Back in 1968, when Shure introduced its Vocal Master P.A. system, that included four anti-feedback control switches, with each one assigned to a fixed frequency: 5,000 Hz; 2,200 Hz; 1,000 Hz; 155 Hz. Shure never stated how wide the Q was for each of these frequencies, but I would venture to say a wide Q would be applied: 4k to 6.3k; 2k to 2.5k; 630 Hz to 1.6k and 100 Hz to 160 Hz. That’s my guess; what the instruction manual does say regarding use of these four switches is this:
“If feedback occurs, locate the one Anti-Feedback switch, which eliminates the feedback. Gain may then be increased or tone control increased until another feedback pitch is apparent. One of the other filters may then be introduced, which will eliminate that feedback. IMPORTANT: No more than two filters should be used simultaneously; the effect of more than two filters is one of reducing overall gain, and the overall tonal quality of the system may be significantly affected.”
Ticket to EQ
It’s important to note that the unit also had master treble and bass controls as well as individual tone controls knobs for each channel, which means that basic EQ was being applied to the overall mix as well as the individual channels.
Right around the time that the Shure Vocal Master P.A. system was hitting the market, Art Davis’ eponymous Cinema Engineering company was releasing a six-band graphic EQ, while George Massenburg (and friends) were busy developing the parametric EQ.
Technically, we have come a long way since those early audio inventions, and while my “Boomer” heart still holds that time near and dear, I am in no way trying to imply that those were the good old days. They were not. They were exciting days of experimentation and innovation leading us up to our current state of the art for live audio. For reference, just looking at the sound system employed in 1965 for The Beatles in Shea Stadium is a good example of how little was known about delivering clear sound to thousands of concertgoers.
Get (Feed) Back
Recently, I saw a video promoting a new Waves plug-in with the title of “Feedback Hunter.” As explained by the Waves promo blurb, “New from Waves, Feedback Hunter is an innovative tool that is revolutionizing the way stage monitors and PA systems are optimized. With Feedback Hunter, users can achieve maximum gain before feedback in less than 30 seconds. The plug-in analyzes the mic and monitor’s response and creates an EQ curve that optimizes the relationship, ensuring clear sound with less risk of feedback.”
I do respect that Waves is promoting a new product, yet while the product may be new, the concept of more gain before feedback is not new, nor is the concept of incorporating a feedback blocker into a sound system a novel idea. Granted, technology has come a long way since the early days of audio equalizers, but while the advancements are new, the science is not.
I have audio techs working for me who were born in this century, and while they are talented, their experience in the world of live audio is vastly different than my own. Just to be clear; I may be skeptical about some of the new digital technology, but I’m not the guy who is going to shun a line array for my old EAW KF850 system. I may be old, but I am not a Luddite! I embrace new technology, but I do so with a bit of whimsy and an eye on the past.
Since the time of the industrial revolution, new technology has not only been greeted with a wary concern that it won’t function properly, but also by a fear that our jobs will be displaced if said technology does operate as planned. For example: self-driving cars do not instill me with a sense of security. Not that it matters, as it’s more than likely that in 20 years all cars will be self-driving. While those of us who have been used to driving our cars may approach the new technology with some trepidation, the generation that grows up with the technology will not think twice about riding in one. It still remains to be seen if self-driving cars will put cab drivers out of business, but that is the downside of technological advancement and the bane of Luddites everywhere.
All You Need is Ohm’s (Law)
Current audio technology is more precise and easier to access than it was when I was up and coming. The skills that were required then are not necessarily needed now. These younger techs will never need to use Ohm’s Law for figuring out speaker load or need to do the math for setting delay time between speakers. They will never have the need to tune a crossover or balance their amplifiers in order to determine the best sound for their speaker system. They never need to question if their speakers are out of phase. They can rest assured that their speakers are neither underpowered nor have mismatched impedance. Hearing and discerning frequencies was a must for any engineer, but now there are tools that take the need for that skill away from the engineer.
While this has, in many cases, made for a more efficient setup, it’s the loss of knowledge that is concerning to me. Unfortunately, pining away over lost audio skillsets is like me waxing nostalgic about the old days before we all started carrying pocket computers. Back then phone numbers were not that hard to remember, and somehow we all managed to navigate from one place to another without GPS.
Now, while I know that Waves makes a good product, I still believe that a good understanding of gain structure is a required ability and might possibly alleviate the need for additional DSP to be added to the mix. As Shure states in their 1968 manual, “using more than two filters at a time may affect the overall tonality of the system.” Not to be the ancient curmudgeon, but everything old…
Contact Baker Lee at blee@fohonline.com
