Fixed Filter Banks - Long-term use, same-y results?

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by Sinamsis » Sat May 09, 2020 7:33 pm

DonaldCrunk wrote:
Sat May 09, 2020 5:32 pm
I'm also considering 'the right' fixed filter bank for me, so this modern thread is interesting.

I've got a rxmx + fxdf combo, and can't recommend it enough. Not a lot of bands, and as mentioned above, it likes to do 'its thing'. Fantastic sound though! The fxdf sounds really great.

The Verbos Bark and Fumana style of west coast "fixed filter" are the most attractive to me at the moment, providing envelope following and a variety of other functions, but at greatest cost. From e-research and a brief play, Bark seems a bit unique and 'character-ful', while Fumana is the overall king of functionality. My heart says Bark but brain says Fumana. My wallet says 'keep on lookin''.

Next in line, then, is the various takes on the Serge Resonant EQ - different choice in frequency bands, and no envelope following or other features, but much less expensive. The Random*Source version is very interesting, but I'm put off by the dramatically lower input amplitude of Euro Serge and the attenuation required to correctly interface with standard 10V pp eurorack modules (even if it is provided on the module). Having to level shift within my case is a pet peeve. There are a Mk 1 and Mk 2 Serge Res EQ filters available in DIY land as well. Also Elby, as adaris mentioned. Maybe those operate correctly at euro levels? Love the idea of feedback patching, and pinging this module with clock / trigger sources.

The third type in my mind is the traditional 'Moog' inductor based type, and I'm least familiar with these offerings. Really eager to hear one of these types in person, and see what happens when patched more creatively than a traditional sound sculpting 'east coast' context. Curious about the sound of inductors!

I dunno man, the Fumana isn’t just a module with a great set of features. It sounds great to me. I was between the Bark Filter and Fumana and have no regrets. Maybe I didn’t listen closely enough, but I didn’t find in my YouTube adventures that the Bark Filter sounded significantly better, and I certainly have no complaints about the Fumana lacking character or sounding sterile.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by blaythe.steuer » Sat May 09, 2020 8:45 pm

Another option if you just want the sound design and sculpting aspects and less so individual outs and modulation there is the Antumba Bank. it is 8hp and way cheaper as well. It is a clone of the moog 914 so it has a lot of bands, HP/LP, and output options.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by wuff_miggler » Sat May 09, 2020 8:54 pm

im looking forward to adding the doepfer Fixed Filter bank to my system at some point - it has 15 bands.
and there's an option to get a breakout box to get individual outputs on a separate panel either pre or post volume.

:D with a trautonium filter, a triple resonance filter and that - that's a shit tonne of sculpting possibilities!

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by galanter2 » Sun May 10, 2020 5:12 pm

Random note - the Behringer Moog 914 "clone" will NOT be using the same inductor based filters as the original. (It's distinctly NOT a clone.) It will, however, be very inexpensive. I'll be interested to hear one.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by Hovercraft » Sun May 10, 2020 10:23 pm

I don’t believe there are any eurorack FFB’s that use actual wound inductors like the original Moog modules—including the AJH.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by wuff_miggler » Sun May 10, 2020 11:12 pm

just did a quick search - apparently the AJH fixed filterbank has inductors:

viewtopic.php?t=211343

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by Hovercraft » Mon May 11, 2020 6:46 am

wuff_miggler wrote:
Sun May 10, 2020 11:12 pm
just did a quick search - apparently the AJH fixed filterbank has inductors:

viewtopic.php?t=211343
The AJH doesn’t use passive wound wire core inductors- it uses active gyrator filter inductors. The AJH sounds lovely, but the circuit is different than the original Moog FFBs.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by wuff_miggler » Mon May 11, 2020 6:50 am

i glossed over the word 'actually' - mah bad - thought i was search hero for a sec :P

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by Gyroscope » Wed May 20, 2020 11:30 am

I don't really understand the two inputs on the Bark filter (Odds in/Evens in). Is it stereo?

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by mattdennewitz » Wed May 20, 2020 11:38 am

Gyroscope wrote:
Wed May 20, 2020 11:30 am
I don't really understand the two inputs on the Bark filter (Odds in/Evens in). Is it stereo?
routing sound to one input: manipulate both even and odd harmonics. even and odd harmonics are normalized.

routing one sound source into even, another into odd: first sound is routed through even harmonics filters, second sound is routed through the odd harmonics filters
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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by Gyroscope » Wed May 20, 2020 12:13 pm

mattdennewitz wrote:
Wed May 20, 2020 11:38 am
Gyroscope wrote:
Wed May 20, 2020 11:30 am
I don't really understand the two inputs on the Bark filter (Odds in/Evens in). Is it stereo?
routing sound to one input: manipulate both even and odd harmonics. even and odd harmonics are normalized.

