harmonics

[rymdis]

Hi there!

wonder if the A @ 1760hz contains all the previous harmonics or just one harmonic?


thanks

/R

[Ogg Vorbis]

Hi there!

wonder if the A @ 1760hz contains all the previous harmonics or just one harmonic?


thanks

/R

Not sure what you mean by "previous" here. Physics dictates that no harmonic will have a lower frequency than the fundamental (1760hz).

[nuffink]

It contains the fundamental at 1760hz. If it's a sinewave that's all it contains. Any more complex waveforms will contain some harmonics above the fundamental. None below.

[llatham]

Hi there!

wonder if the A @ 1760hz contains all the previous harmonics or just one harmonic?


thanks

/R

It depends on the type of waveform.

If the A 1760 is created by a Sine wave, it will have one partial, the Fundamental.

If it's a Sawtooth, Triangle, or Square wave, it will have all partials (fundamental + harmonics) or all the odd-numbered partials.

But it won't contain "previous" harmonics.

You should read up on harmonics.

Steve

[Aroused by JarJar]

That is actually an excellent question, and one that actually has a couple other "well..." answers other than the standard correct answers given above.

Even a sine wave at a given frequency does, in a way, "contain all the previous freqencies"- the subharmonic series. Two complete cycles of the sine represents a frequency of 1/2 the fundamental, three cycles 1/3, and so on, a kind of mirror of the harmonic series which would lie above the fundamental, which would be 2:1, 3:1, 4:1.... (twice the fundamental frequency, three times, four...etc.)

How "real" is this? Well... when you pluck a string or blow on a pipe, the harmonic series above is audible, whereas the subharmonic series is there theoretically/mathmatically. But if you play a sine, then play a sine at half the frequency, it's going to sound like a harmonic relationship (because it is). But it will sound like the first, higher, sine is now the first overtone of the second, lower, sine. Unless the lower sine is much quieter, then you can have a kind of thing where you don't really know which is which. (Same with rythm- you can have rhythms where you can feel that it's one tempo, or another tempo twice as fast/slow. (or three times as fast/slow, that's the "thing" of 6/8, ie, it feels like a slow 2 and a faster 123, 123 at the same time).)

The composer Harry Partch used the subharmonic series in conjunction with the harmonic series, it sounds really nice, but I think most people agree that the subharmonic harmonies are less consonant and defined in relation to the tonic than the harmonic series harmonies are.

Guitar octave pedals actually use the subharmonic series if you think about it- it's a simple process.

So yeah, a tone does contain the "previous" harmonics- in a way.

The other "well..." answer is: not all tones have the percieved fundamental as the lowest partial. This can happen in percussion instruments and FM synthesis for example.

Anyway, generally speaking, we usually think of it the other way around: generally, a tone "contains" the harmonic (integer multiple) series above the fundamental, mathematically and in "real life" to greater or lesser degree.

If this sounds confusing, it's not meant to be- I just wanted to point out why the question is actually quite interesting and relevant in certain maybe more esoteric areas.

[rymdis]

thanks for the replies!! Always fast at KVR!

sorry that my question was a bit vague. what i really was wondering was a thing i saw in an EQ tutorial and i guess this is includes many instruments and i quote:

"boosting around 1760hz would make all the A notes jump out (1760hz is A, and thus harmonics of all A notes below it"

maybe this clearify a bit?

thanks
/R

[Nystul]

thanks for the replies!! Always fast at KVR!

sorry that my question was a bit vague. what i really was wondering was a thing i saw in an EQ tutorial and i guess this is includes many instruments and i quote:

"boosting around 1760hz would make all the A notes jump out (1760hz is A, and thus harmonics of all A notes below it"

maybe this clearify a bit?

thanks
/R

Well let's say we have an instrument playing A at 440 hz. Unless this sounds like a simple sine wave, it is likely to have strong harmonic content at 1760 hz. But let's say we also have an instrument playing a D at about 587 hz, in harmony to that A. Well that D has a third partial around 1760 hz, so it's quite possible that this note also has harmonic content near 1760 even though it is not an A. Now when we drop down into the deep bass register, just about any note *might* have harmonic content at 1760, but those harmonics aren't necessarily going to be very prominent.

If you are making very narrow boosts or cuts, I imagine it could indeed make certain notes stick out in a way if they have strong overtones at that particular frequency, and that may be an undesirable result if those instruments are playing melodic passages.

[rymdis]

so at 1760hz the A note contains all the previous A harmonics and the fundamental at 440hz as well? if i got it right?

thanks
R

[BKK-OZ]

so at 1760hz the A note contains all the previous A harmonics and the fundamental at 440hz as well? if i got it right?

thanks
R

People often say that there is no such thing as a dumb question, but...

