[HN Gopher] Plug a guitar in your C64 and use it as a wah pedal
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       Plug a guitar in your C64 and use it as a wah pedal
        
       Author : stefanorastron
       Score  : 35 points
       Date   : 2022-09-23 09:08 UTC (1 days ago)
        
 (HTM) web link (www.orastron.com)
 (TXT) w3m dump (www.orastron.com)
        
       | rwaksmunski wrote:
       | I think Machinae Supermacy band does this:
       | https://www.youtube.com/watch?v=XKkmyMKbPKE
        
       | classichasclass wrote:
       | Warning to the curious: it is very easy to fry your SID
       | connecting directly to the audio in (don't ask how I know this).
       | Make sure of your levels before you connect, and don't plug this
       | in with the power on in case there's a short.
        
         | diydsp wrote:
         | any suggestions to protect it? e.g. buffer with an op-amp,
         | right? Any way to use diodes for static protection, etc.?
        
           | [deleted]
        
           | satiric wrote:
           | One common way to provide input overvoltage protection is
           | through a pair of schottky diodes. This article is a good
           | resource https://www.digikey.com/en/articles/protecting-
           | inputs-in-dig...
        
             | buescher wrote:
             | That's a pretty good article. Also, the classic one-volt-
             | or-so voltage limiter is a pair of antiparallel silicon
             | diodes. You can put them in series for a bigger limit.
        
           | classichasclass wrote:
           | There are some good practical solutions here ( https://www.le
           | mon64.com/forum/viewtopic.php?t=55483&sid=2710... ) but the
           | most important thing is keep the voltages down. They suggest
           | three volts max peak to peak, which seems prudent.
        
         | the_other wrote:
         | > don't ask how I know this
         | 
         | Tease!
        
       | stefanorastron wrote:
       | ... or emulate the whole thing using a free VST plugin.
       | 
       | (shameless plug)
        
         | TheRealPomax wrote:
         | Find the right garage sale and the C64 _is_ a free plugin =D
        
       | seanhunter wrote:
       | One thing to note about a wah-wah pedal[1] if you ever want to
       | simulate it in software is that if I understand it correctly it's
       | a parametric equalizer and when you wobble the peddle you are
       | affecting the Q (bandwidth) of the equalization. You can hear
       | this for yourself if you use a normal mixing desk, just play
       | something, set a reasonable boost to some mid frequency on the
       | parametric eq and wobble the Q backwards and forwards. You
       | basically get the effect of the pedal.
       | 
       | [1] And it has to be a "wah-wah", not "wah".
        
         | camtarn wrote:
         | This is incorrect.
         | 
         | When you move the wah pedal, you're moving the _cutoff_ of the
         | filter, not the Q. The Q is fixed.
         | 
         | You're also incorrect about the name. Just 'wah' is perfectly
         | acceptable.
        
           | brudgers wrote:
           | Wikipedia has it as "wha-wha pedal."
           | 
           | https://en.m.wikipedia.org/wiki/Wah-wah_pedal
           | 
           | Because of the Wha-Wha (or Wa-Wa) effect.
           | 
           | https://en.m.wikipedia.org/wiki/Wah-wah_(music)
        
             | [deleted]
        
         | wkdneidbwf wrote:
         | > And it has to be a "wah-wah", not "wah".
         | 
         | this is just not true. guitarists regularly call it either. i
         | hear it called a "wah" more often these days than "wah-wah".
         | 
         | anyone will clearly understand and not look at funny if you say
         | "wah pedal"
        
       | myself248 wrote:
       | YES! Someone finally used the audio-in pins!
       | 
       | The SID has audio-in that can be summed with internally-
       | synthesized sounds and routed through the on-chip filters before
       | going back out.
       | 
       | I found this pinout in the programmer's reference guide and
       | tinkered with it a bit as a kid, but I didn't really know what I
       | was doing, so it never went beyond a novelty. Who knew, forty
       | years later, that it'd get proper treatment as an effects
       | generator!
        
         | camtarn wrote:
         | Thanks for explaining - I had no idea there were audio in pins,
         | and was searching the page for how they managed to route audio
         | to the SID without any modification.
        
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       (page generated 2022-09-24 23:00 UTC)