Florian,

thank you for the explanation. I think now I understand this application a
bit better. I think the desired function can be achieved by an mixer with
adjustable followed by an attenuator.

Example 1: If you have an LFO with +/-3V output you have to add 3V to obtain
a 0...+6V signal. With an attenuator you can reduce the amplitude without
changing the zero position.

Example 2 (the opposite): If you have an ADSR with 0...+8V output you have
to add -4V to obtain a zero-symmetrical -4...+4V range that can be
attenuated as well.

So far this can be realized only with the A-138 mixers (newer versions with
input 1 = offset) as they are able to add an offset and attenuate the sum of
offset and the signal with the output attenuator. The most versatile
functions are available at the A-138c as you have control over the level and
polarity of all input and output signals.

If that's right we speak about a new module which is a reduced A-138c with a
manually adjustable offet (positive and negative), an input that is added to
this offset and an output attenuator or polarizer for the sum.

Best wishes
Dieter

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com
> [mailto: Doepfer_a100@yahoogroups.com ]Im Auftrag von Florian Anwander
> Gesendet: Mittwoch, 20. Juni 2007 12:17
> An: Doepfer_a100@yahoogroups.com
> Betreff: Re: AW: 1 Re: adding cv offset
>
>
> Hi Dieter
>
> >> this zero crossing
> > But for this function you have a control at the module (for
> most modules)
> > that is controlled by the ADSR:
> >
> > e.g.
> > Initial gain for VCAs
> > (coarse) tune for VCOs
> > Frequency control for filters
> I think this is not really what is meant by Stu and Ross. Mostly
> regualting the Amount of an offset modulation is cannot really be
> achieved with these general offset parameters:
>
> Imagine a sound, whith no VCA involved and look at the the
> cutoff-frequency. This graph is the cutoff frequency modulated by an
> envelope with the gate added as offset:
>
> ^ Level /\
> | / \
> | -----------------+ / \ +----------
> | | / \----------\ |
> | |/ \|
> +---------------------------------------------------- ->Fq
>
> Of course you could add the Gate as separated voltage, but if you do so,
> you will loose the possibility to control the amount of the resulting
> envelope.
>
>
>
> Other (non graphical explained) example: An LFO generates a symmetric
> rectangle wave from -2.5 V to +2.5V. If you want to use this as tonal
> interval modulation, you want to have a rectangle from 0V to +5V. ok
> simply add 2.5 Volts. But now you want to control the amount of the
> modulation (vulgo the interval).
> Again: This is something you cannot achieve practically with the general
> offset of the basic parameter "tune" (of course in technical theory you
> are right, but you cannot not handle this in a real realtime
> livesituation).
>
>
> Florian
>
>
>
>
>
> >
> > For (nearly) all modules each CV controlled parameter is
> already equipped
> > with an offset control. That's why I still do not understand
> the necessity
> > for an external offset module (with a few exceptions like the
> A-132 or the
> > limited tune range of the A-110).
> >
> > If you have an external offset module and adjust the offset control it's
> > exactly the same as if you move the corresponding control of
> the module as
> > all the control voltages are added up. The only reason could be that you
> > want to have this as kind of a remote control. Otherwise you
> will have two
> > controls for the same function.
> >
> > Best wishes
> > Dieter Doepfer
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
>
> --
> Florian Anwander |ConSol
> Tel. +49(89)45841-133 |Consulting&Solutions Software GmbH
> Fax +49(89)45841-111 |Franziskanerstr. 38, D-81669 München
> email: florian.anwander@... | http://www.consol.de
>
>
>
> Yahoo! Groups Links
>
>
>