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what does an equalizer equalize? what does a compressor compress? etc.

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  • what does an equalizer equalize? what does a compressor compress? etc.

    Does an equalizer equalize only sonics ONLY? I read an article that I'll paraphrase; If one instrument (say a guitar) abruptly stops, another guitar track starts, it is best to set both those guitar tracks in the same EQ setting so that the sonics do not change, which is why an EQ is called an equalizer (it equalizes). I hope I'm on point on this one. So what does a compressor compress? etc. I think the names of these products would infer what they are for; an equalizer equalizes, a limiter limits, a compressor compresses, etc. I don't get what a gate is? What is it "gating"? A sonic maximizer will maximize "sonics", etc. A de esser will de ess the "S's", etc.

  • #2
    an electronic signal. Gate on, no signal. Usually because of too much noise present as in saturated guitar sounds. Mostly hiss when no string tone is present.
    Originally posted by Unconfigured Static HTML Widget...

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    • #3
      Sonics is a vague word to use in this case. All words can have many meanings depending on how they are used. When you consider the thousands of years the English language to develop, terms used in electronics, audio and computers have only been around for a wink of an eye.

      Audio recording is also an art form and a science. You'll come across scientific terms, many of which were named by their inventors and then you have a full array of descriptive and slang terms used by both amateurs and professionals which can be quite baffling to someone new to audio and electronics.

      What I always recommend is when you come across a new term or word, Google its definition, and find many sources for its meaning. You'll find most descriptions have similarities even though they are written by many authors. Its important you read many of these descriptions too because each individual learns these concepts from different teachers in different eras, and different languages. One person may have things explained in one way and comes to an understanding where the light bulb goes off and they finally Get It. Others may have to have it explained a dozen different ways before they can build a frame of reference, a foundation of truths before they can fully understand certain terms.

      I know I had these kinds of issues when I was just getting into electronics. I had been given a collection or Popular electronics and Radio manuals that spanned two decades. I had a passion to build the devices in those manuals but was stymied by many of the terms used and most of all how the components actually did what that did with that almost mythical, invisible thing called electricity. I was the type of person who couldn't be satisfied by black boxing certain things and being told, this is the truth of it and there's no reason to look deeper. Except what you're told and believe when people tell you this goes in and this is what comes out and there's no reason to know exactly how and why it does what it does. I had to know exactly what occurred right down to the atomic level in order to fully visualize what was going on.

      The one thing that doesn't change is the actual science in back of electronics. Its a branch of physics which is mostly math containing allot of algebra, trigonometry and calculus. I had a harder time them most getting through the math portion of electronics because I absolutely hated match growing up. I was into right brain activities like Music and the arts. Electronics was all left brain mathematics but once you get past the basics it actually does become quite creative when it comes to inventing and design, and of course audio recording and mixing. Thank god calculators came of age just as I was getting my education. I never did figure out how a slide rule worked.

      So to your basic questions. lets skip the word Sonics and replace it with Frequency Response. An Equalizer contains filters which either pass or block frequencies which we can hear. Our hearing range is from 20Hz to 20,000Hz. We hear sound as ear pressure changes to our ear drums. the air compresses and decompresses around up and our sensitive ear drums move in response to those changes. if those vibrations are fast we hear a high pitch, if that are slow we hear a low pitch.

      Our ear drums move a set of tiny bones which mover a thin membrane in our inner ear that contains fluid and little antenna nerve fibers that extend into the fluid. As vibrations occur in that fluid those nerve fibers Feel it and send electro chemical pulses to the brain which get interpreted by our conscious and unconscious reasoning.

      You'd be surprised how similar our own hearing system is to audio electronics. Many devices we use today come from our own ears. Alexander Bell copied the ear when inventing both the microphone and speaker and even used chemicals to get it working. Our bodies contain salts suspended in liquids to conduct electric nerve pulses. he simply used acid and water to do something similar for DC voltage to be conducted and when the diaphragm vibrated the liquid it caused a duplicate AC vibration in the voltage.

      An Equalizer uses a number of caps, resistors and coils to pass specific frequencies to ground. One cap may react only to frequencies in the low bands and leave the High bands alone because they are out of its range. Think of how light is split up into different bands. if you have a tinted lens that is red - it will only pass the low red light frequencies and block all the higher bands. Its the pigments in the glass that block the other frequencies but the low frequencies get through. We change the types and sizes of pigments in the glass and they absorb everything but the high frequencies of light so we only see purple - the high frequencies. All others get absorbed by the pigments.

      Caps and coils do things to AC voltages. You use different values which are physically and chemically different and they will pass select frequencies which are grounded out through a variable resistor (a Potentiometer/volume knob or slider) so what you're doing when you push a slider on a graphic EQ is grounding or un-grounding a specific frequency of AC voltage.

      Wires can carry a broad range of frequencies at the same time from 20Hz to 20000Hz same as our hearing except its current flowing through the wire not air wave fluctuations. The microphone diaphragm is connected to a coil suspended in a magnetic field. When the air vibrates, the diaphragm vibrates In this magnetic field and you get a vibrating AC current, much like the nerve impulses that go to the brain.

