[sdiy] Underdamped experiments

[Magnus Danielson]

From: Charles Bisaillon <sdiy at oveloe.com>
Subject: [sdiy] Underdamped experiments
Date: Tue, 14 Dec 2004 22:42:29 -0500
Message-ID: <BDE51CD5.A32%sdiy at oveloe.com>

> Hi all,

Charles,

> I was doing an experiment on frequency responses in my first year
> electronics laboratory in university. The goal was aimed towards obtaining a
> near critically damped response which is more efficient in circuit design.
> My teacher says that underdamped circuits are unstable, but when I was
> checking it out on the scope, my imagination started to tweak. I saw new
> waves coming out of a simple pulse and huge gain boost.
> 
> I am sending this email because I was wondering if these underdamped waves
> were of any use in audio synthesis. Can they actually be creative or are
> they mostly unwanted properties? Can someone use an underdamped response as
> a waveshaper?
> 
> Just dreaming of a different system...

Don't dream on too much. Do you have a filter in your synth? OK, you most
probably have a knob called Resonance, Q or similar, right?

When you have this knob over to the left, then the filter is near critically
damped, as you turn it right, then will it be less and less damped and it may
even go up to selfresonance. Sweep the filter during high resonance and you get
lovely effects.

We've been doing this for at least 40 years now. It is a very usefull
waveshaper and you should use it, it is highly recommended.

Cheers,
Magnus