Originally Posted by Rysa_105
i measure using laser measurer at ear pointing the laser to the center of the tweeter of the speakers (woofer in case of sub). the sub will be a couple of feet ahead of speakers, my question is about phase, so if i only ran the auto process according to you the phase knob doesnt need to be touched? well not according to some articles like the one above, or according to the sub's manual..sub is a JL E112.
What AVR or AVP are you using?
Using a laser pointer and setting the distance setting to the actual physical distance
of the subwoofer is flawed methodology. Most subwoofers have DSP built into their amplifiers, this DSP introduces delay into the signal path. This is why when you run the auto-setup on your AVR/AVP the subwoofer distance is usually set a few feet further than the physical distance...it is accounting for that delay in the sub amp.
If you only have a single sub, and you have an AVR/AVP that will correctly set the distance setting for the sub, it does not matter where you set the phase control before calibration as the AVR/AVP will account for it in the distance setting. There is no need to touch the phase control post-calibration.
However, adjusting the distance setting
post-calibration is encouraged because most AVRs/AVPs do not have the ability to measure both subs and mains together, so they do not get these two "in-phase". When the subs and mains are not in-phase it will result in a dip around the crossover. This procedure is known as the Sub Distance Tweak and I have outlined a simple method below on how to go about it.
Hope this helps!
If you don't have measuring equipment, the distance tweak can be done with an SPL meter (or SPL app on a smartphone) and test tones downloadable from the internet, available on YouTube, from a test disc or with REW (free download). The reason to invert phase in step 3 is because it is sometimes easier to measure the dip than it is the peak when using an SPL meter.
- For the Center Channel, set your AVR to the Dolby PLII surround mode (Dolby Surround on Atmos AVRs), you should be getting output from the CC + sub(s) only
- For the FL/FR channels, set your AVR to the Stereo surround mode, you should be getting output from the FL/FR + sub(s) only
- Invert phase on your subwoofer(s)
- Play a sine wave that corresponds to your crossover frequency (e.g. 80hz) and measure the output with the SPL meter about a foot in front of your face at the MLP
- Gradually increase the sub distance setting in the AVR in 1' increments (both subs equally if you have independent control) (on some AVRs you must make sure to back out of the distance setting menu before the new setting will take effect)
- The sub distance setting that gives you the lowest SPL reading is the setting you want (you can tweak further in smaller increments if you want to, but I have found that 1' increments is usually sufficient)
- Invert the phase on your sub again and you are done