Several Questions Re. TurboFilter

[dmbaer]

I just read through the help documentation for the TurboFilter module ... whoa ... how interesting this one looks!

But I have a few questions.

First, the help says to study the presets, of which there are none at this time. I hope as things develop further we'll see some vintage emulations as part of this. Ideally, I'd love to see more or less the same filters on offer in IKM Syntronik, which are:
M-Type – a Moog ladder (a must-have, of course)
R-Type – a Roland classic based on the IR3109 IC chip
C-Type – a Curtis CEM3320 IC recreation (probably best known for its use in several Prophet synth models from Sequential Circuits)
O-Type – an Oberheim SEM state variable filter

They all have slopes appropriate to the model. Is this where TurboFilter is going?

Question 2: The doc. says:
In front of each module you can specify the number of occurrences ... for example 3lowpass is exactly the same thing as lowpass;lowpass;lowpass.
Is this like a macro? That is, does the "n module" simply expand into the number of occurrences separated by semi-colon, and the interpretation from that point is context dependent? Stated another way, the n module notation has no implication of serial vs parallel, correct?

Question3: The doc. says:
lp / lowpass (frequency = f; q = q; gain = c*20; analog = a) [feedback1, feedback2] lp6 / lowpass6 ... hp / highpass ... hp6 / ...
I have a feeling some ellipses are left out unintentionally. Specifically, do we mean there are a series of lp modules from lp thru lp6? Also, I assume the number after lp is the number of poles. Is the sequence lp, lp2, lp4, lp6, or is it lp, lp2, lp3, lp4, lp5, lp6? Or is it something else entirely? The doc. isn't too clear on this point.

[jmg8]

To the second question.
It works the same as MTurboReverb.
So if you specify the number it will stay as that. However if you use # as the number then the number of instances will follow the complexity parameter (although in MTurboFilter I do not think it is called complexity, rather something else)
Does that answer the question?

[DarkStar]

Q3: That looks like short-hand for:

The basic building blocks are:
lp (frequency = f; q = q; gain = c*20; analog = a) [feedback1, feedback2]
lowpass (frequency = f; q = q; gain = c*20; analog = a) [feedback1, feedback2]
lp6 (frequency = f; q = q; gain = c*20; analog = a) [feedback1, feedback2]
lowpass6 (frequency = f; q = q; gain = c*20; analog = a) [feedback1, feedback2]
hp (frequency = f; q = q; gain = c*20; analog = a) [feedback1, feedback2]
highpass (frequency = f; q = q; gain = c*20; analog = a) [feedback1, feedback2]

and so on for the others. Each one is separate

But, I do not understand the parameter syntax (e.g. frequency = f; ). I'm going to wait for some examples and revised Info.

[jmg8]

Q3.
There are only LP12 or LP6.
LP12 is just named LP for short.
We have to use multiple filters to make the slopes so 4LP will be the same as LP48.

[Tagirijus]

But, I do not understand the parameter syntax (e.g. frequency = f; ). I'm going to wait for some examples and revised Info.

If I understand this correct it just lets you define parameters yourself in th brackets, or use knobs for this. Default seems to be lp(f...), which means that the frequency knob will determine the frequency of this lowpass filter. You probably could build a static filter with lp(400) around 400 Hz. Am I correct here?

[jmg8]

Yes, that's right.
Using the "F" can attach values to the frequency parameter.

[dmbaer]

To the second question.
It works the same as MTurboReverb.
So if you specify the number it will stay as that. However if you use # as the number then the number of instances will follow the complexity parameter (although in MTurboFilter I do not think it is called complexity, rather something else)
Does that answer the question?

No, that was not my question - I saw the "#" business in the help and was already familiar with it from MTurboReverb. However, I found the answer after re-reading the help. The two examples of the Serial and Parallel helper routines (the S is omitted in the first example since that's the default) hold the key:

Example: [2lowpass;comb] = 2 lowpasses followed by the a comb, so the output = lp1->lp2->comb

Example: p[2lowpass;comb] = 2 lowpasses followed by the a comb, each receiving the dry audio signal, so the output = lp1+lp2+comb

This says that the multiple module notation has no implication of serial vs parallel. That's what I was trying to figure out.

[dmbaer]

Q3.
There are only LP12 or LP6.
LP12 is just named LP for short.
We have to use multiple filters to make the slopes so 4LP will be the same as LP48.

Ah, very important thing to know. That is not mentioned anywhere in the help documentation that I can find. That is, there is no mention of LP12 or Lowpass12 being the equivalence of LP. Nor is there an explanation as to what LP6 means either, is there?

[Hanz Meyzer]

I find that turbofilter currently lacks a bit of good UX. Like mentioned in the other thread, the "code" at least could support auto-indented lines.

Then there could be some kind of visual display actually showing the current result, like using a subtraction of the result from a pink noise or so, only updated once a second. At least anything visually.

I agree, designing really other filter colors would be pretty interesting, so maybe it should go even one level deeper. Just providing those standard melda filters may be not enough for this purpose.

Then there is the topic saturation, I think its quite important for "analog" like filter sound. Meq or so already provides those harmonics option, so why is it not in turbofilter?

I actually think, if there is any topic at all where Melda could improve, then it's saturation and filters.

[DarkStar]

You need to vote, then:
viewtopic.php?f=138&t=527655

[drewfx]

No, that was not my question - I saw the "#" business in the help and was already familiar with it from MTurboReverb. However, I found the answer after re-reading the help. The two examples of the Serial and Parallel helper routines (the S is omitted in the first example since that's the default) hold the key:

Example: [2lowpass;comb] = 2 lowpasses followed by the a comb, so the output = lp1->lp2->comb

Example: p[2lowpass;comb] = 2 lowpasses followed by the a comb, each receiving the dry audio signal, so the output = lp1+lp2+comb

This says that the multiple module notation has no implication of serial vs parallel. That's what I was trying to figure out.

Have you tested that? It doesn't make any sense to have two identical filters with identical settings in parallel.

[dmbaer]

Have you tested that? It doesn't make any sense to have two identical filters with identical settings in parallel.

I assume the example was just to illustrate the notation - a well-chosen practical example might have been better. But to answer your question, no I did not test it. I'm really waiting for some presets to study before I do anything else with this module, and even then, I mainly want to be a user, not a filter creator.

[drewfx]

The point is if p[2lp] puts the 2 filters in parallel then, unless I'm missing something, it's exactly the same as 1lp plus a level boost but uses a ton more CPU. Maybe I'll take a look at it to confirm, but it makes much more sense if it was written ambiguously and it really means the 2 lp's in series and together that's in parallel with the comb.

[jmg8]

It means 2LP (in serial) or in other words LP24.
This is in parallel with the comb.

To get it the other way it would be separated with the semi colon.
P[LP;LP;COMB]

Or in other words the semi colon will create a new parallel lane. So:
P[2LP;COMB] has 2 lanes, equivalent of LP24
P[LP;LP;COMB] has 3 lanes, equivalent of 2 LP12

[MeldaProduction]

A little info - LP6 is a 6db/oct low-pass, while LP12 is a 12db/oct low-pass. It's done this way, because filters are traditionally implemented using 2-order sections, which equals 12db/oct, so 6db/oct is a bit "specific".