What qualities can make a filter sound good?

[BlitBit]

What objective qualities can make a filter sound good? What qualities can make it sound bad? Is it the shape of the frequency response? Is it changes to the shape when the filter is swept (and I don't just mean that the cutoff moves)?

This question also came up in another thread. However, I have often wondered about this myself so I decided to dedicate a new thread to it.

[chk071]

Good question.

I think the Minimoog filter is great. I think the Virus filter is great. Totally different filters, totally different resonance behavior.

As to how the character or quality of a filter can be measured: I think there are lots of Youtubers, which all seem to do the same thing: Sweep the filter with no resonance, sweep the filter with 50% resonance, with 75%, and with full resonance. Dial in some short filter decay time, and see how the filter fares with some plucky sounds then, without, or with resonance. Of course that won't answer all the questions about it, but, it gives a good indication (IMO) regarding a filter's character or quality.

Again, though, it's also a highly subjective topic. If you only like analog filters, then no digital filter will do it for me, unless it's specifically analog modelled as well, with ZDF and what not.

[starflakeprj]

And I can't hear at all if a filter is good or bad, or is it totally subjective?

Anyway, I like the filter in LinPlug's Spectral, which you can draw yourself

[chk071]

And I can't hear at all if a filter is good or bad, or is it totally subjective?

I guess it's more of a common denominator, than something tangible.

If 90% of users consider a Moog ladder filter to be good sounding, then... it is good sounding.

[starflakeprj]

And I can't hear at all if a filter is good or bad, or is it totally subjective?

I guess it's more of a common denominator, than something tangible.

If 90% of users consider a Moog ladder filter to be good sounding, then... it is good sounding.

Well, I'm sure many users of the 90% who consider the Moog ladder filter to be good sounding probably say so because that is something you just should think.

[chk071]

I doubt the Minimoog would be such a classic, with a dozen emulation, if it was generally considered a bad sounding synth, or because of blind followership though.

On the other hand, I wouldn't rule out what you said in a few cases as well though. It's also the case with Sylenth1, which gets a bit too much hype IMO. FWIW, I also think the Minimoog is absolutely ace though, and isn't topped by anything else out there.

[zerocrossing]

The qualities that make a filter good are oompf, smudge, velvetosity, phattness and screamo. You must have at least two of those qualities.

[ghettosynth]

The wrong kinds of distortion in the wrong places make it sound bad. The right kinds of distortion in the right places make it sound great.

[Teksonik]

What objective qualities can make a filter sound good? What qualities can make it sound bad? Is it the shape of the frequency response? Is it changes to the shape when the filter is swept (and I don't just mean that the cutoff moves)?
This question also came up in another thread. However, I have often wondered about this myself so I decided to dedicate a new thread to it.

The problem is you won't get a precise answer. "Good sounding filter" is just as subjective as good sounding synth as we all make different music and we all prefer different sounds to make that music.

Example, some people love the sound of the Moog Filter while some hate its sound.

I've seen people posting examples of what a "good" filter sounds like and the example sounds like someone standing on a cat's tail. They think it sounds good, I think it sound horrible so we're right back to square one in search for a definition of good.

I think it's just fashionable for people to complain about filters these days without even understanding what it is they're complaining about.

In the Vital thread someone asked for "better" filters for it and I'm pretty sure they won't be able to convey in a convincing manner what it is those filters are lacking.
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The wrong kinds of distortion in the wrong places make it sound bad. The right kinds of distortion in the right places make it sound great.

Define right and wrong distortion and right and wrong place in precise non-subjective terms. I rarely use Filter distortion so that that definition wouldn't matter much to me anyway and so on.

I only asked the guy who requested "better" filters in Vital to define better since failing to do so doesn't help Matt at all. I find the filters in Vital to be just fine so again it's all too subjective.

Anyway this thread will just end up in a circular argument over personal preferences without ever arriving at a widely accepted definition of "good sounding filter" so I'm out. But please do carry on.....