routing one sound source into even, another into odd: first sound is routed through even harmonics filters, second sound is routed through the odd harmonics filters
Ah ok thanks, makes sense. So the only one that's stereo under 42hp is the Random Source Resonant eq. I already have one and love it but I wanted to add another fixed filter bank. I guess I'll just get another one. Relatively cheap, little hp and sounds great. Would have been nice to have another flavor though.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by Underwood » Wed May 20, 2020 3:06 pm

Gyroscope wrote:
Wed May 20, 2020 12:13 pm
mattdennewitz wrote:
Wed May 20, 2020 11:38 am
Gyroscope wrote:
Wed May 20, 2020 11:30 am
I don't really understand the two inputs on the Bark filter (Odds in/Evens in). Is it stereo?
routing sound to one input: manipulate both even and odd harmonics. even and odd harmonics are normalized.

routing one sound source into even, another into odd: first sound is routed through even harmonics filters, second sound is routed through the odd harmonics filters
Ah ok thanks, makes sense. So the only one that's stereo under 42hp is the Random Source Resonant eq. I already have one and love it but I wanted to add another fixed filter bank. I guess I'll just get another one. Relatively cheap, little hp and sounds great. Would have been nice to have another flavor though.
But you can route left into even and right into odd (or vice versa)

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by Gyroscope » Wed May 20, 2020 5:12 pm

Great I think I understand now, thanks.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by desolationjones » Wed May 20, 2020 5:37 pm

Gyroscope wrote:
Wed May 20, 2020 12:13 pm
Ah ok thanks, makes sense. So the only one that's stereo under 42hp is the Random Source Resonant eq.
R*S ResEq is not stereo. It mixes the two inputs to mono, and the two upper outputs are identical. The extra ins/outs are for Serge-style patch programming / distributed mixing. I use all the jacks in mine in almost every patch.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by Gyroscope » Wed May 20, 2020 5:43 pm

desolationjones wrote:
Wed May 20, 2020 5:37 pm
Gyroscope wrote:
Wed May 20, 2020 12:13 pm
Ah ok thanks, makes sense. So the only one that's stereo under 42hp is the Random Source Resonant eq.
R*S ResEq is not stereo. It mixes the two inputs to mono, and the two upper outputs are identical. The extra ins/outs are for Serge-style patch programming / distributed mixing. I use all the jacks in mine in almost every patch.
I should have written "stereo" yep.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by dooj88 » Thu May 21, 2020 12:21 pm

DonaldCrunk wrote:
Sat May 09, 2020 5:32 pm

Next in line, then, is the various takes on the Serge Resonant EQ - different choice in frequency bands, and no envelope following or other features, but much less expensive. The Random*Source version is very interesting, but I'm put off by the dramatically lower input amplitude of Euro Serge and the attenuation required to correctly interface with standard 10V pp eurorack modules (even if it is provided on the module). Having to level shift within my case is a pet peeve. There are a Mk 1 and Mk 2 Serge Res EQ filters available in DIY land as well. Also Elby, as adaris mentioned. Maybe those operate correctly at euro levels? Love the idea of feedback patching, and pinging this module with clock / trigger sources.
to add to the complexity of the decision are the 3 different reseq flavor mods from dr wiener :

1. NOS Styro
-- Vintage New Old Stock Closely Matched Styroflex Capacitors

2. Tropical
-- NOS Vintage Tropical Fish + Silver Mica Military Capacitors)
-- A combination of Russian Military Silver Mica Capacitors and Tropical Fish Capacitors. All Vintage and New Old Stock.
-- Face Melting sound. Nasty distortions and break ups are achieved.

3. Modern Precision (Swiss made Precision Matched Styroflex Caps)
-- Juicy, liquid Hi-Fi Goodness.

https://www.patch-point.com/eurorack/ra ... q-eurorack
wuff_miggler wrote:
Sat May 09, 2020 8:54 pm
im looking forward to adding the doepfer Fixed Filter bank to my system at some point - it has 15 bands.
and there's an option to get a breakout box to get individual outputs on a separate panel either pre or post volume.

:D with a trautonium filter, a triple resonance filter and that - that's a shit tonne of sculpting possibilities!
where did you see info about the band breakouts?

