Freq Respns

[Leo_Gnardo]

I never even stop and think about this!!!! Middle C(3rd fret of A string) is 261, next C(1st fret of B string) is 522, then 8th fret of high E is 1046, then 20th fret is 2093. Am I missing something?

I understand there are many higher harmonics associate with each note, but still, I never thought the range is so narrow!!!

Not missing anything - those are the fundamentals. Now if you took your guitar signal and passed it thru a sharp cutoff filter at say 82 Hz to 2100 Hz, you'd have "telephone" guitar tone, or old AM radio, like the intro to "Wish you were here." After a couple measures, Dave plays along with the radio, and there's your full frequency acoustic guitar. Best example I can think of.

[Leo_Gnardo]

Gotcha...Thanks (Leo and Enzo)

I guess if I crank my scope, I guess I can see it straight from the guitar.?
What does a Humbucker put out...a few hundred milliamps.?

Yer welcome & I'm sure Enzo agrees & the Dude besides. Sure, watch your guitar on the scope, very entertaining and informative. Neck pickup, tone rolled back, very sine-wave like once the attack dies down. Hit a harmonic and as it fades, the overtones die off and after a couple seconds, there's your sine again. Bridge pickup, tone all the way up, lot's of hashy looking high frequency harmonics. Have fun!

To borrow and alter someone's byline: never trust a sine wave: they make up everything!

[Gingertube]

Handy reference page which has all Bass and Guitar frequencies listed.
The Valve Wizard -Cathode Follower

Print it out and nail it on your wall.

Cheers,
Ian

[Alan0354]

Gotcha...Thanks (Leo and Enzo)
I could not figure out how a guitar with a maximum freq of 1.3kHz could fill a speaker with 5-6kHz.
Never seen the question asked before...was kind of embarrassed to be the first one.
I guess if I crank my scope, I guess I can see it straight from the guitar.?
What does a Humbucker put out...a few hundred milliamps.?

The frequency of the note is the fundamental frequency where half of the wave length is the length of the string where you pressed to the bridge. But there are harmonics as shown in this:Harmonic - Wikipedia, the free encyclopedia. The strings can vibrate at the fundamental, 2nd, 3rd and higher harmonics as shown in the diagram.

If you plug a string and look at it along the length of the string, you will see some part seems to vibrate more than other parts. That's where the note and anti notes are. The Wikipedia really gives a good explanation on this.

We usually look at pickup output as voltage. Go to Dimarzio website, they tell you what is the output of each of their pickup.

[trem]

Thanks for those links.
And yeah...sorry...I meant to type millivolts

[Leo_Gnardo]

If you plug a string and look at it along the length of the string, you will see some part seems to vibrate more than other parts. That's where the note and anti notes are. The Wikipedia really gives a good explanation on this.

Nodes and antinodes. Close 'nuff but to minimise the cornfusion. What's movin' to the max and what ain't movin' at all.

NoTe that guitar pickups are ordinarily placed to pick up the moving parts of the string, unfretted. If a node appears over a pickup, you don't get much signal out of it. For instance the third overtone node (non moving part) is often right above the neck pickup. If you play the harmonic at 5th fret (2 octaves above fundamental) you'll hear it clearly thru the bridge pickup, but at the neck pickup, hardly at all. You can play the same harmonic by placing your finger on the string above the neck pickup. It's quarter-way down the string. So is the 5th fret. I could keep blabbin' and head into Pythagoras' territory. Later for that. Suffice it to say our "Western" scale is based on whole-number divisions of string length, or pipe length in wind instruments. Other traditional scales likely similar, all around the world.

It's a lot of fun to observe strings, drumheads, & speaker cones under strobe light. Makes it easy to see vibration patterns. @ 30 years back Celestion did a lot of research on their cones using laser-pulses similarly to strobes. It's fascinating to see the cone patterns as they're pushed into "breakup" that is, not moving as a simple piston. It's not just random. And that's what enhances your guitar tone with extra overtone help from the speaker. Might help explain a bit of what's going on in that "American vs British" speaker tone discussion. Different breakup patterns. Some we like, some we don't. There's something for everybody. Music & science = fascinating.

[Alan0354]

the speaker thing is just foreign to me. As you can see I have a hard time on that speaker.

[Chuck H]

This whole thing represents one challenge to amp design. Some players are very good at using a broader response amp with their fingers and sensibilities, Others want to be able to attack the strings like an animal and have the amp behave. Both approaches are very valid, but require two different amps. For the designer it creates pigeon holes that complicate marketability to any given demographic. I'd venture to say that 90% of the most touted boutique amps offer a broader than average frequency response. I'd also say that 90% of guitarists would find this tone unusable! They seek these amps because their hero's play them. The magic they seek in the hands and sensibilities.

