To get the best sound in your Home Theater or media room:
I am Audyssey trained and certified calibrator for Denon, NAD, Marantz, Onkyo/Integra and Audyssey Sound Equalizer.
Why Calibrate Your Audio System?
You just spent your hard-earned money on a
new home theater receiver/amp and speakers. If this is one of new
receivers I bet that it has Audyssey capability.
Audyssey’s Room Correction Solution
Movies, music and games are created in calibrated and acoustically treated rooms and meant to be played back at high volumes in large, acoustic theaters. But reflections from walls and furniture in home theaters and cars distort sound resulting in muddy bass, degraded high frequencies and surround envelopment. Decades of scientific research have gone towards trying to fix the room distortion problem. At Audyssey, we’ve finally solved it.
Based on 6 years and $6 million of research at the USC Immersive Audio Lab, MultEQ is the key enabling technology that delivers sound amazingly close to the original recording. Audyssey MultEQ is a patented method that measures and analyzes the acoustical space to compensate for distortion. MultEQ evaluates everything that causes distortion: frequency response variations and reflections that arrive at different times. AVRs, theaters, cars and studio equipment outfitted with MultEQ use this information to produce a more accurate tonal balance, better bass and more realistic imaging. MultEQ removes distortion so that every audio system – from budget home theaters to world-class cinemas and cars – sounds amazing.
Flavors of MultEQ
Audyssey room correction technology comes in four solutions: MultEQ XT32, MultEQ XT, MultEQ and 2EQ. While they are all built on the same core science, each is designed to operate within the constraints of the available DSP processing power.
MultEQ Comparison Chart
* Up to 32 measurement positions with MultEQ Pro. Most AVRs with MultEQ XT32 and MultEQ XT are installer-ready and can be calibrated by an Audyssey Registered Installer to provide even higher performance for even the most demanding large or odd-shaped rooms.
A typical loudspeaker frequency response will have several peaks and dips at various frequencies. These are caused because the sound from the loudspeaker interacts with surfaces and furniture in the room. In some frequencies these interactions add and give rise to a peak and at others they subtract and give rise to a dip.
The first step in correcting the effects of the room on the loudspeaker response is to generate the control points that will be used to morph the response into the desired shape. To capture some of the finer details in the response fluctuations, it is necessary to use hundreds of points. MultEQ dynamically applies the points where they are needed most, typically in the lower frequencies. MultEQ applies hundreds of correction points to each speaker's frequency response curve.
These control points allow MultEQ to form a near-perfect model of the loudspeaker response, which is key to making an accurate filter.
The MultEQ equalization filter is created by inverting the precisely-modeled response. Everywhere that there is a dip, the filter applies a peak with the same shape. Similarly, every peak is corrected by a dip. The more precise the model is (I.e., the more points used to create it), the better the inverse filter will be. MultEQ uses several hundred points to create the model and the corresponding filter.
Once the equalization filter is created, it is multiplied point-by-point with the loudspeaker response to create the desired smooth response in each seat.
The result is a response that can match any desired target shape with very high accuracy.
Parametric EQ is based on a different principle. Rather than using many control points, it uses bands. The theory is that the bands can be shaped to match the shape of the major peaks and dips and then invert them. This may work for a few broader problems, but lacks precision to solve the majority of sound problems. Furthermore, the bands interact with each other so pushing one up causes its neighboring bands to also change. Forcing the bands to be too narrow causes problems in the time domain that sound like ringing or smearing.
Even the most sophisticated parametric EQ systems in receivers today only have a maximum of 10–12 bands. These are not enough to capture the response and the result is a representation that misses many of the problems.
The inverse filter that is created from a parametric EQ model is not able to correct many of the acoustical problems.
As a result, the Parametric EQ response does not match the desired shape with any reasonable accuracy.
Parametric EQ in receivers rarely performs subwoofer correction. MultEQ corrects the subwoofer in every seat providing precise bass reproduction.
In the time domain, the first arrival of sound is seen as a large spike and it corresponds to the sound signal coming directly from the loudspeaker. A few milliseconds later, copies of the direct sound signal arrive after they have been reflected and modified by the room (walls, ceiling, floor, furniture, etc.). Because these reflected copies arrive so close to the direct sound, the brain blends everything together and this results in audible artifacts such as smearing of transients, ringing, and comb filtering. The result is muddy sound. MultEQ filters are specifically designed to address these time domain problems and concentrate most of the signal energy in the direct sound. In the graph on the right hand side, the reflections have been dramatically reduced and the first spike is narrower and stronger thus allowing pure sound from the loudspeaker to arrive at each seat.
Any question? Send me e-mail.