is individually calibrated and sensitivity-matched, and it fits standard 1/2-inch calibrators.
Does the C550H need phantom power?
Yes, 15 to 50 V DC through a 3-pin XLR connector.
What is the C550H's dynamic range?
35 to 135 dB SPL, with a 20 Hz to 20 kHz (±2 dB) response.
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