THX is a well-known and common term in both movie theaters and home theaters. We have already considered the general definition of THX in the overview of surround audio formats, but there are two specific certificates that deserve a little more attention; THX Ultra 2 and THX Select 2.
What is THX?
Those who are new to THX in the context of home cinema systems have probably seen the term in the cinema or seen the logo on DVDs or Blu-ray discs. However, contrary to popular belief, THX is not a surround audio format but a hallmark (also called certificate) for audio and / or video quality, issued by Lucasfilm. With regard to home cinema equipment, this means that equipment with the THX logo meets a specific set of requirements and standards that have been put together by Lucasfilm and that guarantees the best possible audio and / or video quality.
THX Ultra 2 and THX Select 2
On TVs, we increasingly see a picture mode that is THX certified, which means that the image display and settings in this mode meet the high requirements of the company and therefore a true and optimal image is displayed. The THX Ultra and THX Select certificates are used for receivers and speakers. These were introduced a few years ago and in the meantime a lot has changed in the field of home cinema. THX Ultra 2 and THX Select 2 were therefore created and place even higher demands on equipment.
Lucasfilm says it wants to advise consumers when purchasing a home cinema system by handing out certificates to speakers and receivers that offer good performance. However, the right components are only part of an optimal system. Other important parts are placement, calibration, and how room size and acoustics affect performance. To find the best speakers and receivers for your situation and wishes, THX has created different categories.
THX Select 2
Receivers (since 2009) and speakers that have a THX Select 2 certificate can provide an optimal home cinema experience in rooms of approximately 56 cubic meters, with a viewing distance of 3 to 3.5 meters from the screen.
THX Ultra 2
Products, including receivers and speakers, that have a THX Ultra 2 certificate can provide an optimal home cinema experience in rooms of approximately 85 cubic meters, with a viewing distance of at least 3.5 meters to the screen.
THX Ultra 2 Plus and THX Select 2 Plus
Lucasfilm, however, goes one step further for optimal audio reproduction and has developed the Reference Level program. The Reference Level means that THX certified receivers with the volume set to ‘o’ offer an audio reproduction exactly as intended by the filmmaker. Receivers with Reference Level are certified THX Select 2 Plus or THX Ultra 2 Plus.
THX I / S Plus
There is also a certificate for all-in-one home cinema systems (receiver with speakers) called THX I / S Plus. This certificate indicates that the system has sufficient power to provide an optimal sound in a small room with a viewing distance of 1.8 to 2.4 meters.
From the above it becomes clear that the difference between the two certificates has to do with the size of the room in which the home cinema system is placed. Higher requirements are therefore placed on components that receive a THX Ultra 2 certificate and are therefore suitable for larger spaces. For example, dipole surround speakers are recommended for THX Select 2 systems but mandatory for THX Ultra 2 systems. Select 2 receivers also need less power than Ultra 2 receivers.
Theoretically, in a home cinema room of about 56 cubic meters, a THX Select 2 system should deliver the same performance (meet the same standards) as a THX Ultra 2 system.
Is a THX certificate important?
This is a question we often get and the answer to it is not simple or straightforward. If you place a lot of value on it and only look for components that meet all the requirements of THX, you can end up with a system that offers slightly better performance than if you didn’t. However, this is by no means a guarantee. You are almost certain that the various components work together as optimally as possible.