Fore some reason that I cannot figure out, I keep going back to Sugar Bytes WOW1 for simple filter sweeps. Even if I try to match the settings as close as possible to others (for example KHS filter) I got the feeling that it sounds better, but I ask myself if it is just placebo?

So does somebody here know if there really can be such differences in a simple filter? I have no understanding of code programming or the physics behind stuff like this, so I hope somebody can help me. WOW1 also sounds way better to me than WOW2.

 

filter are among the tools that can modify the sound in a very deep way, and unless the filter (plugin or hardware) is "meant to be transparent" it's impossible to find 2 filters having the same results (the more in the analog world, but thats another game...)

For example, FabFilter PRO Q has filters claiming to be very very transparent, even in situation of hipass-lowpass, same the Softube WEISS EQ

Other filters instead are famous for adding a certain effect on the phase/sound. Random example: the Little Lab VOG, which is "just an hipass with resonance" but has something original/weird in the phase results

I dont know the WOW series, if they "claim to be transparent" then they should null with PRO Q3 (which is some kind of a standard in this situation), if they dont null with PRO Q3 it means that have "it's own sound and phase distortion"

So it's very likely that you feel some subtle differences

Try also the free one from Plugin Alliance, it'a a filter with only low pass and hipass, very good sound.

 

In this video DashGlitch shows how to rebuild a specific SEM filter by Arturia.
He's using PluginDoctor and SnapHeap to do it, but it's probably achievable with other tools as well. Basically he shows you how you could exactly recreate that WOW1 filter (if you got the right tools at hand).

The video is very long and setting the starting point isn't possible here on AS. That filter part starts around 2:39:00

I've cut the video down to only 11 minutes with that filter recreation part, can be found here >>
https://gofile.io/d/1qhITX

 

Without knowing more specifics, it's hard to tell. Because you say 'filter sweeps' I'm gonna throw a couple guesses around as to what may be going wrong without the developer noticing:

When you move a filter, no matter by how many Hz, you need to slow down the filter movement from A to B a lot.

Say you flip-flop the filter position between 500hz and 1000hz. The GUI might say the movement is instant, but a well programmed filter will execute that move over a couple thousand samples rather than instantly.

If you don't, then the filter will sound 'bad' if you flip-flop a small amount and crackle and zip if you flip-flop a huge distance.

So smoothing filter movement is really important when modulating/sweeping, and I'm guessing that Sugar Bytes took care to implement this particularly well, because most of their plugins are about creative modulation.

But programmers might not care to smooth out filter movement in an EQ plugin.

Additionally:

Early digital filter designs tended to become unstable at extreme Hz or break down when modulated too fast - which made a lot of early digital synths suck compared to their analog counterparts. Modern IIR filter designs don't suffer from these problems, but you need to smooth out filter movement all the same.

Some developers may be using those really old filters still for one reason or another.

Some filters also saturate as part of their design.

 

Make a double-blind test and you'll find out.

The thing is, a dev can code an analogue emu design in every way he wants. Slope, Q, added harmonics and level can all change just by changing the cutoff. So yes, if you match two filters at a specific freq, they can differ at another one.
I'm often using a small analogue emu EQ with a fixed high shelf freq because it turns into a cut by lowering the shelf's gain and I like this behavior. Ok, I can reproduce it by 'chaning' two bands in Kirchhoff but a single gain is easier to handle.

 

Sugar Bytes WOW is a (very) characteful filter. WOW2 has, in fact, seven distortion modes on top of analog-modeled filters. And then it's a talkbox, with all the ensuing modulation.
Some filters are mathematically precise and don't add any nonlinearities. Some are analog-modeled, and saturate the sound a bit. Some are, well, this. Then there are of course poorly made filters of all kinds that mess up the sound in all kinds of ways, from aliasing to just shitty distortion to phase shift so bad it becomes audible on transients.

 

Last edited: Nov 7, 2023

Thank you guys very much. That's why i like this smaller forum. Only very good and interesting responses. No BS to waste my time. Especially the response from xorome is very interesting.

I found out I like WOW1 more because it seems to add harmonics, even with Overdrive at 0! Which I didn't know. Sadly, its only VST2 and will be abandoned with time....