dumping inapplicable frequencies

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dobro

dobro

Well-known member
The frequency of the low E on my guitar is about 82 Hz, according to my sources. My voice doesn't go that low. At the upper end, 988 Hz is the upper limit for the guitar, and of course my voice doesn't go that high.

Okay, the question is this: what about using EQ to dump all frequencies outside the range of the instrument and voice I'm recording? So, for example, in the mix just getting rid of everything below 80 Hz and above 1000 Hz? Is this standard practice to keep tracks as quiet as possible?
 
Ahhh... But dobro, you are forgetting about the harmonic frequencies up to roughly 12k on voices and 15k on acoustic and electric (if going direct) guitars; max of 5k if the electric is going through an amp.

Pretty standard to filter anything below about 80 or roll-off starting at about 80 on those though.
 
Hey Dobro,

I've heard that you shouldn't dump high or low frequencys, or you will lose harmonics.

It may be a trade off, most of the time EQ is.

I think of EQ as, "a necesary evil".

My short term experience with EQ, is to remove coloration, cupped hand sound at 1Khz, boxy sound at 250hz, attenuated.

Interesting topic as usual.

Would like to hear others comments about the use of EQ.
 
I always have trouble finding the right frequency to cut. Like I can hear the sound that I want to get rid off, but I can just never seem to dial it in correctly.

Anyone have any tips?
 
Mr. Lip
Just up the boost knob and sweep the freq's untill you find the one you need

If you can hear the sound then it should stick out sorely as ou sweep


[This message has been edited by Shailat (edited 06-17-2000).]
 
Ummmm...dobro, the fundamental Low E frequency on a guitar is much higer then 82Hz. More like 340Hz (estimate here). Your open A string is a 440Hz tone (fundamental), half that would be one octave lower of course (220Hz). But the Low E string is a forth below, so about an half of an octave, thus how I got the 340Hz estimate.

Anyway. From there, you guitar produces higher fundamentals then 988Hz too. Your open High E string is somewhere in the neighborhood of 2KHz fundamental. 12th fret High E is over 4KHz. 22nd fret on high E sting is somewhere around 6KHz...etc....

Now, we are only talking about the "fundamental" note, not overtones! First overtone is an octave higher then the fundamental. Second overtone is an octave and a fifth. Third is 2 ovtaves....etc....So, your first overtone on ANY note on a guitar will have a strong presence of the first overtone which is an octave higher. So, that open High E string is going to have a a lot of sonic information at around 4KHz.

Now, a nice guitar tone really needs the presence of at least the first 5 overtones. So, that open High E string is going to need to have frequencies that are over 8Hz to be present at mix. A more brighter and brilliant sounding tone can be achieved with frequencies even higher then that being presented to the listener.

On the lower end of things. The wood of the guitar will produce subharmonic content. Plus, if you are running it through an amp, the volume of the speakers is going to "excite" the walls in a typical room, which will produce it's own subharmonic content too. So, you really need frequencies down to about 100Hz on a guitar to keep the sound full. Not all recordings really need guitar subharmonics below the 340Hz fundamental of the open Low E string, but a lot does to some degree or another.

A good bet for electic guitar is that you could slope out stuff below around 90Hz, and stuff above around 12KHz and not effect the primary tone very much at all.

On acoustics, getting rid of the low end stuff is cool, but, I don't recommend removing ANY higher frequencies at all. Acoustics tend to have far more information in the overtones that are needed to make it sound realistic on tape. Any high eq cut, aside for fixing minor tonal problems, will really take away from the "prettiness" of an acoustic. If anything, I tend to add a little High Shelf eq to acoustics to accent those frequencies.

Ed

[This message has been edited by sonusman (edited 06-17-2000).]
 
Okay, Ed, RE - I understand what you're saying and it makes all kinds of sense, and I'll proceed accordingly. Ed, that bit about the overtones and subharmonic content was clear and really interesting. I liked the bit about 'excited walls' too - I like thinking that when I play and sing, even the walls get excited... :)

Small confusion: I recently bought (and read!) "Practical Recording Techniques" by Bruce and Jenny Bartlett (Hey! How would *you* like to write a long book with your wife/girlfriend?). It's got a table of frequency ranges of instruments/voices. For acoustic guitar, it says the fundamentals are 82-988 Hz, with harmonics 1-15 kHz. This doesn't jibe with what you were saying, Ed. What's going on?

[This message has been edited by dobro (edited 06-17-2000).]
 
I think possibly he was refering to the BASS guitar. It is an octave lower then a regular guitar, and that info is about right.

Take the books with somewhat of a grain of salt my friend. I read many of them years ago, and read one about a year ago that was of more recent creation. While they have somewhat good information, you are not going to get any REAL good info. These dudes are usually just out making a buck.... :)

Inquisision, observation, critical thinking, and some 8 grade math skills are mostly what you need to understand this stuff. Oh, and a burning desire to make everything better sounding.... :)

Ed
 
I remember reading that, in digital recording, any sonic energy below what we can hear (~20hz?) will use up some of the available bits, and will result in a 'darker' sound. In the VS MTK ('Mastering Toolkit' HA!) patch, you can choose the frequency at which you cut the bass. I tend to cut it at 20-25 hz...For acoustic guitar I tend to add a couple of db at 4000 k, as well as boost the mids by the same amount. A lot of what you do with EQ also depends on how good you are at mic placement, as well as the type of mic you are using.
 
