High Precision Electrostatic Laminates

Warwick Audio Technologies’ HPEL transducers operate on the electrostatic principal, whereby an ultra-low mass diaphragm is moved entirely by electrostatic force, without magnetics or high current requirements.

HPELs are lightweight, flexible, have thin form factor, and are highly power efficient, making them the solution of choice for a vast array of applications. In particular, HPELs provide a viable electrostatic solution to mobile and portable applications where previously only traditional transducers could be considered.

Our patented design enables HPELs to be manufactured in volume at significantly lower cost than any comparable planar technology product. As a result, HPELs are exceptionally consistent in unit-unit performance and extremely durable in comparison to other planar transducer solutions.

HPEL transducers are manufactured exclusively by Warwick Audio Technologies Ltd. in the United Kingdom.

The Warwick HPEL transducer is available to OEMs and ODMs for licensing in a range of headphone and loudspeaker products.

  • 15 μm thick diaphragm with ultra-low moving mass for improved high frequency extension and faster transient response
  • Very large diaphragm area without separate suspension components allows for superior low frequency fidelity with lower distortion 
(in headphone applications)
  • Diaphragm driven uniformly across its entire surface area minimises acoustical breakup modes and other anomalies
  • Elimination of magnetic drive systems prevents inherent distortion and hysteresis effects common in traditional transducers
  • Single-ended design eliminates bulky drive structures, reducing acoustical reflections and diffraction
  • Extremely consistent, highly-matched performance; typically < 0.8 dB variation
  • Simple, robust, 3-layer laminate design is exceptionally reliable and durable
  • Thinner mechanical profile enables greater freedom of design
  • Lightweight structure provides improved user comfort and portability
  • Scalable yet precise automated manufacturing techniques deliver high quality at low cost
  • Various sizes, shapes and performance levels can be customized to meet nearly any design requirement

True Hi Res Audio performance means several things:

  1. Wide Bandwidth – linear performance from the lowest (bass) frequencies, around 10 Hz, to the highest (treble) frequencies, above 50 kHz. The human ear is amazingly adept at perceiving musical information – harmonics and transients – well above the established upper limit of hearing (about 20 kHz for steady-state signals).
  2. Wide Dynamic Range – wide dynamic range is not defined by how loud a system can play, but by how quiet it can play while still resolving very low level detail and information accurately. This translates into resolving ability at the bottom end of the dynamic range, defined by the noise floor and distortion limits. Dynamics also means how quickly a system can go from very quiet levels to very loud levels, and vice versa. The transitions between must be “lightning-fast” and effortless.
  3. Freedom from Distortion – there are many types of distortion that can wreak havoc on a system’s realizable dynamic range and perceptual fidelity. Harmonic distortion, intermodulation distortion and transient intermodulation distortion all must be minimized under real-world operating conditions and at all output levels.
  4. Time Domain Fidelity – time domain fidelity can be thought of as transient performance or phase response. Music is transient by nature, and highly dependent on timing; it is not a steady-state test signal. Ideal transient response - a system’s response to a sudden start or stop of a signal - as well as a smooth, controlled phase response, free from gross anomalies and sudden or significant phase shifts, is crucial for proper audio reproduction.

Warwick Audio Technologies’ HPEL transducer has been designed with these requirements foremost in mind. The HPEL transducer has been optimised specifically for the reproduction of Hi Res Audio, but will sound significantly better even with standard resolution and compressed audio.

Of course, HPEL transducers will perform differently in different applications. The following laboratory measurements affirm the HPEL’s typical acoustical response in standard transducer performance tests.



Single-Ended Electrostatic Drive Planar Transducer

Effective Surface Area

3570 mm2

Frequency Response

10 Hz – 65 kHz

Maximum Output

110 dB SPL (peak); meets or exceeds EN 60065/A12:2011 (EN50332)

Load Impedance

120 pF, primarily capacitive

Bias Voltage

1350 VDC

Drive Voltage

145 Vrms maximum


Standard two-wire connection (+ and -)

Dimensions (Panel)

100.00 mm (L) x 70.00 mm (W) x 0.78 mm (H)

Dimensions (Overall)

103.75 mm (L) x 74.00 mm (W) x 10.10 mm (H)

The design and specifications of HPEL transducers are subject to change at any time by Warwick Audio Technologies Ltd.

HPEL transducers are manufactured exclusively by Warwick Audio Technologies Ltd. in the United Kingdom. The Warwick HPEL transducer is available to OEMs and ODMs for licensing in a range of headphone and loudspeaker products.

HPEL transducers are manufactured by a bespoke, automated roll-to-roll process with finished laminates assembled into HPEL support frames or “cassettes”. This means that customization for individual customer needs is both simple and relatively inexpensive.

HPEL transducers can be customized as follows:

  • Overall size – HPELs can be scaled upward or downward in size (surface area)
  • Shape – HPELs can be formed in nearly any shape – round, oval, rectangular, etc.
  • Curvature – HPELs can be flat or curved in any dimension
  • Internal cell size and shape – various internal cell sizes and shapes can be accommodated
  • Mounting frame – custom mounting frames can be molded to specific requirements
  • Electrical termination – HPELs can accommodate various electrical termination schemes from their integrated PCBs

COMSOL FEA Modelling Tools:

A specially commissioned COMSOL FEA modelling, graphical user interface (GUI) is available to aid HPEL transducer customisation for customer-specific design requirements and performance optimisation.