Rane AC 22S Operation Manual - Page 12

5. Now release the MID MUTE switch so that the tone is emitted from both the high and mid drivers. Check the reading on the SPL meter: i. If the meter reads +3 dB, then the drivers are properly phase aligned and no Delay is necessary; leave the MID DELAY control at full minimum. ii. If the meter reads less than +3 dB, slowly turn up the MID DELAY control until the meter just reads +3 dB. Now the drivers are electronically phase aligned and the DELAY control should be left in this position at all times, unless the speaker system is physically altered. 6. Tune the tone generator to the next lower crossover frequency and then repeat steps 2 through 5, using the appropriate Level and Delay controls. Once the Delay control is set, you may re‑adjust any of the crossover Level controls at the beginning of each alignment procedure. Once all of the crossover Delay controls are set, then re‑adjust the output Level controls as outlined in Setting the Output Level Controls on page Manual-11. iii. If you have turned the MID DELAY control all the way up and still do not obtain a +3 dB reading, you will have to physically move the high driver farther forward until the SPL meter reads +3 dB. The amount of displacement corrections available from the Delay depends on the actual crossover frequency: the higher the frequency the less amount of correction capability. If the drivers are built into a single cabinet and/or it is impossible to change relative positions, then you will have to obtain additional delay to achieve proper phase alignment such as the Rane AD 22B. iv. If turning the MID DELAY control up makes the SPL reading decrease instead of increase, this means that the high driver is actually in front of the mid driver; adding delay to the mid driver then only worsens the situation. There are a couple of ways to deal with this: a. Try to move the high driver back as far as possible without losing stability in balancing the speaker stack. You may want to raise it up as well to restore dispersion close to the stack. If you cannot move the high driver, then you will have to obtain an additional external delay source to align the high and mid drivers. The built‑in Delay system in the AC 22S is designed to accommodate the majority of common speaker configurations; if you encounter confusion or difficulty with your particular system, it is best to consult your dealer or the Rane factory for assistance. b. If this decrease in the display due to the LOW DELAY control occurs at a low frequency crossover point below about 150 Hz, set the LOW DELAY control to minimum and leave it there. Frequencies below 150 Hz are actually omnidirectional, so that phase misalignment is virtually inaudible below this point. Subwoofers will often possess long folded or straight horns, resulting in the diaphragm being well behind the rest of the stack. Most authorities agree that phase alignment of subwoofers is unnecessary. Otherwise you will have to obtain additional delay equipment to align these to the rest of the system. Manual-9