Today I returned to Harmony Fellowship to add a Yamaha YDP-2001 parametric EQ to the system to process the stage monitors. The venue has (2) Yamaha SM12V wedges linked together on AUX 1 & a newly acquired Rockville self powered 15″ / horn wedge on AUX 2.

My first measurements were to verify that the two Yamaha SM12V wedges matched each other. They do.

Yamaha Club V series
Specs for the Yamaha SM12V & 15″ sibling:

Having verified that the Yamaha wedges match, I unplugged one of them so I would be measuring only one of the speakers. I took another measurement without any eq as my reference point and began adjusting the new parametric EQ to smooth out the response of the SM12V wedge. Here is an overlay of the before and after frequency response traces.

The SM12V is an affordable floor wedge that measures relatively flat for a 2 way passive design. The one thing I dislike about the SM12V design is how the 40 x 90 horn is turned with the 90 degree side in the vertical plane. Having a 40 degree pattern horizontally in some cases is a good thing but I can’t think of a single reason to have 90 degrees of vertical coverage for a stage monitor. In that configuration you’re covering both your knees and the ceiling. Even so there is some logic behind this design decision. It limits the height of the cabinet (what Yamaha calls low profile) and if the SM12V wedge is used as a main speaker on a speaker stand (which the design allows for), the 90 degree side of the horn is horizontal. What is being sold as a floor wedge in a series of speakers has been optimized for use as a main speaker on a pole.

For a tight patterned floor wedge I would prefer a symmetric horn (40 x 40). One such design is the Meyer Sound UM-1P with it’s 45 x 45 horn. A fantastic sounding stage monitor.
Meyer Sound – UM1P

Having satisfied my desire to tweak the SM12V eq, I moved on to the Rockville RSM15a wedge.

Rockville Audio – RSM15a self powered 15″ wedge

This self powered cabinet provides a 3 band eq as well as a feedback filter sweep on the side of the cabinet. Here is a photo of the control panel taken from the website.

The house audio engineer was thoughtful enough to made sure that the various controls on the cabinet were zeroed out before I began to measure it. Our settings were LINE IN, all 3 bands of EQ set for flat, feedback filter disengaged and volume at unity. One would hope that a self powered cabinet with it’s onboard EQ set to flat would measurement relatively flat but no. The design has some undesirable attributes out of the box.

Note the 15db to 18db of extra 2k and 4k. Not something anyone wants unless feedback is the goal. Consequently, it took most of the available filters to tame the response of that box. It’s possible that using the onboard eq it would be possible to flatten out the peaks but I wanted the house audio engineer to know that the wedge is tuned when the onboard controls are all set to unity.

In conclusion, certainly in smaller rooms, stage monitors have just as much affect on the “sound” the audience hears as the main speakers. They are acting together to fill the room with sound. It would be silly to go to the trouble of tuning the main speakers but leave the stage monitors un-eqed. All speakers in a room should be optimized in their active configuration for that venue.