      From there we have all kinds of audio gear that can Change that AC wave. We can change its height in many ways, and we can also use those vibrations to activate circuits to do very cool things. We can multiply the waves mathematically, cutting the number in half and doubling them. We can put a ceiling on top preventing them from going to high and get compression and distortions. We can run the signal into a storage bin that saves it then lets it pass back out a few milliseconds later to get reverbs and echoes happening. We can stick a speaker on one end of a spring or plate to make it vibrate and use a microphone on the other end to convert that vibration into as signal again containing the changes the metal makes to the vibrations.

      Filters are a bit mystical but once you understand how they selectively react to certain frequencies to change the amplitude of those frequencies they begin to make real sense. The term Equalize refers to changing the frequency spectrum. It comes from the term Equal as in equal proportions. It divides frequencies up so you can even the frequencies up when you have too much of some frequencies and not enough of others. We use our judgment via our ears to decide if the resulting sound is natural and transparent sounding. The components that make up an amplifier and speaker aren't perfect and the recordings we listen to are made by people with their ears, not ours. We also have different listening environments and different speaker systems. An EQ lets us adjust the audio spectrum to our ears in our room through our speakers and amps, etc etc. They can also be used by the music creator and engineers that make recordings to generate a specific response form individual instruments and from an overall mix.


      • #4
        Originally posted by samal50 View Post
        Does an equalizer equalize only sonics ONLY? I read an article that I'll paraphrase; If one instrument (say a guitar) abruptly stops, another guitar track starts, it is best to set both those guitar tracks in the same EQ setting so that the sonics do not change, which is why an EQ is called an equalizer (it equalizes). I hope I'm on point on this one. So what does a compressor compress? etc. I think the names of these products would infer what they are for; an equalizer equalizes, a limiter limits, a compressor compresses, etc. I don't get what a gate is? What is it "gating"? A sonic maximizer will maximize "sonics", etc. A de esser will de ess the "S's", etc.
        A gate is an expander set to extremes. I explained how expanding the volume to make it louder for lead parts and quiet for rhythm guitar and how that was simply automated to give you more dynamics. A gate is simply set so when you stop playing a note the volume slider turns completely off. When you play a note the volume comes up to maximum. There is a threshold knob that can be set to ignore weak signals like the noise of a guitar gain pedals hiss when you stop playing notes. It acts like an water valve, a gate or door that takes time to open and close so the volume doesn't cut off sharply to create a noticeable volume clip like a guitar cord shorting out. It ramps the volume slowly so its musically transparent and natural like a guitarist turning his volume knob off when he stops playing then turns it up quickly and starts playing before you hear the noise from his pedals.

        They call it a gate because that's exactly what it does to the signal it gates the amplitude. Its like a mouse trap. When the mouse puts enough weight on the latch the springs released and snaps shut. same thing when you set the gates threshold. The ambient noise is lower then the trigger so the gates closed, the signal is grounded out and you hear silence. You pick a guitar note and the signal rises above the threshold setting and the mouse trap releases and you get full volume. When you stop playing the mouse trap resets itself to create silence.

        A Sonic Maximizer is a manufactures brand name. They keep the circuit secret so I cant be real specific on what it does.
        The best I can gather is it splits the frequency range I two so you have a low and high band. Then they delay the high frequencies from being reproduced. Bass speakers are thick, stiff, and have allot of weight compared to tweeters which are light and fast. The unit allows the woofer cones which are sluggish to get moving reach maximum amplitude before the tweeters are made to move. This way the sounds from each reach your ears at the same time and the sound is more like what you'd hear coming from a single speaker like headphones vs two speakers driving the sound across the room at different speeds. This way you hear the impact of all frequencies at the same time.

        There may be some frequency exciters built in too which generate waved from the harmonics which is another category of effects but like I sais there are no schematics available for the public so I can only guess.

        A DeEsser can be broken down this way De=Remove Ess=Sibilance Er= action/tool

        The definition of Sibilance helps too. Sibilance is a literary device where strongly stressed consonants are created deliberately by producing air from vocal tracts through the use of lips and tongue. Such consonants produce hissing sounds.

        A DeEsser is a Sibilance Removal Tool. Someone somewhere began calling it an S Noise Eraser or DeEsser for short which does describe what it does.

        Its a tuned filter much like a slider on a graphic EQ which targets a specific band of frequencies. It's automated like a gate and compressor and when those high frequency hisses occur the frequencies in that range are attenuated. They usually have an adjustable frequency range to target specific voices and a threshold and depth to allow you to adjust how much of that frequency is triggered to be removed.

        Sorry for the long posts. Just realize words can have extremely detained meanings. What may seem like a simple slang term has all kinds of detail in back of it.


        • #5
          Should be noted that the signal needn't be confined to audio. There are instruments now and in development that attempt to work on any part of the spectrum.
          Originally posted by Unconfigured Static HTML Widget...

