Phase cancellation

Back in 1987, I bought a 1973 Ford Mustang that I planned to re-build. It had a lot of things I needed to fix. The seats were very dirty, ripped and torn, the headliner was a joke, the engine needed a serious tune up (along with some missing parts) and the wheels looked like they were straight outta the junk yard. Which they were. The one thing I was very confident in repairing was the radio system. But, in the process, I found something very interesting about this particular radio in this semi-mobile rolling classic.

The radio was the old analog style with a physical dial to change stations and those ridiculous push buttons for presets. One day I was listening to this radio as I creaked my way down the road and a familiar song came on. I listened to the intro, and at just about the time in the song that I was expecting to hear the lead vocal start, there was nothing. The music continued to play but there was NO VOCAL! 1987 was way before Karaoke, so to hear a song being played on the air with no vocal was very odd. I kept listening as I thought there was going to be some explanation to this bizarre song. Nothing! The next song came on, and everything was normal. After a few weeks or having similar experiences with “ghost singers” I began to see a pattern. Only certain artists’ songs were affected; Lionel Richie, Kenny Rogers and a few other “nasally” singers. However, while the song played, I could hear a faint echo of their voices far in the background, but the music and instruments in the song outweighed the vocals. I later figured out that the speakers (I only had two of them in the back) had been installed improperly. The two wires (one ‘positive’ wire and one ‘negative wire’) were connected inversely from each other. Each speaker has two polarity poles for the positive and negative wires. While one speaker had Positive on channel 1, the other speaker was opposite…it had Positive on channel 2. Once I switched the wires of one of the speakers, I could hear the songs normally. Lionel and Kenny were back! I could also completely unplug one speaker and the other one would suddenly begin sounding normal. But as long as the two speakers were playing at the same time with their wires crossed, it was Karaoke time!

Phase cancellation occurs when two signals of the same frequency are out of phase with each other resulting in a net reduction in the overall level of the combined signal. Two identical signals that are 100% or 180 degrees out of phase they will completely cancel one another if combined.

Like most audio enthusiasts, I was aware of this phenomenon called phase cancellation, also known as phase inversion, but mostly in theory. I had played around with it before, when I noticed a significant loss of bass in my speakers. But this was my first practical experience, where the phenomenon was so drastically obvious. The output, or strength of the signal, for each speaker was indeed 100%, but when the signal was joined with a completely opposite phase, the combined signals all but disappeared.

This physics phenomenon also has bearing in our lives in other (more practical) ways. What about the output of a person…their work and efforts? If there is a team of people (each with their own “frequency”) working towards a single goal, but they are not working collectively, or in ‘phase’ – they run the risk of a net reduction in the overall signal, or product. The effort or strength of one frequency (person) may be at 100% just as another’s signal (effort) is…but if they are not working together, they could very possibly end up causing cancellation (failure…despite a great attitude or tremendous effort.)

As with just about ANY relationship, communication is the basis or foundation. Working hard is good, but working TOGETHER is better. One bee sting hurts, hundreds of bee stings can kill! The best example of working hard with no clear direction is the old “Terrifying Backyard Water Serpent” otherwise known as the 1970’s successful Water Wiggle toy. It danced and bobbed erratically with the water pressure of a garden hose. It had no direction or purpose other than to spin out of control in just about every direction while randomly spraying water on everyone. As a third party observer, it is easy to see the crazy irregular patterns. Sometimes, we are so close to a situation we can’t see the unpredictable nature of our actions. Effort seems to be lost in confusion for want of a purpose or clear goal.

If we are working alongside other people as a team, make sure that there is a clear definition of the goals; what each individual responsibilities each member has, and what is expected from them. It isn’t favorable to have someone go an extra mile if the work they are doing ends up being canceled out by another’s unknown effort. Being clear about ‘who does what’ is certainly a top priority, but being clear on the final desired result is just as important. When everyone is on the same page (or frequency) you stand a much higher chance for success. Good intentions are never enough if people aren’t working together!