User manual CARVIN EQ2015

[. . . ] CARVIN ENGINEERING DATA EQ2015 DUAL 2/3 OCTAVE EQUALIZER EQ2030 DUAL 1/3 OCTAVE EQUALIZER OPERATING MANUAL RECEIVING INSPECTION--read before getting started INSPECT YOUR UNIT FOR ANY DAMAGE which may have occurred during shipping. If any damage is found, please notify the shipping company and CARVIN immediately. In the event you have to re-ship your unit, always use the original carton and packing material. CARVIN and the shipping company are not liable for any damage caused by improper packing. [. . . ] The 30 columns cover the 10 octave audio frequency spectrum in 1/3 octave steps. Assuming that both the equalizer and the analyzer have their frequency bands centered on the standard (ISO) 1/3 octave frequency centers, then for each slider on the EQ there is a corresponding column in the analyzers display. If music is played through the system, then the analyzer displayed will dance about to indicate the sound energy in the room as it varies in frequency and loudness. The analyzer would not be expected to display a flat response curve under these conditions because music generally does not have equal energy in each frequency band but rather has energy at changing frequencies and with changing loudness. This brings up a question: If music played through the systemcannot be expected to produce a flat frequency response on the spectrum analyzer, then is there a signal that will?And the answer is yes; there is a special test signal that when played through an accurate system and picked up by an accurate microphone will result in a flat frequency response (each column at the same height) on the spectrum analyzer display. Pink noise is simply a signal that contains all the audio frequencies at once with the frequencies in each octave band having the same energy (loudness) as the frequencies in each of the other bands. If the pink noise is fed directly into the spectrum analyzer then a perfectly flat display will result. If the pink noise is fed to the systemand the sound energy from the speakers picked up by the microphone and fed to the analyzer, then the combined response of the loudspeakers and room (and microphone) will be seen on the analyzer display. Now the appropriate sliders on the equalizer can be adjusted to provide a precisely flat frequency response. Because the microphone is included in the system response curve, it is important that the microphone have a flat frequency response itself. Otherwise you'll be equalizing your loudspeakers for the microphone response also. This would result in inaccurate response from the loudspeakers themselves. The description of the equalization procedure may sound complex but the actual procedure can be performed with surprising ease. It is simple to plug the output of the pink noise generator into an appropriate input of your audio system and play the pink noise over the loudspeakers at a level well above the background noise. An accurate microphone is placed near the usual listening position and the output of the speakers is displayed on the analyzer. From the display it can be seen which frequency bands need to be boosted or cut to achieve the same level in each band (flat response). Continue to adjust the equalizer until a satisfactorily accurate response is obtained. Because the response will vary with microphone location, it is a good idea to look at the response for several microphone locations around the listening position and equalize for the flattest average response. One of the shortcomings of the pink noise equalization technique is the fact that the analyzer displays both the direct sound from the loudspeaker and the reverberant sound field set up in the room. Ideally we want to obtain a flat frequency response for the direct sound from the loudspeakers. The reverberant sound field cannot be expected to have a flat response and typically has a decreasing high frequency response. [. . . ] 2) KEEP YOUR EQUIPMENT LOOKING NEW Use caution to avoid spilling liquids or allowing any other foreign matter inside the unit. The panel of your unit can be wiped from time to time with a dry or slightly damp cloth in order to remove dust and bring back the new look. Be sure the unit is dried off and unplugged if a damp cloth is used. IMPORTANT!FOR YOUR PROTECTION, PLEASE READ THE FOLLOWING: WATER AND MOISTURE: Appliance should not be used near water (near a bathtub, washbowl, kitchen sink, laundry tub, in a wet basement, or near a swimming pool, etc). [. . . ]