Here are some frequently asked questions and answers.
All THX Certified receivers have internal test noise that THX verifies during the certification process. When using the test noise in a THX Certified receiver, the volume level is automatically adjusted to the THX Reference Level when utilizing the test noise. If you have a different receiver, it should feature an internal test noise though you may have to select an arbitrary volume level. Likewise when utilizing a test noise track on a DVD or Blu-ray.
When calibrating using the internal test noise in a THX Certified receiver, you should target 75 dB on your SPL meter. If using a test disc, it may be 75 dB or 85 dB, depending on how the tracks were mixed. The disc should provide instructions.
The size of your speakers makes a difference in performance. While many well-known speaker brands push smaller speaker concepts, THX® recommends resisting the temptation to go too small. The smaller the speaker, the more you may compromise in terms of output and low-frequency performance. Try to find a balance between the size you desire and the sound quality you expect. THX® Certified speaker brands are renowned for their design aesthetic, creating high performing speakers that blend with any décor.
Yes. Don’t think about getting a home theater system without a subwoofer. THX recommends getting the biggest subwoofer that your living space and budget will allow. In the world of THX Certified speaker systems, typically a 12-inch or 2×10-inch subwoofer is a minimum requirement.
The best placement for the speaker bar is your bar right below your TV. We don’t recommend placing the speaker bar above your TV or somewhere else in the room. For the optimal sound experience, it should be right below your TV set, should not be tilted, and it should align and face vertically with your TV screen.
We suggest performing a manual loudspeaker calibration instead of automatic setup. There are two parts to the calibration, distance and level.
For distance, simply measure and record the distance from each loudspeaker to the primary listening position. Enter these distances in the loudspeaker setup menu.
To set levels, you will utilize the receiver’s internal test tones and an SPL meter. There are a number of SPL meter applications for both iOS and Android. They may not be as accurate as a standalone, dedicated meter but they’ll certainly work for this.
Position the meter/phone near the ear level of the primary listening position. Start the test tone level calibration in the loudspeaker setup menu and adjust the level up or down for each loudspeaker so that the SPL meter reads ~75 dB SPL, C-weighted. Let the system cycle or manually cycle through each of the loudspeakers. When calibrating the subwoofer level, it is beneficial to move the meter/phone across multiple seating positions near primary as the bass level typically varies by location in the room.
As an aside, THX recommends setting all loudspeaker sizes in the menu to Small as the receiver will perform the bass management and route appropriately to the subwoofer.
Monitor Viewing Distance: There should be a 28-inch viewing distance from your desktop display to your seating position.
Front Speakers: If you have a 5.1 desktop system, the Front Left and Right speakers should be placed to the side of your display, with the Center Channel Speaker either above or below the display —aimed at the listening position.
Surround Speaker Set Up: If you have a 5.1 desktop system, the Surround speakers should be positioned 56 inches from your seating position.
THX® Spatial Audio is a flexible positional audio solution that delivers pinpoint audio accuracy to provide the listener with a heightened, realistic and immersive entertainment experience. Using real-time rendering and spatial positioning of stereo and multichannel content, THX Spatial Audio can be optimized for playback across all devices (speakers, headphones, laptops and mobile phones), content types, and listening genres.
THX® Spatial Audio enhances stereo and surround sound to deliver the highest level of audio that intensifies soundscapes in all forms of entertainment.
THX® Spatial Audio can be optimized for playback across all devices (speakers, headphones, laptops, and mobile phones), content types, and listening genres. You can find the current THX Spatial Audio products here.
THX Achromatic Audio Amplifier (AAA) is an analog amplifier technology that combines the qualities of the finest Class A amplifiers with greatly reduced energy consumption. It has the ability to drive heavy and difficult headphone and loudspeaker loads to full output while maintaining impeccable performance. THX AAA™ produces the purest performance of any amplification technology now available, ensuring that the art of musicians and filmmakers can be experienced as close to the original as possible.
