Yamaha IMX644 Owner's Manual - Page 16
Feedback Suppressor, Priority Ducker, Music Override, Front Panel Static Filter Measurement
View all Yamaha IMX644 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 16 highlights
Mix Functions ■ Feedback Suppressor The Feedback Suppressor effectively controls feedback by identifying the feedback frequencies that will occur naturally as a result of the combined acoustic and electrical characteristics of the sound system within the acoustic space in which it is used. The Feedback Suppressor includes static filters that provide measurement and filtering for specified channels, and dynamic filters that monitor the condition of specified MONO INPUT channels and automatically suppress feedback as it occurs. Static filter measurements can be made either via the IMX644 Manager application or the IMX644 unit itself. Measurement from the IMX644 itself is described in "Front Panel Static Filter Measurement" below. With the initial default settings the static filters are inactive, while the dynamic filters are ON for all MONO INPUT channels. NOTE • The initial default setting is Feedback Suppressor ON. Even though the static filters are inactive, the dynamic filters are still operational so be sure to turn the Feedback Suppressor OFF before using sine waves or test tones to test or calibrate the system. • Feedback Suppressor settings can be stored in the unit's 16 memories. Front Panel Static Filter Measurement To ensure optimum feedback suppression be sure to perform the measurements under the same conditions that will prevail during actual operation (microphone and speaker positions, etc.). 1 Set the OUTPUT channel 1 through 4 level con- trols to 3 o'clock. 2 Set the level control of the MONO INPUT to which the microphone that is to be used for measurement is connected to 3 o'clock. 3 Set up the microphone at least 5 meters away from the speakers. 4 Adjust the output level of the power amplifier. While speaking or singing into the microphone gradually raise the output level of the power amplifier to the level that will be used in actual operation. Also clap your hands near the microphone to make sure that feedback does not occur. 5 Set the level control of the MONO INPUT channel to which the microphone that is to be used for measurement is connected to "0". 6 Make sure the area being measured is silent. 7 Simultaneously press and hold MEMORY but- tons [A], [C], and [D] for longer than two seconds. The MEMORY [A], [C], and [D] button indicators will light and static filter measurement will begin. When the measurement process has finished the static filter will be set according to the results and the MEMORY button indicators will return to their status prior to the measurement. NOTE • If all four MEMORY button indicators light - [A], [B], [C], and [D] - an error has occurred during measurement. To prevent damage to the equipment the measurement will be aborted and the erroneous data discarded. If this occurs try changing the orientation of the microphone and speakers, lower the amplifier output, then repeat the procedure from step 1 above. • Static filter measurement may not be successful if the overall level is too high or the microphone is too close to one of the speakers. ■ Priority Ducker When a signal is applied to the specified MONO INPUT channel the level of all STEREO INPUT signals assigned to the same output are reduced to allow announcements made via the MONO INPUT channel to stand out clearly from background music or other program material, for example. When input to the specified MONO INPUT channel ceases the level of the other "ducked" channels returns to normal. The initial default setting is OFF for all channels. Both the amount of attenuation and the time it takes to return to normal level can be programmed as required. Parameter Mute Level Release Time Range -30.2dB - 0dB 0.0 - 6.0sec Initial value -20dB 2.0sec ■ Music Override When a signal is applied to the specified STEREO INPUT channel all other STEREO INPUT channels assigned to the same output are automatically faded out and muted. When input to the specified STEREO INPUT channel ceases the level of the other muted channels fades in and returns to normal. The initial default setting is OFF for all channels. The time it takes to fade-in to normal level can be programmed as required. NOTE • If Music Override is ON for more than one channel, the lowest-numbered channel takes priority. Parameter Release Time Range 0.0 - 6.0sec Initial value 4.0sec 16 IMX644 Owner's Manual