Why don't you read the very informative post from Aroused by JarJar and at least try to understand it? You need to put a little bit of effort in too, you know.

[nuffink]

so at 1760hz the A note contains all the previous A harmonics and the fundamental at 440hz as well? if i got it right?

thanks
R

No

[rymdis]

so at 1760hz the A note contains all the previous A harmonics and the fundamental at 440hz as well? if i got it right?

thanks
R

People often say that there is no such thing as a dumb question, but...

Why don't you read the very informative post from Aroused by JarJar and at least try to understand it? You need to put a little bit of effort in too, you know.

sorry, i just wanted to know if the tutorial was right about this or not (see previous post). If its not maybe it got other errors? The post as u say is very informative and contains a lot of information.

i know only a bit about this but i know that the first harmonic of A @ 440hz is @ 880hz and the second @ 1320hz and the third @ 1760hz. Accordning to the tutorial all of the previous harmonics would boost if i boost the harmonic @ 1760. Maybe i got things mixed up? i find it strange that the previous get boosted as well. if i boost @ 1760 then i boost the third harmonic of the A note and not the first, right?

thanks
R

[Aroused by JarJar]

so at 1760hz the A note contains all the previous A harmonics and the fundamental at 440hz as well? if i got it right?

thanks
R

People often say that there is no such thing as a dumb question, but...

Why don't you read the very informative post from Aroused by JarJar and at least try to understand it? You need to put a little bit of effort in too, you know.

sorry, i just wanted to know if the tutorial was right about this or not (see previous post). If its not maybe it got other errors? The post as u say is very informative and contains a lot of information.

i know only a bit about this but i know that the first harmonic of A @ 440hz is @ 880hz and the second @ 1320hz and the third @ 1760hz. Accordning to the tutorial all of the previous harmonics would boost if i boost the harmonic @ 1760. Maybe i got things mixed up? i find it strange that the previous get boosted as well. if i boost @ 1760 then i boost the third harmonic of the A note and not the first, right?

thanks
R

Well this is a whole different question than the original appeared to be, because we didn't know that you were refering to a harmonic partial of A 440!

The question appeared to be more like, "is there an undertone as well as overtone series?".

But you're talking about harmonic series.

Anyway whether or not all the harmonics lower than the one you're dealing with are affected depends on some things: first, they actually all have to be there for the "all" to be effected (there are always harmonics "missing" in the case in a square wave or any other pulse wave, to cite the most obvious examples).

And of course it depends on the filter. Are you talking about EQing? What kind of EQ? Or about the boost at the resonance point of a resonating low pass filter? etc. etc.

Typically, unless you are doing some pretty obscure white-lab-coat kind of filtering, anything you do to any harmonic partial is going to have a greater or lesser effect on other partials (and usually greater). And even in the improbable case that you are filtering a single partial without having any effect on the others (well you could be doing additive synthesis of course), there will always be a psychoacoustic/perceptual effect of everything you do.

But we can't say what effect without knowing the process, and what that effect really means in "real life" without knowing the context.

[llatham]

i know only a bit about this but i know that the first harmonic of A @ 440hz is @ 880hz and the second @ 1320hz and the third @ 1760hz. Accordning to the tutorial all of the previous harmonics would boost if i boost the harmonic @ 1760. Maybe i got things mixed up? i find it strange that the previous get boosted as well. if i boost @ 1760 then i boost the third harmonic of the A note and not the first, right?

Ok let's make it easy. Take harmonics out of the equation.

You don't boost or cut harmonics with an EQ - you boost or cut *frequencies*.

If you have an EQ that you can set to exactly 1760 Hz, and you can boost that 12 db, what it's going to do is boost 1760 12 db.

It doesn't matter if 1760 is a harmonic of the note A, or D, or F, etc. It's simply boosting 1760. If you know 1760 IS in fact the note A, you'd know you're boosting an A. That A *might* be an actual A fundamental of some instrument at 1760, and it might be the first, 2nd, 3rd, or Nth overtone of some other note.

Now, I said above that you'd boost 1760. But EQs don't just boost (assume "or cut" hereafter) a single frequency - they boost frequencies above, below, or around that frequency as well.

In the case of a Peak EQ, which is what most Graphic EQ faders are, you're boosting 1760 12 db. But, you're also boosting frequencies above and below that frequency - which is called the Center Frequency. The Center Frequency in our example is 1760. How much above and below that frequency gets boosted depends on the Bandwidth.

What it does is boost 1760, but at say 880 (half) and 3520 (double) it will only boost those frequencies 50%, or 6 db.

