AKG C414 B-XLS
A large-diaphragm condenser that takes a full second to remember what you told it.
Overview
The C414 B-XLS is the standard-voicing member of AKG's late C414 family. It's a one-inch large-diaphragm pressure-gradient condenser built around a dual-diaphragm capsule. The diaphragm is a plastic foil, gold-sputtered on one side only. The manual is explicit about that, because single-sided sputtering is what keeps the diaphragm from shorting to the back electrode at extreme sound pressure levels. The all-metal body isn't cosmetic either. It's there to reject RF interference, which is why the manual notes the mic can be used near transmitter stations and alongside wireless systems.
The headline numbers are respectable rather than spectacular. Open-circuit sensitivity is 23 mV/Pa, or -33 dBV ±0.5 dB. Frequency range spans 20 to 20,000 Hz. Impedance is 200 ohms or less, with a recommended load of 2200 ohms or greater. The self-noise figures are where the design earns its keep: an equivalent noise level of 20 dB to CCIR 468-2, and just 6 dB-A to DIN 45 412, A-weighted, at zero preattenuation. Signal-to-noise ratio is 88 dB referenced to 1 Pa, A-weighted. Dynamic range is 134 dB minimum. Maximum output level is 5 V rms, or +14 dBV.
It will also take a snare drum. Maximum SPL for 0.5% THD is quoted at 200/400/800/1600 Pa, which works out to 140/146/152/158 dB SPL across the 0/-6/-12/-18 dB preattenuation settings. That's a lot of headroom, and it's the reason the C414 has been a default choice on toms, guitar cabs, and kick drums for decades. The manual spells out why the pads exist: they keep the microphone's output level, particularly at low frequencies, from overloading the miniature transformers in mixer input stages. So the pad protects whatever the mic is plugged into, not just the mic.
Five polar patterns are available: omni, wide cardioid, cardioid, hypercardioid, and figure-eight. All are largely frequency-independent, which is the spec that actually determines whether off-axis sound stays usable or turns to mush. For anyone tracking a drum kit with overheads, or a choir with a stereo pair, that's the difference between a mix that holds together and one that needs surgery.
The bass cut is unusual. The filter slope is more than 12 dB per octave at the 40 Hz and 80 Hz settings, but only 6 dB per octave at 160 Hz. That's not a typo. The 160 Hz setting is a different tool. The manual describes it as minimizing the strong proximity effect that arises when close-miking from less than six inches. So the first two positions are for rumble, footfall, and air-conditioning blower noise, and the third is for the low-end bloom you get when a vocalist eats the grille.
One quirk catches almost everyone the first time. The transducer section runs extremely high-impedance circuitry to keep input stage noise low, so a changed polar pattern or preattenuation setting takes roughly 10 to 15 seconds to actually become active. It's not a fault. It's a consequence of the design. Switch patterns mid-session and expect an instant change, and the mic will look broken. It isn't.
Powering is 48 V phantom only, to DIN/IEC. That's a hard requirement, and the manual is emphatic about it: do not connect the microphone to any power supply other than a phantom power source to DIN/IEC with a floating connector, using a balanced cable with studio-grade connectors to IEC 268-12. AKG limited the powering options deliberately, because meeting the low-self-noise and high-headroom targets simultaneously left no room for anything else. For feeding resistors, the manual gives a standard value of 3300 ohms for a single Rv at 48 V ±4 V, or 6800 ohms for 2 x Rv, with 0.5% maximum tolerance on the paired resistors to satisfy the symmetry requirement.
The control scheme is a real change from earlier C414s. Previous versions used rotary switches. The B-XLS and its sibling use three separate dual pushbuttons for polar pattern, preattenuation pad, and bass cut filter, each with an LED bar indicating the selected setting. The selectors and indicator LEDs are only active while 48 V phantom power is on. Settings are saved in memory when phantom power is switched off and automatically reloaded when it comes back on. There's also a lock. Holding one of the arrows on the polar pattern selector for at least three seconds locks all three selectors against accidental changes, and holding it again, or cutting phantom power, unlocks them.
