EVERY "BEST MICROPHONE IN THE WORLD" DOESN'T WORK WITHOUT THIS
The solution for an unknown challenge is the professional's experience and preparation.
Even a small and simple gig in an unknown environment can go from an easy mission to an almost impossible one and the symptoms of this finding by the audio professional is expressed by the amount of tools, accessories, equipment and "stuff" that he/she carries with him/her to each gig. I was once recording at the splendid Teatro Amazonas in Manaus, Brazil, under the supervision of the dear and great Clement Zular, a renowned sound engineer based in São Paulo, very experienced in everything related to audio (laughs), when he enters our Control Room and admires a small toolbox I had brought with me to that recording: "- W-O-W, a toolbox! Sign of professionalism, huh?! Congratulations!” he told me. I confess that day after day, those words echoes louder and louder in my head as if they were in a continuous and growing “feedback loop.” Clement was right, because he had a better understanding about everything that can go wrong in a gig, whether it's 'live', on the field or on a studio. As he told me in another story, which he heard a testimony from a client of his: "-How good it is to work with someone who's been screwed a lot times in life..." said the client referring to the pleasant surprise of having found a spare fuse taped to the power cable of one of the equipments he had rented from Clement for an important country music recording date. Even before the third curse came out of his mouth, the client had already found there, glued with adhesive tape, the solution to his problem. This is the result of experience and a lot of previous frustration, my friends. It's moments like this, of total despair that we've gone through, that will make us the type of professional that every client wants to hire: The type who doesn't succumb to challenges and delivers the expected result. So I want to share with you some of the equipment or tools that save me from disaster every santa gig (job).
1-POCKET DIGITAL MULTIMETER
Pocket multimeter, compact, inexpensive and indispensable.
I was once hired to design a sound system for a church and, once the system components were purchased (all imported, very expensive, italian stuff), I went to install the system. In the previous days, I had asked the church to look for an electrician they trusted to carry out an inspection of the entire electrical system of the church, dimensioning a new power line dedicated to the sound system, I provided information about the expected load that that line should support (for correct sizing of the thermo-magnetic circuit breakers), I specified the voltage of each outlet since the subs and the top speakers had different voltages from each other (subject to the availability of the brand distributor) and i did insist that I would test the outlets when I arrived. The electrician called me several times during the week leading up to the installation, asked me too many questions, and when installation day came, he insisted that everything was tested, checked, and labeled correctly. I asked if I could test his work and he very pointedly replied: "- It's all tested, chief!", trying to show a good execution to his contractor, who showed me that he trusted the electrician. I said: "- Ok then, let's plug this 127V sub into this jack that says 127V and... POW!! The brand new 18" amplified subwoofer exploded in front of us to everyone's silence while that explosion reverberated through the temple's "5 seconds of RT60" of the temple under construction. Result? Since that day, I swore to myself that I would never plug a piece of equipment into an outlet that I hadn't made or hadn't previously tested and labeled. It is a risk that is not worth it, as a pocket multimeter costs less than a McDonald's happy meal and my frustration for not having the outlet tested cost dearly for the customer, who consented to the electrician's decision. Using the multimeter, I can measure the frequency of the power line (or generator), check the voltage between the socket terminals, find out even the type of socket connection (Phase+Phase or Phase+Neutral) and also check the existence and, to certain extent, the quality of the grounding. And lack of grounding, my friends, is one of the few factors that can cause a sound system to kill people, due to electrocution. As for grounding, I don't know anyone who has a better understanding of this subject than my dear friend, Henrique Elisei, from Pentacústica, an excellent Brazilian manufacturer of audio gear and distribution, conditioning and power protection equipment for events and installations. To learn more about the subject, watch Elisei in this sensational lecture about the subject, presented by the EducaSom channel. At a recent gig, I found that the power extension I was about to use was phase connected to the neutral pin (wrongly made) and fixing it took me precious 15 minutes, but it freed the extension owner from relevant and future damages in whatever equipment he would have plugged in there.
2- Microphone Windscreens
It's important to have one (or several levels of) windscreen(s) for each one of your microphones.
