<div dir="ltr"><div>Thanks, Matthias. <br></div><div>Looks like the PAL filter used the 3320 to do an APF (and switchable to LPF). Well, that's exactly what I did. It sounds lovely as a phaser, just like what you'd expect. It's so easy to build and so much better than all my digital phasers. Not sure why, but I really find the digitals fail in this department.</div><div>I haven't found a lot of implementations of this APF topology in pitch shifting applications. <br></div><div>This UAD article opens a new can of worms by introducing the APF type used in reverbs, which I think is different from the analog/filtering type of APF, in that it adds a delay component. Anyone, please correct me if I'm wrong. This is actually another thread topic I've been wanting to start for ages.*Phaser type APF vs reverb type APF.*<br></div><div>Also, can you explain like I'm stupid the difference between pitch and frequency shifting? It sounds like a linear vs exponential thing, but must be more to it than that...</div><div>C<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Mar 11, 2020 at 1:36 AM Matthias Herrmann <<a href="mailto:Matthias.Herrmann@jeppesen.com">Matthias.Herrmann@jeppesen.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div lang="EN-US">
<div class="gmail-m_-1487329553934478869WordSection1">
<p class="MsoNormal"><span style="font-size:11pt;font-family:"Calibri",sans-serif;color:rgb(31,73,125)">Thomas Henry did this with his 1982 “PAL Filter”. And by mixing the original signal into the filtered signal you can mimik both pitch-shift and frequency shift
effect. I am currently building his filter and wil soon be able to check this with my own ears.<br>
<br>
The effect is shortly discussed here:<br>
<a href="https://www.uaudio.de/blog/allpass-filters/" target="_blank">https://www.uaudio.de/blog/allpass-filters/</a><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:"Calibri",sans-serif;color:rgb(31,73,125)"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:"Calibri",sans-serif;color:rgb(31,73,125)">Cheers,<br>
Matthias<br>
<br>
<br>
<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt;font-family:"Calibri",sans-serif;color:rgb(31,73,125)"><u></u> <u></u></span></p>
<div style="border-color:currentcolor currentcolor currentcolor blue;border-style:none none none solid;border-width:medium medium medium 1.5pt;padding:0in 0in 0in 4pt">
<div>
<div style="border-color:rgb(225,225,225) currentcolor currentcolor;border-style:solid none none;border-width:1pt medium medium;padding:3pt 0in 0in">
<p class="MsoNormal"><b><span style="font-size:11pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11pt;font-family:"Calibri",sans-serif"> Synth-diy [mailto:<a href="mailto:synth-diy-bounces@synth-diy.org" target="_blank">synth-diy-bounces@synth-diy.org</a>]
<b>On Behalf Of </b>ColinMuirDorward<br>
<b>Sent:</b> Wednesday, March 11, 2020 3:01 AM<br>
<b>To:</b> *SYNTH DIY <<a href="mailto:Synth-diy@synth-diy.org" target="_blank">Synth-diy@synth-diy.org</a>><br>
<b>Subject:</b> [sdiy] frequency shifter<u></u><u></u></span></p>
</div>
</div>
<p class="MsoNormal"><u></u> <u></u></p>
<div>
<div>
<p class="MsoNormal">Hi, I got a little lost trying to understand what a frequency shifter is. I mean the pre-digital method used by Moog (I think?).<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">I recently built a 4pole APF, and was really impressed with some of the pitching effects I could achieve with it. I'm guessing this is an entirely different method than the frequency shifters like Moog and JH have done.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">Is the APF method used by anyone? What are its limitations, and what is it even doing? <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">Well, I guess I'm just looking for some conversation on the topic of analog frequency/pitch shifting methods. If anyone has any thoughts/experience they'd like to share.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">Cheers,<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">Colin<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><br>
<br>
<u></u><u></u></p>
</div>
</div>
</div>
</div>
</div>
_______________________________________________<br>
Synth-diy mailing list<br>
<a href="mailto:Synth-diy@synth-diy.org" target="_blank">Synth-diy@synth-diy.org</a><br>
<a href="http://synth-diy.org/mailman/listinfo/synth-diy" rel="noreferrer" target="_blank">http://synth-diy.org/mailman/listinfo/synth-diy</a><br>
</blockquote></div><br clear="all"><br>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><a href="https://www.instagram.com/colinmuirdorward/" target="_blank">https://www.instagram.com/colinmuirdorward/</a></div><div><a href="https://www.instagram.com/colinmuirdorward/" target="_blank">-<br></a></div><div><a href="https://www.instagram.com/ssdp_synthesis/" target="_blank">https://www.instagram.com/ssdp_synthesis/</a></div></div></div></div></div></div></div>