<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="">The Roland SPV-355 Pitch to Voltage Synthesizer sends the signal through a simple “dome filter” or 90 degree phase shifter before the follower. This allows the 4 phases to be diode OR’ed together and fill in the space between the umps in low frequencies. I have tried it in my pitch to voltage experiments and it didn’t help too much, but it is an interesting idea to get some frequency-decay independence.<div class=""><br class=""></div><div class="">Mark</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""> <br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Dec 16, 2021, at 1:23 AM, Tom Wiltshire <<a href="mailto:tom@electricdruid.net" class="">tom@electricdruid.net</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=us-ascii" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""><br class=""></div><div class=""><blockquote type="cite" class=""><div class="">Begin forwarded message:</div><br class="Apple-interchange-newline"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, "Helvetica Neue", Helvetica, sans-serif;" class=""><b class="">From: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">Mr&MrsAccount <<a href="mailto:hbissell@wowway.com" class="">hbissell@wowway.com</a>><br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, "Helvetica Neue", Helvetica, sans-serif;" class=""><b class="">Subject: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class=""><b class="">Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?</b><br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, "Helvetica Neue", Helvetica, sans-serif;" class=""><b class="">Date: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">15 December 2021 at 15:19:38 WET<br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, "Helvetica Neue", Helvetica, sans-serif;" class=""><b class="">To: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">Tom Wiltshire <<a href="mailto:tom@electricdruid.net" class="">tom@electricdruid.net</a>><br class=""></span></div><br class=""><div class=""><div class=""><div style="font-size: 12pt; font-family: "times new roman", "new york", times, serif;" class=""><div class=""> </div>
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<div class="">The worst case for the envelope follower is at the lowest frequencies, 80Hz for guitar. That is where the ripple is the greatest. If you make the filtering</div>
<div class="">slow enough to filter 80Hz there is a very long tail when the input signal goes away. The normal guitar decay can be as long as seconds... but if you stop the strings</div>
<div class="">if can be MUCH shorter, and the classical approach will still allow the envelope to decay slowly.</div>
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<div class="">The reset clock should be set to about 100Hz (not 8KHz). </div>
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<div class="">Its easy to filter the high frequencies and there is no benefit to the circuit for short tone bursts like in the comparison paper. The circuit is also not the best for triggering</div>
<div class="">on an input signal where the lowest frequency is unknown or cannot be specified (like wideband music etc.) It is intended for something like guitar or bass.</div>
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<div class="">Harry Bissell</div>
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<hr id="MESSAGE_DATA_MARKER" class=""><strong class="">From: </strong>Tom <<a href="mailto:tom@electricdruid.net" class="">tom@electricdruid.net</a>><br class=""><strong class="">To: </strong>Mike <<a href="mailto:mbryant@futurehorizons.com" class="">mbryant@futurehorizons.com</a>><br class=""><strong class="">Cc: </strong><a href="mailto:rburnett@richieburnett.co.uk" class="">rburnett@richieburnett.co.uk</a> <<a href="mailto:rburnett@richieburnett.co.uk" class="">rburnett@richieburnett.co.uk</a>>; synth-diy <<a href="mailto:synth-diy@synth-diy.org" class="">synth-diy@synth-diy.org</a>><br class=""><strong class="">Date: </strong>Wednesday, 15 December 2021 7:05 AM EST<br class=""><strong class="">Subject: </strong>Re: [sdiy] Best & fastest envelope follower schematic.. anybody ?<br class=""><br class="">Some envelope generators do feature a "Decay" pot to change the time constant of the filter. <br class=""><br class="">Depends on the use case whether that is worth it. In a bit of studio gear where it might get used for various sources, yes, it probably makes sense. For a stompbox where the input is going to be a guitar, you have more knowledge about the signal and you can optimise the design for that. <br class=""><br class=""><br class="">> On 15 Dec 2021, at 11:37, Mike Bryant <<a href="mailto:mbryant@futurehorizons.com" class="">mbryant@futurehorizons.com</a>> wrote: <br class="">> <br class="">> Why not have both fast and slow filters, and a blend pot between the two so you can find the best trade-off for the incoming signal ? <br class="">> <br class="">> <br class="">> -----Original Message----- <br class="">> From: Synth-diy [<a href="mailto:synth-diy-bounces@synth-diy.org" class="">mailto:synth-diy-bounces@synth-diy.org</a>] On Behalf Of <a href="mailto:rburnett@richieburnett.co.uk" class="">rburnett@richieburnett.co.uk</a> <br class="">> Sent: 15 December 2021 11:21 <br class="">> To: Tom Wiltshire <br class="">> Cc: <a href="mailto:synth-diy@synth-diy.org" class="">synth-diy@synth-diy.org</a> <br class="">> Subject: Re: [sdiy] Best & fastest envelope follower schematic.. anybody ? <br class="">> <br class="">>> With such a simple filter <br class="">>> there *will* always be a trade-off between speed and ripple. <br class="">> <br class="">> Or to put it another way... Increasing the order of the filter gives you a more favourable trade-off between speed of response and residual ripple. <br class="">> <br class="">> -Richie, <br class="">> <br class="">> _______________________________________________ <br class="">> Synth-diy mailing list <br class="">> <a href="mailto:Synth-diy@synth-diy.org" class="">Synth-diy@synth-diy.org</a> <br class="">> <a href="http://synth-diy.org/mailman/listinfo/synth-diy" class="">http://synth-diy.org/mailman/listinfo/synth-diy</a> <br class="">> Selling or trading? Use <a href="mailto:marketplace@synth-diy.org" class="">marketplace@synth-diy.org</a> <br class="">> <br class=""><br class=""><br class="">_______________________________________________ <br class="">Synth-diy mailing list <br class=""><a href="mailto:Synth-diy@synth-diy.org" class="">Synth-diy@synth-diy.org</a> <br class=""><a href="http://synth-diy.org/mailman/listinfo/synth-diy" class="">http://synth-diy.org/mailman/listinfo/synth-diy</a> <br class="">Selling or trading? Use <a href="mailto:marketplace@synth-diy.org" class="">marketplace@synth-diy.org</a> </blockquote>
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