AKG PCC170 Half-Supercardioid Boundary Layer Stage Floor Microphone

AKG PCC170: Half-Supercardioid Boundary Pickup for Stage and Lectern

The AKG PCC170 is a half-supercardioid boundary layer microphone for surface-mount stage, lectern and conference-table pickup, covering 50 Hz to 20,000 Hz at 22 mV/Pa sensitivity. Boundary layer, sometimes called surface-mount, means the capsule is held in a shallow cavity right at the mounting plane, so the direct sound and the sound reflected off that surface arrive at the diaphragm in phase and reinforce each other rather than fighting. Self-noise of 22 dB-A and a 120 dB SPL ceiling at 3 percent THD give it both the quiet noise floor needed for a talker several feet away and the headroom for a loud source sharing the same surface. Powering is flexible at 12 to 48 V phantom and only 4 mA of drain, and the detachable 15 ft (4.6 m) cable makes it simple to wire into a console or an installed rack. It is the microphone theatre and worship engineers reach for when the pickup has to work perfectly and be seen by nobody.

How Boundary Mounting Adds 6 dB Instead of Comb Filtering

Placing the capsule at the boundary produces roughly a 6 dB rise in effective sensitivity, a result the manufacturer calls Phase Coherent Cardioid design. Any microphone near a hard surface receives two versions of the same sound, the direct wavefront and the reflection, and when the capsule sits a few inches above the surface those two arrivals are delayed relative to each other and cancel at a series of frequencies, the ragged response known as comb filtering that makes a stand-mounted microphone on a stage floor sound hollow and phasey. Setting the diaphragm level with the surface collapses that delay to essentially zero, so the two arrivals sum coherently across the band and the microphone gets louder and flatter at the same time. For a theatre sound designer working the apron, that difference is the whole reason the technique exists: dialogue from an actor twelve feet upstage arrives with usable level and natural tone rather than needing gain that would ring the room.

Half-Supercardioid Pattern and Gain Before Feedback

Pickup is half-supercardioid, meaning the microphone behaves as a supercardioid within the hemisphere above the mounting boundary and hears essentially nothing from below it. Supercardioid is a tighter pattern than cardioid, with a narrower front lobe and deep nulls to the rear sides, and cutting the pattern in half at the surface removes an entire hemisphere of room reflections and stage wash from the equation. That combination is what buyers mean when they report noticeably more gain before feedback than a conventional cardioid on a short stand in the same spot, because the microphone is simply not listening toward the wedges, the front fills, or the ceiling. A house of worship with a live room and a loud main system gains real headroom at the pulpit from this, and a courtroom bench keeps each position intelligible without picking up the whole gallery.

Bass-Tilt Switch for Rumble, Footfall and Thin Voices

A three-position bass-tilt slide switch on the housing selects bass cut, flat, or bass boost, and it is the control that turns an acoustically difficult position into a usable one. Boundary microphones are mechanically coupled to whatever they lie on, so a hollow stage deck, a suspended floor, or a table that gets knocked will feed low-frequency energy straight into the capsule, and the bass cut position trims that subsonic and low-bass region before it ever reaches the mixer. The boost position does the opposite job for a talker whose voice sits thin in the mix or a position that needs added weight, so one microphone covers both problems without an outboard EQ channel. Owners cite this switch repeatedly as the fix for stage rumble and footsteps on a wooden theatre deck, and it is equally welcome under noisy air handling in a conference room.

Powering, Termination and Installed-System Wiring

Phantom power from 12 to 48 V on pins 2 and 3 referenced to pin 1 runs the microphone at a nominal 4 mA drain, and the balanced 150 ohm output wants a load of 1,000 ohms or greater. A wide phantom window matters in installed sound because not every mixer, DSP input, or older console actually delivers a full 48 V, and a microphone that works from 12 V upward can be dropped into equipment already on site instead of forcing a rack change; where no phantom exists at all, a single-channel PH1A or four-channel PH4B supply provides it. Termination at the microphone is a 3-pin locking mini connector, and the supplied 15 ft (4.6 m) two-conductor shielded cable ends in a standard 3-pin male XLR, so the cable can be swapped for a longer run or replaced after damage without pulling the microphone out of the install. Built-in radio-frequency interference suppression rounds it out, keeping the buzz of a phone left on the same conference table out of the program feed.

Switched Versions and Where the PCC170 Belongs

Two switched siblings share this housing and electroacoustic design: an SW version adds a silent programmable membrane switch with touch on/off, momentary on, or momentary off behavior plus an LED, and an SW O version adds extra leads in the cable so a mixer or control system can remotely sense the switch state. Choosing between them is a workflow decision rather than an audio one, because the base model reviewed here is the right call whenever muting lives at the console or in the DSP, while the switched models suit rooms where each talker needs a local mute at the seat. Theatre aprons and orchestra pits, lecterns and altars, boardroom and courtroom tables, council chambers, distance-learning desks, choir risers and piano lids taped along the inside of the lid are all standard positions for this low-profile plate microphone. Long service life in permanent installations is a recurring comment from owners, many of whom report units still working after a decade of daily use.