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by FatKingTubby » Thu May 21, 2020 2:17 pm

The Fumana v. Bark Filter quandry has been on my mind since finally indulging on a Fumana back in October. I've never doubted my decision but more wondered if I could justify a set up that includes both or if I'm covering too much similar ground. Neither has an extensive amount of audio examples or youtube demos, but what's out there is definitely more weighted towards the Fumana, if only someone would come around with a decent side-by-side comparison! As someone's already mentioned, the major difference between the two is the tuning of each band. The Fumana is much more focused on bands below 1kHz (9/16 bands) and the Bark has way more above 1kHz (8/12). With this difference alone it seems like the audio sculpting possibilities are varied enough that both could be useful in their own applications, as well as being able to compliment each other. I'm not quite ready to take a shot on the Verbos yet, but I feel like I'm only 1-2 really good demo videos away from it, but we'll see. Until then, here's a table comparing the frequencies of each module's filter bands so you can better visualize the ranges and gaps between the two.
FumanaBark Filter
15 hz-
65-
90-
-< 100 hz
122-
170-
230-
-300
320-
435-
-510
600-
-770
825-
-1.08 k
1.1 k-
-1.48 k
1.5 k-
2 k2 k
-2.7 k
3 k-
-3.7 k
4 k-
-5.3 k
5.5 k-
-7.7 k
->10.5 k
22 k-

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by starthief » Thu May 21, 2020 2:30 pm

I wound up ordering the EMW FFB. It seemed like a good middle ground between something more advanced but large and expensive, and a more basic choice like an EQ pedal or Ladik F-110.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by dooj88 » Thu May 21, 2020 3:33 pm

starthief wrote:
Thu May 21, 2020 2:30 pm
I wound up ordering the EMW FFB. It seemed like a good middle ground between something more advanced but large and expensive, and a more basic choice like an EQ pedal or Ladik F-110.
i've got that one. works quite well for the price. (is there a difference between a filter bank and resonant eq?) anyway if you create dense soundscapes like me it's great for clearing away extra clashing frequencies or accentuating ones you like.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by wuff_miggler » Thu May 21, 2020 3:51 pm

dooj88 wrote:
Thu May 21, 2020 12:21 pm
DonaldCrunk wrote:
Sat May 09, 2020 5:32 pm
wuff_miggler wrote:
Sat May 09, 2020 8:54 pm
im looking forward to adding the doepfer Fixed Filter bank to my system at some point - it has 15 bands.
and there's an option to get a breakout box to get individual outputs on a separate panel either pre or post volume.
:D with a trautonium filter, a triple resonance filter and that - that's a shit tonne of sculpting possibilities!
where did you see info about the band breakouts?
hey dooj88,
it's mentioned on the Doepfer A-128 as a mod you can perform/or special order:

If you want to add a single audio output for each filter we have instructions for this modification available: A128_single_outputs.pdf. If desired we carry out this modification in the factory (price for blind plate 8HP + 15 sockets + 3 special adapter boards + sockets/cables + about one hour working time, about Euro 120 altogether). Please specify if the single outputs should be pre or post the attenuators.

Here's link to instruction:
http://www.doepfer.de/service/A128_single_outputs.pdf

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by MindMachine » Fri May 22, 2020 7:25 pm

starthief wrote:
Thu May 21, 2020 2:30 pm
I wound up ordering the EMW FFB. It seemed like a good middle ground between something more advanced but large and expensive, and a more basic choice like an EQ pedal or Ladik F-110.
Righteous. I love EMW modules. Some are odd and some are plain. For the price they are excellent. Let us know your thoughts after a few uses.
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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by blaythe.steuer » Sat May 23, 2020 12:42 am

anyone wanna build me an antumbra bank? :yay:

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by KSS » Sat May 23, 2020 9:34 am

dooj88 wrote:
Thu May 21, 2020 12:21 pm
to add to the complexity of the decision are the 3 different reseq flavor mods from dr wiener
There's really only two. 1 and 3 -audiophoolish words aside- will be *very* similar.
1. NOS Styro 3. Modern Precision (Swiss made Precision Matched Styroflex Caps)
2. Tropical -- NOS Vintage Tropical Fish + Silver Mica Military Capacitors)

Replace the tropical fish with Orange Drops or Greenies and you'll have the same sound.

The Russian Mica will be different from 'domestic' brown silver mica, but that's mostly because they aren't sealed well, moisture gets in and that's the source of the nasty distortions and break up claimed. Not really a good thing, as it will progessively get worse with time.

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by damase » Sat May 23, 2020 10:42 am

FatKingTubby wrote:
Thu May 21, 2020 2:17 pm
FumanaBark Filter
15 hz-
65-
90-
-< 100 hz
122-
170-
230-
-300
320-
435-
-510
600-
-770
825-
-1.08 k
1.1 k-
-1.48 k
1.5 k-
2 k2 k
-2.7 k
3 k-
-3.7 k
4 k-
-5.3 k
5.5 k-
-7.7 k
->10.5 k
22 k-
really cool plot, thank you
whats interesting to me, when i think about how i use the bark filter as a processor... i very often end up lowering the width to accommodate 1-1.5 bands while sweeping the center with an lfo. It creates that spectral twinkle kind of effect that i really love. it seems like this would have a radically different character based on the frequencies chosen

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Re: Fixed Filter Banks - Long-term use, same-y results?