[Tj Shredder]

If 90% of users consider a Moog ladder filter to be good sounding, then... it is good sounding.

But if BONES hates the moog filter and thinks its bad? In the end its a matter of taste. I had this issue with the CA 2600 not ringing when set to self oscillation, but cherrydan corrected that behavior and now it sounds better than the original...; - )

[FapFilter]

The qualities that make a filter good are oompf, smudge, velvetosity, phattness and screamo. You must have at least two of those qualities.

pretty spot on scientific dissection!
Would add: familiar sounding to this list aswell

[ghettosynth]

The wrong kinds of distortion in the wrong places make it sound bad. The right kinds of distortion in the right places make it sound great.

Define right and wrong distortion and right and wrong place in precise non-subjective terms. I rarely use Filter distortion so that that definition wouldn't matter much to me anyway and so on.

Generally you're not going to hear that kind of distortion as obvious distortion. It's not something that you use as such, it's about the non-linearities built into a filter design. So called "good filters," talking about digital filters here, model these well and we get the good kinds of distortion in the right places. It's also possible to get unwanted distortion that doesn't sound good, and this contributes to the perception that a filter is bad. It's not a simple subject and there's no value to talking about it here because, in general, you can't be certain of these details about any closed source product. Some vendors are reasonably open, e.g., Uhe, others shroud their tech in more marketing-speak, e.g., Artuira, Roland.

Practically speaking, the qualities of a good digital filter is that it was developed by someone who understands some of the technical details of filter design. But also, that they're willing to implement the methods that make a filter sound good. These methods often lead to higher CPU consumption, hence, as a first, and not always correct, approximation, one can say that good filters are those that are found in high CPU synths from knowledgeable vendors.

However, a vendor may choose to limit these implementations because of the belief that high CPU usage means a smaller market. So you also need commitment to sound despite market perceptions.

So, there you go: Good filters are found in synths that have higher CPU usage, were developed by knowledgeable vendors, and those vendors are committed to high quality sound despite market perceptions of high CPU usage.

[biscuitdough]

Some people don't like the workflow step of compensating for a ladder filter's loss of gain when resonance is increased. I think that's the main reason for ladder filter hate, rather than the sound you get once that's sorted.

But yeah it's all subjective. Some people love the D50, Kawai K4 and other primitive digital filters.

[SoulState]

In the Vital thread someone asked for "better" filters for it and I'm pretty sure they won't be able to convey in a convincing manner what it is those filters are lacking.

I already answered that i think good or bad filter.

The main feature of good filter is the sound that INSPIRES you to make some music. Super-clinical sound can't be inspiring (for me). But it very good for filtering some radiowave signals for example. Are you making music as an piece of art or piece of engineering? You should decide first.

If you want some mathematical terms about "good sounding" filter, in first i want to ask you to describe in same mathematical terms about what equations exacltly makes good and bad music? Good and bad picture? Story? Movie? Please describe some equations, so i can code it is some c++ code.

In the area of SOUND is all the same. Sound in NOT just pure math, it's ART in very first domain. If you can't hear good or bad sound of anything, then you just don't have taste for that, that's all. For example i totally ignorant about any sports, someone totally ignorant about sound. You shoud hear it and feel it. Have taste for it.

If you want to dig deeper in that theme you should find some psychoaccoustic research, i think. But it covers theme only partly, like "even harmonics sounds pleasing and odd harmonics is not", and blah blah balh.

In the filter domain "rich" sound is mostly nonlinearities, in very complex way. Pleasing sounding non-linearities. Without aliasing. Sharp, clean sound at same time, not muddy. Etc, etc.
The main problem that "Pleasing" is highly subjective therm. You need massive hearing experience to form you own taste in "pleasing or not" (for you) sound.

[MitchK1989]

For me a lot of it is down to having an input gain control and then getting a wide variety of pleasing timbres based on that input gain rather than just being a naive digital filter that doesn't respond to input gain at all (or worse, a filter that does respond to input gain but with no easy way to manage that level)