[sdiy] Pitch detector Envelope follower!

[Harry Bissell]

I'm not sure I understand. Do you need to have Pitch tracking or envelope tracking ?

Envelope tracking can be quite simple if the input signal is (somewhat) predictable.
Generating a 'filter sweep' can be done with a peak detector very easily. This works well for
percussive sounds (syndrum dooooo....).  The trouble is detecting a sudden drop of the input
signal, if you need to track that. Often a filter sweep completing with no input can reveal
a lot of unacceptable noise...

If pitch detection ~is~ needed, how fast does it need to respond ?  Do you need a slow response
to control (let's say) the general range of filtering, or are you trying make a VCO follow a pitch
input ?   

I don't know why, but it seems in these posts that no one wants to say (in any detail) what their
application will be.  I'd be happy to discuss the benefits and shortfalls of the various methods either
on-list (preferred) or in private.

H^) harry



----- Original Message -----
From: KD KD <pic24hj at gmail.com>
To: Paul Perry <pfperry at melbpc.org.au>
Cc: synthdiy diy <synth-diy at dropmix.xs4all.nl>
Sent: Tue, 01 Nov 2011 10:06:31 -0400 (EDT)
Subject: Re: [sdiy] Pitch detector Envelope follower!

yes i know, im not looking for a perfect analogue pitch tracker, just
something that tracks reasonably, that uses few components.
A simple decay generator, diode+resistor+ cap works surprisingly
well for trigger a filter sweep from an audio source.

KD

2011/11/1, Paul Perry <pfperry at melbpc.org.au>:
> The 'best' simple circuit will depend on what kind of signal you are feeding
> to it.
> For example, a flute would be much easier than a guitar string.
> Also, it is a lot easier if you do not need it to work below 200Hz.
>
> paul perry Melbourne Australia
>
>
> ----- Original Message -----
> From: "KD KD" <pic24hj at gmail.com>
> To: "synth DIY" <synth-diy at dropmix.xs4all.nl>
> Sent: Tuesday, November 01, 2011 12:45 AM
> Subject: [sdiy] Pitch detector Envelope follower!
>
>
>>I need a quick fix for a pitch tracker and a envelope detector.
>>Suggestions?
>>
>> LM2907 seams to rippling alot yet linear, perhaps Harrys 3 way
>> solution are a lot better?
>> What are a decent evelope detector? The regular full-wave rectifier
>> with switch able times?
>>
>> Something similar to MS 20 but way less components, it dont need to work
>> 100%,
>> to about 80% would be OK, well do any analogue pitch tracker actually
>> work properly
>> do, i doubt.
>>
>> KD
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
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-- 
Harry Bissell & Nora Abdullah 4eva