Fundamentals for Dummies

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mattkw80

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Can anybody tell me, how can I tell which frequency is the fundamental of a particular source?

I have a frequency analyzer, will this help?

Is it the loudest frequency present?
 
In short the fundamental frequency is the lowest frequency produced by any particular instrument. A fundamental tone is the lowest frequency in a harmonic series. You can find them in charts like in the interactive chart following this link:

http://www.independentrecording.net/irn/
 
mattkw80 said:
Can anybody tell me, how can I tell which frequency is the fundamental of a particular source?

I have a frequency analyzer, will this help?

Is it the loudest frequency present?
Click to expand...
I'm curious as to why you need to know that. :confused:

The easiest way is to have perfect pitch :D. Probably the next easiest, and the most accurate, way is to look at their fingering and see what note or root note of a chord they are actually playing.

If you can't do any of that and you have a frequency analyzer, the fundamental is *usually* the lowest peak in the series, but that's not guaranteed (there can be sub-harmonics present as well). Nor is it guaranteed that the fundamental is the loudest thing you hear; guitar (for example) tends to be louder at the first overtone than at the fundamental.

G.
 
Sometimes knowing the fundamental in the bass range can help. For example if the kick drum and bass are both strong at 90Hz it may cause too much of a buildup at that frequency. Or if a bass guitar has one note that jumps a lot in volume it may help to know the fundamental frequency so you can attack it with EQ or a multiband compressor or whatever (although best solution in this case might be volume automation). Often you can see this effect on a spectrum analyzer. Fundamentals in the midrange and higher are harder to distinguish.

It's likely that you won't perceive the fundamental as the loudest sound, even though it may have the highest amplitude. For example, you can cut 83Hz (Low E fundamental) out of a guitar track and it will still sound like a low E being played on guitar because of the strong harmonic content.

Normally there's no reason to pay attention to fundamentals IMO.
 
mattkw80 said:
haha - that was my next question......

...Why would I need to know that?

:D
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To improve your performances. Knowing about fundamentals and harmonic structures helps your ability to play leads.

Take for example a song with a simple melody line for the bass player. When you play lead guitar over his bass line, as long as you stay in the same key(normally determined by his notes), your lead notes can ride his secondary harmonics. The bass harmonics will enhance your fundamentals too. You can even do this to an extent solo by sustaining riffs on the low end and switching up into higher octaves. You can do it with any instruments including vocals. My keyboardist is real good at it too but you have to have a 'decent' bass player that will maintain that melody line fundamentally :).

If you get real good at doing this the end product is very musical because you end up with a sweet sounding dynamic harmonic structure.
 
Wow, glad I asked.

Great info guys, thanks.


So.... If I have a Bass line playing, and I am watching my analyzer, I should look for the first peak, lowest in the spectrum, and that will be the fundamental ?
 
mattkw80 said:
So.... If I have a Bass line playing, and I am watching my analyzer, I should look for the first peak, lowest in the spectrum, and that will be the fundamental ?
Click to expand...
Usually...mostly...but not necessarily, for the reasons already given.

G.
 
mattkw80 said:
So.... If I have a Bass line playing, and I am watching my analyzer, I should look for the first peak, lowest in the spectrum, and that will be the fundamental ?
Click to expand...

Maybe you're asking about the definition of fundamental. The answer to your question is 'yes' by definition. The definition of a fundamental is the lowest frequency in the harmonic series of a sound. So if a bass is playing you will probably be able to see the fundamental pretty easily.

However, in real recording situations lots of funny things can happen like speaker response, microphone response, distortion, reflections, resonances, phase cancellation, etc that alter the recorded spectrum so you won't see a nice clean spectrum. So in general spectral analysis has little value. Certainly you won't find any professional mixer staring at a spectrum analyzer very often, usually not at all.
 
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