ADAU1701: Stereophaser project
Hi everyone,
I'm experiencing some troubles creating a stereophaser effect for demonstration purposes at our university.
I'm still new into that DSP stuff, so I took a former thread as a basis for my project (Custom IIR block on Sigma Studio)
There were really helpful posts to get me more into this.
So I started a new project and I already have played around with the coefficients and the frequency of the oscillator to make it already sound like a phaser.
But currently I'm trying to make the phaser controllable by using the 4 AUX ADCs.
I use the Elektor ADAU1701 Board, so there are 4 pots soldered to the auxiliary ADC.
I'd like to use those pots to control parameters such as Mix, Depth, Rate and Feedback.
Currently just the mix-input is working. I can't really take notice of the inputs for rate and feedback I have done.
How is depth control different than mix? Does it just mean the amplitude of the VCO?
I have attached a screenshot of the main schematic and the SigmaDSP project below.
Hopefully someone could help me. Thank you!
BR
Martin
Audio Signal Processors
SigmaDSP Audio Processors
adau1701
Hello Martin,
The only thing I see so far to correct is within the Modulator section of your project -- it appears you need to replace the multiplier shown below with an adder to obtain you desired coefficient range.
There may be additional problems, but you'll be more likely to find them after making this change.
Best regards,
Bob
Hi Bob,
thanks for the info. I corrected that one!
And ... oh boy, i forgot to set up the other ADCs in the GPIO register.
So far the pots are doing, what they are intended to do.
The sound of the feedback control is quite insane, so I had to damp the input for the feedback path.
Any ideas how I could make this one sound in a useful way?
I attached the new version.
BR
Martin
Hello Martin,
Yep, you do need to configure those Aux ADC inputs, I make that mistake all the time. And yes, a little feedback goes a long way. Remember that whatever you do with feedback gets added in 48000 times a second.
Your project sounds good! I had to modify it to run on my ADAU1701MINIZ board:
Substituted three on-screen "pots" because the ADI eval board has only one (wired to ADC3)
Changed the output DACs to # 2, 3 as these go to the board's headphone jack.
I experimented with cross-connecting the feedback L -- R, also adding delay to each. See if you like the effect.
Best regards,
Bob
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