At Rotel, we have been asked many times why our audio/video receivers don’t feature an Auto-Eq set up. The short answer is that while these devices do change the sonic characteristics, we don’t believe that they provide a real sonic improvement at this level of product manufacturing. Further, that the cost of including this feature comes at the expense of overall audio performance.
The electronics industry continues to evolve at a remarkable pace and surround-sound electronics along with big screen TVs have brought the cinema experience home. However, not every new feature should be taken at face value as a real benefit. Auto EQ is the latest feature touted to add more value to home theatre receivers. The premise of Auto EQ is that it takes the guesswork out of smoothing acoustic room variables through the use of a microphone and some digital signal processing. However, you don’t need to look much further than the comprehensive article from Keith Howard – “Anti-Node: Active Room-Acoustics Correction” in Stereophile – January 2008 to understand how difficult this is to do well, even with far more expensive dedicated EQ systems. While it might be construed that we are denigrating Auto-Eq because we don’t include it in any of our models, we stand behind our belief that this feature adds a cost factor that is far better off spent on higher performance parts, which can result in true sonic improvements.
As an analogy, it is a bit like purchasing a cheap automobile with heated leather seats, a powered sunroof, and 20” chrome wheels. Your car is then a little fancier than a others, but it still drives like a cheap auto. In fact, in some instances, auto-correction equalisation can do more harm than good. This is due to the fact that digital EQ processing at this level is nowhere near as sophisticated as it needs to be. A manufacturer’s home theatre receiver BOM (Bill Of Materials), will quickly show that they simply can’t afford to add the processing horsepower (cost of the chip) required to get the job done properly and still be competitive. The end result is that a value engineered Auto-EQ chip makes a guess about the worst offending frequencies, but by dramatically altering those sound waves, they also end up changing others that can affect the sound negatively.
If you are really concerned about getting the very best sound out of your home theatre, or stereo system, you should consult a Rotel audio/video specialist. They know how it all goes together: how to position speakers in a room properly and how to set up your system’s software for bass management and speaker levels to get the best sound. If you are looking to achieve the absolute best in performance, they can also consult with you regarding room mode correction treatment materials, or on designing a proper acoustic environment from the ground up.
At Rotel, we have not ignored the importance of having some flexibility in controlling room modes. Did you know that the new 15 series components have very flexible bass management options? They can provide independent speaker configurations and crossover settings for each channel and surround mode. You can even create basic “notch filters” for troublesome frequencies. As an example, if you had a room node at 90Hz, you could set the speaker mains to roll off at 100 Hz and the subwoofer at 80Hz. For even more flexibility, there are contour adjustments at 10kHz and 100Hz that can be set independently for each channel. These are acoustic adjustments that can subtly improve the performance of your system without creating wider problems. However, there is simply no substitute for a home theatre system that is designed and installed by knowledgeable experts.