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01-introduction.Rmd

@@ -190,7 +190,7 @@ Table: (\#tab:price) The cost of modular, semi-modular, and computer synthesizer
 
 | Decade | Synthesizer                  | Cost |
 |--------|------------------------------|----------------------|
-| 1960s  | Moog modular synthesiser     | $96,000              |
+| 1960s  | Moog modular synthesizer     | $96,000              |
 | 1970s  | Minimoog semi-modular        | $10,000              |
 | 1980s  | Yamaha DX7                   | $6,000               |
 | 1990s  | Gateway computer with Cubase | $8,000               |

02-physics-perception.Rmd

@@ -13,7 +13,7 @@ A good example of this is [equal loudness contours](https://en.wikipedia.org/wik
 As shown in Figure \@ref(fig:elc), sounds can appear equally loud to humans across frequencies even though the actual sound pressure level (a measure of sound energy) is not constant. 
 In other words, our hearing becomes more sensitive depending on the frequency of the sound.
 
-(ref:elc) An equal loudness contour showing improved sensitivity to frequencies between 500Hz and 4KHz, which approximately matches the range of human speech frequencies. Image [public domain](https://en.wikipedia.org/wiki/Psychoacoustics#/media/File:Perceived_Human_Hearing.svg).
+(ref:elc) An equal loudness contour showing improved sensitivity to frequencies between 500Hz and 4kHz, which approximately matches the range of human speech frequencies. Image [public domain](https://en.wikipedia.org/wiki/Psychoacoustics#/media/File:Perceived_Human_Hearing.svg).
 
 
 ```{r elc, echo=F, out.width="100%", fig.cap="(ref:elc)"}
@@ -103,7 +103,7 @@ The red dots are markers to help you see how much the air is moving as a result
 As you can see, every red dot is staying in their neighborhood by **moving in opposite directions** as a result of compression and rarefaction cycles.
 If you select the `Both` radio button, you can see the outlines of waves on top of the air molecules.
 Note how each red dot is moving back and forth between a white band and a dark band.
-If you further select the `Graph` checkbox, you will see that the white bands in this simulation correpond to increases in pressure and the black bands correspond to decreases in pressure.
+If you further select the `Graph` checkbox, you will see that the white bands in this simulation correspond to increases in pressure and the black bands correspond to decreases in pressure.
 This type of graph is commonly used to describe waves, so make sure you feel comfortable with it before moving on.
 
 (ref:sim-wave) [Simulation](https://phet.colorado.edu/sims/html/waves-intro/latest/waves-intro_en.html?screens=2) of sound waves. Simulation by [PhET Interactive Simulations](https://phet.colorado.edu/), University of Colorado Boulder, licensed under [CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/).
@@ -178,7 +178,7 @@ p1 + p2
 
 You might be wondering if there's point at which pitches are low enough that the notes run together!
 It seems the answer to this is that our ability to hear sound at all gives out before this happens.
-Going back to the 88-key piano keyboard, the two lowest keys (keys 1 & 2; not shown) are about 1.5 Hz appart, but the lowest key^[Also called A0] is 27.5 Hz.
+Going back to the 88-key piano keyboard, the two lowest keys (keys 1 & 2; not shown) are about 1.5 Hz apart, but the lowest key^[Also called A0] is 27.5 Hz.
 Humans generally can only hear frequencies between 20 Hz and 20,000 Hz (20 kHz).
 Below 20 Hz, sounds are felt more than heard (especially if they are loud), and above 20 kHz generally can't be heard at all, though intense sounds at these frequencies can still cause hearing damage.
 

03-harmonic-and-inharmonic-sounds.Rmd

@@ -145,12 +145,12 @@ It may have already occurred to you that you could create any sound by adding to
 This is exactly what [additive synthesis](https://en.wikipedia.org/wiki/Additive_synthesis) does!
 Running a Fourier analysis to get sine wave partials of a sound and then recombine them to reproduce the sound is very appealing.
 However, even though the idea of additive synthesis has been around a long time, it was not practical with analogue technology because of the many oscillators and precise timings involved.
-<!-- As digital technology improved, sampling and [wavetable synthsis](https://en.wikipedia.org/wiki/Wavetable_synthesis) became more popular than additive synthesis in achieving similar goals. -->
+<!-- As digital technology improved, sampling and [wavetable synthesis](https://en.wikipedia.org/wiki/Wavetable_synthesis) became more popular than additive synthesis in achieving similar goals. -->
 Conceptually, the alternative to additive synthesis is [subtractive synthesis](https://en.wikipedia.org/wiki/Subtractive_synthesis), which has been a very popular approach in analogue synthesis to the present day.
 Subtractive synthesis starts with complex waveforms and then removes harmonics to create the desired sound.
 Harmonics can be removed with relatively simple analogue electronics as we'll discuss in a later chapter.
 
-While the simulation in Figure \@ref(fig:fourier-waves) is useful for understanding how Fourier analysis works, it's difficult to see all of the frequenecy components because they are stacked on top of each other.
+While the simulation in Figure \@ref(fig:fourier-waves) is useful for understanding how Fourier analysis works, it's difficult to see all of the frequency components because they are stacked on top of each other.
 An alternative way of visualizing a Fourier analysis is a frequency spectrogram.
 A frequency spectrogram shows each sine wave based on its frequency and amplitude.
 Figure \@ref(fig:freq-spectrum) shows a frequency spectrogram of the same four waveshapes at 1 Hz with harmonics side by side and amplitudes normalized so all harmonics sum to 1.

04-fun-mod-basic-concepts.Rmd

@@ -47,7 +47,7 @@ Audio signals are a voltage representation of sound.
 Recall that sound is a pressure wave with high and low phases of pressure.
 It's perhaps not surprising that audio signals use corresponding positive and negative voltage to represent a sound wave.
 This kind of voltage is [AC voltage](https://en.wikipedia.org/wiki/Alternating_current#Mathematics_of_AC_voltages). 
-Anytime a signal is bipoloar, i.e. it crosses zero, you can assume the voltage is AC.
+Anytime a signal is bipolar, i.e. it crosses zero, you can assume the voltage is AC.
 
 Control signals represent everything besides audio.
 Unlike audio signals, control signals are unipolar voltage representations, i.e. they don't cross zero, and thus use [DC voltage](https://en.wikipedia.org/wiki/Direct_current#Various_definitions).^[Under this definition, low frequency oscillators are audio signals, not control signals.]
@@ -171,7 +171,7 @@ It's the most basic because it only has one real module, which is a *generator*
 We'll use an oscillator for the generator and one extra module, an audio interface module, to connect the oscillator output to our speakers.
 For this patch only, I'm going to demonstrate using the video in Figure \@ref(fig:drone-demo) to explain the user interface of the modular software.
 
-(ref:drone-demo) [Youtube video](https://www.youtube.com/watch?v=EfIWUOgHmhM) describing the VCVRack/Cardinal interface and builing a drone patch.
+(ref:drone-demo) [Youtube video](https://www.youtube.com/watch?v=EfIWUOgHmhM) describing the VCVRack/Cardinal interface and building a drone patch.
 
