THX Tech Tip

Not Hearing Enough Bass From Your Subwoofer? It Could be your Room

 

 

Your subwoofer is a critical element in your home theater system. The low frequency from the subwoofer is what puts the boom in an explosion, the rumble in a spaceship and the thud in a gunshot. However, even the biggest and baddest subs may not meet your expectations if they aren’t placed and set up properly.

“It’s a classic story amongst Home Theater Professionals – the client spends all this money getting a giant subwoofer to complement the rest of their system. But, when they sit down to watch a movie, the person next to them complains about too much bass, while others feel the bass is too weak.
– John Dahl, Director of Education at THX Ltd.

It could simply be a difference in personal preference, but more than likely it’s the room itself that is the root of the problem.

THX Certified pm3 Studio

THX pm3 Certified DiMAGIC Studio

THX Certified pm3 (multichannel mixing and monitoring) Studios are ideal for motion picture pre-mixing and producing television programs, music, video games and other content for non-theatrical release. THX sets strict standards for pm3 studio acoustics, noise levels and production equipment performance, resulting in a technically flawless production environment for capturing multichannel soundtracks and high definition visuals.
THX pm3 Certified Studios can be found at Sony Computer Entertainment, the Cleveland Institute of Music and Fox Studios.

THX Certified Studio Specifications

THX Certified Studios and pm3 rooms are designed to offer the world’s premier standard for quality.

THX pm3 and Studio Specifications

• Listening and Viewing Environment
• Acoustic performance
• Structural isolation
• Reverberation time
• Preferred dimensions
• Color scheme and ambient light for optimum video monitoring

• Working Area Layout and Equipment
• Loudspeaker position
• Video monitor position
• Optimum listening positions
• Site lines
• Speaker focus angle

• Audio and Video Equipment
• Front and surround speakers
• Subwoofers
• Power amplifiers
• Bass management system for multi-channel monitoring (applies only to THX Certified pm3 rooms)
• Multi-channel equalizers and digital delays
• Video monitoring

• Calibration
• Audio and video calibration
• Specific test equipment and signals
• Performance requirements

THX Cinema Certification

THX Certified Cinemas

Designed to recreate the acoustics and ambience of the studio, our cinemas allow audiences to experience their favorite movies exactly like the director intended.

THX Certified Cinema Reverberation Control

Reverberation is the presence of sound after its source has stopped – much like an echo. In a movie theater, reverberation often builds as sound reflects off surfaces such as walls, floors and ceilings.
For example, in an action film, such Iron Man, there are several instances where the movie’s hero (Tony Stark) is being chased through the sky by two fighter jets, followed immediately by quiet, more dialogue-driven moments. In a THX Certified Cinema with tightly controlled reverberation, the sound of jet engines and explosions ends immediately, never bleeding over into the next scene.
Among the methods THX uses to control reverberation is covering the rear wall of the auditorium with thick, absorptive material. This prevents the direct sound of the screen speakers from reflecting into the seating area. THX also requires the placement of absorptive materials on the sidewalls, down to the audience’s ear level. This reduces the amount of sidewall reflections.

Image caption with acoustic paneling

Acoustic paneling controls reverberation, or echo effect, in a THX Certified Cinema.

Image caption without acoustic paneling

Sound bounces off the walls without acoustic paneling, interfering with the movie’s soundtrack.

THX Auditorium Isolation

THX Certified Cinemas are quiet. They feature massive wall structures to isolate the cinema from the outside world—creating a pristine audio sanctuary. With these walls, audiences can focus on the movie experience in front of them, as opposed to distracting sounds from neighboring cinema auditoriums, outside traffic and lobby activity.

THX Sound Isolation Methods

• Large quantity of building material
• Isolating air gap
• Large quantity of building material

With THX Sound Isolation

The walls in a THX Certified Cinema are constructed to provide sound isolation from other auditoriums.

Without THX Sound Isolation

Without the use of the recommended building materials, thin wall construction allows sound to pass through to neighboring auditoriums.