SergeModular

--- In SergeModular@yahoogroups.com, "roelelec" <r.steverink@...> wrote:
>
> Hi all,
>
> I want to know more about the scaling buffers I have in my Quadslope.
> There's little information on the internet, none in the Gold book or in further Serge catalogs.
>
> I know you can attenuate, amply and invert a signal, due to it's processed pot and you have an offset with a range between -5 and +5 volt.
> But what more can you further do with it?
>
> I thought I can meaby use it as a cv source, but that didn't work.
> I didn't got an extra rate knob, just the same only with a broader range.
>
> And can someone explain me what scaling means?
> This word has many connotations, but what does it mean in this regard I don't know?
>
>
> Thanks for any help.
>
> Cheers,
>
> Roel
>

--- In SergeModular@yahoogroups.com, "Guy" <guy@...> wrote:
>
> Hi Roel,
>
> What you've already said about the SB, is true (except for the "amplify" part).
> The lower pot (-/+) attenuates the In signal, and/or inverts it, in a gradual way.
> Turning that pot fully CW or CCW does *not* add gain; it merely passes the incoming signal completely.
> The upper pot (-5/+5) simply *adds* a positive or negative steady DC voltage to what is fed into the [attenuated] Input . So it "scales" the input either up or down (het werkwoord 'scalen' betekent o.a. omhoog- of omlaag gaan; bvbd. 'scaling a wall' betekent 'op een muur klimmen').
> Used on its own -- that is, without any signal fed to the Input -- it just puts out that steady DC voltage. In that sense, it is indeed a CV source; only, it's a *steady* and manually-controlled CV source. There's no LFO or something hidden underneath it...
>
> And that's it.
> Just a simple utility module, but nonetheless a powerful one.
>
> The most common use of the SB, is when you need to attenuate (or 'attenuvert', as it is sometimes called nowadays) a signal fed to an input which has no attenuator pot (which happens frequently on Serge modules).
> I sometimes use the -5/+5 pot simply to tune oscillators, by setting it to exact voltages (1V, 2V...), but of course the combination with the processing attenuator makes it seriously more funky.
> I use the Scaling Buffers in almost every patch.
>
> Hope that helps,
> _g
>
>
> --- In SergeModular@yahoogroups.com, "roelelec" <r.steverink@> wrote:
> >
> > Hi all,
> >
> > I want to know more about the scaling buffers I have in my Quadslope.
> > There's little information on the internet, none in the Gold book or in further Serge catalogs.
> >
> > I know you can attenuate, amply and invert a signal, due to it's processed pot and you have an offset with a range between -5 and +5 volt.
> > But what more can you further do with it?
> >
> > I thought I can meaby use it as a cv source, but that didn't work.
> > I didn't got an extra rate knob, just the same only with a broader range.
> >
> > And can someone explain me what scaling means?
> > This word has many connotations, but what does it mean in this regard I don't know?
> >
> >
> > Thanks for any help.
> >
> > Cheers,
> >
> > Roel
> >
>

>No. And yes.
>The incoming signal doesn't get attenuated when you turn the pot >either CW or
>CCW. The signal is fully attenuated (=0) when the pot is at its >center position.
>Turning the pot either way "opens" the signal more and more, until >you arrive at
>the full CW- or CWW positions, where the signal reaches its maximum >level, or
>the inverse thereof.
>But I'm sure you knew this; you just misplaced the word >"attenuated". :-)

>They 'could' or they 'can', yes.
>In this case, no.
>AFAIK, most attenuator pots on a Serge system do not provide for >extra gain,
>except where it makes more sense (VCA's, etc.). In that case, it's >called...
>Gain. Note however that "gain" also doesn't necessarily mean there >will be a
>possible greater gain than the original signal. Amplifying a signal >[in a
>modular synth] can be a tricky business... what with those >vulnerable speakers.
>In other words: an attenuator pot allows you to manually set a >signal between
>'nothing' and 'all', but not 'more'. A gain pot *could* potentially >make the
>signal larger, but not necessarily so. It depends on the >application. The
>electronic circuitry behind both is totally different. An attenuator >is (mostly)
>a passive device, whereas a gain circuit is an active device: it >amplifies a
>signal, and sometimes it can amplify above unity gain (=bigger than >the
>original).

