is there a way on how to find opposite frequencies

[djclueveli]

is there a way or formula to find opposite frequencies? e.g. say i wanted to bring out more 8000khz but didnt wanna boost to aviod coloration, so i cut say about 250hz. is there a mathmatical calculation to find what are the to opposite frequecies?

 

[mixsit]

Hmm. I get your concept. But if that's what it needs (vs it being a compensation for too much of something else) 8k it is.
I guess I'd rather do one filter there than two on either side.. It's simpler, maybe just as clean because of it.

 

[punkin]

Hmm...trying to undertand where you're going with this. If I get your concept, the idea that high freqs will cancel out low freqs simply doesn't work. "Sound" is the sum of it's parts. You can get the impression that the lows are diminished by pumping up the highs but really, all you're doing is adding power. You can get into phase cancellation but you use the original frequency 180 degrees out of phase. This is tough to do with compound signals and generally isn't real pleasing to listen to when working with the "usual" tools of the trade. I'm sure there are some seriously hi-tech pieces of gear that do this better than simply hitting the old phase reversal switch on the mixer.

Not sure if you're familiar with the parametric EQ. These things can be very selective when adding or attenuating specific frequencies/bands. These things are SO handy when trying to cut out an objectionable freq. . Another tool to look at (A lot of the pros hate them) is a mult-band compressor is another tool which is band restricted/selective which give you a good deal of selectivity when "mauling" the mix.

Hope this helps

 

[ecktronic]

Cutting is usually better than boosting when it comes to EQ. 8K is is the high end region of the frequency range, so if you want to bring out 8K without boosting you could try cutting some "mud" out at around the low mid region. Id play about around the 200-300Hz region. You could also put a hi pass filter around 20-40Hz.

Eck

 

[mixsit]

In this case the 'cut doing less damage' might not apply. (I'm going with the presumption that you're less apt to hear the faults of a filter pulled down vs raised.)
Pulling down hot spots for example, does the eq's fix' for the tone while it deemphasizes the filter. In this case everything except 8k goes through at least two filters?
Or this is all so much second guessing likely and I could be full of it..

 

[SouthSIDE Glen]

There's no such thing as "opposite" frequencies, therefore no formula.

However, a few things to consider, in addition to the good advice already given above:

- Perhaps the closest thing to a formula for something related would be to look at the closest harmonic frequencies; i.e. those nearest frequencies that are neat multiples of the frequency in question. Sometimes, boosts or cuts (especially cuts) at some of the nearest harmonic or even sub harmonic frequencies can help with a problem timbre that just isn't reacting properly to direct EQ. Use this sparingly, it takes practice to learn when it works and when it doesn't.

- Use the old tried and true parametric sweep thang to find bad resonant frequencies in a track and cut those. That's probaby the fastest and most efective way of surgically removing mud from any track and in turn accentuating the "good" frequencies.

G.

 

[RAMI]

There's no such thing as "opposite" frequencies, therefore no formula.

However, a few things to consider, in addition to the good advice already given above:

- Perhaps the closest thing to a formula for something related would be to look at the closest harmonic frequencies; i.e. those nearest frequencies that are neat multiples of the frequency in question. Sometimes, boosts or cuts (especially cuts) at some of the nearest harmonic or even sub harmonic frequencies can help with a problem timbre that just isn't reacting properly to direct EQ. Use this sparingly, it takes practice to learn when it works and when it doesn't.

- Use the old tried and true parametric sweep thang to find bad resonant frequencies in a track and cut those. That's probaby the fastest and most efective way of surgically removing mud from any track and in turn accentuating the "good" frequencies.

G.

I use the parametric swee thing most of the time.

Glen,

What I did find is that if I needed to cut (for example) 200hz, I usually end up finding that the next frquency that really hums and needs cutting is 400hz.
Same thing if I need to cut 250hz...I usually find I also need to cut 500hz. Is this co-incidence, or is that what you're refering to when you say "neat multiples of the frequency in question"???

 

[XLR]

is there a way or formula to find opposite frequencies? e.g. say i wanted to bring out more 8000khz but didnt wanna boost to aviod coloration, so i cut say about 250hz. is there a mathmatical calculation to find what are the to opposite frequecies?

With classical gtr there's something along this line but I don't think it's formulaic, just the character of the instrument. The areas around 350 Hz and 3 kHz are often problems with nylon string gtr, and are somewhat opposite in their contribution to the tone color balance. ...one being richness (or boomy mud), and the other clarity (or harshness). A slight cut in one tends to boost the emphasis of the other like a seesaw. But other freq ranges of the instrument, of similar ratio, don't balance each other out like that IMO. So I don't see a formula to it.

 

[SouthSIDE Glen]

What I did find is that if I needed cut (for example) 200hz, I usually end up finding that the next frquency that really hums and needs cutting is 400hz.
Same thing if I need to cut 250hz...I usually find I also need to cut 500hz. Is this co-incidence, or is that what you're refering to when you say "neat multiples of the frequency in question"???

Yep, exactly. Harmonic frequencies. They can be a real nuiscance sometimes when they get out of control. ID'ing them as a culprit is one of the few reasons I ever advocate the use of an RTA. They also make EQ plugs that contain harmonic filtering options indenspesible tools.

Check out this post from a while back for a graph where harmonic series within the background noise on a client's recording was causing some major issue until it was found and filtered out. (Ignore the rest of the vitriol in that post. I'm only bringing it up because this anemic BBS software won't let me use that graphic again here.)

G.