Environmentally, the mic is rated from -10°C to +60°C, with relative humidity tolerance of 95% at +20°C and 85% at +60°C. Not a spec most people will ever test, but it's the kind of thing that explains why these turn up in touring rigs and outdoor broadcast work.
Period coverage of the B-XLS and its XL II sibling was generally positive, with reviewers treating the pair as a refinement of an established studio standard rather than a reinvention. Mix (September 2004, p.130) noted that since the original C 414 Comb's 1971 introduction, AKG had upgraded and optimized the line's specs and feature set as better electronic components and advanced manufacturing techniques became available, and observed that all parts were by then surface-mount devices. The same piece listed the supplied accessories: a square-shaped foam windscreen, an external metal gooseneck two-stage pop filter that mounts to any mic stand or boom, a dust cover, an individual frequency plot of the microphone, and a multilingual manual, with a stereo kit bundling two sets of the same. EQ (August 2004, p.72) listed the C414B-ULS at $999 and the C414B-XL II at $1,099. That listing pairs the B-XLS's standard voicing against the XL II's brighter alternative rather than quoting the B-XLS price directly.
The sibling relationship is the main thing to understand before buying one. The C 414B-XL II is identical to the C 414B-XLS with one exception: a slight high-frequency rise at 3 kHz and above. AKG's own manual recommends the XL II specifically for solo voices and solo instruments, and notes it's also an excellent choice for distant miking, such as suspended from a concert hall ceiling. The B-XLS keeps the very smooth frequency response and the typical sound of AKG large-diaphragm microphones. The manual describes that sound as having hardly changed over the many years the C 414 has been in production, and says it has made the C 414 an industry standard against which most competitive or new products are compared. That's manufacturer copy, so take it with some skepticism.
The manual's placement guidance is more specific than most. For lead vocals, AKG suggests a working distance of 6 to 12 inches with cardioid and the bass cut engaged at 40 or 80 Hz, plus a W 414X windscreen or PF 80 pop screen. For acoustic guitar, the recommendation is a C 414B placed 8 to 12 inches away aimed at the sound hole, paired with a small-diaphragm mic such as a C 451B near the bridge from about 3 1/2 feet or at the body from below and behind. For grand piano, use a single C 414B or an XY, MS, or ORTF pair aimed at the middle strings from 5 to 7 feet up. For a rock or pop sound, use two mics roughly 8 to 16 inches above the strings, one aligned with the treble strings and one with the bass, both about 6 inches behind the dampers. Upright piano uses the same approach with the lid open. Drum overheads call for two C 414Bs in AB or XY about 2 3/4 to 4 feet above the drummer's head, with the manual's blunt advice to use little or no EQ. Toms get one mic per tom or per pair of toms, aligned with the rim of the top head, with HF above 10 kHz attenuated on the channel to reduce leakage. Double bass gets the mic aligned with an f-hole from about 16 inches, moving closer with a hypercardioid pattern when tracking alongside an ensemble.
The documentation doesn't give production years, original list price for the B-XLS specifically, weight, dimensions, or connector type. Collectors pricing one today are working from the used market rather than a published MSRP. The B-XLS is new enough to be a modern surface-mount production mic and old enough to have been superseded in AKG's lineup. That makes it a working tool rather than a collectible, and the ones that survive tend to have been used hard.
The caveats are plain. The 10-to-15-second settling time on pattern and pad changes rules it out for anyone who needs to switch settings on the fly. The 48 V phantom-only requirement means it won't run off a T-powered supply or a tube preamp's oddball voltage. The 2200-ohm minimum load impedance is a real constraint with some vintage preamps. And the pushbutton-and-LED scheme, while more precise than the old rotary switches, is also more to go wrong. A locked selector that the operator has forgotten about will read as a dead mic to anyone who doesn't know the three-second hold.
None of that changes what the mic is for. It's a workhorse large-diaphragm condenser with genuine headroom, low self-noise, five usable patterns, and a filter set designed by someone who understood the difference between rumble and proximity effect. For anyone tracking a wide range of sources with one mic, it's a defensible answer. Mix (September 2004, p.130) framed the pair as improvements to a studio standard rather than a new direction, and that's the right way to think about it — a refinement of a long-running design, not a departure from it.
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