Dave Rat demonstrates a little known but very common loudspeaker distortion

Dave Rat – Demonstrates a Little known but very common Loudspeaker Distortion

This concept makes me lose sleep at night. This is solid justification for using different PA speakers to reproduce different material. For example having a PA for amplifying the band and another PA for amplifying the vocals. We should all be thinking about how low frequencies are affecting the rest of our frequency response.

I like Dave Rat. He is willing to invest his time in better and better sound and take what he learns from his own experimentation and incorporate it into his work flow.

His current Red Hot Chili Peppers PA is proof.

QUOTE: “With the double hung PA concept I was able to implement and demonstrate that having instruments and vocals coming from separate sources is not only an advantage for stage monitors but can be applied on a grand scale. Also, since I could move any instrument to either the outer or inner PA in real time, I became very aware of the important advantages gained in using separately located sources. With monitors, I would find out after the show if separate sourcing worked, with the double hung main system, I was in the listening position personally (along with 20,000 of my best friends) and could hear the immediate and direct effect.”

Dave Rat double hung PA

What Dave is doing with his PA system x 2 is called an A/B sound system and is sometimes used on Broadway shows. Dave may be the first rock & roll mix engineer to take the leap though.

WIKI – A/B Sound System


“An A/B Sound System is a type of Sound reinforcement system or Public address system. Unlike a more typical sound reinforcement system, an A/B Sound System provides two electrically isolated signal paths from microphone to speaker, resulting in a system where signals from two microphones only interact acoustically and never interact electronically. This is accomplished by placing two separate loudspeakers at each speaker position and feeding the two speakers separate signals from separate microphones.[1] The purported benefit of such a system is a reduction in phase cancellation and intermodulation distortion, and an improvement in speech intelligibility when two microphones are used simultaneously. A/B Sound Systems are unusual because they require double the speakers and therefore have double the cost.”

The first time I ever heard an A/B system was on Disney’s first touring production of Lion King @ Bass Hall in Fort Worth. During the sound check and went to the farest balcony to listen and was amazed that I could understand every syllable. When two actors were speaking, each one’s voice was routed to a different set of speakers covering the same zones. As I recall, the choir was coming from a different set of speakers and the orchestra from another.

Speaking of Lion King, the Broadway show as designed by industry heavy Tony Meola. Here is a Meyer interview with the man himself from 2002.

Meyer Sound – Interview with sound designer Tony Meola