The Audio-Technica AT4047/SV represented a deliberate departure from the transformerless designs that characterised several of the company’s earlier professional condenser microphones. Introduced in 1999, the microphone was developed to recreate certain sonic characteristics associated with classic field-effect transistor studio microphones of the 1960s and 1970s, while incorporating contemporary improvements in capsule manufacturing, electrical performance and mechanical reliability.
During the 1990s, Audio-Technica had established its professional 40 Series through microphones such as the AT4033, AT4050 and valve-powered AT4060. While these models demonstrated the company’s commitment to modern condenser microphone technology, the Audio-Technica AT4047/SV was conceived with a different objective. Rather than pursuing an exclusively neutral, transformerless design, Audio-Technica combined a specially tuned condenser capsule with a transformer-coupled output stage to achieve the warm, full-bodied reproduction associated with earlier generations of studio microphones.
At the centre of the Audio-Technica AT4047/SV is an externally polarised, or DC-biased, dual-diaphragm condenser capsule. Unlike the permanently polarised capsule employed in the earlier AT4033, the Audio-Technica AT4047/SV uses a true condenser design in which the polarisation voltage is generated by the microphone’s internal electronics. This arrangement forms part of a carefully engineered acoustic system designed to maintain consistent sensitivity and directional characteristics across the microphone’s operating frequency response.
The capsule incorporates two specially contoured diaphragms manufactured from an exceptionally thin, 2-micron material with a vapour-deposited gold coating. The reduced diaphragm mass contributes to accurate transient reproduction and improved response to rapidly changing acoustic signals. Audio-Technica developed the diaphragm construction specifically for the Audio-Technica AT4047/SV, combining low mass with sufficient mechanical stability for professional recording applications.
Each diaphragm undergoes a proprietary five-stage ageing process intended to stabilise its mechanical characteristics and maintain consistent performance over extended periods of operation. This manufacturing technique helps preserve the capsule’s sensitivity and acoustic behaviour while reducing the potential for changes caused by mechanical relaxation of the diaphragm material.
Although the Audio-Technica AT4047/SV employs a dual-diaphragm capsule, it operates with a fixed cardioid polar pattern. The dual-diaphragm arrangement was designed to maintain precise cardioid pattern definition throughout the microphone’s frequency response, providing consistent rejection of unwanted sound arriving from the sides and rear.
The microphone’s cardioid pickup pattern makes it suitable for close vocal recording and individual instruments where separation from surrounding sound sources is required. By reducing the pickup of unwanted room reflections and neighbouring instruments, the Audio-Technica AT4047/SV allows greater control over the recorded signal in both isolated studio environments and recording spaces containing multiple performers.
One of the most significant aspects of the Audio-Technica AT4047/SV is its transformer-coupled output circuitry. Unlike the transformerless architecture of the AT4050 and several other 40 Series microphones, the Audio-Technica AT4047/SV employs an output transformer as an integral part of its electronic design. This transformer works in combination with the microphone’s specially tuned condenser element to produce the harmonic characteristics associated with classic FET microphone technology.
The transformer-coupled circuitry contributes to the microphone’s distinctive low-frequency character and overall tonal balance. Rather than simply reproducing the electrical behaviour of Audio-Technica’s transformerless models, the Audio-Technica AT4047/SV was designed to provide a warmer and more rounded presentation while retaining the clarity, sensitivity and dynamic capabilities required for modern studio recording.
The microphone’s frequency response extends from 20Hz to 18kHz, providing broad coverage of the audible spectrum. Its acoustic tuning delivers a controlled upper-frequency response with a gentle presence characteristic, allowing vocals and instruments to retain definition without excessive high-frequency emphasis.
For vocal recording, the Audio-Technica AT4047/SV combines the detail of a large-diaphragm condenser capsule with the smoothness associated with transformer-coupled electronics. Its low self-noise allows quieter vocal passages to be captured without significant microphone-generated noise, while its high maximum input capability accommodates powerful performances without overloading the microphone’s internal circuitry.
The Audio-Technica AT4047/SV is also suitable for acoustic guitar, strings, piano and other instruments requiring detailed reproduction of harmonic content and transient information. Its dual-diaphragm capsule and carefully tuned frequency response allow it to capture the attack and decay of acoustic instruments while maintaining the tonal character of the original source.
The microphone was designed to accommodate demanding sound sources, including electric guitar amplifiers, brass instruments and percussion. Its maximum input sound pressure level is rated at 149dB SPL at 1kHz with 1% total harmonic distortion. Engaging the integral 10dB attenuation pad increases this capability to 159dB SPL, enabling the microphone to be positioned close to powerful amplified and acoustic instruments.
