<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">At the time that this was a tough problem, people were trying to solve "the pitchshifting problem" using entirely analogue means. The problem didn't really get solved until Eventide did it digitally with the Harmonizer.<div class=""><br class=""></div><div class="">But we don't have the same limitations today. It seems to me that a BBD-based pitch shifter would be possible if you had a uP to produce the required control voltages. Of course, such a thing is still *ludicrous* by most measures, but it would be *possible*. You need at least two and possibly several BBD delay lines with voltage-controlled clocks and VCAs on their outputs. Each delay line then has a CV for the clock rate, and a CV for the volume. A decent uP+DAC and a decent programmer can then generate a pile of control voltages to give you up/downshifted delayed signals, and all the necessary crossfading to avoid the glitches when the ramps jump back to zero.</div><div class=""><br class=""></div><div class="">I'll have to think harder about this to work out for how long a given delay line length can give you a specific pitch shift. That'll help determine how many delaylines would be required. More shift is steeper ramps (e.g. higher modulation frequency) and probably more BBDs required?</div><div class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 6 Oct 2024, at 19:05, Michael E Caloroso via Synth-diy <<a href="mailto:synth-diy@synth-diy.org" class="">synth-diy@synth-diy.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">I can't find my hard copy, but Roland had a US patent for a BBD based pitch shifter.<div class=""><br class=""></div><div class="">MC</div></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Oct 6, 2024 at 2:55 AM houshu--- via Synth-diy <<a href="mailto:synth-diy@synth-diy.org" class="">synth-diy@synth-diy.org</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><u class=""></u> <div class=""><div dir="auto" style="unicode-bidi:embed" class=""><div class="">Hello Didier,</div><p class=""><br class=""></p><p class="">A set of schematics of BBD based pitch shifter is here:</p><p class=""><br class=""></p><p class=""><a href="https://www.experimentalistsanonymous.com/diy/index.php?dir=Schematics/Vibrato%20and%20Pitch%20Shift" target="_blank" class="">https://www.experimentalistsanonymous.com/diy/index.php?dir=Schematics/Vibrato%20and%20Pitch%20Shift</a></p><p class=""><br class=""></p><p class="">Please check Wacky harmonizer (an article from a Japanese magazine).</p><p class="">As discussed here, cross fading seems to be a problem.<br class=""></p><p class=""><br class=""></p><p class="">Osamu Sam Hoshuyama</p><p class="">Kawasaki JAPAN. <br class=""></p><br class=""><blockquote style="margin:0px auto;padding:0px 2em;border-left-width:2px;border-left-style:solid;border-left-color:rgb(0,173,229);white-space:pre-wrap" class=""><br class=""><br class="">------ Original Message ------<br class="">差出人: "Didier Leplae via Synth-diy" <<a href="mailto:synth-diy@synth-diy.org" target="_blank" class="">synth-diy@synth-diy.org</a>><br class="">To: "synth-diy@synth-diy org" <<a href="mailto:synth-diy@synth-diy.org" target="_blank" class="">synth-diy@synth-diy.org</a>><br class="">送信済み: 土曜日, 2024/10/5 02:44<br class="">件名: [sdiy] Frequency shifted from BBD?<br class=""><br class="">I recently re-read the section in Barry Klein’s Electronic Music Circuits on bucket brigade devices and noticed a brief mention of using them as a frequency shifter by modulating with a ramp wave.<br class="">
He acknowledges that there will always be an audible glitch and some noise issues. <br class="">
I experimented with this idea a little to minimal success, but curious if anyone else has tried this or seen it used in interesting ways.<br class="">
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