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          • #6
            Essentially, a compressor makes the louder bits softer and the softer bits louder.

            A good application for a compressor is on vocal where the singer sometimes shouts into the microphone. The volume of the mic would need to be turned down to the point where the shout does not cause distortion. This could result in the quiet parts being too quiet, perhaps even inaudible.

            The compressor will automatically 'turn the volume down' when the parts get louder than the threshold setting so the overall volume of the microphone can be turned up resulting in a more even sound.
            Last edited by onelife; 09-25-2016, 01:07 AM.
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            • samal50
              samal50 commented
              Editing a comment
              Does the compressor do it automatically? When things are loud it softens it, when things are soft it loudens it? I've often wondered why some songs I hear on the radio does not sound like the singer is actually yelling while vocal tracking yet on the final song, the vocals do sound loud where it needs to be, perhaps the volume while tracking was high? Which I doubt otherwise it would have noise clips.

              What could be a "perfect threshold" (50/50, center?) so that when vocals are "whispered" it doesn't sound inaudible, or when screaming into the mic it won't get out of hand in the final mix? I tend to just stick with the preset vocal effects. It has compressor, de esser, etc. Are you saying compressor and de esser are the essentials for vocals? I've often wondered how those notoriously bad singers during live performances did so well in the recording studios? One I could think of is David Lee Roth (Van Halen) was said to be horrible live, yet his vocals are perfect on the records. I would think some very SENSITIVE compressor threshold setting were applied? LOL. Considering his screams and whispers are just over the top that it was still perfectly captured on the records.

              I'm also curious if Kurt Cobain was actually yelling (the way we all would yell) on "Smells like Teen Spirit" or was it all compressor? Yelling the way he did could blow out his voice if he does it all the time which is why I'm assuming all those yelling really were not actual yelling but were louden with compression so it gives the effect of yelling? I ask this because those death metal growlers who play dozens of shows a month are able to pull it off on a constant basis, I'd assume those vocal techniques are "controlled yelling/growling" and are louden with compression.

              I can understand how a compressor could soften something loud, but I don't get how it could louden something "soft". One example of this struggle I had was when I added vocal tracks to a song on different days, they tend to sound like they were recorded as such, on separate days. Let's say I tracked the first verse of a song today and tracked the vocal chorus on another day, sometimes they do not sound like they were even tracked at the same time. I didn't change the volume setting on the mic for each day, maybe perhaps my mouth was in a different position on the mic on the other days even if a few centimeters may have made a difference. Should I track with compression or it's best to do it AFTER tracking? Or both?
              Last edited by samal50; 09-26-2016, 03:49 AM.

            • onelife
              onelife commented
              Editing a comment
              The compressor reduces the volume of the loud bits allowing the overall volume to be increased which essentially makes the quiet parts louder. This is commonly known as 'make up gain'.

          • #7
            What sounds like yelling to you is actually vocal technique, not someone ripping their vocal cords to shreds. If you heard AC/DC's singer in a room singing without a mic he wouldn't be much louder then someone talking in a normal voice.

            You should think of these tools as crutches to aid inexperienced singers, and not essential tools that must be used.
            A highly experienced singer like say a Frank Sinatra didn't need any more then a mic and simplest sound of sound systems to sound great because he had a great voice to begin with. Opera stars have performed for many hundreds of years without any electronics, simply the voice reverberating in a large hall.

            A person must first learn to sing well. Second they must learn to work a mic to get the most from it. Third you can get into enhancements to remove innate flaws in their ability to sing well, but again, these are cosmetics, not a substitute for skill as a performer. That can enhance what a performer does well and mask what they don't do so well, and if the performer sucks they can draw even more attention to how badly they perform.

            The kinds of question you've been asking require some effort on your part to learn and much of its is pretty simple, but it does take some time and hands on which only you can provide.

            You have to do some self education on these topics before you can understand how any why they are used.
            You have to know what a Hammer and a Nail are and actually practice using them before an experienced carpenter can teach you how to use them in creative ways. He wont be able to instruct you in using the tools if you haven't even held a hammer before and likely has better things to do then teach you your basic ABC's. Many of the techniques used with compression have evolved over a hundred years involving hundreds of thousands of people actually using them. There are hundreds of different compressor designs and unlimited creative ways of using them, but explaining any one of them has to begin some place. Again, you have to be shown what a hammer and nail is and practice using them first before you can answer many of the questions you post. You can of course admire the final results a master carpenter gets with all his experience using the tools, but if you want to get into hoe he did it you have to retrace his steps one by one starting at the beginning.

            This description is as simple and basic as it gets. If this is still fuzzy, give it some time and experimenting using the tools. The light bulb will go off eventually.

            This description has those same basics with more technical details.

            As a compressor operator, its not essential you memorize every technical detail, but knowing details doesn't hurt and it can surely help. Its like a person who drives a car, they don't have to know how to rebuild the engine to drive it but they better know when its time to change the oil or they'll be paying to have it rebuilt. If you want to race cars for a living, its best to learn how to drive one first.