With an exceptionally low self-noise figure of 9dB SPL, the Audio-Technica AT4047/SV offers particularly quiet operation for a large-diaphragm condenser microphone. Its signal-to-noise ratio of 85dB and typical dynamic range of 140dB provide sufficient operating headroom to reproduce substantial variations in acoustic level, from delicate instrumental passages to high-level sound sources.
An integral high-pass filter operates at 80Hz with a slope of 12dB per octave. This allows unwanted low-frequency information to be attenuated before reaching the microphone preamplifier. The filter is particularly useful for reducing environmental rumble, mechanically transmitted vibrations and low-frequency disturbances associated with close vocal recording.
The microphone incorporates separate switches for the high-pass filter and 10dB attenuation pad. These controls allow the Audio-Technica AT4047/SV to be adapted to different recording situations without requiring additional external processing or changes to the microphone’s position.
The Audio-Technica AT4047/SV features a precision-machined, nickel-plated brass acoustic element baffle designed to provide mechanical stability and maintain consistent capsule sensitivity. The acoustic structure supports the condenser assembly while minimising unwanted internal reflections that could otherwise influence the microphone’s frequency response.
The capsule is also mounted within an internal suspension arrangement designed to reduce the transmission of mechanically generated noise. This construction complements the external shock mount, helping isolate the sensitive condenser element from vibrations transmitted through the microphone body and supporting stand.
Audio-Technica incorporated surface-mount electronic components into the Audio-Technica AT4047/SV to maintain manufacturing consistency and reliability. The internal circuitry operates from standard 48V phantom power, drawing approximately 3.0mA, and provides a balanced output through an integral three-pin XLR connector.
The microphone’s output impedance is rated at 250Ω, allowing connection to professional microphone preamplifiers, recording consoles and audio interfaces. Its open-circuit sensitivity of -35dB, equivalent to 17.7mV at 1Pa, provides an output level appropriate for professional studio recording applications.
Visually, the Audio-Technica AT4047/SV is distinguished by its satin silver finish, which recalls the appearance of several classic studio condenser microphones. The substantial cylindrical metal housing measures 170mm in length and 53.4mm in maximum body diameter, with a weight of 410g. Its side-address configuration positions the condenser capsule behind a protective metal grille, with the principal pickup direction facing the front of the microphone.
The Audio-Technica AT4047/SV is supplied with a matching AT8449/SV shock mount designed to provide additional mechanical isolation from microphone stand vibrations. A protective dust cover and carrying case are also included, providing protection during storage and transportation.
Following its introduction, the Audio-Technica AT4047/SV attracted attention within the professional recording industry for its combination of traditional transformer-coupled sound and modern condenser microphone performance. Its design offered an alternative to the increasingly common transformerless studio microphones of the period, providing recording engineers with a different tonal option within Audio-Technica’s established 40 Series.
The success of the Audio-Technica AT4047/SV subsequently influenced the development of the AT4047MP, introduced in 2009. The later microphone expanded the original concept by incorporating selectable omnidirectional, cardioid and figure-of-eight polar patterns while retaining the transformer-coupled design philosophy established by the AT4047/SV.
The Audio-Technica AT4047/SV remains a significant model in the history of the company’s professional microphone development. By combining an externally polarised dual-diaphragm capsule, exceptionally low-noise electronics and a deliberately voiced transformer-coupled output stage, it demonstrated Audio-Technica’s ability to incorporate the sonic characteristics of classic studio microphone technology into a modern, precision-manufactured recording instrument.
Features
- Professional large-diaphragm cardioid condenser microphone introduced in 1999
- Externally polarised dual-diaphragm condenser capsule with fixed cardioid polar pattern
- Specially contoured, 2-micron-thick vapour-deposited gold diaphragms with proprietary five-stage ageing process
- Transformer-coupled output circuitry designed to reproduce the warm characteristics of classic FET studio microphones
- Dual-diaphragm construction maintains precise cardioid polar pattern definition across the frequency response
- Precision-machined, nickel-plated brass acoustic element baffle for improved capsule stability
- Exceptionally low self-noise of 9dB SPL and wide 140dB dynamic range
- High sound pressure level handling up to 159dB SPL with attenuation engaged
- Switchable 80Hz high-pass filter and 10dB attenuation pad
- Satin silver housing with 48V phantom-powered operation and supplied AT8449/SV shock mount