 ```{r drone-demo, fig.cap="(ref:drone-demo)", echo = F}
 embed_youtube("EfIWUOgHmhM",2)
@@ -181,7 +181,7 @@ After you watch the demonstration, try to make the patch yourself using the butt
 When you press the button, you'll see an interface that also includes `Instructions`, `Solution`, and `Close` buttons.
 These are self-explanatory, but in particular the `Close` button will return you to the book.
 
-(ref:drone-vco-out) [Virtual modular](https://cardinal.olney.ai) for making a drone patch.
+(ref:drone-vco-out) [Virtual modular](https://olney.ai/ct-modular-book/modular-for-pdf.html?starter=empty.vcv&solution=See+the+video+demonstration+in+the+book+%28open+video+in+separate+tab+as+needed&instructions=%3cul%3e%0a%3cli%3eUse+the+video+demonstration+as+a+guide+%28open+video+in+separate+tab+as+needed%29%3c%2fli%3e%0a%3cli%3eFor+each+wave+output%3cul%3e%0a%3cli%3eConnect+just+it+to+the+audio+inputs%3c%2fli%3e%0a%3cli%3eSweep+the+frequency+knob%3c%2fli%3e%0a%3cli%3eSweep+the+volume+knob%3c%2fli%3e%0a%3c%2ful%3e%0a%3c%2fli%3e%0a%3c%2ful%3e%0a) for making a drone patch.
 
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@@ -217,7 +217,7 @@ So whatever you patch into them is copied exactly on their output jacks.
 This makes it easy to put a scope in between other modules without changing the resulting sound.
 Try adding a scope between the modules in the previous patch using the button in Figure \@ref(fig:drone-vco-scope-out).
 
