Audyssey Laboratories Sound Equalizer
Audyssey Laboratories offers the Sound Equalizer, a stand-alone component that, when properly installed, removes frequency response irregularities and sound coloration from multiple seating locations in a listening room. The Sound Equalizer is designed for systems with separate amplifiers and preamplifiers and requires professional installation and calibration by a professional installer using the Audyssey MultEQ Pro software application. The system measures the acoustic properties of the system and applies appropriate filters in the Sound Equalizer to equalize the sound system. It can be used with systems ranging from 2.0 to 7.1-channels.My first experience with the Audyssey system was with the Wisdom Audio Sage L-75 speaker system I recently reviewed for Home Entertainment magazine. The Wisdom Audio speakers require professional installation using the Audyssey MultEQ Pro software, which calibrates the crossover that comes with the Wisdom system. The audible results were so remarkable I decided to test the Audyssey Sound Equalizer. I tested the Sound Equalizer in my two-channel music system and my 5.1-channel home theater system.<p>The Audyssey system is also built into high-end receivers and preamp/processors from Denon, Onkyo, Integra and NAD, which also require the use of Audyssey software to setup and calibrate.
Installation & Measurement Process
The Audyssey Sound Equalizer has standard component width of 17.25 inches and almost two inches in height. It is available with unbalanced RCA or balanced-line XLR inputs and outputs for use with a variety of amps and preamps. The Sound Equalizer is connected between the amp and preamp and to a PC via a USB control cable. A calibrated microphone also connects to the Sound Equalizer for acoustic measurement of the room. Each calibrated microphone has a unique frequency curve and serial number that must be matched with a specific MultEQ Pro CD application.When the MultEQ software application launches, the installer enters the system owner's audio equipment, room dimensions, number of speakers and other information. At the conclusion of the measurements, a certificate is produced for the customer with a frequency response graph and that shows results before and after room measurement and calibration.
Audyssey recommends a minimum of eight and a maximum of thirty-two room measurement positions, depending on the size of the room and the number of seating positions. The installer begins by measuring the primary listening position(s) then proceeds to other areas of the room. In essence, the more the Sound Equalizer 'knows' about the room, the more accurate the results of the equalization will be.
For each measurement, the Sound Equalizer outputs 10 full bandwidth chirps or test tones. Each measurement position takes about 30 seconds followed by a prompt for the installer to select another calibration position or move to the next step.
Measurement Results & Target Curves
Following the room measurement the Sound Equalizer generates Detection Results, which identifies the speaker distance and recommended trim (volume) level of the speakers based on the first measurement and the recommended crossover settings for each speaker derived from all measurements. The crossover frequencies and trim levels from the Detection Results should be set in the preamp/processor. (Note: some preamps don't allow individual settings for each speaker and there are instructions for preamps with varying levels of adjustment).The next step in the process produces four Target Curves to cover a wide range of room types. The Target Curves are recommended frequency response curves that the customer can audition then select one based on preference. When a curve is selected it is temporarily transferred to the Sound Equalizer where the customer can hear an A-B comparison with and without equalization. When the best Target Curve is selected it is permanently saved to the Sound Equalizer. At any point, additional room measurements can be added to the original measurements, thus giving the Audyssey more information about the room.
The four Target Curves are described as Flat (required for a THX home theater system), High Frequency Roll Off 1 (a slight roll-off of high frequencies, recommended for smaller rooms), High Frequency Roll Off 2 (a greater roll-off of high frequencies, designed for larger rooms) and SMPTE 200M (an international EQ standard for movie theaters, mixing spaces and dubbing stages and can be used for very large residential rooms).
Two-Channel Results
After listening to the Target Curves, I chose the High Frequency Roll Off 1 curve, which noticeably improved the upper midrange and treble clarity and evened out the bass. Guitar, vocals and other elements sounded much more open and present as if a blanket was lifted from in front of the speakers. The planar magnetic drivers opened up with crisper detail and much greater resolution. See Diagram 1 (large image). You can also see in Diagram 1 that below 100 Hz the bass was flatter after equalization.
I also measured my Paradigm speakers, which I use as in a reference 2-channel system (no subwoofer). In my room the Paradigm speakers sounded somewhat heavy in the bass. After measuring ten listening positions, I selected the High Frequency Roll Off 2 curve, but the bass sounded too lean. The solution was the Target Curve Designer, which can customize a Target Curve. Any frequency between 20 Hz and 20 kHz and can be adjusted +/-3 dB to achieve the desired sound. This takes some time but allows the installer to perfectly dial-in the system. I raised frequencies in the 40-60Hz range to restore some of the bass.
