dual band splitter

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Tnx! Both of you for the explanation. I have been struggling with Eagle, but I think I have sort of my 450Hz LR Filter schematic.
Still so much to learn. haven't been able to find the symbol for ground. And not the right triangle symbol (that is an opamp right?)
But apart from that, this filter should work... right?

Tnx Erik

PS JR: interesting thought... I will experiment more once I have a good vst clone of the overdrive I want to use for the higher band...
 

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when making a schematic in eagle you have to use the green round-thingies to join the green line's otherwise the program will not join the net's. thus your board will be inconsistent with what you thought was a correct schematic.

Eagle is as simple as it gets as far as board and schematic software, but like most thing's in life you only get what you put into it. Don't expect your first board to work perfectly and double check everything.

greetings,

Thomas
 
Thanks Thomas....

Updated version with the green round thingies and ground...

From the subtractive crossover networks article (http://sound.westhost.com/articles/derived-xovers.htm):

In the circuit diagrams below, all buffers are unity gain, and all circuits are driven from a low impedance (voltage) source. This is a requirement for all filters, so the input buffer is not shown for clarity. The voltage source shown is an ideal voltage source - zero ohms output impedance.

Likewise, for clarity, the power supplies are not shown. All the results below are from the SIMetrix simulator, and while somewhat idealised, are representative of reality with any reasonable opamp in a real world circuit - especially within the audio band.


So I have to find out what a input buffer is, and put it in, as with a powersupply, and I have to use / choose actual opamps.... start reading!
 

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Hi
Your project is very close to what I'm trying to put together. In the middle of sketching ideas and reseaching. The dual band thing is a really cool thing!

You talk about what to do with the high part. I've been greatly inspired by this plugin for mac called Airwindows' Density. When you drive it it goes from nice and good compressor-spanking into a great sounding, heavy smacking blend of nasty compression and distortion, which isn't normally associated with compressors. If that makes any sense ;) - And Density works as  a dual band, but only driving the high part. It has a mix slider as well. Very easy to get something nice out of.

But how to make that happen, I'm not quite sure of. Maybe having a compressor then going in to an overdrive that only works at extreme settings? But it should only have to be a one knob "drive" for the easyness of use i would think.
Maybe just finding a compressor that can be made to severe sound spanking. Something fast.



 
Hey Tim

Nice to hear someone else is having the same thoughts and is in the same stage of development. Funny that your inspiration comes from a dual band unit as well. I have been trying to look into the density, but there is very little info on it, and having a pc I can not use it myself. Interesting that the description of the density on their website is very similar to the Austin Gold's description. Except the hugely different thing that you say it only processes the high band. The core of my idea is the great sounding Austin Gold on the low frequencies. You got me thinking though. The reason why I love the Gold's sound on the low frequencies is sort of explained in the marketing material of Rocktron:

Unique to the Austin Gold is its "Pre-Bass" control. Other typical overdrive pedals have a fixed value which cannot be altered. But the Austin's Pre-Bass control allows you to cut the pre-distortion low frequency information, eliminating problems with too much "fuzzy" bass. This control also allows you to increase the pre-distortion frequencies when the tone is too weak or thin. With the Pre-Bass control, many overdrive textures can be exploited. It's almost like having an entire arsenal of various overdrive pedals in one, by simply adjusting one control!

Maybe it could be worth checking out what that pre bass exactly does in the Gold. If we find that out, maybe we could change it's design to create a Gold that will sound brilliant on the high band (with a "pre-high" control?). Maybe even add a bit more distortion for the high band. .. Interesting... maybe that way there is a way of processing the high band without the highs getting to cluttered as well... hmmm.... :)
 
Actually my memory served me wrong. The Density plugin simply has a pre hp-filter and not a crossfilter. So it's just like the Austin Gold but it beeing a compressor + a dry/wet-slider.
That makes me wonder if I still find the crossover filtering such a neat thing, for my uses. Still I do like experimenting..

From the description "pre-bas" my guess (without having heard the sound of it!) is you have a shelving filter or broad q at 100 Hz, +10/-10 dB before the distortion. So from your design it makes sense adding a low pass filter before the distortion of the upper band. In fact it might be cool filtering post distortion for the upper band. Have a pre/post switch...  8) I think this kind of "pre-high" would definitely help a great deal.
Another thing btw if I where you I would stick to your original idea of having an adjustable cross filter point. I think that makes a huge difference in the flexibility of the design. I'm pretty sure you won't gain anything from having a high class cross filter as used in speaker designs etc. Also a band swap at the cross filter might be a nice addition(?), at least if you're having different overdrive-circuits low/high.


