Continuing from Part 1, this second article delves deeper into what you need to know about THX, and answers the most asked question I received from readers.
That question related to having a room that was slightly larger than the THX Select2 Plus recommendation, and wondering if they needed to buy a THX Ultra2 Plus-certified receiver.
For many people, even a THX Select2 Plus Certified system (speakers designed to power rooms up to 2,000 cu./ft.) would be overkill given the size of the room. However, up until now, the market for smaller spaces has been saturated by underperforming, highly promoted products - leading many people to believe that the best they could get was somewhat tinny sound, hardly any bass, and limited upgrade options.
The goal at THX is, and has always been, to bring the best possible sound and video quality to the consumer. Speaker designs, build materials, components, amplifier power, and other factors have prevented smaller, less expensive systems from being able to pass the strict certification performance benchmarks.
With recent technology advancements in the audio world, THX has been able to develop a certification program, without lessening the criteria, for smaller systems that perform well above what their diminutive size would imply.
Going back to the article itself, there are a few other things worth noting.
Of course no small system could fill a big room, nor should it ever be expected to do so. Rather, the THX Compact Speaker System certification program is designed and engineered to power rooms up to 1,000 cu./ft. - for example, rooms that are approximately 13.5 feet long by 10 feet wide with eight foot ceilings.
Just because the speakers power smaller rooms doesn't mean the certification criteria isn't asking them to do a lot. THX demands high output (up to 105dB) with low distortion. In a radical change from many other small speakers, THX also requires a flat frequency response, just like all THX-certified speakers.
Understanding that not all small rooms can fit a full surround sound system, the THX Compact Speaker System Certification program is flexible in that it will be found on 2.1 systems (two speakers and a sub) as well as up to 7.1 systems.
THX Reference Level
All movies are mixed in the post-production mastering suite at 85dB average loudness with 20dB headroom. On a properly calibrated theatre (be it home or commercial) this level is reached when the volume dial is set to 0dB (meaning zero attenuation of the output signal). However, since this level is very loud for home applications, most people will listen to -10dB to -20dB lower than reference. By moving the volume level down, the details of the soundtrack will change and not be as intended by the sound engineer. To solve this problem, THX invented the THX Loudness Plus algorithm as mentioned earlier in this article.
Can THX Certification Be "Bought?"
NO! For a receiver, for example, 2,000 tests with 14,000 data points must be passed before it can receive the THX certification badge. For a display, 200 tests covering 400 data points is required before it can receive the THX certification badge.
So does it mean that once you've purchased everything "THX" that your system doesn't need calibration? No. Having every unit be THX-certified means the units you've bought have passed (and or surpassed) the THX minimum standard requirements. You will then need to hire a THX Certified Professional to calibrate your system to the THX standards.