-(ref:drone-vco-scope-out) [Virtual modular](https://cardinal.olney.ai) for making a drone patch with a scope.
+(ref:drone-vco-scope-out) [Virtual modular](https://olney.ai/ct-modular-book/modular-for-pdf.html?starter=drone_vco-out.vcv&solution=%3cimg+class%3d%27rack-image%27+src%3d%27images%2fpatch-solutions%2fdrone-scope_vco-scope-out.png%27+style%3d%27height%3a+300px%3b+width%3a+auto%27%3e&instructions=%3cul%3e%0a%3cli%3eAdd+%e2%80%9cScope%e2%80%9d+between+VCO+and+Host+Audio%3c%2fli%3e%0a%3cli%3eConnect+VCO+wave+out+to+Scope+In%3c%2fli%3e%0a%3cli%3eConnect+Scope+out+to+Host+Audio%3c%2fli%3e%0a%3cli%3eFor+each+waveshape+try%3cul%3e%0a%3cli%3eAdjusting+time%3c%2fli%3e%0a%3cli%3eAdjusting+frequency%3c%2fli%3e%0a%3cli%3eAdjusting+gain%3c%2fli%3e%0a%3cli%3eChanging+the+waveshape%3c%2fli%3e%0a%3c%2ful%3e%0a%3c%2fli%3e%0a%3c%2ful%3e%0a%3cimg+class%3d%27rack-image%27+src%3d%27images%2fsolo-modules%2fscope-solo.png%27+style%3d%27height%3a+300px%3b+width%3a+auto%27%3e%0a) for making a drone patch with a scope.
 
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@@ -248,13 +248,13 @@ modular_caption()
 You're probably realized why the drone patch has its name - it just produces a constant pitch at a constant volume.
 To make things more interesting, let's control the pitch that goes into the oscillator.
 You'll need a *controller* for this.
-Let's use the "Twelve-Key" (12 key), which has a miniture keyboard built into the module.
+Let's use the "Twelve-Key" (12 key), which has a miniature keyboard built into the module.
 The output of the 12 key that we are interested in is the control voltage (CV) that outputs V/Oct.
 If you connect that output to the V/Oct input of the VCO, the VCO will change its frequency every time a key is pressed.
 This is analogous to precisely and instantly moving the frequency knob on the VCO.
 Try adding the 12 key to the left of the VCO in the previous patch using the button in Figure \@ref(fig:drone-12key-vco-scope-out).
 
-(ref:drone-12key-vco-scope-out) [Virtual modular](https://cardinal.olney.ai) for making a single voice patch with a scope and keyboard control of pitch.
+(ref:drone-12key-vco-scope-out) [Virtual modular](https://olney.ai/ct-modular-book/modular-for-pdf.html?starter=drone-scope_vco-scope-out.vcv&solution=%3cimg+class%3d%27rack-image%27+src%3d%27images%2fpatch-solutions%2fkey-drone_12key-vco-scope-out.png%27+style%3d%27height%3a+300px%3b+width%3a+auto%27%3e&instructions=%3cul%3e%0a%3cli%3eAdd+%e2%80%9cTwelve-key%e2%80%9d+to+the+left+of+the+VCO%3c%2fli%3e%0a%3cli%3eConnect+12+key+CV+output+to+VCO+V%2fOCT+input%3c%2fli%3e%0a%3cli%3eObserve+what+happens+when+you+click+different+keys+on+12+key%3cul%3e%0a%3cli%3eIn+terms+of+sound%3c%2fli%3e%0a%3cli%3eIn+terms+of+wave+on+scope%3c%2fli%3e%0a%3c%2ful%3e%0a%3c%2fli%3e%0a%3cli%3eChange+OCTAVE+on+12+key+and+repeat%3c%2fli%3e%0a%3c%2ful%3e%0a%3cp%3e%3cem%3eIf+you+don%26%2339%3bt+hear+sound%2c+check+if+your+frequency+is+below+20+kHz%3b+your+computer+speakers+may+not+produce+sound+below+100+kHz%3c%2fem%3e%3c%2fp%3e%0a%3cimg+class%3d%27rack-image%27+src%3d%27images%2fsolo-modules%2f12key-solo.png%27+style%3d%27height%3a+300px%3b+width%3a+auto%27%3e%0a) for making a single voice patch with a scope and keyboard control of pitch.
 
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@@ -288,7 +288,7 @@ That way, each time a key is pressed, two control voltages will be sent out at t
 The VCA will "open" and let the full amplitude of the wave through when the gate voltage is high, and the VCA will "close" and let nothing through when the gate voltage is zero.
 Try adding a VCA between the VCO and Scope modules using the button in Figure \@ref(fig:drone-12key-vco-vca-scope-out).
 