I attach my own sketches for the sake of inspiration and discussion :)


 

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Hey Tim

Tnx a lot for inspiration and discussion! Without judging, just to get it right, there is a fundamental difference between our sketches. If I get it right, yours has two effects (drive and comp) that can be placed in series and parallel, both with a mix/blend function. After those, eq is applied.
My design is based on applying different amounts of drive on different eq bands.
I would love to hear why you went for/ came up with you concept.  Why would you want to compress one band, and distort the other. Iam not judging, just curious if it comes from a theory, real life experience or you "just" think it would be a cool thing.
Your theory of the pre-bass could be right. I have attached the schematic of the Austin Gold, maybe you or someone else can see out of that what is does. In my next post, I will elaborate a bit more on why I went for my design (that is already adjusted after your post) but I can not attach two attachments.
 

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Attached my revised conceptual design. Hope you're happy now, because of you there are loads more options I want to build in. Bye Bye easy concept :). Edit: after writing the last bit of this I decided to leave the eq and compressors out for now... hello nice clean concept!

So what do I want, what is the "thing" I want to build, what is my "project mission statement" (PMS,  :D).
I want to build a 19" unit, preferably finished this decade, that enables me to use, as flexible as possible, overdrive to a signal, mono and stereo. KTS (key target sources) are drumbuss, (drum)loops and single drum hits (mostly snare and kick). The flexible lay out will have to encourage experimenting. Of course, in 25 years it will turn out that this will be THE classic mandoline mangling device.
My musical background is being the guitarplayer in an alternative pop band and producing Hip Hop / D&B / Dub.
A lot of inspiration for this unit comes from an article in Sound on sound: http://www.soundonsound.com/sos/apr10/articles/distortion.htm.

What I want the unit at least to do is:
1. add oomp and agressiveness to low end
2. add bite and agressiveness to mid/high end
3. distort the shit out of anything or add mild almost inaudible edges of drive
4. help sounds to cut through mixes

1&2 call for a multiband distortion. Low freq react so much different on drive than high freq that if you wanna do serious distortion of multiple sources, imo, you have to split somewhere around 400Hz. After my tests I found that I always came back to a crossover frequency between 350 and 500hz. Also, that split needs to be pretty drastic. If there was too much overlap, the end result became horrible, and not in a good way. That is why Iam thinking towards what you call a high class crossover. I absolutely loved the concept of a fully adjustable crossover, but I just did not feel the need for it at all when experimenting with it.

As with the overlap on the crossover filters, I noticed that blending too many copied and or processed signals together just got messy. That is why I decided  to go for a design that leaves the original signal as intact as possible. That is why I dropped my originally mix/blend functionality per band / drive and replaced that by adding the different bands to the original. That way you prevent mixing two signals that each are a blend of the same original signal with a different added distortion. When Iam thinking user interface, I see something like a small mixer at the far right side of the frontpanel with levels for the original and the different processed signals.

With distortion, you add harmonics to the signal that were not there before. Filtering before distortion to my mind therefore makes less sense then filtering after distortion. On the other hand, a pre/post switch can't be that difficult, so why not.
Pre distortion filtering makes no sense however for a third drive / distortion I added to my concept: a copy of the original signal goes through a bad ass distortion and then through a bad ass high pass filter. That way the high harmonics could add some excitement and brightness. Reading about that way of excitement while I am writing this however tells me that the usual route is high pass before distortion... makes no sense in my mind... would love to get input on that one.

This big story leads me to 4 different audio signals mixed together at the end. One clean and three distorted and filtered. Damn I might as well just buy Craig Anderton's  quadra fuzz :)

I think I am not going to bother with EQ and compression in the design for now. First build the distortion units, and then start thinking about adding the eq and comp, and where.

Pffff.....



 
 

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Back to the filter. I did some reading of what an opamp actually is... that makes a lot clear. And I spotted a major mistake in the crossover design, basically mixed up pins 2 and 3 of the opamp. Now for the powering and the input buffer!
 

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Hi Erik

Yeah, I realize this design of mine has changed after I first saw and wrote here in your thread. Mainly leaving out the crossfilter does change it quite a bit. I guess either you do the crossfilter thing or you do parallel dry/wet, both becomes to messy.
My inspiration comes from the way I mix ITB. Adding a bit of distortion does amazing things for me. Especially I like parallel processing; eg. copy tracks, distort and filter the copy, make the blend between orig-copy. Of course now a days many plugins simply have mix slider like Density or Reaper, which does it on every plugin inserted! I also really like the Sansamp Paradrivers blend funktion. Furthermore I've found that specific combination of compression and distortion to be fantasticly usefull (very nice for drums..).
I'm a total newbie at electronics it self and just bought some kits to get started. Guitar pedals, though I'm not a guitar player, just seemed an easy path when wanting to dig in to Distortion. Also I couldn't help thinking about making something that would be really usefull in the studio. Wether recording or mixing.

