Cytomic "The Drop" Resonant Filter

[FrankT]

I've been hard at work in the Cytomic Labs, and have something very cool to report, a 2 pole high pass transistor core Sallen Key filter, which put in easier to understand terms is an MS20 rev1 high pass filter that is 2 poles instead of the original circuit which is only one pole. I'm very happy with the results.

The reason Korg only had a one pole high pass, as far as I can tell, was to lower costs. They just re-used the same Korg35 chip for both the two pole Sallen Key low pass and the high pass, but that meant the high pass could only be one pole because of the fixed circuit topology of the chip. I've come up with a new design which uses pnp instead of npn transistors, and is a full 2 pole Sallen Key structure with the same resonance drive as the 2 pole low pass. As far as I know this design doesn't exist in any form anywhere else.

Here is an audio demo to show it off, all audio is processing without oversampling at a sample rate of 44.1 kHz, and The Drop is the only thing on the master bus:

https://cytomic.com/files/thedrop-one-sided-tranny.mp3

This and previous audio examples can be found here:

https://cytomic.com/cytomic-announces-d ... ter-plugin

Much looking forward to this

[themossinator]

I've been hard at work in the Cytomic Labs, and have something very cool to report, a 2 pole high pass transistor core Sallen Key filter, which put in easier to understand terms is an MS20 rev1 high pass filter that is 2 poles instead of the original circuit which is only one pole. I'm very happy with the results.

The reason Korg only had a one pole high pass, as far as I can tell, was to lower costs. They just re-used the same Korg35 chip for both the two pole Sallen Key low pass and the high pass, but that meant the high pass could only be one pole because of the fixed circuit topology of the chip. I've come up with a new design which uses pnp instead of npn transistors, and is a full 2 pole Sallen Key structure with the same resonance drive as the 2 pole low pass. As far as I know this design doesn't exist in any form anywhere else.

Here is an audio demo to show it off, all audio is processing without oversampling at a sample rate of 44.1 kHz, and The Drop is the only thing on the master bus:

https://cytomic.com/files/thedrop-one-sided-tranny.mp3

This and previous audio examples can be found here:

https://cytomic.com/cytomic-announces-d ... ter-plugin

beautiful sound!

[andy-cytomic]

Could I please get some help naming a couple of things in The Drop? Does anyone have any ideas or opinions on the following names? If you have any suggestions please keep in mind that ideally each name needs to be below 12 characters in total length.

1) A button that limits keeps the resonance knob below 98% so that self oscillation doesn't happen. "Res Limit" is the only idea I currently have for it, but that sounds like there may be some dynamics processing in the resonance path which there is not, it literally just makes res = min (98%, res knob)

2) Filter circuit names. I don't want to trade off the names of famous circuits too much, but I do want people to not be confused with names they have no idea which circuit it actually is.

The actual filter circuits roughly being emulated are:
Moog Prodigy, Jupiter 8, MS20 rev1, MS20 rev2, SEM 1a

The confusing and long but technically correct names are:
Ladder, Cascade, Sallen Key 1, Sallen Key 2, State Variable

Another alternative is to use three letter acronyms, do people think these are informative and still tasteful enough?
MGF, JPF, MSF 1, MSF 2, SMF

[softska]

Could I please get some help naming a couple of things in The Drop? Does anyone have any ideas or opinions on the following names? If you have any suggestions please keep in mind that ideally each name needs to be below 12 characters in total length.

1) A button that limits keeps the resonance knob below 98% so that self oscillation doesn't happen. "Res Limit" is the only idea I currently have for it, but that sounds like there may be some dynamics processing in the resonance path which there is not, it literally just makes res = min (98%, res knob)

2) Filter circuit names. I don't want to trade off the names of famous circuits too much, but I do want people to not be confused with names they have no idea which circuit it actually is.

