[sdiy] Audio Trigger circuits

[Paul Wagorn]

how about just overdriving a transistor (to make a 5v square wave) & thowing
a small cap in parallel (as a cheesy slew) to do it...?

i've actually had luck just throwing an audio signal though a distortion
pedal (dialed to 11!) to trigger devices

paul

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Oren Leavitt
Sent: Friday, June 27, 2003 10:32 AM
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Audio Trigger circuits


Hello,

It sounds like what you're after is the combination of these basic building
blocks:

Filter(Lo/Hi/Bandpass, etc) -> Envelope Follower(Full wave
rectifier/filter) -> Gate/Trigger Extractor(Comparator w/adj. threshold).

Oren

-------Original Message-------
From: steve jones <stevejones at hotpop.com>
Sent: 06/27/03 06:36 AM
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] Audio Trigger circuits

>
> Hi All,
Does anyone have a fairly simple circuit to produce a +5v trigger from
an audio input? I know these are widely used but I haven't been able
to find  a complete schematic.

Ideally it would have a variable threshold and be tunable (ie to be
able to trigger from high or low frequencies only, eg hihat vrs kick
drum).

It would also be handy to have the option of choosing between a fixed
(but variable) trigger output voltage or have the input dynamics
reflected in the size of the trigger output voltage. While the latter
option is perhaps more "musical" because dynamics are included, the
former would be useful for dance / techno where slight variations can
detract from the pure "machine" feel.

The context for using this audio to trigger would be in triggering say
a synth kick drum from a  microphone signal from a live drummer (at
the desk end so it would probably be gated / EQed). As a live engineer
I would like to be able to beef up the drum sound with some analogue
Umph, without attaching triggers to drum skins, ie. on the sly ;)

Any thoughts / experiences / urls most welcome.
Steve


>