Doepfer

Hi there.

I am wondering what type of envelope is used on the A-141-2 ADSR. There is no manual on the doepfer website, but the earlier A-141 has a manual and the envelope looks to have a 'convex' attack slope and a 'concave' decay and release.

Even though this is a common envelope type, I find it quite strange that it is not linear. It would then be easy to change from linear to convex to concave for each section of the envelope by using the CV inputs. Can somebody veryify if this ADSR is indeed linear or does it follow the style shown in the A-141 manual.

It would be a shame if it's not linear as there really don't seem to be many CV controlled envelopes out there.

It is an exponential envelope, and you can't change the curve shapes. However it is very useful and if you combine it with a VCA that can be switched from expo to linear then you have a very flexible setup. It is also very fast for percussion sounds.

Neil

Sent from my iPhone

> On 30 Jan 2015, at 07:35, racc00nb0y@yahoo.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> 
>  
> 
> Hi there.
> 
> I am wondering what type of envelope is used on the A-141-2 ADSR. There is no manual on the doepfer website, but the earlier A-141 has a manual and the envelope looks to have a 'convex' attack slope and a 'concave' decay and release.
> 
> 
> Even though this is a common envelope type, I find it quite strange that it is not linear. It would then be easy to change from linear to convex to concave for each section of the envelope by using the CV inputs. Can somebody veryify if this ADSR is indeed linear or does it follow the style shown in the A-141 manual.
> 
> It would be a shame if it's not linear as there really don't seem to be many CV controlled envelopes out there.
> 
>  
> 
>

Hello Racoonboy,

Analoge envelopes are based on the loading/unloading curve of a 
capacitor, and these curves are never linear.
Our recognition and hearing is based on exponential functions in many ways:
* what we hear as a linear increase of pitch is in fact an exponential 
increase of the frequency
* what we hear as a  linear increase of loudness is in fact an 
exponential increase of the signal level
Since we have mostly linear voltage sources, the target modules 
(VCA/VCF/VCO) have exponentiator circuits at the CV input. So you can 
select whether you want exponential control or linear control (everyone 
knows this from lin and log CV-ins at the VCOs). And because there are 
typically more voltage generating modules than voltage target modules, 
it makes sense to keep the selection between lin and exp at the targets 
and not at the sources.
This is why the envelopes typically have not a selection between lin and 
exp. Adding the circuitry for lin/exp conversion at the envelope would 
increase the costs of the module immediately and significantly, because 
the converter circuit requirs manual alignment. And the work hours for 
the alignment are more expensive than the complete hardware.

Florian



Am 30.01.2015 um 08:39 schrieb Neil Kagan blinkenlicht@yahoo.com 
[Doepfer_a100]:

>
>
> It is an exponential envelope, and you can't change the curve shapes. 
> However it is very useful and if you combine it with a VCA that can be 
> switched from expo to linear then you have a very flexible setup. It 
> is also very fast for percussion sounds.
>
> Neil
>
> Sent from my iPhone
>
> On 30 Jan 2015, at 07:35, racc00nb0y@yahoo.com 
> <mailto:racc00nb0y@yahoo.com> [Doepfer_a100] 
> <Doepfer_a100@yahoogroups.com <mailto:Doepfer_a100@yahoogroups.com>> 
> wrote:
>
>> Hi there.
>>
>> I am wondering what type of envelope is used on the A-141-2 ADSR. 
>> There is no manual on the doepfer website, but the earlier A-141 has 
>> a manual and the envelope looks to have a 'convex' attack slope and a 
>> 'concave' decay and release.
>>
>>
>> Even though this is a common envelope type, I find it quite strange 
>> that it is not linear. It would then be easy to change from linear to 
>> convex to concave for each section of the envelope by using the CV 
>> inputs. Can somebody veryify if this ADSR is indeed linear or does it 
>> follow the style shown in the A-141 manual.
>>
>> It would be a shame if it's not linear as there really don't seem to 
>> be many CV controlled envelopes out there.
>>
>
>
>

Hi thanks for the explanation.

I was just wanting to experiment with things such as linear decay, as I've heard this is good for 909 type sounds and also would like to try convex decay as to make it more boomy on drums etc.

When I use the CV ins can I flatten (to an extent) or reverse the curve to with modulation? If not, what do the CV ins do? I read it changes the time, which according to my calculations should make this somehwat possible with LFOs or another ADSR for example.