The actual filter circuits roughly being emulated are:
Moog Prodigy, Jupiter 8, MS20 rev1, MS20 rev2, SEM 1a

The confusing and long but technically correct names are:
Ladder, Cascade, Sallen Key 1, Sallen Key 2, State Variable

Another alternative is to use three letter acronyms, do people think these are informative and still tasteful enough?
MGF, JPF, MSF 1, MSF 2, SMF

1. Maybe just "Limit Res" instead?
2. Correct name please, least confusing w something you can actually look up at the end of the day (IMO anyhow)

[ariston]

How about "res cap" or "safety"?

I would keep the real filter names, I think we've all gotten used to them by now. And if you don't know them, it's much easier to do some research if you have the names.

[filter303]

1:

No self-osc

2:

I personally like
"Ladder, Cascade, Sallen Key 1, Sallen Key 2, State Variable "
I don't see nothing wrong with it to be honest.
The last option was the worst IMO. I hate three letter acronyms except LFO, VCA, VCF, OSC, MOD etc

[Viktor [TUC]]

Preventing it to go into self oscillation is a very useful feature, I must say.
I like softska's suggestion "Limit Res".
Also possible maybe:
"No Self-Osc" (just saw that filter303 beat me to it)
"Limit Range"

If I may say so, please don't use three letter abbreviations, I find them the most confusing in the "heat of the battle", since they just look too similar from a distance. I also prefer the technically correct names. Also, I think people like knowing terms like that, something that enables them to be smartasses when meeting other geeks. Really. And if you're a little further away from the screen you can tell better what to select since it's easier to tell the longer names apart. Or abandon words and use little symbols instead, something that's visually instantly recognizable.

[MFXxx]

Could I please get some help naming a couple of things in The Drop? Does anyone have any ideas or opinions on the following names? If you have any suggestions please keep in mind that ideally each name needs to be below 12 characters in total length.

1) A button that limits keeps the resonance knob below 98% so that self oscillation doesn't happen. "Res Limit" is the only idea I currently have for it, but that sounds like there may be some dynamics processing in the resonance path which there is not, it literally just makes res = min (98%, res knob)

Res Terminus

2) Filter circuit names. I don't want to trade off the names of famous circuits too much, but I do want people to not be confused with names they have no idea which circuit it actually is.

The actual filter circuits roughly being emulated are:
Moog Prodigy, Jupiter 8, MS20 rev1, MS20 rev2, SEM 1a

Twisted Ant, Big Nut 8, My Sweet 1, My Sweet 2, St.Ego Maniac

Stuck for thoughts this mornig

[Liero]

I personally _strongly_ dislike the three letter filter names in Alchemy, so I definitely prefer something that's actually a word or similar. 2c.

[michu]

1:

No self-osc

i'd just invert it, as in i'd like a button called "self-osc" that has to be depressed to remove the resonance limit.

2:

I personally like
"Ladder, Cascade, Sallen Key 1, Sallen Key 2, State Variable "

+1 to that

[Bathrobe]

1. How about '<98%self-osc' or 'non-self-osc'

2. Fxpansion uses this for Geist and Tremor and i got used to like it:

Three Oh! Three -> Roland TB303
Hoover -> Roland Juno 106
Grandad -> Moog Minimoog Ladder
Little Fatty -> Korg MS20
Child Genius -> Moog Prodigy
Japan -> Roland SH101

[filter303]

"i'd just invert it, as in i'd like a button called "self-osc" that has to be depressed to remove the resonance limit."

Excellent idea.
This is the way it should be done...

[michu]

quick additional thoughts: i'd gladly see a feature of "res boost +12dB", which i'm sure would be usable, at least with Sallen Key algos. it could be placed on "res limit" control as one of the states...
i think poetic naming of algorithms, in the vein of "treadplate" for Mesa DR emulations in eg. Line6 products would go well in a Cytomic plugin. at least i cannot make it fit mentally, in my head Andy's work is all about technical accuracy
(poetically, the res control could have 3 states: dull, normal, insane )

[risome]

Res Limit
The filter acronyms sound reasonable

[andy-cytomic]

How about "res cap" or "safety"?

I would keep the real filter names, I think we've all gotten used to them by now. And if you don't know them, it's much easier to do some research if you have the names.

Cap and Safe are both very good, thanks for the suggestions, thanks!