The PSI Audio A23-Ms Studio Red is a Swiss-made, fully analogue 3-way active studio monitor for high-resolution nearfield and midfield monitoring. With PSI’s AOI input-overload protection, CPR phase-response control, individually measured drivers and powerful dedicated amplification, it delivers accurate translation, controlled bass extension and a stable, depth-rich stereo image for mixing, mastering and critical listening.
 
The PSI Audio A23-Ms Studio Red is a compact but substantial three-way active monitor designed for engineers who need trustworthy full-range monitoring without moving to a physically much larger main-monitor system. Handmade and individually calibrated in Switzerland, the A23-Ms combines dedicated analogue amplification, close driver matching and careful phase control to make tonal balance, transient detail, depth and stereo placement easier to judge.
PSI Audio’s engineering philosophy is deliberately analogue. The A23-Ms does not rely on DSP processing or built-in digital room correction in the audio path. Instead, it uses custom analogue electronics, purpose-built drivers and measured crossover integration. Its balanced XLR input feeds a fully analogue crossover and three dedicated amplifiers: Class G/H amplification for the low-frequency and midrange drivers, plus a Class A/B amplifier for the tweeter. This arrangement provides substantial headroom while maintaining the direct, continuous and low-latency response valued in critical monitoring.
 
The three-way system consists of a 170 mm woofer, a 56 mm dome midrange driver and a 25 mm tweeter. The midrange/tweeter assembly can be rotated by 90 degrees, allowing the A23-Ms to be used in vertical or horizontal orientation while preserving the intended dispersion behaviour. This adds useful flexibility in studios where console bridges, room geometry or screen placement determine monitor orientation.
 
A23-Ms reaches down to 34 Hz at −6 dB, with a specified ±1.5 dB tolerance from 39 Hz to 20 kHz. In practical terms, this gives the monitor enough low-frequency extension for confident work on kick, bass, synth substructure and the bottom octave of a mix without automatically requiring a subwoofer. For larger rooms, immersive systems or work demanding extension below the monitor’s natural range, it can be paired with PSI Audio’s A225-M subwoofer and an AvAA acoustic absorber.
 
The A23-Ms is built around several PSI Audio technologies. CPR—Compensated Phase Response—is designed to maintain phase behaviour through the crossover regions, supporting accurate transient reproduction and stable imaging. AOI, Active Output Impedance, monitors loudspeaker behaviour and controls driver motion to reduce unwanted resonance and improve low-frequency control. PSI also uses its ALG overload-limiting system to protect the monitor and keep behaviour controlled at high playback levels. These technologies are particularly useful when making decisions about bass contours, compression, reverb tails, spatial placement and mono compatibility.
 
The monitor delivers 140 W RMS to the woofer, 70 W RMS to the midrange driver and 50 W RMS to the tweeter. PSI specifies 108 dB continuous SPL at 1 metre, 111 dB short-term SPL and up to 122 dB peak SPL at 1 metre. This combination of output capability, controlled dispersion and three-way driver allocation makes the A23-Ms suitable for professional project studios, mix rooms, production suites, editing rooms and midfield positions where a smaller two-way monitor may run out of headroom or lose clarity under demanding programme material.hifitest+2
The “Studio Red” finish gives the A23-Ms a distinctive professional appearance without changing its acoustic platform. More importantly, every monitor is measured and matched in PSI Audio’s anechoic test environment before delivery. For the engineer, that approach means a monitor intended to reveal what is in a recording rather than to flatter it: tight and differentiated low end, clear midrange information, clean high-frequency detail and a stable stereo image that remains useful across long working sessions.
 
The A23-Ms is primarily a ProAudio monitor and should be assigned first to Studio Monitors. Its exceptional analogue design, active three-way architecture, Swiss manufacture and full-range capability also make it relevant for audiophile active-stereo listening—but its product page should lead with professional monitoring, mix translation and critical listening rather than conventional HiFi language.
 
Key features
Swiss-made 3-way active analogue studio monitor
Studio Red finish
Fully analogue signal path with no DSP processing
Suitable for nearfield and midfield monitoring
170 mm woofer, 56 mm dome midrange and 25 mm tweeter
Rotatable midrange/tweeter assembly for vertical or horizontal placement
Separate analogue amplifiers for all three drivers
Class G/H amplification for woofer and midrange
Class A/B amplification for tweeter
140 W + 70 W + 50 W RMS amplification
Frequency range: 34 Hz–23 kHz at −6 dB
Frequency tolerance: ±1.5 dB from 39 Hz–20 kHz
Crossover frequencies: 620 Hz and 3.3 kHz
CPR compensated phase-response technology
AOI active output-impedance technology
ALG overload protection
85° × 40° horizontal/vertical dispersion
Continuous SPL: 108 dB at 1 m
Short-term SPL: 111 dB at 1 m
Peak SPL: up to 122 dB at 1 m
Balanced XLR input
Individually measured and calibrated by PSI Audio
Compatible with PSI Audio A225-M subwoofer and AvAA acoustic-treatment solutions
5-year warranty, extendable by one year upon registration
 
Applications
Nearfield and midfield mixing
Stereo mastering and critical monitoring
Music production, editing and post-production
Accurate judgement of low-frequency balance and bass translation
Stereo-image, depth and reverb-tail assessment
Drum, bass and electronic-music production
Vocal, acoustic-instrument and orchestral mixing
Professional project studios and mix rooms
Editing suites and broadcast/post-production environments
High-resolution active stereo listening where neutral studio reference is desired