The best microphone in the world is useless if exposed to the plosive sounds of a speaker/singer's voice or if exposed to strong gusts of wind, which will cause low frequency explosions to the sound picked up by the microphone and these are very difficult to remove. hoping to solve this, many audio technicians overuse the high-pass filter and end up eliminating much of the low frequencies captured by the microphone, resulting in a "thin" and artificial sound, which is totally undesirable. Every time we take our microphones outdoors, we know that we may have problems with wind and each microphone must be properly "dressed". The more directional the microphone, the more sensitive to plosive noises caused by the wind it will be. We observe this phenomenon especially in super or hyper-cardioid microphones and shotgun (pressure gradient) microphones and for this reason we must find the most appropriate level of protection from the wind, always preferring the lowest level possible, in order to not sacrifice the pickup of high frequencies which will be absorbed in part by the windscreen. Blimp models with long-fur covers (deadcats) are very effective weapons against strong winds, but such phenomenon can also occur indoors where air conditioning columns can hit the microphones and cause plosive wind noises. If the task is to keep the wind from hitting lavalier microphones while hiding them in the artist's costume, away from the reach of camera lenses, the task can be even more difficult and involves a number of specific products or homemade adaptations ranging from wig adhesive tape to nail polish removal foam (laughs)!
3- Wireless Radio Frequencies Coordination
The last minute arrival of a film crew in your venue can have disastrous consequences.
The subject of radio frequencies (RF) is one of the oldest and most explored in this blog, due to the complex task of making RF transmitters and receivers work in harmony, without the work of one transmitter interfering destructively in the work of another transmitter. This is due to phenomena such as intermodulation, where each wireless microphone can create transmission by-products related to its carrier frequency that will affect the transmission of another transmitter. To avoid such a problem, we carry out a procedure called frequency coordination, where a new backstage professional, the RF Coordinator, with the help of software (or spreadsheets) and an RF scanner will analyze the RF spectrum of that environment and will search for traffic-free roads (frequencies) for each of its wireless systems, which include microphones, in-ear monitoring, intercoms, video transmitters, wi-fi, bluetooth, 3G, 4G, 5G, etc...
The best equipped models from brands such as Shure, Sennheiser, Lectrosonics and others already offer Scan and Frequency Coordination tools in the band of interest of the device, which in my opinion are indispensable for a reliable performance of wireless systems in virtually any event in an urban environment. To get an idea of how vulnerable these systems are, it might be fatal if someone enters the room carrying a wireless transmitter or wireless microphone and turns it on so that the chances of interference in some other system used on stage increase exponentially. Not long ago, some friends reported that the microphone of the main singer in their stage suffered a sudden interference (translated into very loud noise) that left the whole band and the audience temporarily paralyzed and deaf in the middle of the show. The reason? One of the stage technicians went to the parking lot to receive a shipment of wireless transmitters that would be used for a theatrical performance the following night at the same venue. The delivery man wanted to assure that the transmitters had fresh batteries and when he turned on the first of several transmitters to be tested, it was tuned to the same frequency as the main singer's microphone, which was located 30 meters away, inside the venue. It was enough to stop the presentation and learn a lesson that they will never want to repeat.
User manuals for every serious wireless transmission system offer literature explaining that when we use several wireless systems at the same time, we must space the frequencies used by them harmonically to avoid intermodulation, for this there are frequency banks, mathematically calculated to allocate several similar wireless systems at the same time, minimizing problems, a fact that most users are unaware of. Just select the same bank for all wireless systems and allocate each of those frequencies to each wireless system. Homogeneity in brands, models and operating bands of the systems helps a lot at this time, but having several different systems does not prevent a harmonious coordination.
Free softwares like Shure's Wireless Workbench (WWB), and the Sennheiser WSM (Wireless System Manager) offer this type of feature, allowing the user to insert various models that make up their systems and import (from a dedicated RF spectrum analyzer) an analysis (scan) or do it in real time (requires receivers with Scan function, as in the case of Shure, the Axient, some UR, ULX-D, QLX-D, P10T and the SLX-D lines, and in the case of Sennheiser the models are: Digital 6000, Digital 9000, 2000 Series, 2000 IEM, EM 373x (COM), EM373x-II (COM), ew 300 G4, ew 500 G4, ew IEM G4, ew 300 G3, ew 500 G3 and the ew 300 IEM G3) in order to avoid frequencies already occupied by TV channels, mobile telephony and other radio transmission technologies for the transmission of their wireless systems. On the brand's website there are several videos showing the WWB operation worth watching. Another important fact is to access databases that offer information about the local RF spectrum of each country in order to identify the frequencies available for wireless systems such as microphones and inear monitoring, such as the excellent Sennheiser's SIFA. This topic of RF and the current challenges of wireless systems has already been addressed by some of our previous posts, such as:
INICIADA, NO BRASIL, COOPERAÇÃO INTERNACIONAL EM SOLUÇÕES DO ESPECTRO RF: https://www.enginear.com.br/single-post/2018/12/07/iniciada-no-brasil-coopera%C3%A7%C3%A3o-internacional-em-solu%C3%A7%C3%B5es-do-espectro-rf
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From Jerusalem,
Tairo Arrabal
(Enginear Audio Solutions)
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