One more round the ring!
Quote:
Originally Posted by
EvilDragon
β‘οΈ
It's a matter of feedback gain. Any 12 dB filter can self-oscillate with enough feedback gain for the resonance. You don't need 4 poles to do that.
Actually no, the 12 db has to have the right phase shifts and gain and topology, gain alone just saturates not oscillates with a nice sine. The key here is "nice sine". E.g DSI 2pole mode of the VCF, not possible to increase gain and 2 poles is disconnected of the 4 available.
Quote:
Originally Posted by
RunnyKine
β‘οΈ
It sounds like you're mixing up Multi-Mode (LP *and* HP/BP/etc) and State Variable (a subset of Multi-Mode that not only has multiple modes but you can sweep between them). While I guess one could argue that a Multi-Mode one is literally State Variable, too, that's definitely not the common usage as I understand it.
There are lots of Single Mode filters, some Multi-Mode filters, and a few State Variable Multi-Mode filters, and even more rare is something like the Belgrad which is a Dual Peak, State Variable, Multi-Mode filter. Right?
When someone says or writes an SVF there is an implied [Multi-Mode] between the V and the F... a State Variable [Multi-Mode] Filter...
e.g OSCar is dual corner peak with peak separation, so called Battman filter who in reality is just two 12dB SVF in series, in Battman mode first is HP second LP.

.... Multimode just means you have multiple filter modes available, like LP, BP. HP etc. Whether the manufacturer gives you access or not is a different matter. .....CS15 to CS80 some enables corner peaking, some enables serializing and paralleling , some not.
Quote:
Originally Posted by
Deleted 2c2ba78
β‘οΈ
On the One there is no "blend knob" for the SVF llike you have on the SEM, for example, but you can do the same thing with the SPACING parameter which moves the two cutoff thresholds within the current configuration, which is a mod destination and makes it able to sweep all modes in a variety of ways - it's like a blend knob on steroids. I think.

The spacing is nothing more then Cf going in opposite direction by one knob. The word state variable have nothing to do with blendknob/mode sweep as in SEM its just a pot level balancing the LP and HP outputs.
Quote:
Originally Posted by
Deleted 2c2ba78
β‘οΈ
The One really has 3 filters, 2 in the SVF and 1 Ladder. According to the manual, the 2 filter elements in the SVF are identical and from the manual: "their arrangement and interaction is determined by the choice of NOTCH, Bandpass (BP), High Pass (HP), or Low Pass (LP) Modes on the Front Panel, and by other parameters located in the Filter MORE page."
With a software update Moog could easily give separate access to Q and Cf on both SVF from the LCD as long there is separate CV's internally. Let them know you want it, MoogOne owners deserves it on a 8000USD synth with 1.25usd rotary switches (Paul Shreiber note) and noisy fans and outputs and non oscillating SVF's!
Quote:
Originally Posted by
psionic11
β‘οΈ
The One's ladder filter self-oscillates in 2 pole mode easily enough. In fact, all 4 modes self-oscillate.
Thats because the resonance circuitry is always in 4pole mode, had it been in 2 pole you would not get self oscillation. So what you have is a 4pole VCF with 4 pole resonance whos 2 pole LPF signal if chosen on output.
Tricky isnt it!...
Quote:
Originally Posted by
jmcecil
β‘οΈ
hehe .. yeah. I get that there are some functions like the spacing. But you have that same spacing function on the Voyager in HP/LP mode. Is it SVF? I think so. Is it continuously state variable between BP & Notch? No. I just think its a mishmash of terminology.
V-ger is 2 Bladder's and sorta fake HP i recall i.e Q not constant when Cf varies. I dont remember but it has been debated on various forums in the past.
Disclamier: noone here knows how MoogOne looks internally and there are many ways to design and structure a VCF.