September 24, 2009

ntegra, Parasound, Snell and Diodes Zetex Semiconductors Develop THX “Big Room” Product Concepts

By Gary Reber

THX Ltd. has introduced THX “Big Room,” a new product design and certification concept that brings professional audio quality and performance to prosumer amplifiers, pre-amplifiers and loudspeakers. THX “Big Room” bridges the gap between the consumer and professional audio worlds, offering custom installers more hardware choices for designing large, multi-row media rooms and home theaters.

THX showcased this new category of THX Certified concept products from Snell Acoustics, Parasound, Diodes Zetex Semiconductor and Integra at CEDIA Expo 2009.

The THX “Big Room” certification builds upon the THX Ultra2 Plus program, ensuring speakers, amplifiers and preamps are designed with the performance necessary to deliver studio Reference Level volume (85dB) and headroom in large home theaters where the viewing distance from the screen is 20 feet and beyond—rooms 660 square feet or 8,000 cubic feet in size. This expanded THX specification will let audiences experience the raw power and emotion of cinematic soundtracks in the largest home theater environments.

“The THX ‘Big Room’ concept is bringing together premium audio brands from the professional and consumer worlds to fill a critical need in the custom install market,” said Warren Mansfield, director of consumer technology at THX. “THX is setting a design and performance benchmark for audio products in the large room category, providing CEDIA professionals a wider portfolio of products for their most challenging installations.”

“Snell has always wanted to design an audiophile product that would set a new precedent for audio performance in large room applications,” said Joseph D'Appolito, Snell’s Chief Engineer. “We’re thrilled to be part of the ‘Big Room’ project with THX and look forward to bringing custom installation professionals the tools they need to create truly astounding large-room home theater audio systems.”

Most consumer-grade speakers and receivers are designed for average sized residential home theaters and living rooms—1,000 to 3,000 cubic feet in size. When used in rooms that exceed this size, consumer components are often overdriven, causing clipping, distortion and physical damage to loudspeakers. THX “Big Room” systems include at least two rows of monopole/bipole side surround speakers and four individually calibrated and delay-adjustable subwoofer outputs to ensure enveloping coverage throughout the seating area.

“With the vast number of large, private screening rooms that we have been designing over the years, we are very excited to now have the choice of fully THX Certified ‘Big Room’ systems,” said Anthony Grimani, president of Performance Media Industries (PMI). “These products will be a great complement for our new generation of large-screen PMI 2.0 venues.”

THX “Big Room” systems require higher power transducers and speaker bi-amplification. This provides the maximum flexibility to speaker designers, as well as protects the speaker drivers from damaging harmonics when driven hard. The crossover and amplification can be either internal or external, allowing for self-powered or externally powered systems.


Snell Acoustics demonstrated the world’s first prototypes of THX “Big Room” LCR speaker systems. These bi-amplified loudspeakers are powered externally with an active crossover and equalizer. The high power and high sensitivity design uses compression driver horns.

Parasound showed the world’s first THX “Big Room” power amplifiers. The concepts shown at CEDIA feature variable gain design, higher voltage rails and higher power than traditional consumer amplifiers. This provides the amplification necessary to fill large home theaters with high impact sound.

Integra has a new pre-amplifier that follows the “Big Room” requirements, featuring lower noise and additional side surround and subwoofer channels.

Diodes Zetex Semiconductors provided the bi-amping frequency division and equalization in a crossover processor. This is achieved using their ZXCZEVB80DAC multi-channel DAC and digital preamplifier demonstration board using the Zetex Direct Digital Feedback Amplifier (DDFATM) chipset. The chipset is available to hardware manufacturers on an OEM basis for implementation into audio video products.

Tags: - CEDIA 2009 - - THX Ltd - - Big Room certification - - prosumer amplifiers - - pre-amplifiers and loudspeakers - - Snell Acoustics - - Parasound - - Diodes Zetex Semiconductor - - Ingegra -