>DC can be fluctuating too. A LFO comes to mind...
>Look at it this way: AC (Alternating Current) fluctuates around the >zero axis.
>DC doesn't.
>When an AC signal isn't fluctuating *centered* around the zero axis, >it has as
>DC component (offset), which is mostly A Bad Thing.
>To make matters more complicated, a DC signal can be "shifted" >around and about
>the zero axis as well. This is what the SB buffer can do (with the >-5/+5 pot).

>When in the audio range, there is no correlation to what you hear >when a signal
>is AC or DC. A triangle audio wave sounds exactly the same when it's >either DC-
>or AC-coupled (respectively: above or below the zero axis, or >centered around
>that axis).
>When the signal is sub-audio, and it is used as a modulation source, >it makes a
>big difference. However, in the world of Serge, you can easily >adjust that
>difference by shifting that low frequency up or down. Again, the >Scaling Buffers
>come to mind...

>I understand where your confusion comes from. And Serge's paradigm >of being able
>to shift signals at will doesn't make it easier.
>I'm not very good at explaining this, though. Perhaps you could look >up a few
>things in Wikipedia ?

>It can be dauntingly complex, yes. See above about the Serge >paradigm. But this
>is one of the strengths of a Serge system: it allows you to freely >"play with
>signals", regardless if they're DC or AC. A Serge system doesn't >really make a
>difference between audio and low frequencies. It's just... a signal, >and it is
>left up to you as to what to do with those signals. This in sharp >contrast with
>a Buchla system, where audio and CV are strictly separated.

--- In SergeModular@yahoogroups.com, "roelelec" <r.steverink@...> wrote:
>
> Hi Guy,
>
> So the In signal gets attenuated when you turn the knob to the plus (CW) and
of course inverts when you turn it ccw.


> Isn't it strange that this particular processed pot doesn't amplify like all
the others do? I mean in the Gold book and other places there's written that
processed pots can attenuate, amplify and or invert a cv voltage!

They 'could' or they 'can', yes.
In this case, no.
AFAIK, most attenuator pots on a Serge system do not provide for extra gain,
except where it makes more sense (VCA's, etc.). In that case, it's called...
Gain. Note however that "gain" also doesn't necessarily mean there will be a
possible greater gain than the original signal. Amplifying a signal [in a
modular synth] can be a tricky business... what with those vulnerable speakers.
In other words: an attenuator pot allows you to manually set a signal between
'nothing' and 'all', but not 'more'. A gain pot *could* potentially make the
signal larger, but not necessarily so. It depends on the application. The
electronic circuitry behind both is totally different. An attenuator is (mostly)
a passive device, whereas a gain circuit is an active device: it amplifies a
signal, and sometimes it can amplify above unity gain (=bigger than the
original).

> I always thought DC voltage (non-fluctuating) is always below zero (subaudio)
and AC voltage (fluctuating) above zero (audio), but I discovered that DC
voltage can be in the plus also!

DC can be fluctuating too. A LFO comes to mind...
Look at it this way: AC (Alternating Current) fluctuates around the zero axis.
DC doesn't.
When an AC signal isn't fluctuating *centered* around the zero axis, it has as
DC component (offset), which is mostly A Bad Thing.
To make matters more complicated, a DC signal can be "shifted" around and about
the zero axis as well. This is what the SB buffer can do (with the -5/+5 pot).

> Is there no correlation with the hearing sound?

When in the audio range, there is no correlation to what you hear when a signal
is AC or DC. A triangle audio wave sounds exactly the same when it's either DC-
or AC-coupled (respectively: above or below the zero axis, or centered around
that axis).
When the signal is sub-audio, and it is used as a modulation source, it makes a
big difference. However, in the world of Serge, you can easily adjust that
difference by shifting that low frequency up or down. Again, the Scaling Buffers
come to mind...