Crossover distortion occurs in many amplifiers when the audio signal is “handed off” from an amplifier’s positive-going output device to its negative-going device and vice versa. This transition is never perfect, resulting in crossover distortion that is spiky in nature and rich in high-frequency distortion products. This is easily heard.
Moreover, the problem becomes more audible as the signal level decreases. The more delicate the music, the more it will be masked and obscured by crossover distortion. THX’s patented distortion-reduction circuit reduces crossover distortion to vanishingly low levels (less than 0.0001% @ 1 kHz), resulting in a more accurate reproduction of the original content.
The distortion reduction in the THX AAA™ technology has an additional benefit: it dramatically reduces power supply-induced distortion and noise — a high PSRR (power supply rejection ratio). This means it can achieve exceptionally low noise and distortion floors.
In any amplifier, when the power supply works hard under heavy load conditions, it can sag and ripple, introducing unwanted distortion and noise in the amplifier output signal. The THX patented solution is particularly effective in blocking power supply ripple from reaching the output.
That means more of what you hear is music, and less of what you hear is the character of the power supply noise associated with the amplifier.
Combining this with meticulous layout and design, the THX AAA technology delivers a signal- to – noise ratio (SNR) in excess of 130 dB — this is 30 dB greater than most amplifiers. That’s 30 times less noise than typical amplifiers — the perfect amplifier for a high-resolution audio playback system.
One way to reduce amplifier power consumption is to reduce the bias current flowing through the output devices. This has two effects: it reduces the idle dissipation (good) but increases the crossover distortion (bad).
By applying the THX patented circuit, it is possible to virtually eliminate the crossover distortion while retaining the benefits of lower power consumption.
For portable devices with AAA, this means unlocking a Class-A experience with long battery life and small form factor.
For desktop devices with AAA, this means cool operation and minimal carbon footprint.
The MPAA requires all domestic (U.S.) trailers that they rate to be TASA certified.
The maximum turnaround from receipt of completed TASA form and trailer files is 24hrs, excluding holidays and weekends. If a trailer is received by 4pm, it is typically completed the same day.
The fee for TASA Certification is $550 for standard audio trailers, and $780 for immersive audio formats such as Atmos.
Leqm measures decibels averaged over time with a weighting curve that is more sensitive to annoyance frequencies: breaking glass, explosions, and other piercing sounds. This allows for trailers to have loud explosions with enough quiet parts to balance it out so as not to fatigue or annoy the audience.
TASA approved LeqM meters:
The current TASA upper limit is 85 LeqM measured on a TASA approved meter.
Trailers that are non-compliant (exceed the upper limit) will need to be adjusted and resubmitted with a new form. An email will be sent to the client and MPAA notifying them of the trailer and its measurement. The revised trailer will be measured with a reduced retest fee of $280.
A Blind Trailer Check ensures compliance by measuring the trailers that are sent to the theaters to check against the certified measurements. BY participating in the TASA program, studios grant THX the ability to randomly check trailers of theatrically distributed DCPs.
For further information, you can find the TASA Standard Technical Document on the official TASA website.
For optimal viewing, you want your line of sight to be more or less aligned with the center of the screen. We suggest 15 degrees or less, above or below the center, as seen in the image below.
For 4K or ultra-high definition (UHD) TV models, they have various layers of LCD enhancement that focus light in specific ways. If you elevate your TV, you’re going to distort the picture quality.
A good rule of thumb is to divide your screen size by .835. This will give you the ideal maximum gap (in inches) between your couch and your 4K set.
To determine what size TV you should purchase, we recommend you measure the distance between your couch and where your TV will be located (in inches). Then multiply that number by .835, and that should help you determine what screen size you should get.
But for 4K or UHD TV sets, the process is a little different since the nearer you sit to these models, the more detail you’ll be able to pick up.
Different content requires different needs from your display. Many TVs include viewing modes optimized for genre-specific content. THX® Certified TVs offer THX Cinema Mode, THX Game Mode, and THX Bright Room. Read more about viewing modes here.