Mono & Mirror / Midrange Tuning.

This is the fourth installment on the acoustic aspects of room tuning a Zu loudspeaker. And just like last week’s post about bass tuning, this article on midrange is best understood if you have read the previous posts.

Now that the lower octaves (bass decade) are sounding good­, turn your attention to getting natural and vibrant midrange. Remember midrange tuning is a dance of inches [decimeters and centimeters], somewhat similar to what we did tuning the bass but finer strokes, and we also begin messing with directivity aspects of the wavefront—the firing axis. Also different from the bass tuning is how we listen for midrange changes—while changes in midrange can be heard at the speaker it may prove useful to solicit some help. Invite a family member or friend to position the speaker while you listen at the chair. This in addition to the on-your-knees wobblehead thing. Also, your recording selection changes. To help your brain focus select cuts that are less bass heavy­—jazz, singer-songwriter, violin solos, guitar, stuff with good overtone color... bass and kick drum free, or at least way back in the mix. If you’re more sensitive to midbass and power bass then midrange tune in two steps, first select cuts from Bootsy Collins, Mike Watt, Kim Deal, Tony Levin, Jah Wobbel…. Sure, these are thunder broom and thud stuff giants, but a lot of their color climbs solidly into the midrange.

First step will be pivoting (rotate on vertical axis) the speaker. The inside-front footer is the pivot, i.e., the footer nearest the captain’s chair. Staying with the same loudspeaker room-tuned for bass (you’re still only playing the one speaker) and with your midrange-centric recording playing, pivot-rotate the speaker. Initial firing position is straight into the room, orthogonal the front wall. Pivot-rotate slowly moving the firing path—first straight into the room, rotating toward then right at the listener-on-chair, then falling away and finally shining down the hall or whatever. Do this a few times to help the mental map resolve and stick. Most of the time the final position is right at the listening chair give or take five, maybe ten degrees. Rotating the face of the speaker like this makes massive differences, and the dramatic arc will help you better understand the speaker and the room.

By pivot-rotating from that inside front footer, it’s easy to make changes to the left and right loudspeaker at some point down the road without having to wonder, are they still mirrored? Drilling down on the desired toe (that’s what we are doing here) midrange color will transition from low-presence and masked to open and intimate. Set that angle where you like it. You are pretty close to great sound here, but additional gains might be had by going back to nudging the speaker. Listen first (kneeling and wobbling your head) at the speaker and see if you find better sound a bit to the side or front/back from where it sits. If you can’t tell kneeling next to the speaker, return to the listening chair and have your buddy move the speaker an inch or two [3 - 5 cm] left, then right, forward and back - all while keeping that same toe-in angle. If no difference, great, let your choices stand and move to treble tuning.