> I mean on the NTO, the sinus has a black ring which means it outputs between
-2,5 and + 2,5 volts

AC-coupled, yes.

and triangle and saw have blue rings which indicates 0 - +5 volt.

DC-coupled :-)

Does this mean -2,5 - 0 of the sinus is DC which as soon as it goes higher then
zero, it turns into AC? Or is this nonsense!
> Can you please explain this!

I understand where your confusion comes from. And Serge's paradigm of being able
to shift signals at will doesn't make it easier.
I'm not very good at explaining this, though. Perhaps you could look up a few
things in Wikipedia ?

> Thanks, yes now I understand what scaling in this context means and does! But
I suspect that scaling on another funktion is more complex than that.

It can be dauntingly complex, yes. See above about the Serge paradigm. But this
is one of the strengths of a Serge system: it allows you to freely "play with
signals", regardless if they're DC or AC. A Serge system doesn't really make a
difference between audio and low frequencies. It's just... a signal, and it is
left up to you as to what to do with those signals. This in sharp contrast with
a Buchla system, where audio and CV are strictly separated.

> Which panels does your Serge contain?

Less than it matters. Or more than it matters. :)

_g


>
> Cheers,
>
> Roel

>
> I see, it's the other way around. That's why the signs for positive and negative open wide on both sides! So there's no attenuation to - and + (only at 0) and it's not amplification either.
> How do you call that then?

> This is tricky!
> What is the range of HZ for DC and AC?

> I don't dare to give an answer myself, since DC can overlap AC.

> I only now that our range of hearing lies between 500 hz and appr. 20 khz.

> I now understand that you can hear DC as well. I didn't know this under till now. Always thought it's a cv, so sub-audio only.

> Yesterday I found some explanation about coupling on the internet.
> It's states that DC is directly given, but with AC there's a capacitator in the way.
> You say: "adjust that difference". What do you mean by that?

> This is not easy. I look in Wikipedia, but it only touches on AC and DC and such, but doesn't talk about the things I need to know. Beside that AC and DC linked with synths it seams almost impossible to find on the internet! I'm going to search for a good book on this subject.

> I agree with you; it's definitely one of the strong points of the Serge. But on the other hand it's important for the us, the makers to know what their doing. I mean outputing a signal below 500 hz result in silence!

>As soon as you patch it into f.e. a cv in of a NTO, you hear the signal again!
> Which in Buchla system also means that you need different kabels.
> This way of patching can be very handy, but it also limites the freedom of experimentation.

