How was phonetics performed with a phonograph? From the Wikipedia excerpt below, I guess it went something like this:

  1. A segment was recorded on a phonograph.
  2. That segment was Filtered each time with a different band-pass filter (I don't understand what this means)
  3. A spectrogram was built up (from what?)

The study of acoustic phonetics was greatly enhanced in the late 19th century by the invention of the Edison phonograph. The phonograph allowed the speech signal to be recorded and then later processed and analyzed. By replaying the same speech signal from the phonograph several times, filtering it each time with a different band-pass filter, a spectrogram of the speech utterance could be built up.

I'm really interested in learning how phonetics was done before the advent of computers, so any insight into these steps would be very much appreciated. I also read about analysis being done on wax cylinders... That's another story.


1 Answer 1


A band-pass filter is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range. That gives you information about a particular frequency range. An electromagnetic oscillograph is an oscillograph which measures variations of electric current by having it go through a magnetic coil....Some models ... were ... fitted with a pen to record values. You can then print that on paper, and use a ruler to measure how far up the page the point of interest is (you need to calibrate it first).

  • Thanks! But I saw the Wikipedia page too - I'm just wondering what a bandpass filter "is" (as a device of some sort). What did it look like? Also, was the tuning you mentioned performed with a tuning fork or...?
    – Teusz
    Mar 11, 2015 at 5:59
  • Well, as for appearance, it could be a box of sorts. It's an electronic circuit. In the old days it could be about the size of a shoebox (our was), and it has a dial. I guess there are a couple of basic designs, one specifically passing signals plus and minus the target frequency, and one that passes everything above a threshhold and everything below another thresshold. Opening the box invalidates the warrantee. Calibration is usually via a signal generator (another box) with a lot of dials and you spend forever trying to figure out what they do.
    – user6726
    Mar 11, 2015 at 16:30

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