Crossover & Mixer Stompbox

Fred, I've listened to the files, and looked at the waveforms and you're right -24db and -24db/octave are not enough. 

The other approach, which is a lot cheaper and 100% effective would be a loop switcher or a loop blender that can be controlled with a treadle. Bright Onion in the UK do more variations on this theme than you can shake a stick at! 

http://www.brightonion.co.uk/true-bypass-loopers/

Yeah - Manually controlled.. There are some functions we can still probably do better without automation! ;-)

However, I do believe this is an area where a small DSP may do the job - perhaps even a low cost (<£60) DSPic from MicroChip, or one of the Spartan boards..

Sadly, the best DSP board I ever played with (Analog Devices EZ-Kit Lite) has the new Blackfin processor and is >£200 (I paid about £80 for an earlier board some years ago) - The PSoC 5 could probably do the job too - it has dedicated processors on chip specially configured for digital filtering, and clocks in at about £50 for a small DK.

I found myself getting into sharpening the filters in my present design following this thread, but stopped myself - Most of what im doing only needs 12db/octave and the +/-8db from the Ambler or +/- 16db from a pair of Amblers was enough.. I have however gone over to a modified State Variable filters now as a result of this thread - its simplified things a bit and gives me switchable 12/24db / octave and independent tuning for HP/LP - actually makes the whole filter side much more versatile, so thanks for bringing this topic up!

These pedals are pricey for what they are though! >£200 for a 24db filter !? Hell, I was looking at targeting that sort of price for my box which has filters to split the signal, independent distortion channels, a pair of two of perhaps 3  formant vocal filters, output tube emulation and output equalizer... Perhaps I should put it in a pedal and add another £200 ;-)

Fred.

Absolutely. It's not what it costs to make, it's how much the customer will pay. <sigh>

And the pedal is in a budget box, with a pretty sheet of plastic on top. 

The downside of not automating is I currently have three treadles ranged under the theremin (ring mod, chopper, talking machine, it sounds like this youtu.be/Ug32EKZK9uo) - and I have another foot operated device in mind that could well be a permanent fixture, which along with a blender would bring it up to five. 

Suddenly I feel like a fresh water fish in the sea: what with DSPics from MicroChip and PSoC5's and Spartan Board DKs!

Brings back a conversation with a neighbour over the garden fence where he was telling me that his car was acting up, not accelerating properly, sluggish and juddering when the accelerator was pressed.
Ronnie (the neighbour) had been a mechanic and knew his stuff but is now retired and so had to leave the diagnosis to the chaps in the car workshop.
So here we are, Ronnie telling me the car's symptoms and me thinking, 'I can maybe suggest something', to which i suggested that the fault might either lie in a blocked carburettor jet or maybe the points needed adjusting.
He looked at me and said, in all seriousness, 'Roy' cars haven't had points for around 30 years.'

Aye, ok...

"Suddenly I feel like a fresh water fish in the sea: what with DSPics from MicroChip and PSoC5's and Spartan Board DKs!" - RoyP

Roy, its more a sort of "shorthand" than anything with real depth - What I said (all those incomprehensible words) could have been said by many morons who dont have a clue what theyr talknig about - in fact, apart from PSoC5, I could be such a moron!

So, apart from DSP and DK (Digital Signal Processing and Development Kit) all the other words are company names or brand names or specific products.. If you dont know the MicroChip company, you probably wont know that their chips are named PIC's and wont recognise DSPic as a mix of DSP and PIC.. If you dont know FPGA's (Field Programmable Gate Arrays) You wont know that Spartan is one of these vendors product lines, and if you dont know Cypress Semiconductors, you wont know their PSoC family (Programmable System on Chip) or the PSoC 5.

But this "shorthand" serves several useful functions - Those who want to scan a post can do so more quickly than if I used longhand (even if I only wrote about what I fully understand ;-) - And by giving rather "obscure" words, those who are interested in exploring matters further can simply enter these words in a search engine (Spartan DSP for example) and will get plenty of hits which will probably allow them to learn more about the subject in 1/2 hour than I know! ;-)

As for cars, I dont understand them - they just seem to be engineerd with way too much complexity... I have for a long time only bought used vehicles (well, actually, Ive never bought a vehicle less than 8 years old) and looked for cars with the least electronics - Alas, you cannot get drivable cars without electronic engine managment and key fobs and all manner of horrors anymore... Driving down the motorway and suddemly a big red "STOP"! flashes, then the EMU triange starts to flash, then temperature guage goes to the red...

