Class - D Audio Power Amplifiers:


The Class-D Audio Power Amplifiers used in all Charles Grecco products are the culmination of over 12 years of development.
Features include:

* Compact size: 4.25 x 4.1 x 1.75" (108 x 105 x 45mm)
* High output power: >1000Wrms
* Wide bandwidth: <5Hz to >35kHz
* Low distortion: <0.02% at 10W output, <0.1% at rated power
* High efficiency: >90%
* On-board microprocessor for amplifier control and status
monitoring and communications
* Full protection against load faults and thermal stress
* Isolated crystal-controlled clock for minimum noise
* Proprietary feedback network that minimizes frequency response
errors related to variations in load impedance
These state-of-the-art amplifiers are powered by a companion switchmode power supply, that also features high efficiency and compact size. Its switching frequency is specifically optimized  to minimize noise artifacts in the audible range.

Each powered loudspeaker also features a DSP-based active crossover driving its array of up  to 4 amplifiers. This DSP provides steep crossover slopes to minimize loudspeaker out-of-band response anomalies and advanced pattern control. It also provides additional time-alignment  and fine equalization of all drivers in the array.
John Levreault
Orvelle Technologies, Inc.
Amplifier Design


Vance Dickason called long time friends and woofer designers Patrick Turnmire, and Enrique Stiles of Redrock Acoustics. These two men are truly remarkable at what they do. When you hear Dickason say that “they may be the world’s best driver designers” you know you have something. Working exclusively with the world’s largest driver manufacturer, Sonavox, Turnmire developed the world’s standard in driver modeling software, SpeaD. Turnmire and Stiles developed for Charles Grecco what they believe is the world’s most advanced line of raw drivers.

Ranging from 4 inch midrange drivers to 15 inch woofers and sub-woofers, these products not only meet the stringent requirements for use in the pro audio industry but they have also helped develop and incorporated the most sophisticated real-time sensing devices which will continually monitor the temperature of the coil and its excursion in future designs. The four-inch mid bass driver used in the line array was tested with pink noise at 200 watts for 8 hours of continuous use with a compression loss of only 2dB. This is a result of the cooling provided by their mMag technology is licensed exclusively in pro audio by Charles Grecco.

Ribbon Tweeter:

The use of planar magnetic drivers for pro sound provides a remarkable clarity and detail that is simply not possible with compression drivers and horns. The large radiating surface area and extremely low moving mass of the tensioned film diaphragm provides unparalleled speed and openness.

Planar magnetic drivers; sometimes referred to as ribbon speakers, have long been regarded as the best high frequency devices available. Additionally, they have also had a reputation for being fragile and inefficient. Currently, with the availability of neodymium iron boron magnetic material and significant advances in the materials science related to the construction of etched foil clad polymer film, today's planar magnetic drivers are as efficient and handle several times the power of even the best compression drivers with a fraction of the distortion.

The sensitivity of the 11.5" driver designed for Charles Grecco is 105 dB@1w/1m, and is capable of handling 3600 watt peaks for 200 ms. The output is fed into a manifold wave guide to create a radiating source width of 0.75", resulting in a remarkably wide, (110 degree) and even horizontal radiating pattern. High frequency extension is well beyond 20kHz.

The subjective experience when listening to these systems is that of hearing the best audio reproduction available anywhere, including the highest priced, most sophisticated consumer loudspeaker systems. That fact that this design when used in tandem in the Charles Grecco line array can effortlessly attain the SPL levels required for live sound in even the largest venues is a monumental technical achievement.

David Graebener
Ribbon Designer


BMS 4595 COAX Compression driver:


Extended Bandwidth (300 - 22000 Hz)
Neodymium Magnet Assembly
With two Subsystems in one, each Driver covers a smaller Frequency range for increased Power Handling, high Dynamic and extremely low Distortion
Excellent Phase Coherence
Perfect Time Alignment without Problems of Multi-Source Interference
Ultra light Weight and small Size

The 4595ND is a 1,5" coaxial compression driver delivering a real coherent single point wave front without hot spots with excellent phase coherence and perfect time alignment. The driver is in fact a 2-way system employing two concentric annular ring diaphragms. Each driver covers a smaller frequency range for increased power handling, high dynamic and extremely low distortion.

The larger of the two reproduces middle frequency from 300 Hz upward, crossing over 6,3 kHz to the HF transducer which is capable of reaching 22 kHz. The large diaphragm excursion of max. + / - 0,8 mm results in high output and increased power handling up to 1300 W peak. The voice coils may be driven in conjunction with a passive crossover or driven individually from an active crossover. The outer casting features extensive heatsinking ensuring high power handling and low compression.



Constant Directivity Horns

All of the horns in our product line have been exclusively design by Mr. Charlie Hughes. You will find several articles in Live Sound Magazine, as well as Syn-Aud-Con white papers. He is also a member of the EASE and EASERA Developers Group.

The main design criteria we set out when developing this line of horns was precise pattern control, as well as exceptional sound quality. Mr. Hughes has not disappointed. These horns are the most accurate and musical horns I have ever offered.

There are four standard horn patterns for the Installation Series and the Wedge Trap Series. They are: 60X45, 60X60, 90X45, and 90X60. The front fills have a 120 degree Slot horn, (pictured) as well as 45X90 and 45X60. As needed, we can add specific horn patterns to suit your customers’ needs.


Cabinet Designs and Testing:

The boxes are manufactured in Nashville TN, using the latest in automated machinery. We use 13 ply Baltic Birch. Once coated with truck bed liner, the cabinets are sent to another facility in Nashville for component loading and final assembly. All products are acoustically tested before leaving the facility. All EASE data is independently provided by NWAA labs (