>
> >It can be dauntingly complex, yes. See above about the Serge >paradigm. But this
> >is one of the strengths of a Serge system: it allows you to freely >"play with
> >signals", regardless if they're DC or AC. A Serge system doesn't >really make a
> >difference between audio and low frequencies. It's just... a signal, >and it is
> >left up to you as to what to do with those signals. This in sharp >contrast with
> >a Buchla system, where audio and CV are strictly separated.
>
> 'morning Roel,
>
> --- In SergeModular@yahoogroups.com, "roelelec" <r.steverink@> wrote:
> >
> > Hi Guy,
> >
> > So the In signal gets attenuated when you turn the knob to the plus (CW) and
> of course inverts when you turn it ccw.
>
>
> > Isn't it strange that this particular processed pot doesn't amplify like all
> the others do? I mean in the Gold book and other places there's written that
> processed pots can attenuate, amplify and or invert a cv voltage!
>
> They 'could' or they 'can', yes.
> In this case, no.
> AFAIK, most attenuator pots on a Serge system do not provide for extra gain,
> except where it makes more sense (VCA's, etc.). In that case, it's called...
> Gain. Note however that "gain" also doesn't necessarily mean there will be a
> possible greater gain than the original signal. Amplifying a signal [in a
> modular synth] can be a tricky business... what with those vulnerable speakers.
> In other words: an attenuator pot allows you to manually set a signal between
> 'nothing' and 'all', but not 'more'. A gain pot *could* potentially make the
> signal larger, but not necessarily so. It depends on the application. The
> electronic circuitry behind both is totally different. An attenuator is (mostly)
> a passive device, whereas a gain circuit is an active device: it amplifies a
> signal, and sometimes it can amplify above unity gain (=bigger than the
> original).
>
> > I always thought DC voltage (non-fluctuating) is always below zero (subaudio)
> and AC voltage (fluctuating) above zero (audio), but I discovered that DC
> voltage can be in the plus also!
>
> DC can be fluctuating too. A LFO comes to mind...
> Look at it this way: AC (Alternating Current) fluctuates around the zero axis.
> DC doesn't.
> When an AC signal isn't fluctuating *centered* around the zero axis, it has as
> DC component (offset), which is mostly A Bad Thing.
> To make matters more complicated, a DC signal can be "shifted" around and about
> the zero axis as well. This is what the SB buffer can do (with the -5/+5 pot).
>
> > Is there no correlation with the hearing sound?
>
> When in the audio range, there is no correlation to what you hear when a signal
> is AC or DC. A triangle audio wave sounds exactly the same when it's either DC-
> or AC-coupled (respectively: above or below the zero axis, or centered around
> that axis).
> When the signal is sub-audio, and it is used as a modulation source, it makes a
> big difference. However, in the world of Serge, you can easily adjust that
> difference by shifting that low frequency up or down. Again, the Scaling Buffers
> come to mind...
>
> > I mean on the NTO, the sinus has a black ring which means it outputs between
> -2,5 and + 2,5 volts
>
> AC-coupled, yes.
>
> and triangle and saw have blue rings which indicates 0 - +5 volt.
>
> DC-coupled :-)
>
> Does this mean -2,5 - 0 of the sinus is DC which as soon as it goes higher then
> zero, it turns into AC? Or is this nonsense!
> > Can you please explain this!
>
> I understand where your confusion comes from. And Serge's paradigm of being able
> to shift signals at will doesn't make it easier.
> I'm not very good at explaining this, though. Perhaps you could look up a few
> things in Wikipedia ?
>
> > Thanks, yes now I understand what scaling in this context means and does! But
> I suspect that scaling on another funktion is more complex than that.
>
> It can be dauntingly complex, yes. See above about the Serge paradigm. But this
> is one of the strengths of a Serge system: it allows you to freely "play with
> signals", regardless if they're DC or AC. A Serge system doesn't really make a
> difference between audio and low frequencies. It's just... a signal, and it is
> left up to you as to what to do with those signals. This in sharp contrast with
> a Buchla system, where audio and CV are strictly separated.
>
> > Which panels does your Serge contain?
>
> Less than it matters. Or more than it matters. :)
>
> _g
>
>
> >
> > Cheers,
> >
> > Roel
>

>An attenuator. :-)
>More specifically, in this case, a bipolar attenuator.
>Or, since more recently, "attenuverter" has been doing the rounds ~ >a word
>coined by Matthias "Fonik", afaik (personally, I think it's an ugly >word).
>Serge (and other, more technically-inclined folks) call it a >"processor pot".

> I only now that our range of hearing lies between 500 hz and appr. 20 khz.

>Well, I sincerely hope you're going to see a doctor soon, if you >think that is
>your hearing range. :-)
>Those numbers differ from person to person, and rapidly decline once >you're past
>a certain age (appr. 25yo). A teenager with very good hearing can >discern
>audible sounds somewhere between 30Hz and 18kHz or thereabouts. Most >(familiar)
>sounds and music we hear on a daily basis sit in the 200Hz to 2kHz >range.

> I now understand that you can hear DC as well. I didn't know this under till

>What you hear is air compressed by a source (e.g. a speaker system). >This makes
>stuff-inside-your-ear vibrate, which is then translated by your >brain as
>"sound". It has nothing to do with AC or DC.

> Yesterday I found some explanation about coupling on the internet.
> It's states that DC is directly given, but with AC there's a capacitator in

> You say: "adjust that difference". What do you mean by that?

