User manual JBL RMC

[. . . ] RMCTM Room Mode Correction User Guide Table Of Contents RMCTM Room Mode Correction System What Is RMC What is Included in the RMC Calibration Kit How To Use The RMC Kit 3-5 3 4 4-5 Speaker Placement Where To Place The Loudspeakers - Smooth Response - Mounting Options - How Close Should The Loudspeaker Be To The Listener - What About Setting Up In Small Spaces Boundary Compensation 6-7 6-7 6 6 7 7 7 Calibrating Your System I. LSR6328P System Taking Measurements Analyze Your Measurements Adjusting The RMC System II. LSR6328P Systems with LSR6312SP Subwoofer Taking Measurements Analyze Your Measurements Adjusting The RMC System III. LSR6332, or Other Passive, Systems with LSR6312SP Subwoofer Method One Method Two IV. [. . . ] You may proceed to equalize the LF room mode for flat response. One Low Frequency Peak 0dB -1 dB -2dB -3dB -4dB -5dB -6dB -7dB -8dB -9dB -10dB -11dB -12dB -14dB -16dB 20Hz 22 24 25 26 28 31 35 41 45 47 50 53 57 62 68 76 85 90 95 105 115 126 Example B: There are no room mode effects here, but there is a dip due to floor or possibly wall reflections. If the dip is no greater than about 4 or 5 dB, you can ignore it - and let this response remain as is. If the dip is greater than about 6 dB, you might try moving your listening position forward just a bit. Otherwise, no equalization is required One Dip 0dB -1 dB -2dB -3dB -4dB -5dB -6dB -7dB -8dB -9dB -10dB -11dB -12dB -14dB -16dB 20Hz 22 24 25 26 28 31 35 41 45 47 50 53 57 62 68 76 85 90 95 105 115 126 Example C: This is a very common pattern you will see in fairly live small to moderate size spaces. The dip may result from both floor and wall reflections and as such may be fairly wide. Try moving the monitor and/or your listening position to minimize the dip's width before proceeding. Equalize the peak. One Peak and Dip Exceeding 6 dB 0dB -1 dB -2dB -3dB -4dB -5dB -6dB -7dB -8dB -9dB -10dB -11dB -12dB -14dB -16dB 10 20Hz 22 24 25 26 28 31 35 41 45 47 50 53 57 62 68 76 85 90 95 105 115 126 Example D: This is a near-ideal case, and the recommendation is to do nothing. Your system will be fine as it is. Variations Within ±3 dB 0dB -1 dB -2dB -3dB -4dB -5dB -6dB -7dB -8dB -9dB -10dB -11dB -12dB -14dB -16dB 20Hz 22 24 25 26 28 31 35 41 45 47 50 53 57 62 68 76 85 90 95 105 115 126 Example E: Two interference response dips; no peaks due to room modes. This pattern may be seen in small spaces where two different delay paths are evident, such as from the floor and a wall. The absence of a mode peak indicates that the listener is located toward the center of the room. Slight repositioning of both listener and loudspeaker may change the situation markedly. Otherwise, no equalization is required. Two or More Sharp Dips 0dB -1 dB -2dB -3dB -4dB -5dB -6dB -7dB -8dB -9dB -10dB -11dB -12dB -14dB -16dB 20Hz 22 24 25 26 28 31 35 41 45 47 50 53 57 62 68 76 85 90 95 105 115 126 Example F: Two LF peaks. In general, you should equalize the peak that has the greater area between the curve and baseline. You may wish to engage the boundary compensation to lower the level below 150 Hz, and then repeat the RMC measurement process. Two Low Frequency Peaks 0dB -1 dB -2dB -3dB -4dB -5dB -6dB -7dB -8dB -9dB -10dB -11dB -12dB -14dB -16dB 20Hz 22 24 25 26 28 31 35 41 45 47 50 53 57 62 68 76 85 90 95 105 115 126 11 Adjusting The RMC System When you have identified the peak you wish to equalize, 1. ) enter its center frequency in the space provided at the bottom of the chart paper; 2. ) in the space provided, enter the level of the peak which is the distance in dB between the peak value and your baseline; finally, in the space provided, enter the width as determined by the width template. Figure 10a PULL Figure 10a shows the Width Template. As shown in Figure 10b, the template is placed over the peak in a plotted curve and adjusted so that the shape of the template matches that of the plot. The corresponding percentage value of width is then read directly from the vertical index of the template. 3. ) Enter the width value in the space provided on the chart paper. PULL Figure 10b 5% 10% 15% 20% 25% 30% 40% 50% 0dB -1 dB -2dB -3dB -4dB -5dB -6dB -7dB -8dB -9dB -10dB -11dB -12dB -14dB -16dB 20Hz 22 24 25 26 28 31 35 41 45 47 50 53 57 62 68 76 85 90 95 105 115 126 Frequency Hz Level dB Width % 12 4. ) Enter your tabulated values into the LSR6328P RMC equalizer using the table below: Data Entry in RMC Equalizer Table: Control Position Width (%) Frequency (Hz) Depth (dB) 0 (CCW) 4. 5 24 0. 0 1 5. 0 25 0. 0 2 7. 5 26 0. 0 3 10. 0 28 0. 5 4 12. 5 31 1. 1 5 16. 5 35 1. 9 6 20. 5 41 2. 9 7 23. 0 45 4. 4 8 26. 0 47 6. 4 9 28. 0 50 7. 9 10 29. 5 53 8. 3 11 31. 0 57 8. 9 12 34. 0 62 9. 5 13 39. 0 68 10. 2 14 41. 5 76 11. 0 15 43. 5 85 11. 7 16 45. 0 90 12. 7 17 46. 5 90 13. 1 18 48. 0 95 13. 5 19 49. 0 95 13. 9 20 (CW) 50. 0 95 14 (CCW) counter-clockwise (CW) clockwise Begin with the three controls in their far left (CCW) counterclockwise position and adjust each one, a click at a time, until you have reached the values entered at the bottom of your measurement chart. See Figure 11. Figure 11 Making these entries requires carefully counting the clicks. If you make a mistake, or have lost count, turn the control to the full counter-clockwise position and start over. Rechecking the system: After you have made the equalizer entries it is time to re-measure the system, using Tracks 4 through 26 just as you did when making your first sequence of measurements. Turn on the LSR6328P RMC function by engaging the ENABLE switch, the green LED will illuminate. Perform the same calibration procedure for the other speakers in the system. [. . . ] Recheck the overall sub and main system balance by playing tracks 2 and 27 as well as a track of music that you know well. Make any small changes in subwoofer balance that seem appropriate. 18 R out Method Two Many engineers are quite happy with the response of their existing stereo or surround loudspeakers. They may only want to add a subwoofer to their system for more extended bass. You can get a subwoofer feed by sending a parallel or "multed" feed of the LCR front channels - or by using the Direct In to the subwoofer if your signal source has a SUB or 0. 1 (point-one) output. Figure 18 amplifier in Left Right amplifier in out Source out L in R in Subwoofer Measurements, Analysis and Adjustments - The next step is to play Tracks 4 through 26 for correcting the major room mode, and then to make final adjustments to your taste. [. . . ]