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A channel strip plus a graphic equalizer: good idea?

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  • A channel strip plus a graphic equalizer: good idea?

    I've been spending weeks reading about EQs, preamps, and compressors for home recording. I have a Tascam, not a DAW, and I want to be able to improve the signal going into the 'scam. No one unit does it all, so I'm wondering if it makes sense to get two units - for instance, the dbx 286s channel strip and the dbx 131 graphic EQ.

    Does that make sense, or is it a recipe for trouble?

    Last edited by Delmont; 03-16-2017, 02:30 PM.
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  • #2
    No, you'd be fine...studios routinely run signals through multiple pieces of outboard gear. Do take a few minutes to read about "gain staging" in a general sense as it relates to recording. Basically, gain staging is ensuring that what ever signal you are processing (or recording) is at a "good" level, if it's too loud, you'll get distortion; if it's too low, noise (especially hiss) can work it's way into the signal.
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    • #3
      If you run the channel strip into the EQ you should be OK for gain staging. The channel strip should output a line level signal and the EQ should input and output a line level signal. You just need to be sure your recorder is set for a line level input.

      Both the channel strip and EQ will likely have volume controls - to follow up on what MR Grumpy was talking about your want to have one unit feed the next at the proper gain levels. Each piece of gear can be unique here. Often times manufacturers target the gain knob so it has zero gain or cut when the knob is set to half way up, but because your devices also have things like EQ boost, cuts, Compression etc, you may need to tweak the gain setting depending on how much the device is boosting or cutting the signal.

      There's a couple of ways you can do this. The best would be to first feed your recorder with a 1K test tone and set its meters to a fixed amount.
      1Khz is in the middle of the frequency response range and its easy to download a sample you can use. I'd either download a frequency generator to your computer or download wave files at fixed levels. -6db is a common level for setting up gear.

      Burn the files to a CD so you can play back the CD to your recorder and know its outputting the -6db. Then you'd adjust your recorders recording volume to the -6db.

      From there, you'd then connect your EQ, have all its EQ setting set flat to zero and feed the EQ with the same signal. You'd adjust the EQ output volume (if it has one) so your recorder meters are reading the same -6 dB you had before you connected the EQ. This gives you 1:1 gain. Unless you use extreme boost of cut settings you shouldn't have to mess with the output gain. I'd even suggest taking a sliver of masking tape and marking the zero gain setting so you can always get back to it.

      After this you'd connect your channel strip and do the same thing. Feed the unit at line level with no additional effects or EQ boosting or cutting the signal. Because preamps often have an Input and an output level it may be harder to know where your gain setting need to be. If the channel strip has a meter then its fairly simple. You sat the input gain so the meter in the preamp reads -6 - then set the output level so your recorder reads -6.

      All of this is done so you know your gear is starting at a 1:1 - no gain boost or cut. From there you can use gain staging to overcome some of the tone sucking that can occur using multiple pieces of hardware. You should always realize you don't get something for nothing. More circuitry means more losses. You gain the ability to remove unwanted frequencies with an EQ and then boost what's left. An EQ cannot invent frequencies that don't exist to begin with.

      The only gear that can actually add frequency information is an octave generator/harmonizer/auto tune device or a harmonic tool that generates high frequencies overtones from lower frequencies. Alesis and others made hardware versions of these tools that could generate high frequency enhancements where they simply don't exist otherwise. Of course sub bass tones can also be produced synthetically by octave type generators.

      All your normal Graphic and parametric EQ's are filters. These filters can only cut existing frequencies. I say cut because they all produce maximum frequency response with all the sliders boosted and when the sliders are set in the middle they are all cutting the frequencies by 50%. They simply add gain to boost the DB level so that 50% mark is 0dB instead of -12db

      Your old vintage EQ's were completely passive and had no additional preamps in them (much like your guitars tone control) They too could only filter the signal except you had no makeup volume so you took a huge hit on volume when using extreme cuts. This is one reason pro gear used +4dB as a standard line level. There was more gain there to push through the old passive EQ's used. In comparison, Most newer EQ's have preamps and makeup volume and are normally run at -10dB.

      Anyway, the goal is to get a 1:1 signal passing through all the pieces of gear first. Then when you connect your mic and record you set the preamps input gain so it peaks around -6db and all your other controls should have enough tweak able range on them. When you work with analog gear you will eventually find sweet spots where the gear sounds its best producing the least noise. Sometimes its a slightly hotter setting then what you calibrated it for, and sometimes a little less. Finding those spots is much like dialing your guitar up for its best tones, you feel your way there using your ears. So long as the settings aren't too low and you get muffled weak signals or too high where one device overdrives the next you should be OK so long as your recorder meters are right. You may in fact prefer to use an over gained signal to get some hotter then normal tones happening.

      Key is to first calibrate and mark those settings to 1:1 then you can do what you want and always get back to home base before you tweak things for another instrument. Bass may be great at 1:1 or less and overdrive when driven harder. Guitar/ Vocals/Snare have more midrange and therefore less raw power and may sound better running hotter. This is where there are no roadmaps to follow. The path comes form the engineers skill and experience gained through experimentation and getting to know his gears capabilities. You want to intentionally push gear to its limits just like you step down on that accelerator pedal of a new car so you know what it can and cant do.


      • Delmont
        Delmont commented
        Editing a comment
        All good info. Thanks again!