>BTW: please answer posts inline *under* the quotes, not above. It's >very
>confusing to read an answer to something which isn't said yet.

>What I said about "adjusting that difference", is that you can >easily shift a
>signal down or up (around the zero Volt axis). A Scaling Buffer can >do this.

> This is not easy. I look in Wikipedia, but it only touches on AC and DC and

>"AC coupling" and "DC coupling" aren't always mentioned in books >related to
>synthesizers, true. The reason why, is because mostly it doesn't >matter all that
>much.

>I think you're putting to much thought in this right now... Go on, >and make some
>music instead. All of this stuff will become much clearer at one >point in time.



--- In SergeModular@yahoogroups.com, "roelelec" <r.steverink@...> wrote:
>
> I see, it's the other way around. That's why the signs for positive and
negative open wide on both sides! So there's no attenuation to - and + (only at
0) and it's not amplification either.
> How do you call that then?

An attenuator. :-)
More specifically, in this case, a bipolar attenuator.
Or, since more recently, "attenuverter" has been doing the rounds ~ a word
coined by Matthias "Fonik", afaik (personally, I think it's an ugly word).
Serge (and other, more technically-inclined folks) call it a "processor pot".

> This is tricky!
> What is the range of HZ for DC and AC?

Whot !?
Erm, I think somewhere between 0.00000000000001Hz en 1,000,000,000,000,000 Hz...
The frequency range of an electronic device is only limited by the boundaries
dictated by the hardware used. The range of "natural sources" is defined by the
laws of physics.

> I don't dare to give an answer myself, since DC can overlap AC.

Whot!?
It's the same.

> I only now that our range of hearing lies between 500 hz and appr. 20 khz.

Well, I sincerely hope you're going to see a doctor soon, if you think that is
your hearing range. :-)
Those numbers differ from person to person, and rapidly decline once you're past
a certain age (appr. 25yo). A teenager with very good hearing can discern
audible sounds somewhere between 30Hz and 18kHz or thereabouts. Most (familiar)
sounds and music we hear on a daily basis sit in the 200Hz to 2kHz range.



> I now understand that you can hear DC as well. I didn't know this under till
now. Always thought it's a cv, so sub-audio only.

What you hear is air compressed by a source (e.g. a speaker system). This makes
stuff-inside-your-ear vibrate, which is then translated by your brain as
"sound". It has nothing to do with AC or DC.

> Yesterday I found some explanation about coupling on the internet.
> It's states that DC is directly given, but with AC there's a capacitator in
the way.
> You say: "adjust that difference". What do you mean by that?

BTW: please answer posts inline *under* the quotes, not above. It's very
confusing to read an answer to something which isn't said yet.

What I said about "adjusting that difference", is that you can easily shift a
signal down or up (around the zero Volt axis). A Scaling Buffer can do this.

> This is not easy. I look in Wikipedia, but it only touches on AC and DC and
such, but doesn't talk about the things I need to know. Beside that AC and DC
linked with synths it seams almost impossible to find on the internet! I'm going
to search for a good book on this subject.

"AC coupling" and "DC coupling" aren't always mentioned in books related to
synthesizers, true. The reason why, is because mostly it doesn't matter all that
much.

I think you're putting to much thought in this right now... Go on, and make some
music instead. All of this stuff will become much clearer at one point in time.

> I agree with you; it's definitely one of the strong points of the Serge. But
on the other hand it's important for the us, the makers to know what their
doing. I mean outputing a signal below 500 hz result in silence!

I really need to give you a doctor's address. Seriously. ;-)
You can check for yourself first: if you're going to a club where the DJ is
spinning some groovy tunes, and you see everyone around you dancing whilst you
stand still and wonder why they do so: you need to see a doctor... The "beat" of
modern dance music sits somewhere between 50Hz and 200Hz (the latter being
-very- fast). And it's quite audible, yes.

>As soon as you patch it into f.e. a cv in of a NTO, you hear the signal again!
> Which in Buchla system also means that you need different kabels.
> This way of patching can be very handy, but it also limites the freedom of
experimentation.

