update readme

README.md

@@ -45,7 +45,7 @@ Feel free to grab printable PDFs for your desired modules, or clone the reposito
 
 1. Clone this repository using `git clone` or download this repository as a .zip and unpack it.
 2. Navigate to the directory of the module you wish to edit.
-3. Make your own personal changes `<module-name>.md` to include your customizations!  Sticking with [Markdown](https://www.markdownguide.org/basic-syntax/) formatting is easiest, but Pandoc supports many other formatting methods!
+3. Make your own personal changes to `<module-name>.md` to include your customizations!  Sticking with [Markdown](https://www.markdownguide.org/basic-syntax/) formatting is easiest, but Pandoc supports many other formatting methods!
 4. Run `pandoc <module-name>.md --metadata-file=metadata.md --filter myfilter.py -o <module-name>.pdf` to generate of your new manual!
 
 *NB: Font, paper size, and line spacing settings can be edited in `metadata.md`.*

mangrove/mangrove.md

@@ -198,7 +198,7 @@ In addition to acting as timbral controls, *FORMANT* & *BARREL* can provide an a
 
 Many synthesists are likely familiar with the [overtone](https://en.wikipedia.org/wiki/Harmonic_series_(music)) (or harmonic) series, or the collection of all frequencies that are integer *multiples* of a fundamental frequency.  For a fundamental frequency of `100Hz`, this would be `100Hz, 200Hz, 300Hz, 400Hz, ...`  The increases in frequency correspond to moving up an octave, followed by moving up a fifth, then up a fourth, then a third, and so on.  Common synthesis waveforms (such as triangle, saw, ramp, square) can be created (or represented) by adding sine waves from a harmonic series with various amplitudes.
 
-The undertone (or subharmonic) series is created by *dividing* the fundamental frequency by integers, rather than multiplying it.  For a given frequency `f`, the undertone series would be all frequencies `f/n`, where `n` is an integer.  For example at `100Hz`, the undertone series would be `50Hz, 33Hz, 25Hz, 10Hz, ...`  The intervals correspond to moving down an octave, followed by moving down a fifth, then down by a fourth, and so on.
+The undertone (or subharmonic) series is created by *dividing* the fundamental frequency by integers, rather than multiplying it.  For a given frequency `f`, the undertone series would be all frequencies `f/n`, where `n` is an integer.  For example at `100Hz`, the undertone series would be `50Hz, 33Hz, 25Hz, 20Hz, ...`  The intervals correspond to moving down an octave, followed by moving down a fifth, then down by a fourth, and so on.
 
 MANGROVE can create the undertone series by setting the impulse duration to exceed the period of the oscillator core.  Begin by setting *FORMANT* to noon and *BARREL* to minimum (CW) (indicated on the panel by *utone*, a helpful reminder for when you want to create the undertone series!).  Set *AIR* to noon, switch to *constant wave*, and monitor the *FORMANT* output.  The output should be a ramp wave - every time the impulse is triggered by the oscillator core, it ramps slowly to its maximum and then falls immediately to its minimum before being retriggered.