-(ref:drone-12key-vco-vca-scope-out) [Virtual modular](https://cardinal.olney.ai) for making a single voice patch with a scope and keyboard control of pitch and note duration.
+(ref:drone-12key-vco-vca-scope-out) [Virtual modular](https://olney.ai/ct-modular-book/modular-for-pdf.html?starter=key-drone_12key-vco-scope-out.vcv&solution=%3cimg+class%3d%27rack-image%27+src%3d%27images%2fpatch-solutions%2fkey-note_12key-vco-vca-scope-out.png%27+style%3d%27height%3a+300px%3b+width%3a+auto%27%3e&instructions=%3cul%3e%0a%3cli%3eAdd+VCA+between+VCO+and+Scope+modules%3c%2fli%3e%0a%3cli%3eConnect+VCO+wave+to+VCA+In%3c%2fli%3e%0a%3cli%3eConnect+12+key+GATE+output+to+VCA+CV+IN%3c%2fli%3e%0a%3cli%3eConnect+VCA+OUT+to+Scope+IN%3c%2fli%3e%0a%3cli%3eWhat+happens+when+you+click+different+keys+on+12+key%3cul%3e%0a%3cli%3eIn+terms+of+sound%3c%2fli%3e%0a%3cli%3eIn+terms+of+wave+on+scope%3c%2fli%3e%0a%3c%2ful%3e%0a%3c%2fli%3e%0a%3cli%3eTry+holding+down+key+instead+of+short+pressing+it+and+repeat%3c%2fli%3e%0a%3c%2ful%3e%0a%3cimg+class%3d%27rack-image%27+src%3d%27images%2fsolo-modules%2fvca-solo.png%27+style%3d%27height%3a+300px%3b+width%3a+auto%27%3e%0a) for making a single voice patch with a scope and keyboard control of pitch and note duration.
 
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@@ -323,7 +323,7 @@ Finally, when the trailing edge of the gate is detected (meaning the key has bee
 Remember that an envelope generator doesn't do anything by itself; if we want to control the volume of the signal with the ADSR, we must connect the ADSR to the VCA.
 Try adding an ADSR module between the VCO and VCA modules using the button in Figure \@ref(fig:drone-12key-vco-env-vca-scope-out).
 
-(ref:drone-12key-vco-env-vca-scope-out) [Virtual modular](https://cardinal.olney.ai) for making a single voice patch with a scope and keyboard control of pitch and note duration, and an envelope to control dynamics during the note.
+(ref:drone-12key-vco-env-vca-scope-out) [Virtual modular](https://olney.ai/ct-modular-book/modular-for-pdf.html?starter=key-note_12key-vco-vca-scope-out.vcv&solution=%3cimg+class%3d%27rack-image%27+src%3d%27images%2fpatch-solutions%2fkey-envelope_12key-vco-env-vca-scope-out.png%27+style%3d%27height%3a+300px%3b+width%3a+718px%27%3e&instructions=%3cul%3e%0a%3cli%3eAdd+ADSR+module+between+VCO+and+VCA+modules%3c%2fli%3e%0a%3cli%3eConnect+12+key+GATE+output+to+ADSR+GATE+input%3c%2fli%3e%0a%3cli%3eConnect+ADSR+OUT+to+VCA+IN%3c%2fli%3e%0a%3cli%3eWhat+happens+when+you+click+different+keys+on+12+key%3cul%3e%0a%3cli%3eIn+terms+of+sound%3c%2fli%3e%0a%3cli%3eIn+terms+of+wave+on+scope%3c%2fli%3e%0a%3c%2ful%3e%0a%3c%2fli%3e%0a%3cli%3eChange+the+attack%2c+decay%2c+sustain%2c+release+knobs+and+repeat%3c%2fli%3e%0a%3c%2ful%3e%0a%3cimg+class%3d%27rack-image%27+src%3d%27images%2fsolo-modules%2fadsr-solo.png%27+style%3d%27height%3a+300px%3b+width%3a+auto%27%3e%0a) for making a single voice patch with a scope and keyboard control of pitch and note duration, and an envelope to control dynamics during the note.
 
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@@ -383,4 +383,4 @@ From there we will continue to spiral outward into increasingly complex modules
 6. `r mc_question("What module interprets loudness information?", list(  answer="VCA",
             "VCO",
             "controller",
-            "envelope"))`
+            "envelope"))`