I can see your design becoming a great sound mangler! Probably a good decision to leave out the eq and comp for now.
Just some crazy thoughts:
- How about a phase switch? Like on each of the 4 signals beeing mixed. For fucked up sounds... If that's in your interests.
- How about playing with optocouplers/vactrols adding some kind of dynamic (voltage) control of the distortion?
- Have you tried using a Sherman Filterbank? (Another great sound mangler)
- Maybe explore each distortion circuit for mods and extra variables? (this seems to be a huge subject)
- Internal feedback?

 
First of all, a bit of progress on the filter. Input buffer added. Still some small things to be added, but getting there...
 

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Tim Ragnur said:
Hi Erik

Yeah, I realize this design of mine has changed after I first saw and wrote here in your thread.

I hear you, my design (and all designs I guess) is in a constant state of change, but that's part of the fun actually.

Tim Ragnur said:
Mainly leaving out the crossfilter does change it quite a bit. I guess either you do the crossfilter thing or you do parallel dry/wet, both becomes to messy.
My inspiration comes from the way I mix ITB. Adding a bit of distortion does amazing things for me. Especially I like parallel processing; eg. copy tracks, distort and filter the copy, make the blend between orig-copy. Of course now a days many plugins simply have mix slider like Density or Reaper, which does it on every plugin inserted! I also really like the Sansamp Paradrivers blend funktion. Furthermore I've found that specific combination of compression and distortion to be fantasticly usefull (very nice for drums..).
I'm a total newbie at electronics it self and just bought some kits to get started. Guitar pedals, though I'm not a guitar player, just seemed an easy path when wanting to dig in to Distortion. Also I couldn't help thinking about making something that would be really usefull in the studio. Wether recording or mixing.
I think be both agree on a blend function, we just blend at different stages. Ive attached a picture with a slighty changed concept, so it is a bit clearer to see that the processed bands are all blended in with the original, clean signal. I have been a guitarplayer for almost 30 years now, and I have used a lot of my pedals for drum processing in the studio. And now with my new diy hobby, there is a lot to be found on them and they make nice, relatively easy building blocks, which is great for newbee's like me!

Tim Ragnur said:
I can see your design becoming a great sound mangler! Probably a good decision to leave out the eq and comp for now.
Just some crazy thoughts:
- How about a phase switch? Like on each of the 4 signals beeing mixed. For f*cked up sounds... If that's in your interests.
- How about playing with optocouplers/vactrols adding some kind of dynamic (voltage) control of the distortion?
- Have you tried using a Sherman Filterbank? (Another great sound mangler)
- Maybe explore each distortion circuit for mods and extra variables? (this seems to be a huge subject)
- Internal feedback?

I love crazy ideas!
- phase: could be interesting, and maybe even needed with all the blending going on!
- octocouplers? WTF?
- I have used it once or twice in a studio, defenitely a great device, although something very different from this....
- I am in the process of modding the austin gold for the high freq band. Found ways to add more drive. Just still looking how to change the pre bass in a pre high... I have also found a circuit for the high high distortion band: Jules Ryckebusch's "Harmonic Sweetener". I was tipped for it by a guy who modded it and posted the drawing here: http://www.montagar.com/~patj/harmswtn.gif. It uses LEDs for clipping to create as much harmonics as possible, by also boosting the originally available harmonices.
-internal feedback? What do you mean?

Cheers

Erik
-
 

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Hello,

I used the band-splitting solution often in recording and mixing. I started somewhere in the early 80's with using BSS 4-way crossovers that had limiters per band section, summing the outputs with a simple 4-way summing amp.
Especially on drum-tracks this sounds really good. Later I have tried all sorts of effects/equipment in between the band outputs and the summing amp.
Another thing you might consider is balancing between the processed signal and the original signal (like on some master compressor's).

The band-splitting technology is often used on broadcast limiters like Orban.
Try to find a used set of variable crossovers and build a simple summing amp, have fun!

Theo
 
What a brilliant idea to start with a second hand variable x-over for experimenting! Tnx Balion!

Or with a cheap new one: http://www.bax-shop.nl/equalizer-crossover/behringer-cx-2310-crossover/product-details.html

Obviously I wanted to be able to balance the levels of the different bands / signals... probably just adding a bit of distortion on different bands...
 
erikb1971 said:
I love crazy ideas!
- phase: could be interesting, and maybe even needed with all the blending going on!
- octocouplers? WTF?
- I have used it once or twice in a studio, defenitely a great device, although something very different from this....
- I am in the process of modding the austin gold for the high freq band. Found ways to add more drive. Just still looking how to change the pre bass in a pre high... I have also found a circuit for the high high distortion band: Jules Ryckebusch's "Harmonic Sweetener". I was tipped for it by a guy who modded it and posted the drawing here: http://www.montagar.com/~patj/harmswtn.gif. It uses LEDs for clipping to create as much harmonics as possible, by also boosting the originally available harmonices.
-internal feedback? What do you mean?

