Applications

CONEQ™ is a radical new approach to sound system analysis and correction. Developed by Latvian based Real Sound Lab, CONEQ is a patented technology that stands for CONvolution EQualization. Differing from virtually all known measurement systems in use today, CONEQ technology is based on Acoustic Power (also known as Sound Power).

The development of CONEQ began about 20 years ago when its inventor, Raimonds Skuruls, hypothesized that the traditional method of measuring a sound system might not represent the complete behavioral pattern of the system being analyzed. Mr. Skuruls’ musings led him to conclude that an alternate measurement method could be of significant value in understanding, and therefore ultimately improving, the sonic quality of a sound reproduction system. Conventional acoustical measurement systems rely on the use of Sound Pressure Level techniques. By definition, a Sound Pressure Level measurement is the deviation in the local ambient pressure (p0) caused by a sound wave at a given location and given instant in time. In the case of a loudspeaker measurement, the sound wave is of course generated by the loudspeaker under test.

An SPL measurement is always taken at a single point in space. As such, an SPL measurement is analogous to a voltage measurement. It can realistically be compared to measuring the voltage of a main or branch circuit in a town or neighborhood. You learn something about the power distribution system, namely its voltage at that specific measurement point, but you learn nothing at all about the power that is, or is not, being developed.

Conversely, an Acoustic Power measurement is analogous to measuring the electrical power that’s developed within a circuit. In loudspeaker terms, an Acoustic Power measurement concerns itself with the sound field emitted by the loudspeaker, rather than just its on-axis response and/ or discreet off-axis response points.

Polar Response measurements have been used for decades to acquire and display a loudspeaker’s directional response characteristics. More recently, spherical (or half-spherical) measurements taken at 5 degree intervals have become something of a standard, being commonly used to drive acoustic modeling programs. Both techniques are, however, a series of unrelated pressure measurements taken at geometric intervals around a sound emitting device.

Conversely, a CONEQ Acoustic Power Measurement consists of hundreds of measurement points taken around the loudspeaker system in the span of approximately two minutes. Following the data acquisition, CONEQ calculates the complex conjugate of the hundreds of separate datum using a proprietary algorithm. The calculation integrates the several hundred measurement points into a composite response plot. The result is an accurate characterization of the sound emitter’s Acoustic Power Frequency Response.

Displaying the Acoustic Power Frequency Response of a loudspeaker system, however interesting it might be academically, would have relatively little value if something constructive couldn’t be done to improve the loudspeaker’s performance. With this in mind, CONEQ was developed to provide a high-resolution inverse-response correction curve that is then applied to the loudspeaker, or loudspeaker array. The corrective response curve is the precise mathematical inverse of the loudspeaker’s deviation from a theoretically flat response.

A CONEQ correction, as typically used for recording and sound reinforcement systems, consists of a 4096 point FIR filter, although lower resolutions and higher resolutions (up to 65,536 points) are possible, depending on available hardware. CONEQ employs minimum phase filters, rather than linear phase filters, keeping latency manageable at 1.2 ms.

In addition to CONEQ’s basic algorithm, which is intended to solve for an absolutely flat response, CONEQ may be used to solve for one or more specific target curves. A few examples of target curves include flattening the response of a computer’s sound card to improve measurement accuracy; compensating for deviations in the measurement microphone itself; applying a preferred ‘house’ response curve; compensating for air absorption loss over distance, and making one type of loudspeaker sound nearly indistinguishable from another.

CONEQ provides a user selectable high-pass filter in order to avoid exciting small format low frequency drivers with excessive low frequency energy. Additionally, in both the high and low frequencies, the extent to which correction is applied may be controlled by the user in order to avoid excessive use of power in an attempt to overcome severe driver deficiencies.

Once acquired, a CONEQ corrective response curve may be applied entierly within software - CONEQ P1 Equalizer, CONEQ A1 Equalizer, or may be uploaded to a CONEQ Acoustic Power Equalizer Realization Tool- APEQ-2PRO. The primary benefit of CONEQ’s extremely high-resolution correction is the exceptional linearity brought to the loudspeaker system, which results in unusual sonic accuracy and realism.

In addition to sonic realism, CONEQ increases intelligibility in live sound applications while reducing feedback. In recording applications, a CONEQ corrected monitoring system improves translation to other playback systems, even those that are not themselves CONEQ corrected.

Presently available in a two channel version with more models soon to come, a CONEQ Acoustic Power Equalizer is a balanced-in, balanced-out 1U device that provides a simple means of inserting two CONEQ corrective filter channels into the signal chain of a professional sound system.

Of special interest to manufacturers, CONEQ may be licensed for inclusion in audio products such as powered loudspeakers, amplifiers, loudspeaker management systems and other signal processors, in both the professional and consumer markets. Properly applied, CONEQ is cable of closing the ‘content uniformity loop’ between content origination in recording studios and post production facilities, and content experience in homes, cinemas, automobiles and other consumer environments.