Basics of Acoustics: Timbre (I) : How to modify timbre

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By Los Teignos on 03/21/2008

Basics of Acoustics: Timbre (I)
How to modify timbre

You must always keep in mind that all EQing on an instrument will be destructive with respect to the recorded sound, just as the latter is also, in many cases, an imperfect copy, of the original. So one must be careful! Before touching anything, think about what you want to accomplish with EQing: I want a "warmer" sound, I want to cut the bass, I want my instrument to stand out in the mix, I want to get rid of that annoying resonance that came from the studio... The spreadsheet below is offered to you as a kind of "quick guide" chart. It will serve as a check-list that will enable you to control and master your timbre EQing. Don't forget, however, to listen: your ears are the ultimate judge.

type of EQing	your goal	Action	useful comments
adjust the timbre of an instrument recorded by a mic.	change the timbre of an instrument that has too much or not enough highs or lows.	Determine what frequency band needs to be changed: 1) put the gain to +12 db and then, turn the knob until you hear the zone where the signal increases the most. You have found the frequency to cut! 2) lower the gain to 0 dB, then lower the gain gradually until you get what you want. 3) Compare, by bypassing, the original signal with the new one.	Make the adjustments while the chosen instrument is in solo mode. Then, un-mute the other instruments to evaluate the new sound in the mix. Keep a large bandwidth (hump shape) and narrow it if necessary.
adjust the timbre of an instrument recorded by a mic.	Make an instrument stand out or blend into the mix.	1)as above, determine what frequency band needs to be changed. Maybe you'll need two filters, if the instrument has a large range. 2) tighten the Q as much as possible around the limits of the instrument. 3) Slightly raise the gain (not more than 3 to 5 dB!) of the filter.	This doesn't always work because other instruments could be in the same frequency range. So boosting the soloist boosts them up too. In this case we have to fall back on a multi-band compressor.
Bad quality of a spoken voice recorded by a mic.	correct "problems" on certain consonants.	It's probably the "pa", "da" and similar types of syllables that cause problems: the solution is at the bottom end of the frequency spectrum, and more specifically in the noise of the attack. Certain consoles feature a fixed high-pass filter whose purpose is precisely to try and limit this problem. Choose the "low" EQ, and reduce the gain by 2 to 3 dB. Use "shelving" if it isn't already the default type of filtering. If there's no shelving, try widening the bandwidth (Q) as much as possible.	Again, it doesn't always work. Bit it's still easier on a spoken voice than on a singing voice. If, in spite of your efforts, the problem persists, you'll have to use a compressor.
Unwanted sound during playback or in the recording.	delete a parasite or a noise in the background linked to the place it was recorded.	Find the parasite frequency, just like you did above, if it's a cable or electricity problem, it'll be around 50Hz or one of it's harmonics. As soon as the frequency has been found, narrow the Q as much as possible and bring down the gain...as much as it takes for the signal not to be a nuisance anymore.	You should have noticed it during the recording! All we can do now is "make the best of what we can"! The EQing applied will be more efficient if the frequency is accurately targeted. But...everything else in the same range will disappear with that parasite!