Originally Posted by plouie10
Just looking for some quick help on where to take the readings from for the mic on Anthem MRX-510. If you can see the attached drawing I have the surrounds speakers on 5.1 setup on either side of the couch. There is no room behind the couch or beside to move the speakers and there are walls and windows blocking, so they are stuck where they are. In the manual it says to have the 1st listing position in the middle and the basically in the corners of the 1st listening position. I can't do it for the backs as I can't move the mic any further back. So wondering if you have any suggestions as to where to position the mic for calibration.
I have a similar setup with the same constraints. I positioned the mic at three seating positions along my sectional couch and 2 in front using this guidance from an earlier post by Bob. Don't remember which post # but I saved this to guide me. I adjusted based on my constraints.
Try it and see how it sounds.
"^ Follow the guidance in the Manual.
The idea is to give ARC a chance to detect significant room response factors. The variation caused by the presence of people in the seats is not what ARC is trying to Measure. Things that affect the geometry of the room (doors open/closed), or the reflective characteristics of the room (curtains open/closed, projection screen down/up, rugs in place or not, furniture in place or not), or the relationship between the room coupling, speaker positioning/pointing, and speaker dispersal patterns (mic positioning) are what's important.
Use the stand to hold the mic, pointing straight upwards, with the tip at seated ear height.
Put mic position #1
at center seating. #1
is special as it's the position that sets the volume trims.
Subsequent positions should alternate either side of #1
. No two positions, whether or not sequential, should be closer than 24 inches apart (I use 30 inches). Include some forward backward spacing in the positioning as well as the side to side. For example, if seating is a typical sofa, you could have 3 positions spaced along the head line at the back of the sofa plus 2 more positions just outside the chair arms and shifted forward about the distance of the front edge of the sofa. Like this:
Adjust the positions as necessary to keep the tip of the mic away from reflective or blocking surfaces such as walls or tall seat backs. Raise the mic tip a few inches or shift the position about a foot closer to the screen to clear it away from a seat back. Try to keep the mic 18 inches away from walls. Do not stand near the mic, or in the line between any of the speakers and the mic while the test tones are playing. Often the easiest solution for this is simple to sit on the floor while the tones are playing.
The mic is omnidirectional. It is designed to hear sounds coming from throughout the hemisphere above the mic tip. To get valid readings it needs to be able to hear sounds approaching it from 360 degrees around -- and it has to be pointing straight up. (ARC applies correction factors to adjust for how the polar response of the mic changes with frequency).
The mic positions need to be spaced as described. The spacing is what allows ARC to detect variations due to room response (which vary in location) and distinguish them from the inherent output of the speakers themselves. Squeezing the positions together will produce poorer results.
The idea is to sample the listening area. You don't need mic positions to match seated head positions so long as you sample the listening area. The above positioning -- sometimes called an arc -- works well for one row of seating. With two rows, or a single seat, a box configuration is also good. Like this:
perhaps with position #1
just behind the first row of seating or at the single seat.
5 positions are the minimum, and for most small home theaters 5 positions are also ALL you need. I.e., the reason to add more positions is because you feel 5 positions doesn't cover enough ground to sample the larger seating area.