Thanks

Hello

The most important thing: The VCA for the loudness envelope must be a 
linear VCA! Log VCAs are intended for lineare modulation voltages.

If you want to change the curve of an standard envelope like the A-140 
you need a linear DC-coupled VCA like the A-130 series after 2001.

Connect the envelope out to the VCA-Signal-In
Connect the inverted envelope out with the CV2-In of the A-130
Raise VCA Gain to about 75% and set CV2-In to 0%
Now start increasing the CV2-In amount and raise synchronously the VCA Gain.
Take the VCA-Out as envelope source for the Audio-VCA.

The inverted envelope will now dampen the normal envelope the more, the 
higher the envelope is.

The same can be achieved basically with the A-141-2 using its inverted 
envelope out and sending it to its Level CV In, but that is missing the 
correction in the total amount, that we can do with the VCA-Gain at the 
A-130.

Florian



Am 30.01.2015 um 13:56 schrieb racc00nb0y@yahoo.com [Doepfer_a100]:

>
>
> Hi thanks for the explanation.
>
> I was just wanting to experiment with things such as linear decay, as 
> I've heard this is good for 909 type sounds and also would like to try 
> convex decay as to make it more boomy on drums etc.
>
> When I use the CV ins can I flatten (to an extent) or reverse the 
> curve to with modulation? If not, what do the CV ins do? I read it 
> changes the time, which according to my calculations should make this 
> somehwat possible with LFOs or another ADSR for example.
>
> Thanks
>
>
>
>

Am 30.01.2015 um 19:01 schrieb racc00nb0y@yahoo.com [Doepfer_a100]:

> But I still don't know what the
> individual CVs (Attack CV, Decay CV and Release CV) are for if they do
> not modulate these individual components.
They do, but they modulate the time (fast<->slow), not the shape 
(lin<->log).

Okay thanks.

Just my little brain thought if you modulated the time slowly then quickly over the course of the attack for example this would therefore change the shape.. :\

Dan

On 30/01/2015 20:55, florian anwander fanwander@mnet-online.de [Doepfer_a100] wrote:
> Am 30.01.2015 um 19:01 schrieb racc00nb0y@yahoo.com [Doepfer_a100]:
>
>  > But I still don't know what the
>  > individual CVs (Attack CV, Decay CV and Release CV) are for if they do
>  > not modulate these individual components.
> They do, but they modulate the time (fast<->slow), not the shape
> (lin<->log).

Modulating the time can change the shape.
e.g. ( forgiving the exactness the example )

If you had a linear decay, and fed back the output inverted to
modulate the decay rate you'd get more like an exponential drop.


I'm sure I've heard something like that before, but anyway
  the maths says it works.

andy

Yeah, I thought that might work.

Sounds good. I'll probably comproimse on having an envelope that does everything, cos it doesn't really exit, and just get one that does what it does well.

It'll take me a while to decide on the best option for envelope. There are so many out there. The doepfer ones do look good. I love doepfer :D

Dan

> Hi there.
>
> I am wondering what type of envelope is used on the A-141-2 ADSR. There is no manual on the doepfer website, but the
> earlier A-141 has a manual and the envelope looks to have a 'convex' attack slope and a 'concave' decay and release.
>
> Even though this is a common envelope type, I find it quite strange that it is not linear. It would then be easy to
> change from linear to convex to concave for each section of the envelope by using the CV inputs. Can somebody veryify if
> this ADSR is indeed linear or does it follow the style shown in the A-141 manual.
>
> It would be a shame if it's not linear as there really don't seem to be many CV controlled envelopes out there.

The A-141-2 has an exponential shape as most ADSR. But it's possible to change the slope form. The info page of the A-141-2 says:

"The control voltage inputs for A, D and R can be used also to change the shape of each segment. To change the shape of the Attack
curve the inverted envelope output (Inv. Out) has to be patched to the CVA input. Then the CVA control is used to modify the shape
of the Attack segment (CCW = usual exponential shape, about center position = linear shape, CW = inverse exponential shape). Same is
valid for the shapes of Decay and Release also. But for this the non-inverted output (Fixed Out) has to be patched to the CV input
in question (CVD or CVR or both)."


Best wishes
Dieter Doepfer
(back from NAMM)