I have a Sherman Filterbank myself and in many ways i find it to be the ultimative sound mangling tool. I like the modular synthish approach.
Herein lies my fascination with these optocouplers (sometimes called vactrols). It's just a LED and a light sensitive resistor. This is totally out of my league, since I've only just been reading about it :-[ But I think it's relatively easy to play around with. As far as I understand it you can use it to add "voltage control" from outcoming sources to your circuit. It has a certain kind of slow response.
So in the end it might add some Sherman-like functionallity (wether the Sherman uses optocouplers or not). I would chase places where you'd have a pot.

Feedback - again I don't know what I'm talking about, just screwing around :D I like plain old feedback and noise and unpredictability.
 
erikb1971 said:
What a brilliant idea to start with a second hand variable x-over for experimenting! Tnx Balion!

Or with a cheap new one: http://www.bax-shop.nl/equalizer-crossover/behringer-cx-2310-crossover/product-details.html

Obviously I wanted to be able to balance the levels of the different bands / signals... probably just adding a bit of distortion on different bands...


As I mentioned in my earlier suggestion loudspeaker crossovers will not electrically sum back to unity without issues.

Back in the '70s a lot of radio stations experimented with multi band compression that way... and there was some ugly ass sounding radio, until more professional solutions were available to broadcasters. 

JR
 
JohnRoberts said:
As I mentioned in my earlier suggestion loudspeaker crossovers will not electrically sum back to unity without issues.

Back in the '70s a lot of radio stations experimented with multi band compression that way... and there was some ugly ass sounding radio, until more professional solutions were available to broadcasters. 

JR

John, is that not summing back nicely also the case when they use the LR filters?
from the behringer website: Professional stereo 2-way/mono 3-way crossover featuring state-of-the-art Linkwitz-Riley filters with 24 dB/octave. That was what made me think it was a good idea actually...
 
Hi Erik,

yes, no problem, our ears are summing for years.....
We have been building loudspeaker systems for decades build on this principle.

It is basically comparable to running a compressed and eq-ed voice channel in parallel with a unprocessed original channel.
In theory, mathematically and by measurement, it is as wrong as can be, but boy does it sound right.

Just do it, test, learn and share your experience with us, I can borrow you a unit if you like. 

John:
Did you actually try this? or is this only theory? Sure you have some phase-shift at the crossover-points and maybe a ripple, depending on the accuracy of the components and who's curve you pick. What are we doing in Equalizer sections is a complex adding and subtracting phase behavior too, we do not bother to make a point of it.

grT

grT

grT
 
erikb1971 said:
JohnRoberts said:
As I mentioned in my earlier suggestion loudspeaker crossovers will not electrically sum back to unity without issues.

Back in the '70s a lot of radio stations experimented with multi band compression that way... and there was some ugly ass sounding radio, until more professional solutions were available to broadcasters. 

JR

John, is that not summing back nicely also the case when they use the LR filters?
from the behringer website: Professional stereo 2-way/mono 3-way crossover featuring state-of-the-art Linkwitz-Riley filters with 24 dB/octave. That was what made me think it was a good idea actually...

I already talked about this in passing earlier in this thread...

The L-R alignment is attractive for loudspeaker crossovers for a couple reasons. #1) the phase shift is so much (45' per pole at tuning) that the phase shifted signal from 4 poles rotates back to into "relative" phase.  So for a steady tone the +180' of lead, and -180' of lag, look like 360' that looks and acts like 0'... for steady state tones.  #2 because they are back in relative phase, the two pass bands can be summed at -6 dB instead of the -3dB typical of other crossover alignments.  Since the primary goal of loudspeaker crossovers is to keep HF signals out of LF drivers and vice versa the LR -24db per octave slope and _6dB at tuning is GOP (great on paper).

OTOH combining these signal in the electrical domain instead of in 3D acoustic space will reveal other things.

Looking at the response of those filter sets to a single transient is a completely different story. Since a transient can't come out of a filter before it enters, the HP and LP outputs will never combine to resemble the input signal... thus my original suggestion for the derived topology that does in fact preserve transients.

While I am speaking about the "paint", I am not making this stuff up. I was designing speaker crossovers back 3 or 4 decades ago.

But do not take my word for it... and who know a speaker crossover may work fine for your purposes.

As I also suggested much earlier in this thread , build some stiff up and listen to it... that is the bottom line.

JR
 

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