Don Buchla once decided to separate audio and CV signals because he wanted to
have a "very clean" audio path. Audio can be offset and 'disturbed' by
(low-frequency) DC signals. It's just a practical decision -- which can be
debated -- but Buchla users in general don't see this as a limitation...
Furthermore, there *are* ways to intermix both (on a Buchla).
OTOH, Serge and most other modular synth makers did not want to make this
separation.
Debating the merits and weaknesses of both is as useful as debating the pros and
cons of banana jacks vs. minijacks. It's mostly a matter of personal taste.

_g

--- In SergeModular@yahoogroups.com, BooleanYulian <a.b@...> wrote:
>
> Hi..
>
> As per my understanding of things following Rex's explanation, it is very important to differentiate AC and DC-coupled ins/outs (in SERGE speak) when the signal is used for modulation, but not so important when the signal is used for audio. This is mainly apparent when modulating the level of a VCA when used to control audio levels; if the said VCA's (say a UAP) level is set to unity gain (no attenuation and no gain; level in = level out) and you use an AC coupled LFO (SIN out from PCO) to modulate that level, the result would be a change in level alternating from less-than-unity-gain (aka attenuation) to more-than-unity-gain (aka gain or level boost) centred around the preset level (in this case, unity gain). If a DC coupled LFO (TRI or SAW out from the same PCO as above) is used, then the resulting change in level will alternate between the preset level (here, unity gain) and more-than-unity-gain. This is supposed to be not much of an issue when we look at AC or DC coupled audio signals. Probably a good way to check is to patch a DSG to cycle and dial it into the audio range, then do an A/B comparison between it's AC and DC coupled outputs.
>
> I was faced with a similar dilemma when buying the Matrix Mixer m-odule; had to choose between the AC or DC coupled version
>
> As far as Bakis' mention of new and/or upcoming m-odules; this is would be done with Rex's consent or by his request and I think he'd be pretty adamant that the product description be posted word for word as per his text.. and we all know how detail oriented and meticulous Rex is. That being said, if the given STS product sports AC and/or DC coupled jacks, it would make sense that it'd be mentioned.
>
> Hope this helps, I apologize if I've repeated anything that's already been said on the thread and I definitely welcome corrections :)
>
> cheers
> Yulian
>
> On 2010-09-09, at 4:50 AM, roelelec wrote:
>
> > But I think on the Serge it's even more important cause of the different approach, structure-wise Therepnin took. If it really didn't matter if a signal in a Serge is audio or cv, why would the Gold book go to great length to explain it all in detail. That's why it's so invaluable to the Serge musician. BTW when Bakis announced a new module, he mentioned if it was AC or DC coupled. He wouldn't do that it was only in the interest of theory goers.
>

On 9/10/2010 3:00 AM, roelelec wrote:

Hi Yulian,

Thanks for your welcome input!
Your example is very clear, I understand it perfectly. I will try this. To get a better picture and sound picture of AC and DC coupling.

Are different couplings of waveform outs of an oscillator uniquely Serge? Or is this common practize among other brands as well?

One question still begs for an answer: why is it then not important if in/out's are DC or AC coupled when they produce signals in the audio region? When we take your example of the VCA again. When we audio rate modulate that with an osc we get amplitude modulation at 20 hz or higher. Does this mean that amplitude modulation sounds practically the same with DC and AC coupled audio signals?
Let's try this too! Meaby were still in for a nice suprise.

Absolutely, when Rex mentions something, it's always significant.

And coming back to volt and hz. I now understand that volt and hz are part of two different worlds; you can't bring them together.
Hertz is correlated to sound, cause frequency is the number of cycles per second which is expressed in hertz. And within the range of 20 hz - appr. 18 khz we can hear this as sound.
But what about volt? I want to understand this musically. Say a signal raises another signal by +5 volt, the output of this modulation we can hear soundwise. So there must be a link between voltage and sound, like there is between hertz and sound!
Can someone explain this?

Cheers,

Roel