Pull over, check what I can, all looks ok so head off again - all seems ok.. antil I am in the worst possible place and the warnings start up again... Then the vehicle wont turn on because theres an engine fault....

ALWAYS its the bloody electronics giving false warnings based on reading the sensors wrong... Except for my last vehicle which didnt warn me of an oil leak / low oil pressure, and I ended up high in the Lake district with a blown head gasket.. Or perhaps I phrased that wrong.... ;-)

Fred.

" it sounds like this youtu.be/Ug32EKZK9uo) - and I have another foot operated device in mind that could well be a permanent fixture, which along with a blender would bring it up to five. " - GordonC

Interesting piece - its getting to the level where it almost sounds "sequenced" and if I didnt know it was you, I might not guess that the theremin was the sound source! - Impressive how clean the sound is though - I dont hear anything bothersome (hum or hiss or unpleasant distortions) and the components all retain a clarity and definition despite the complexity.

Anyway - you are looking for a box that takes a mono audio input with reasonably pure waveform (sine), has a frequency (cut-off) control, and has two outputs - one output is all frequencies below the cut-off, the other is all frequencies above it. The sharper the cut-off the better - perhaps 60db/octave or better..

Im not going to look for this or spend any time on it, but will keep it in mind - the answer may just find me in the course of me doing something else. I strongly suspect DSP is the only realistic way to implement this.

Fred.

"almost sounds sequenced"

It is a bit of a change for me. Every now and then I set out to change some of the rules I have made up for myself to see how it changes the nature of the finished product. Here I changed several all at once.

"clean sound"

I got a tiny little looper for my birthday (a Boss RC-3) - not with the intent of looping, but as a quick and easy way of recording myself without fiddling about with the computer. I'm quite impressed with the quality of the sound and how easy it is - Swan Grinder started out as three mono tracks overdubbed directly on top of each other in a tiny SIM card in the looper that I then plugged into the computer. 

"hum or hiss"

Recordings come out of the looper pretty clean - at least as good as taking it through the mixer on my SR Technology amp and into the computer with an M-Audio audio interface. And, as I mentioned, Amadeus Pro has some nice clean-up tools.

"clarity and definition"

I have mostly migrated over to 64 bit on the computer, which I think is a contributing factor, and I have a nice little free VST to apply faux stereo that opens the sound out and makes complexity less impenetrable. Also, I applied several effects in the computer, using GarageBand's facility to separate the high frequency and low frequency components and process them separately, including how they move in the stereo field, to give more separation. (That was what set me looking for a stomp box that could do the same thing in hardware.)

There are a couple of other pieces where I used the looper to overdub tracks on my soundcloud account that change fewer of my made-up rules, namely Snippetymen and The Boglia Of Barrators (both also make heavy use of the Gig-FX Chopper - I'll have quite a lot to say about staccato and theremins in a few days when I have got it all straight in my head, so I'm not dwelling on that aspect now.)

"I'm not going to look for this"

Good - I have plenty of other things ongoing, so please don't expend time or effort on a better crossover box. It's just one item on a list of things for me to think about sooner or later. :-)

Just looked at the RC-3 and the other loopers.. Damn impressive!

Loopers of that kind didnt exist when I was buying kit many years ago - The RC-505 looks like it has everything a solo musician (particularly synth) would need to put a whole track together - acting as a multi-track recorder, looper, MIDI and audio interface, effects processor..

There is something really boring about using the PC as ones main tool for recodrding / processing.. Listening to what you are doing with the RC-3 makes me think it could be a worthwhile purchase.. Oh, the 505 is what I really want, with 5 independent channels - but at more than twice the price.. Perhaps its time to sell my Juno 6..

Darn you!  ;-) ... I understand how you feel when I try to tempt you to go for voltage control! ;-)

Fred.