alright, what we're going to do in this
video is a demonstration of the
acoustics of vowels. if you have not
watched the acoustics of vowels lectures
and introduction to vowels lectures yet i
would recommend that you actually watch
those lectures before you come and view
your lab demonstration of the acoustics
of vowels. so what we're going to do here
today is I'm actually going to record
the sounds |a| |e| and |o| and i want to draw the
spectrum, not me, the computer will draw
the spectrogram of those vowels and we're
going to look at the formants. what I
want you to pay attention on the
spectrogram is how the formants are
spaced, which is the F pattern, so if you
have forgotten what the F pattern is or it
doesn't come to your mind just go back to your
lecture notes where we have a slide that
says the F pattern, right here, which
talks about the F pattern for the vowels
|e| |a| and |o| and then i'm going to show
those exact patterns over here so you can
take a look at that. once we take a look
at the F factors we also talked about the
relative numbers of the formant
frequencies and they're not absolute
numbers, so i have my teaching assistant
Ashley, made up here with me and Ashley
and I are both going to record the vowels
look maybe the r and then we're going to
show you how the formant frequencies can vary
because of our vocal tract
configuration because of our dialects
and so that'd be something interesting for
you to observe.
ok so let's get started
|a|, |e|, |o|
ok what you see here is just like the
wave form of that that is captured. now what
we're going to do is we are going to
draw a spectrogram and in the bottom
screen that you see here is a
spectrogram of the vowel |a| that's the first
one and then the |e| and then the |o|. ok now
what I'm going to do is draw a formant
history. so remember again,
what is a spectrogram, a
spectrogram is the time on the x-axis,
frequency on the y-axis; darker the
striations that you see on the
spectrogram meaning they have more
aptitude.
ok so that is a spectrogram and now if I
draw the formant history, you see those
beautiful colored lines that came up, and
the red line represents formant
frequency one, the yellow line represents
the, yellow-orange i'm colorblind,
represents the formant frequency two and
the green one represents f3, so we're
only concentrating hear about f1 f2 and
f3. so if you recollect and then go back
to your lecture notes and say what are
the f1 f2 and f3 for |a| it's around 700, 1090,
2,000, greater than 2,000. for |e| it is around
300, this formant frequency 2 is greater
than 2,500 on right, and your formant
frequency three is around 3000 and higher.
for |o| your formant frequency is lower
first one which is at 300, the second one
is around 800 the f3 is a greater than
2,000, ok.
the interesting thing that I want you to
observe is this F pattern, look at the
distance between f1 and f2 here versus
the distance between f1 and f2 here
versus the distance between f1 f2, that's
the f pattern. this f pattern is what helps
us perceive these vowels more than just
the absolute number of the formant
frequencies. so if you look again, here is
this y-axis here tells you the
frequency, so my r is almost
closer to 900 the first formant and my
second format is almost closer to 1500
right. again remember yes we talked about
it being 700 and 1100 but my numbers are
a little different,
maybe influence of my dialect, influence
of a female vocal tract that has a
smaller vocal tract then males right. so
that a lot of those changes to and here
your f1 as around 300 my f2s
almost closer to 2900 hertz right, and for |o| if
you look at it it's about closer to the
same thing 300 and this is almost a
little over a thousand Hertz but the
idea that i want you to see is this, the
accoustics of vowels I want you to look at the
different formant frequencies and the f
pattern of these vowles.
ok now what we're going to do is I'm
going to start a new recording and i'm
going to get Ashley and myself, we're
going to record on the same screen the
vowel |a| and then we're going to see how
there is differences to prove that the
numbers are relative and not absolute
numbers for forming frequencies.
|a|
ok those are two spectrograms that you
see, one a spectrogram by me where the |a|
that I produced and the other
spectrogram by Ashley, let's now draw the
formant history for that spectogram
and you can clearly see how that the
pattern, if you just look at the distance
between f1 and f2 and f2 and f3 is
almost the same except a little bit of
difference between f2 and f3, but f1 and f2
the distance between the two
formants is almost the same, making us
to perceive that as |a| but the numbers
are different, so this is an indication
that the one that helps us perceive
the different vowels is the F pattern more
than the absolute numbers of forming
frequencies.
ok so i think this is exactly what we
talked about in the acoustics of vowels, we
talk about three different patterns and
hopefully this will give you a better
idea of what a spectrogram is, what are
forming frequencies for the vowels, what
is an F pattern and why do I keep
emphasizing the f pattern more than
the absolute numbers of formant
frequencies and how it helps us perceive
the different vowels in respective
dialectal radiations, respective vocal
tracks size and shape changes all right.