Post by KSS » Sat May 23, 2020 11:19 am

FatKingTubby wrote:
Thu May 21, 2020 2:17 pm
The Fumana v. Bark Filter quandry has been on my mind since finally indulging on a Fumana back in October.
...............
As someone's already mentioned, the major difference between the two is the tuning of each band. The Fumana is much more focused on bands below 1kHz (9/16 bands) and the Bark has way more above 1kHz (8/12).
That may be because Mark's Bark is missing some -over half- of its 'bite'! And its 'tooth' alignment is off by half.

Here's the complete Bark filter center freqs:
50, 150, 250, 350, 450, 570, 700, 840, 1k, 1k17, 1k37, 1k6, 1k8, 2k15, 2k5, 2k9, 3k4, 4k, 4k8, 5k8, 7k, 8k5, 10k5, 13k5

Here are the complete bark edges:
0, 100, 200, 300, 400, 510, 630, 770, 920, 1k08, 1k27, 1k48, 1k72, 2k, 2k32, 2k7, 3k15, 3k7, 4k4, 5k3, 6k4, 7k7, 9k5, 12k, 15k5

Here's Mark's frequencies.
<100 hz, 300, 510, 770, 1k08, 1k48, 2 k, 2k7, 3k7, 5k3, 7k7, >10k5

I've bolded the Verbos above to make clear what Mark has chosen. And it's somewhat LESS 'verbose' than a bark filter should be. The whole point of bark filters is that they represent a mapping of our ear to the world. The different frequency edges represent points of 'banding' in our own audio perception. They are intended to be steep edges. Notice that the Verbos has not only skipped over half of these, he's also put his center freq's at the Bark edges instead of the intended Bark center frequencies.

This means he's given us a familar name, but -possibly- missing the meaning behind it. Which is to apply filtering in a way that matches our physical audio perception.

A Bark filter's 24 bands *should* range like this:
0-50-100
100-150-200
200-250-300
300-350-400
400-450-510
510-570-630
630-700-770
770-840-920
920-1k-1k08
1k08-1k17-1k27
1k27-1k37-1k48
1k48-1k6-1k72
1k72-1k8-2k
2k-2k15-2k32
2k32-2k5-2k7
2k7-2k9-3k15
3k15-3k4-3k7
3k7-4k-4k4
4k4-4k8-5k3
5k3-5k8-6k4
6k4-7k-7k7
7k7-8k5-9k5
9k5-10k5-12k
12k-13k5-15k

Given this, you can see that the lack of filtering on the low end that you made comment on, is well founded. The true bark filter has NINE bands below 1K. Even if we eliminate the lowest as Mark has done, there are still eight. The Verbos 'Bark' filter gives us 4 or 5. But even these do not appear to be matched to the science behind the Bark Frequencies existence. Verbos spec say they are 6 pole, and therefore should be plenty steep. What is their width? See link below and final note at bottom. With half of them missing, there are either gaps -if the width is held- or incorrect widths.
With this difference alone <between Fumana Freqs and Verbos> it seems like the audio sculpting possibilities are varied enough that both could be useful in their own applications, as well as being able to compliment each other.
<Added for clarity>

Getting to the underlying results of this is that none of this means the Verbos 'Bark' filter isn't a good product, or isn't capable of manipulating your sounds in useful and effective ways. It surely can do that. And to the point of your concern, it will definitely be different in practice from the Fumana.

Just don't expect you've experienced the point behind a Bark filter after using it. It's another set of FFB frequencies with a Fancy name.

I recently designed a true 24 band Bark filter -not for Eurorack- so all this is fresh and recent experience. I've never listened to the Verbos Bark Filter. All of this is going on their published specs, and an understanding of Bark Frequencies.
--------------
Freq centers and edges for this post were taken from here:
https://ccrma.stanford.edu/~jos/bbt/Bar ... Scale.html

This Wikipedia Article adds an important point. Ain't the vagaries of perception grand!
https://en.wikipedia.org/wiki/Bark_scale
Wikipedia wrote: Since the direct measurements of the critical bands are subject to error, the values in this table have been generously rounded.[1]

In his letter "Subdivision of the Audible Frequency Range into Critical Bands", Zwicker states:
"These bands have been directly measured in experiments on the threshold for complex sounds, on masking, on the perception of phase, and most often on the loudness of complex sounds. In all these phenomena, the critical band seems to play an important role. It must be pointed out that the measurements taken so far indicate that the critical bands have a certain width, but that their position on the frequency scale is not fixed; rather, the position can be changed continuously, perhaps by the ear itself."

Thus the important attribute of the Bark scale is the width of the critical band at any given frequency, not the exact values of the edges or centers of any band.
edit: Allen Strange covers Bark Filters briefly on Pg 145-146 of his seminal book electronic music, 2nd ed. He also emphasizes the bandwidths /edit

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