360 Systems MAXX Operation Manual

Contents

360 Systems MAXX Operation Manual Manual pdf 110 page image

108 MaintenanceAudio Level CalibrationThe input gain and output gain of the analog audio circuits are factory calibrated to a +4 dBustandard. Each circuit includes a trim pot with a range of approximately ±2.5 dB. The followingprocedures may be used to calibrate these for unity gain. Each trim pot is located above the XLRconnector with which it is associated. Refer to the preceding drawing (Figure 27) for the locationof trim pots and jumper blocks referred to in the calibration procedures.Calibration ProcedureThis procedure assumes that the technician is fully familiar with test procedures employing theAudio Precision® test equipment, or its equivalent.1. Position the jumper block J5 and J6 for Channel 1 output to obtain an analog output.2. Play the test clip titled zTONE present on the Image Server disk. This stereo clip isrecorded at a level equivalent to a +4 dBu output level.3. While observing the output level of audio Channel 1 Left, adjust trimmer RV4 until a levelof exactly +4.00 dBu is obtained.4. Repeat this procedure for audio Channel 1 Right, while adjusting trimmer RV3, and also foreach subsequent audio channel using its associated trim pot.Having established accurate gain settings for all analog audio outputs in steps 1 through 3above, calibrate the Image Server’s input gain as follows:5. Using the graphic user interface, place server Channel 1 in the E-E mode, so that an inputsignal will appear at its output.6. While observing the output level of audio Channel 1-L, apply a 1 kHz sine wave from theaudio generator to audio Input 1-L.*7. Adjust input trimmer RV2 until a level of exactly +4.00 dBu is obtained at the output ofChannel 1L.8. Repeat this procedure for audio Input 1-R, making the gain adjustment with input trimmerRV1.The preceding steps establish a gain of unity through the server.* In the absence of a generator, use the calibrated outputs of Channel 2 playing zTONE tofeed the inputs.