JM said:
Hello,
I am working with my child on a science project that is measuring volume of
different strings on stringed instruments. Does anyone know of a simple
software (or not so simple) that measures decibels/amplitude using a
microphone?
thank you,
jm
I'll add to the replies from the other posters. I don't see why a
program that provides a measurement in decibels, such as Audacity,
wouldn't work.
I have a background in both music psychology and audio (as well as
music). I use real-world phenomena a lot in my music teaching work. I'll
comment from that perspective.
Sound output from an instrument is measured in different ways. For
example, there's a difference in the output measured right at the violin
itself, vs. from the position of the player's ears, vs., from a distance
of 10 feet away, vs. from the position of a listener in the fourth row
in a given concert hall. And how strongly the violinist is bowing the
instrument will, in fact, affect the results: the instrument produces a
range of intensities.
You need to know the actual real-world decibels that the microphone is
picking up, so you need to calibrate the microphone. Once you know that,
you can extrapolate the level using the seat-of-the-pants method. For
example, you can use a sound level meter held at the same distance from
the violin as your microphone that'll be connected to the computer. That
will give you a "zero reference." The decibel scale is logarhythmic --
it's fixed in the real world of acoustical sound, but there's no
"absolute zero" when it comes to sound processing -- a meter on a
professional tape recorder, for example, measures relative to other
things. You may be able to borrow a sound level meter from an amateur
music recording person or a someone in professional recording. They're
not hard to find: even Radio Shack sells them.
This may be way beyond what you anticipated getting into, but it'll give
you good ballpark results. Because both the tonal and dynamic ranges of
a violin are not extreme, and because the quality of cheap microphones
has improved a lot over the years, you can actually get surprisingly
decent results for your experiment with a modern inexpensive microphone.
I believe that what you'll find out is that relative to sound levels
that can damage human hearing, a violin up close can be surprisingly
loud, but nothing to be alarmed about.
I think that it's a great experiment! I wish that music was taught from
perspectives like this -- I often think that I'm teaching in a vacuum,
but I get enthusiastic comments from students -- so it seems that I'm on
the right track. I realize that you didn't ask for all this advice, but
you really caught my attention with your question, so I jumped in.
Please let us know how you made out.
Richard Steinfeld
