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HELP !!! Theory behind harmonic content

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November 10, 2004 3:30:53 PM

Archived from groups: rec.audio.pro (More info?)

hi, i thought this might be a good place to post my query, if not
please direct me to a more suitable place lol.

ok my question - i've got to write an essay on "Wave Theory, Harmonics
& Acoustic Phenomena".

ok so i've basically said that all sounds are made up front a
collection of sine waves, the most basic sound wave .. i've then said
that tehre must be something differentiating between sine waves and
the more complex sounds we here (such as speech etc.) i've then said
that tehre can be some differential between waves - that is to say
amplitude and frequency have a part to play in varying a sound. but
that can only go so far as to give us different pitch and volume
loudness (are you still with me? is this making any sense lol!?!) so i
want to then go on to explain about fouriers theorum - but what is the
theory behind harmonic content - who thought of it etc. ?

i hope i haven't made people too confused lol

any comments or answers would be great thanks

alternatively you can e-mail me at adam_gardner_dj@yahoo.co.uk

Thanks a load in advance

cya

adam
Anonymous
November 10, 2004 6:56:38 PM

Archived from groups: rec.audio.pro (More info?)

In article <371406d0.0411101230.6322f03e@posting.google.com>,
Adam <adam_gardner_dj@yahoo.co.uk> wrote:
>hi, i thought this might be a good place to post my query, if not
>please direct me to a more suitable place lol.
>
>ok my question - i've got to write an essay on "Wave Theory, Harmonics
>& Acoustic Phenomena".
>
>ok so i've basically said that all sounds are made up front a
>collection of sine waves, the most basic sound wave .. i've then said
>that tehre must be something differentiating between sine waves and
>the more complex sounds we here (such as speech etc.) i've then said
>that tehre can be some differential between waves - that is to say
>amplitude and frequency have a part to play in varying a sound. but
>that can only go so far as to give us different pitch and volume
>loudness (are you still with me? is this making any sense lol!?!) so i
>want to then go on to explain about fouriers theorum - but what is the
>theory behind harmonic content - who thought of it etc. ?
>
>i hope i haven't made people too confused lol

More complex sounds can all be considered as a series of different sine
waves mixed together.

There is a Schaum's Outline on the Fourier theorem.

The basic notion of representing any function as a series of sines is
due to Fourier, but it was more or less forgotten. Oliver Heaviside
in the 19th century came up with the same basic notion, and developed a
very clumsy notation to describe waveforms in terms of their individual
sine components. By the 1920s, the Fourier series had been rediscovered
and Fourier's notation was being used. Occasionally I will see old papers
using the Heaviside calculus and it is very clear why it got replaced.

I think there is some discussion of this in the MIT Press book on the
history of electric power distribution. Understanding AC power line
waveform distortion was a huge application of this theory and it was
a huge advance toward understanding some of the problems that kept AC
power from being popular in the early electrical era.

Some discussion of this is in Helmholtz's 19th century book _On the Sensation
Of Tone_ but without much mathematical background. He makes it clear that
additional waves being added together change the tone color of the fundamental
but he doesn't discuss the reduction process of breaking a complex wave down.
He does discuss the process of additive synthesis (as used in pipe organs).
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 10, 2004 11:33:23 PM

Archived from groups: rec.audio.pro (More info?)

On 10 Nov 2004 12:30:53 -0800, adam_gardner_dj@yahoo.co.uk (Adam)
wrote:

>hi, i thought this might be a good place to post my query, if not
>please direct me to a more suitable place lol.
>
>ok my question - i've got to write an essay on "Wave Theory, Harmonics
>& Acoustic Phenomena".
>
>ok so i've basically said that all sounds are made up front a
>collection of sine waves, the most basic sound wave .. i've then said
>that tehre must be something differentiating between sine waves and
>the more complex sounds we here (such as speech etc.) i've then said
>that tehre can be some differential between waves - that is to say
>amplitude and frequency have a part to play in varying a sound. but
>that can only go so far as to give us different pitch and volume
>loudness (are you still with me? is this making any sense lol!?!) so i
>want to then go on to explain about fouriers theorum - but what is the
>theory behind harmonic content - who thought of it etc. ?
>
>i hope i haven't made people too confused lol
>
>any comments or answers would be great thanks
>
>alternatively you can e-mail me at adam_gardner_dj@yahoo.co.uk
>
>Thanks a load in advance
>
>cya
>
>adam

Have a poke around Pythagoras on the web. He was the man who
formulated all the theory.

d
Pearce Consulting
http://www.pearce.uk.com
Related resources
Anonymous
November 11, 2004 9:24:11 AM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:cmtva6$2v9$1@panix2.panix.com...

> Some discussion of this is in Helmholtz's 19th century book _On the
Sensation
> Of Tone_ but without much mathematical background. He makes it clear that
> additional waves being added together change the tone color of the
fundamental
> but he doesn't discuss the reduction process of breaking a complex wave
down.
> He does discuss the process of additive synthesis (as used in pipe
organs).

You might look for a copy of Arthur Benade's "Horns, Strings and Harmony".
It covers a lot of this territory (along with some very cool information on
why woodwinds are so weird).

Peace,
Paul
Anonymous
November 12, 2004 1:00:30 PM

Archived from groups: rec.audio.pro (More info?)

Paul Stamler wrote:

> You might look for a copy of Arthur Benade's "Horns, Strings and
> Harmony". It covers a lot of this territory (along with some very
> cool information on why woodwinds are so weird).

I second this suggestion. This slim but highly informative book is
still in print as an Anchor Doubleday paperback, and is well worth a
afternoon's reading. I'm grateful that the local public library in
my home town of New Castle, Pa. had a copy of it 40 years ago.

If every musician and recording engineer knew what is shown so clearly
in that book, we would all understand each other a lot better, I think.
!