The shape around the center frequency is usually a bell curve, which means frequencies closer to the center frequency will get adjusted more than frequencies further away. For example, in our example, A 110, and A 220 might not even get adjusted at all, but 440 might show a 3 db boost, and 880 a 6 db boost, etc.

In Graphic EQs, you can Boost or Cut them - the frequency you're adjusting and the bandwidth is set by the manufacturer.

In Parametric EQs, you can adjust all the parameters of the EQ - whether you boost or cut, what frequency will be your center frequency, and how wide the bandwidth will be (also known as Q, or Quality).

There are also semi-parametric EQs which allow you to boost/cut, and select the center frequency, but not change the bandwidth.

In addition to the Peak EQs you find in Graphic Equalizers, there are also High Shelf and Low Shelf EQs (often, Bass and Treble knobs in home stereos are of this type).

Now, in these, you pick a Cutoff Frequency, and everything above (for High Shelf) or everything below (for Low Shelf) will be boost/cut.

So, if you have a Low Shelf EQ, and you set the Cutoff Frequency at 1760, every frequency below 1760 will be boosted (or cut assumed hereafter again).

If your boost is 12 db, then 110, 220, 330, 440, 880, 20.5, 113.4659, etc. will all be boosted 12 db - EVERYTHING up to 1760. From 1760 up, frequencies will NOT be boosted (or affected in anyway) except that there is a "slope" on the EQ - so again, frequencies above 1769 will be boosted, but less and less so the farther you get from 1760. If it's a 12 db per octave slope (octave is a doubling in frequency) then 1760 will be boosted 12 db, and 3520 will not get boosted. If it's a 6 db per octave slope, 1760 will be boosted 12 db, and 3520 will be boosted 6 db, and the next octave will be at 0 boost.

So forget about harmonics.

Yes, true, if someone's playing an A 110, and it's a waveform rich in harmonics, you'll have 110, 220, 330, 440, 550, 660, 770, 880,.....1760. If you use a Low Shelf and boost it, with 1760 as the cutoff, yes, all those harmonics will get boosted as well. Of course, so will every other frequency below 1760 (and those sloping off above it to an extent).

So, you asked:

if i boost @ 1760 then i boost the third harmonic of the A note and not the first, right?

Yes, if you're using a *very* narrow bandwidth EQ set to 1760. However, it depends on how adjustable the Q is on your EQ. Your EQ might just be a plain old graphic EQ, and if it's bandwidth is, say, 4 octaves, it's going to adjust 1760, but also 3520 and up to 7040, and 880 and down to 440.

That's a big bandwidth for a Graphic EQ though - most are 1/3 of an octave or 1/2 an octave (meaning there are 3 or 2 adjustable frequencies per octave) and some of the plug in versions go as wide as 3 octaves (1.5 up and 1.5 down).

So here's the catch: It depends on what the fundamental is, as to which numbered harmonics you'd be adjusting.

Let's say you got a graphic EQ set to 1760, and it's got a 2 octave bandwidth (that's an octave up and an octave down).

If the fundamental is 880, then the first harmonic is at 1760. Since the fundamental is right at the edge of the bandwidth curve, it will get affected very little, if at all.

But, if your fundamental is 220, you've got 220, 440, 660, 880, 1100, 1320, 1540, and 1760. 1100, 1320, and 1540 would all fall within the octave range (880-1760) so your 4th, 5th and 6th harmonics would all be being affected.

And in both cases, things above will be being affected too.

I think thinking of EQ in terms of "harmonics" is a little misleading. They adjust frequencies. Some of those frequencies *might* line up with harmonics of notes, but which harmonics are being adjusted depends on what the fundamental is, and what type of EQ is being used.

I think it's more helpful to thin about frequencies, period. It's OK to *relate* those frequencies to note - since we often deal with pitched sounds - but that's about as far as the relationship is useful.

HTH,
Steve

[jof]

Accordning to the tutorial all of the previous harmonics would boost if i boost the harmonic @ 1760.

No, it doesn't say that. It says that you would boost all A notes, NOT all harmonics.
What the person who wrote it is trying to say is that all lower A notes contain the frequency 1760 Hz, so that boosting this frequency will make them all "jump out".
This is not completely true, however, since not all waveforms contain all harmonics. For example, a square wave only contains odd harmonics, so square waves at A frequencies would not be affected if you boost 1760 Hz.

[rymdis]

superthanks for the great answers!!!!

a bit advanced for me though

so does an A note with the fundamental tone at 440hz always contain the upper freq at 1760hz?

its hard to see the difference between harmonics and frequencies i think
isnt harmonics just frequencies?


so to sum it up; if i boost at 1760hz it doesnt mean by default that all A notes below "jumps out". it depends on the bandwidth and how much i boost, right?




thanks again!!

/R