Now I have to come clean and say that I generally attack the strings like a Neanderthal. So my amps are designed to limit HF and LF somewhat. I think this makes them more accessible to the average player, but I don't limit entirely. My ideal being that there is still enough chaos to add interest to the tone and the ability to accent nuance for articulate players, yet still enough control not to sound harsh or boomy for the average player. I'm pretty proud of my amps but that's only because I judge them on my own criteria My customers (all six of them!) seem happy.

The OP came off with the impression that this was strictly a guitar issue. If it's an amp design issue that changes things. Since guitar amps are NOT reproduction tools, but rather "signal processors", we need to consider frequency limitation as it applies to creating a useful tone that will fit into a specific niche of the mix rather than what is needed for reproduction of a musical program.

Harmonics and recognizable timbers are relevant up to about 10k WRT guitar. Especially acoustic guitar. For clean tones the timberal nuance is both less discernible and more important. This is also a challenge to any amp designer. That guitar speakers are basically useless beyond 5k or 6k is a TREMENDOUS help

Just to back posters like Dude and Enzo, consider instruments that naturally have a tremendous amount of overtones and harmonics like saxophone and cello. Instruments like these would be greatly limited if confined to the fundamental frequencies of a guitars range. Likewise, dynamic clean guitar and clipped guitar tones shouldn't be limited to the fundamentals of the guitar notes.

[trem]

Hey Chuck _
Like with Enzo, Fahey, RG, and the others...I appreciate the unique timbre/info that come with your posts. I do not always understand all the info, but I guess we world never be able to learn anything, if we already knew everything...what would be the fun in that.?
There is also a kind of "Blue Collar" tilt to many of your replies.
Anyway....Thanks

So, if I can ask another obvious question.....being that a piano, guitar, viola, etc are musical instruments, and not tone generators....how does a guitar tuner work, what does it focus on.
If I plug into a tuner, and it says something like A-440, what are those parameters.?
How can the tuner distinguish 440 Hertz from a vibrating string.?
Thank You

[eschertron]

So, if I can ask another obvious question.....being that a piano, guitar, viola, etc are musical instruments, and not tone generators....how does a guitar tuner work, what does it focus on.
If I plug into a tuner, and it says something like A-440, what are those parameters.?
How can the tuner distinguish 440 Hertz from a vibrating string.?
Thank You

Ooh! Ooh! I know this one!

If you look at a spectral analysis of, say, a plucked guitar sound or a bowed cello one thing you'll likely see is that the fundamental (the note that is nominally being sounded) is much louder than any other partials. Since the fundamental note has more energy in it than the harmonics, your tuner will lock onto that note and give you it's frequency. I have had tuners tell me otherwise - maybe you have too - and tell me I'm sounding a note a perfect 5th above the one I'm actually sounding. That's when the tuner was fooled by the harmonic overtone and locked onto it instead of the fundamental. I'm sure someone here designs phase-lock circuits and could tell you more about how they work. The take-away is that the fundamental is *generally* the loudest partial in a sound, restricting ourselves to natural acoustic sounds that have not been filtered or processed in any way.

[Leo_Gnardo]

There is also a kind of "Blue Collar" tilt to many of your replies.

Doing my Richard Feynman best.

How can the tuner distinguish 440 Hertz from a vibrating string.?

Strobe tuners compare the incoming signal to a known frequency generated by the tuner. Then the 'dots on the wheel' spin clockwise if your instrument is sharp, ccw if flat, stand still if it's same as the test frequency.

You've noticed I'm sure that tuners, whether strobe or meter, are more easily read if you dial the tone control back. Then you're not confusing them with lots of overtone signal.

I'll get out of the way, here comes more explanations.

[Enzo]

All the overtones in a guitar string are related, they are not random. So on a scope 440 and 880 look alike but 880 has twice the humps across the screen. And there are intervals too. Like playing a chord. The three notes in a simple chord are not the same note, but you will instantly hear if one of them is not tuned with the others. So your visual indication from a tuner is related. The visual pattern that is strobed into stillness will relate to the fundamental in some way, or at least will have enough fundamental in it to appear steady on the strobe.


Imagine a four blade table fan cooling your room. Now the only light is a strobe. If the fan spins at 1000 revolutions per second and our strobe flashes at 1000 per second, then our blade will appear to be still, even though spinning. Every 1/1000th of a second an image is lit of the blade, and due to the timing, the blade appears in the same position, so it looks still.

[trobbins]

Organs, and especially electric organ development, has focussed on attempting to reproduce the basic timbre characteristics of various instruments, and as such is somewhat enlightening to appreciate the different contributions of harmonic structures to what we perceive as a particular instrument. Not a guitar-centric topic to look in to, but can give a wider appreciation of the importance of harmonic structures.

Colin Pyket has prepared articles on this (such as Waveforms and Spectra - or - Amplitude and Phase), and I located a few interesting early articles which are on Dalmura Pty Ltd

[trem]

OK...that all makes sense.
Thanks