What a rare occasion, but you're wrong on this one Sonus.

Bass guitar
* Low E: 41
* Low A: 55

6-string:
* Low E: 82
* Low A: 110

Check it with a tone generator. But if you don't trust your ears, check http://www.kettering.edu/~drussell/guitars/electric.html

Remember, sometimes the first or second harmonic sounds more prevalent than the fundamental.
 
That book was one of my college text books years back... It does say 82 for acoustic guitar.

Mmmm... 41 is average for a standard bass guitar. And if a bass guitar is "an octave lower then a regular guitar", then that would call for 82 for acoustic guitar.

Also, I wouldn't consider Bruce Bartlett "just out making a buck...."... Just my opinion.
 
I am telling ya all, the fundamentals are higher then that. Sorry. Open A string on guitar = 440Hz, on Bass= 220. The Open Low E is "about" an half an octave lower then the Open A = 330 and 115. Now maybe he was talking about how Korn tunes.... :)

Not out to make a buck? Why don't they EVER tell you anything usefull for "production". Those books are worse then I am about not revealing anything about how to actually get good sound on tape.... :) and I give my vague "pointers" away from free. Now, there IS a whole lot of usefull information in those books to pass a test in school, based upon the premise that about 90% of what you learn in a school has just about no real world use... :D

About the frequency range thing again. Go about 1 octave below the lowest fundamental of the instrument to figure out the lowest frequency that is going to be usefull in the recording. Strong harmonic content below that usually starts conflicting with other instruments.

Peace.

Ed
 
I always thought that 440Hz was the A below middle C, which would be an octave above the open A string on a guitar.

No?
 
Well, if that's the case, then A at the second fret of the G string is 220, and A at the fifth fret of the upper E string is 440 (same as my tuning fork, which is what it sounds like), and A up near the sound hole on the upper E string is 880, which makes the table in the Bartlett's book sound reliable (82-988 Hz is the range of fundamental frequencies of an acoustic guitar, they say).
Which means it's pretty safe to roll off frequencies below 80 Hz for acoustic guitar. Yes, I have a one-track mind. :)

Geetarzan: if frequencies are below the audible range, I don't see how they can make the sound 'darker'. I'm not challenging, because I don't know, but it doesn't make sense to me. If it's inaudible, you can't hear it, right?
 
I agree. I am only relating what I read in a thread on another recording forum a while back. A bunch of people were talking about the 'darkness' of the sound of their VS1680, which they claim to have fixed by using the bass cut parameter of the Mastering Toolkit patches. The theory goes that even though that energy is inaudible to anything other than elephants, the converters ARE picking it up, and are using some bits that could be better used on the frequencies we can hear. I am not a propeller head when it comes to these things, but some of the guys who were doing the arguing and then the testing of their hypotheses ARE tech heads. In any case, I'd thought I'd relate this because it seems to make sense. Especially with the discussion turning to harmonics and such. The thing is, the MTK patches are 'Mastering Patches', meant to be used for tweaking the final stereo pair. They didn't talk about this subaural energy being nipped in the bud during tracking, which seems a more logical place to me for getting rid of these freqs...

YMMV,

Glenn
 
even if you cant hear it, it can still "do things" The most awesome sound I ever heard was on my buddies stereo... some souped up Marantz and some CRAZY speaks... his meter said it produced tomes down to 5 Hz. And it vibrated parts of my body I didnt know I had.

So what im saying is, theres more to music than what you can hear.

xoxoxo
 
So all of the books are completely useless? There are no useful tidbits in them on music production at all?

School is completely useless?

Have you been drinking again?
 
sonusman:

I got the college vs. real world joke/truth... hehe

Oh they are very "real world" (especially literally before sound is converted into electrons) if you solidly understand it all and remember it all; which I still don't after reading it over and over again for 7 years now. I probably never will.

"Those books are worse then I am about not revealing anything about how to actually get good sound on tape...."

They tell you the "best" way (IMHO) to get the "best" sound (IMHO) to tape.

The idea being, get it to sound as close to your final sound as much as you possibly can before hitting tape (at least acousticly); mainly the idea of doing the minimalist "corrective mixing" as you possibly can. Not only that, but also, I know you know a lot of mastering is actually "correcting" the mix.

After that, they are VERY LIMITED to the "real world"; which is know the "sound" of your eqipment (IMHO). The second "real world" thing to learn would probably be know how to maintenance your equipment (half a text book thing). Third? Know the sound of other's equipment. Next? Probably know what the equipment is actually doing so you can use other's equipment; and reading the info at the Digital Domain website, for example, would be another branch off this limb.

After all that, it's probably a good idea to read the "other" type of text book material so you can fix all your equipment.

Ofcourse it can all be all at the same time too; if one so chooses...

My point is how many people have you seen post questions here over and over again to the answers found in these text books (which you say are filled-up with 90% non-"real world" information) about basic stereo miking techniques or masking or any other text book material? Which I'm all for... Choose your media/tool for your text book material learning.

Yes
Peace
 
Hey PGLewis, sorry but you did not put in the fudge factor that the tests were done on an Epiphone guitar. This should throw the results off by at least 40Hz.

Just kidding.............

Acutally, that is a great article.
 
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