From Brian Willoughby Sent Sun, Sep 29th 2019, 22:21
From Brian Willoughby Sent Sun, Sep 29th 2019, 22:21
The original question was, =E2=80=9CWhy isn=E2=80=99t everything = 1V/oct?=E2=80=9D The answer is, =E2=80=9CBecause everything is CV, and CV includes 1V/oct = as well as anything else you might need.=E2=80=9D CV is generic, and Quincas did a great job of summarizing many = variations. 1V/oct is just a very specific subset of CV, and even 1V/oct can vary, = so it=E2=80=99s not necessarily compatible across all synths. Some VCO = modules will accept negative 1V/oct, and those are =E2=80=9Cthrough-zero=E2= =80=9D VCO modules. Some VCO modules are limited to 5V, so they can only = handle 5 octaves of range with a single control. Other VCO modules can = accept 10V, so they might be able to handle 10 octaves of range, but the = accuracy might suffer at the extreme ranges unless it=E2=80=99s a very = expensive VCO. All of these synths that apply a 1V/oct source to a VCA or ADSR are = scaling the CV to a usable range, and thus it ceases to be 1V/oct after = it has been scaled (see Quincas=E2=80=99 comments about math and other = CV processors). The Sequential Circuits Pro-One has a Keyboard Amount knob in the VCF = section, and it is incredibly difficult to tune that to 1V/octave. On my = Pro-One, the calibrated setting falls at about the 70% point on that = knob. Below or above that position, it=E2=80=99s no longer 1V/octave. I = usually do not let guests touch the Keyboard Amount knob! ;-) The Prophet 5 has a switch to add Keyboard to the VCF, and it=E2=80=99s = surely 1V/octave. Some famous synth that I=E2=80=99ve used many times, but do not own (so = I forgot which one it is), has a 3-way switch for VCF keyboard tracking, = with Off, Half, and Full as options. When set to =E2=80=9CHalf=E2=80=9D = it works out to be 500mV/octave. In the last three examples, even the VCF, which can actually interpret = octaves, does not always use 1V/octave when applying keyboard CV to the = Cutoff. As soon as you apply 1V/octave to a VCA or ADSR, you will surely = need to scale the CV to something other than the 1V/octave starting = point. Once you scale, it doesn=E2=80=99t really matter whether the CV = started out as 1V/octave or not (unless you have a digital synth where = the math is precise and repeatable across varying temperatures). Brian Willoughby On Sep 29, 2019, at 10:36 AM, Jason Proctor <xxxxx@xxxxxxx.xxx> wrote: > Well of course, but that's true of any voltage. The point is that the > level input has no way of interpreting a 1v/oct protocol in the way > that an exponential pitch input does. >=20 > On Sun, Sep 29, 2019 at 10:31 AM DJ Maytag <xxxxxxxx@xxxxxxxx.xxx> = wrote: >>=20 >> You could route 1V/oct to the Dual ADSR=E2=80=99s level controls. The = higher the pitch, the stronger the effect of the envelope. >>=20 >> ________________________________ >> From: Jason Proctor <xxxxx@xxxxxxx.xxx> >>=20 >> I don't see any mention of 1v/oct in the Dual ADSR docs. The level >> input is a linear input to the output VCA. Some looping envelopes = have >> 1v/oct inputs to use them as VCOs, but although the Dual ADSR does >> loop, it doesn't have any CV control of envelope timings. >>=20 >> Perhaps OP can give us some indication of what he might expect from >> 1v/oct on inputs other than exponential VCO/VCF etc? >>=20 >> On Sun, Sep 29, 2019 at 8:34 AM DJ Maytag <xxxxxxxx@xxxxxxxx.xxx> = wrote: >>>=20 >>> I=E2=80=99m pretty sure that=E2=80=99s 1V/oct modulating ENV amount = and/or timing, as I mentioned. Now that I think of it, I think there=E2=80= =99s an input to Intellijel=E2=80=99s Dual ADSR that could be used to = scale the ADSR intensity by sending it 1V/oct. >>>=20 >>> ________________________________ >>> From: John Emond <xxx.xxx@xxxxxx.xxx> >>> Sent: Sunday, September 29, 2019 10:21 AM >>> To: Quincas Moreira >>> Cc: DJ Maytag; Tristan; Dustin Sedlacek; Analog Heaven >>> Subject: Re: [AH] Why isnt everything 1 v/o ? >>>=20 >>> What about Keyfollow on the Jupiter 8 envelopes? >>>=20 >>> Cheers, >>>=20 >>> John >>>=20 >>> On Sep 29, 2019, at 9:17 AM, Quincas Moreira <xxxxxxx@xxxxx.xxx> = wrote: >>>=20 >>> 1v/oct is a standard for tuning pitches. That makes sense in = exponential inputs of VCOs and VCFs, everything else is simply measured = in voltages, and sometimes the response curve, like log, lin or expo. In = my experience most cv outputs in eurorack 10vpp, being 0 to 10v if = positiv only, and -5 to +5 if bipolar, though there are plenty that = output double that (-10 to 10). Inputs often can be set to respond = linearly or log/expo and often go through attenuverters. And a system is = never complete without utilities for conditioning voltages to what you = need. I have quite a few voltage processors myself which I use for = attenuation, inversion, offset, amplification, mixing etc... >>>=20 >>> Sent from my iPad >>>=20 >>> On Sep 29, 2019, at 12:09 AM, DJ Maytag <xxxxxxxx@xxxxxxxx.xxx> = wrote: >>>=20 >>> The only use I could see for a 1V/oct input on a VCA is if you want = some intentional bleed/droning as you play higher up on the keyboard. >>>=20 >>> The second use wouldn=E2=80=99t be on the VCA itself, but on an = envelope/ADSR controlling a VCA. The higher the pitch, the shorter the = overall envelope timing. >>>=20 >>> ________________________________ >>> From: Tristan <xx@xxxxxxxxx.xxx.xx> >>>=20 >>> I presume by 1 v/o you mean 1 volt per octave. While this makes = sense for oscillator or filter cutoff >>> frequency it does not necessarily make sense for a VCA or other = module without a common unit of >>> calibration. A VCA could have a logarithmic, linear or other = non-linear control law for the gain. To calibrate >>> a logarithmic control to 1V/6dB gives a gain range of 60dB over the = typical 0-10V control source range >>> which is not adequate to fully cut off the sound. To allow for this = a VCA will often have a voltage mixer for >>> the input control voltages to allow them to be scaled to the desired = control depth. >>>=20 >>> /Tristan >>>=20 >>> On Sun, Sep 29th, 2019 at 10:29 AM, Dustin Sedlacek = <xxxxxx.xxxxxxxx@xxxxx.xxx> wrote: >>>> Every time I talk to eurorack guys about 1 v/o VCA or wavefolder = they don't >>>> seem to understand why anyone would want that. >>>>=20 >>>> Isnt control the thing that everyone wants? >>>>=20 >>>> What about 1v/o inputs are not desirable? Is their something I am = not >>>> understanding? >>>>=20 >>>=20 >=20