[PD] Echo-effect

Pierre Massat pimassat at gmail.com
Mon Mar 28 10:26:09 CEST 2011

So you don't want the original sound and the echo to overlap? Then the
question is : how do you define silence? Do you have a reliable means of
knowing for sure when silence begins? In my experience you can never get an
amplitude of 0 in a sound originating from a microphone. If you can manage
to know exactly when silence starts, then i think you could achieve what you
want by using a single delay line. I would feed the delay line (delwrite~)
with the incoming sound continuously, and i would switch off the output of
the line (delread~, use *~ 0 after it to switch it off). The length of the
delay would be constant and equal to 1600 ms. The feedback level XX (use *~
XX between the output of delread and the input of delwrite) would be equal
to 0 when the delay is off (so that you only get the last 1,6 seconds of
sound when you switch it on). Then everytime you detect silence you wait for
0,8 seconds and you send messages to both the output switch (ramp up from 0
to 1) and the feedback (ramp from 0 to whatever suits your needs). Also, i
would turn the delay off automatically after a fixed period of time
(depending on the feedback level) to make sure that the echo will be off
when a new sound occurs.
Hope this helps...


2011/3/28 Stefan Magnusson <stefan.magnusson at gmail.com>

> Hi!
> I only want the effect to kick in after a certain amount of silence (where
> silence is defined as amplitude zero) so that does not interferer when there
> is continuous sound. Clear enough?
> /Stefan
> On Mon, Mar 28, 2011 at 10:02 AM, Pierre Massat <pimassat at gmail.com>wrote:
>> Hi Stefan,
>> I'm sorry i didn't get your first requirement "Starts when there has been
>> no sound for 0,8 seconds". Could you be a little more specific?
>> If you need to have a strong control over the echo i think you should
>> probably use tables instead of delay lines, because you can write and read
>> to an from a table at any moment and at any point in the table.
>> Pierre
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.puredata.info/pipermail/pd-list/attachments/20110328/dd2f8d7b/attachment-0001.htm>

More information about the Pd-list mailing list