<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="">In a full wave rectifier, you would have the 0 degrees and the 180 degrees (flipped over) signals run through diodes to only use the positive part. In this case, you have 4 phases. Like in a frequency shifter, you need to do phase shifters at each octave in your range, so it gets parts heavy fast. In the end, it’s probably not worth it. <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 5:34 PM, Martin Klang <<a href="mailto:mars@pingdynasty.com" class="">mars@pingdynasty.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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<div class=""><p class=""><br class="">
</p><p class="">Is that analogous to using a Hilbert transform (to get the
analytic signal) to calculate the envelope? It works perfectly on
continuous sine waves, and I believe it is used to extract
amplitude modulation from a carrier wave. But not so good for
audio.<br class="">
</p><p class=""><br class="">
</p><p class="">Martin</p><p class=""><br class="">
</p>
<div class="moz-cite-prefix">On 16/12/2021 12:29, mark verbos via
Synth-diy wrote:<br class="">
</div>
<blockquote type="cite" cite="mid:91AF5180-D85C-4015-BD86-C4D7780793E2@gmail.com" class="">
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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 class=""><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="" moz-do-not-send="true">tom@electricdruid.net</a>>
wrote:</div>
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<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="" moz-do-not-send="true">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="" moz-do-not-send="true">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>
<div class=""> </div>
<div class="">
<div class=""> </div>
<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>
<div class=""> </div>
<div class="">The reset clock should be set
to about 100Hz (not 8KHz). </div>
<div class=""> </div>
<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>
<div class=""> </div>
<div class="">Harry Bissell</div>
<div class="">
</div>
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<blockquote style="margin: 0 0 0 .8em;
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<div class=""> </div>
<hr id="MESSAGE_DATA_MARKER" class=""><strong class="">From: </strong>Tom <<a href="mailto:tom@electricdruid.net" class="" moz-do-not-send="true">tom@electricdruid.net</a>><br class="">
<strong class="">To: </strong>Mike
<<a href="mailto:mbryant@futurehorizons.com" class="" moz-do-not-send="true">mbryant@futurehorizons.com</a>><br class="">
<strong class="">Cc: </strong><a href="mailto:rburnett@richieburnett.co.uk" class="" moz-do-not-send="true">rburnett@richieburnett.co.uk</a>
<<a href="mailto:rburnett@richieburnett.co.uk" class="" moz-do-not-send="true">rburnett@richieburnett.co.uk</a>>;
synth-diy <<a href="mailto:synth-diy@synth-diy.org" class="" moz-do-not-send="true">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="" moz-do-not-send="true">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="" moz-do-not-send="true">mailto:synth-diy-bounces@synth-diy.org</a>]
On Behalf Of <a href="mailto:rburnett@richieburnett.co.uk" class="" moz-do-not-send="true">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="" moz-do-not-send="true">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="">
>
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