Resistors are usually used to slow the current flow into the capacitor to alter its 'time constant' (how long it takes to charge/discharge it.) This alters the frequencies that are passed and this technique is used to 'fine tune' circuits to operate at specific frequencies.īecause a capacitor's voltage takes time to change, any input signal will be time-delayed a certain amount on the other side of the capacitor. Rarely used in audio circuitry as you would need an extremely high value inductor to prevent audio frequencies from being shorted to ground. Inductor (Parallel) = High-pass (DC and 'lower' frequencies taken down to ground and high frequencies allowed to pass. Inductor (Series) - Low-pass (Higher frequencies find it harder to pass.) The term 'Phase-shift' is used when the delay amount is frequency dependant, as it is in filter circuits.Ĭapacitor (Series) = High-pass (Blocks DC / allows higher frequencies to pass.)Ĭapacitor (Parallel) = Low-pass (Takes higher frequencies down to ground, only allowing the lower frequencies to pass.) The term 'Time-delay' is only used when all frequencies are delayed by the same amount. ![]() For infinite reduction of any particular frequency, it is dependant on the transfer function - the steepness of the curve / -3dB cutoff point / all the other things I don't understand. So for no gain reduction, there's no delay but for infinite reduction, the filtered signal is 180º out of phase to the original? Everything else just slots in between.There can be more than 180° of phase-shift on any signal. So I swept an EQ and found the fundamental pitch, then boosted that a few dB with a very high Q. So I didn't get enough of that cool ringing tone Djembes are known for. I'm not much of a drummer, and my touch is not very good. The other day I recorded myself playing a Djembe. ![]() Otherwise you're adding resonance which is often obnoxious. I'll also add that cutting resonances is best done with narrow (high Q) settings, but for boosting a shelving or broad shape is better. I'd say that identifying and squashing offensive resonances is one of the more important skills for a mixing or mastering engineer to develop. So it's not that cutting is generally preferred to boosting, or vice versa, but rather simply identifying the real problem. When you find and reduce that resonance, all of the sudden the sound becomes brighter and cleaner and often fuller by comparison. Often when something sounds not bright enough the real culprit is a nasal or boxy sounding resonance. Just as common is what people sometimes call "surgical" use of EQ - to reduce offensive resonances. ![]() Another is overall low frequency muddiness, and for that an EQ LF shelving cut or high-pass is appropriate. One is overall lack of brightness, and in that case EQ shelving boost is the most direct solution. There are a few common problems that people use EQ to solve. People say that cutting sounds more natural than boosting, what is the reasoning for the difference in sound?The answer has nothing to do with phase shift. ime, a desk where most of the knobs are turned backwards tends to spit out a more focused, musical sound. with 24 channels of boosted eq, you're hearing phase artifacts all over the place. I'll go further and say that this is why cuts sound better when accumulated in a mix: the affected freqs are lower in level than the rest of the spectrum (they've been cut), so what you tend to hear in the mix is mostly the unsmeared stuff. some circuits have a more pronounced smear around the filtered freqs than others do, and often this is what we hear as the 'sound' of the eq. you take a dry signal, split it in two, run one side thru filters and blend it back with the other, that filtered side is a little delayed. Phase shift tends to come into the picture with analog eq because of the nature of the process. the greater the gain of the bandpassed signal, the greater the cut or boost. if you flip the polarity of that bandpassed section and add it back in, you've got a cut. ![]() If you bandpass a section of the spectrum and add that back in with the original, you've got a boost of the bandpassed freqs. It seems like you might have the gist of it, but your wording is a little off. So for no gain reduction, there's no delay but for infinite reduction, the filtered signal is 180º out of phase to the original? Everything else just slots in between.
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