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Hello Japon18,

I do not know how I missed your question until now? 

Yes, you can use these DSPs to create sound effects. The only issue is that this DSP has limited instructions per sample period so it is a little limiting for some of these effects. Like Reverb can use a LOT of instructions for a really involved algorithm. 

You should search the forum. Many people have discussed some of these effects using the 1701. Then for controlling parameters of audio running through the core there are probably hundreds of posts showing how to control different things using the AUXADC inputs. 

You asked what kind of adjustments? The answer is what do you want to adjust? It is open to your imagination. Some things are more difficult and this DSP core is a little limiting. The Sigma300/350 cores are much more flexible. 

Have you found my YouTube channel? I have a video about AUXADCs that goes over the basics.

Here is a link to the video:

AUX ADCs

 Dave T

     Hi Dave and Japon18,

     Although the ADAU1701 is limited compared to its siblings, it's arguably a fine choice to begin with.  

     Here's a Wah pedal project using the State Variable Filter.  The -1701's Aux ADC outputs a decimal (5.23 format) number between 0 and 1.0 according to its connected pot.  You can insert additional blocks to modify this output as needed to work the control input(s) of any block.  In this example, I squared the Aux ADC level with a multiplier to control the frequency of the filter -- this makes the pot more smooth since frequency is perceived as octaves rather than linearly.  The ABCD Comparator and Multiplexer selects the filter only when the pedal is depressed (Aux ADC output > 0.05).  The links refer to the SigmaStudio Toolbox Wiki entry for each block.

     To make Aux ADCs work, you need to select them in the HW Configuration / Register Control tab.  I only selected Aux ADC3 at the MP8 pin since my eval board connects its lone pot there:

     For additional effects:  As Dave said, by searching Engineer Zone you can see more of what you can do with a -1701.  Here's some examples:

The Chorus Block fits into a -1701 and works well.

ADAU1701 Guitar Reverb -- This one uses nearly all your delay memory, then multiplies it by four to get a usable reverb (at an effective 12 KHz sample rate) from a -1701.  Playing with additional attenuated feedback paths might either improve the effect or kill it.

Look at stmoeller60 's posts for more guitar-related content.  He's got a distortion pedal and much more.

     By the way, the Japanese TV series Radiation House presently on Netflix is really good!  Too bad there's only 2 seasons available.

     Best regards,

     Bob

Wahwah-2.dspproj

First of all, thank you. However, what I'm looking for is exactly this: I want an algorithm for shifting octaves and pitches, like a Whammy pitch shifter pedal. I need more details from experts like you about whether this is possible.

First of all, thank you. However, what I'm looking for is exactly this: I want an algorithm for shifting octaves and pitches, like a Whammy pitch shifter pedal. I need more details from experts like you about whether this is possible.

     Hello Japon18,

     I'm afraid the short answer is no, yet read on.   A Pitch-Transposing block is available.  Its sound quality isn't up to shifting the pitch of an entire ensemble; for example as a karaoke key changer.  However, shifting the pitch of a single voice or a single instrument is often more forgiving, so you might as well try it and see.

      The red Control pin adjusts the amount of pitch shift:  Zero for no shift, positive inputs increase pitch, negative reduces pitch.  The Wiki entry suggests a relatively simple formula for the input needed for a given shift -- at this rate, the math blocks shown should allow for a range of -50% (one octave down) to +100% (one octave up).   Increasing the Delay Reserved to 2000 makes it sound better, however this uses up nearly all your delay memory.  Also, I discovered that the pitch shift is sensitive to this Delay Reserved number (evidently, the formula to figure the required control input is more complex than the Wiki suggests).

     There's certainly better pitch transposers, but they won't fit into a ADAU1701.  Levi experimented with a pitch shifter from a Matlab article which used sawtooth waveforms to control  alternating variable delays.  The discussion and the resulting project is here.  It sounds way better than ADI's Pitch Transposer -- however, we only built it for the special case of one octave up, and it runs on a ADAU1452.

     Best regards,

     Bob