Search found 53 matches

by donstavely
Thu Apr 23, 2020 9:05 am
Forum: Algorithm development
Topic: Spring reverb
Replies: 35
Views: 106450

Re: Spring reverb

Hello all. I haven't checked in on the forum in a while. I am glad that there is still interest in this effect. As for the interaction between the tremolo and the reverb, I believe that it is just that. The longer the reverb, the more it is going to interact with the tremolo; and the faster and deep...
by donstavely
Sat Oct 21, 2017 10:17 am
Forum: Algorithm development
Topic: New Phaser code
Replies: 7
Views: 8674

Not crazy.

No need to clear registers at run time.
by donstavely
Fri Oct 20, 2017 11:16 am
Forum: Algorithm development
Topic: New Phaser code
Replies: 7
Views: 8674

Good stuff, Doug. I also find that I fight for every instruction. A couple of things that might save a few lines: The final "sof 1, -0.04" I believe was only necessary to avoid a glitch around zero in the D/A converter on an early rev of the FV-1. Note that there was a "sof 1, 0.02&qu...
by donstavely
Mon Mar 06, 2017 1:40 pm
Forum: Algorithm development
Topic: Trying to make really long exponential decay
Replies: 5
Views: 7730

Thanks, D.L. Assuming that the decay value is used as some sort of control voltage, a 0.2% step in amplitude would not be noticeable. On the other hand, it very well could be noticeable as a step change in pitch. I 'll bet a coefficient closer to 1.000 could be used, but I haven't done the math abou...
by donstavely
Mon Feb 20, 2017 3:30 pm
Forum: Algorithm development
Topic: Trying to make really long exponential decay
Replies: 5
Views: 7730

Long exponential decay

I don't know if you are still interested in this, but I recently hit on an easy way to do very long decays. Instead of your: rdax pulse, 0.999 wrax pulse, 0 Use a delay memory in place of the register, so the delay time is multiplied by the delay length: rda pulse_dly+1000, 0.998 ; use long delay fo...
by donstavely
Wed Apr 06, 2016 3:39 pm
Forum: Algorithm development
Topic: Spring reverb
Replies: 35
Views: 106450

Spring reverb

I said I was hesitant to post the code, but what the hell: ; SPRING REVERB (c) 2016 Don Stavely ; Please, not for commercial use! ; Description: ; Spring reverbs sound "boingy" because of dispersion in the spring - ; higher frequencies travel slower than low frequencies. ; A "spectral...
by donstavely
Tue Mar 29, 2016 10:43 am
Forum: Algorithm development
Topic: Spring reverb
Replies: 35
Views: 106450

Spring reverb

Hello all. I haven't been doing FV-1 stuff for a while, but my son asked me if I could do a spring reverb. I was surprised at how little info there was on the forum. Learning more about it, I see why now. It is totally unlike other reverb algorithms, and it is hard to do. Being a retired electrical ...
by donstavely
Fri Jun 27, 2014 1:57 pm
Forum: Algorithm development
Topic: Latency "trick ?" in Pitch Transposition algo.
Replies: 14
Views: 20292

Now donstavely is correct in that writing into the buffer could shorten the delay but it can cause an audible discontinuity. Ramps are used and crossed between the pointers to try to hide the discontinuity as the pointer wraps around the buffer, by writing higher into the buffer you are allowing ol...
by donstavely
Fri Jun 27, 2014 1:35 pm
Forum: Algorithm development
Topic: Improved octave-up routine
Replies: 6
Views: 10085

Yes, the tradeoff is latency. In the application I am working on I am going for more of a chorus effect - i.e. multiple instruments rather than a single instrument like a 12-string. Notice that I write 512 words into the 4096-word delay. This reduces the latency by that amount. The reason you can do...
by donstavely
Tue Jun 17, 2014 10:08 am
Forum: Algorithm development
Topic: Improved octave-up routine
Replies: 6
Views: 10085

tremolo effect

Sweetalk, a year ago I tried for weeks to reduce the tremolo without much success. For example, I tried to smear things out with some allpass filters, but it sounds "reverby" and only makes the latency worse. Maybe adding some "wobble" to the ramp LFO rate, i.e. a little bit of v...
by donstavely
Tue Jun 17, 2014 7:14 am
Forum: Algorithm development
Topic: Improved octave-up routine
Replies: 6
Views: 10085

Improved octave-up routine

Hey all. Folks who have played with the pitch-shift routine for octave-up and octave-down know about the "crossfade phase cancellation" issue. For octave-down, you get a tremolo effect due to the slower ramp speed (-8192). But for octave-up, the fast ramp (16384) results in an unpleasant w...
by donstavely
Wed Oct 16, 2013 4:12 pm
Forum: FV-1 software questions
Topic: Resetting a sine LFO
Replies: 3
Views: 6195

Resetting a sine LFO

Hey Frank, is there any way to reset the phase of a sine LFO? I had hoped that executing another WLDS instruction would set the sine value to zero and the cosine value to one (or the amplitude value). But it doesn't seem to work that way. I suppose I can build my own oscillator and reset the initial...
by donstavely
Wed Dec 28, 2011 12:36 pm
Forum: Algorithm development
Topic: Reverb allpass and delay lengths
Replies: 1
Views: 5710

Reverb allpass and delay lengths

I wish Kieth were here to answer this. Frank, please give it your best shot. Or if Sean is still listening, you might have the best insight based on your work in reverb and discussions with Kieth. The question is, how does one come up with a good set of delay lengths for the allpasses and delays in ...
by donstavely
Fri Dec 02, 2011 8:53 am
Forum: Algorithm development
Topic: Octave up and down
Replies: 34
Views: 47678

Sorry, Fulcrum. I can't share the code itself for several reasons: a) Much of the code will be used in a commercial product (though not octave up/down), so I want to keep it proprietary. b) It is very hard to understand, even with comments and help, and even for someone fluent in DSP and on the FV-1...
by donstavely
Sat Sep 10, 2011 4:17 pm
Forum: FV-1 hardware questions
Topic: Pot Tracking Speed
Replies: 17
Views: 31396

Thanks, Sean. I am thinking that this method should work fine, even with the variable speed clock of the Z-DSP. Since the built-in lowpass filters on the pots are implemented digitally, they should track exactly with the compensation filter code. So the code I posted should work regardless of clock ...