Installing the soundhole pickup. Before mounting the M1 Active, I inserted the 3.5mm plug at the other end of the endpin jack harness into the pickup’s output jack (Fig. 7).
Fig. 8. Gently tighten the pickup mounting brackets until they’re snug. Don’t overdo it!
Two brackets on either side of the pickup secure it in the soundhole. To make it easier to slide the pickup into the soundhole without damaging the finish, I loosened these brackets by turning their screws counterclockwise. After positioning the pickup in the soundhole—advanced slightly toward the neck—I gently tightened the brackets until they were snug (Fig. 8).
Tip: When you install a magnetic soundhole pickup, double-check that it’s truly secure. You don’t want it to fall into the body while you’re performing. That said, to avoid marring the finish or crushing the soundhole wood, don’t overtighten the mounting brackets.
Adjusting the pole pieces.This is the last step, one that lets you tweak a modern mag pickup to your playing style—something you can’t really do with an under-saddle pickup.
Fig. 9. Adjusting the pole pieces with a hex wrench.
The M1 Active typically ships with the 2nd-string pole piece removed, but included in the packaging. (This is because the B string tends to be much louder than the rest.) I recommend not installing it unless you really need it to balance the volume. The rest of the pole pieces are easy to adjust using the included 3/32" hex key.
First, make sure that the volume control is turned up all the way. To adjust the volume for each string, simply turn your hex key clockwise to lower the pole piece or turn your hex key counter-clockwise to raise it. Only raise the pole pieces a little at a time, and then test the volume by playing through an amplifier. It’s not necessary to raise them a lot—only about one full turn.
I usually lower the 6th-string pole piece flush to the top of the pickup, then adjust the rest of them to match sonically (not physically). You’ll probably find that the pole piece for the 3rd string is closest to the strings. Once all the strings have equal volume, you’re ready to perform or record with your new soundhole pickup.