Monday, 15 November 2021

Very very good article on the inner workings of the Yamaha DX7

I rarely do links to other blogs, but today is an exception! Go to the 'Doing it Right!' section near the end, to see the details of a link to a wonderful article on the inner details of the Yamaha DX7!

Getting it wrong!

The way the Yamaha DX7 synthesizer is treated on the InterWeb is interesting because they are very often full of myths and errors. 

Some articles say it uses FM (Frequency Modulation), when it actually uses PM (Phase Modulation). Some articles say that it sold more units than any other synthesizer, ever, (over 150,000 units - definitive figures are tricky to find and verify), forgetting another digital synth from slightly later, the Korg M1 (over 250,000 units - again, difficult to verify), and several other contenders since... (There again, you can always spiral down into the black hole of clarifications: digital, 12-bit (kind of), hand-built, custom chips...) Some articles say that the DX7, and FM, are difficult to program, but then so is C++ (and many other things) - and yet a lot of people managed to program the huge number of patches/presets/sounds that are available for the DX7 (including a few hundred from myself), so it can't be that tricky! Oh, and some articles say that Yamaha synthesisers do not output MIDI velocity above 100 (instead of up to 127) - which was true for the first few DX7s, and was then fixed, so it not only wasn't correct very soon after the launch in 1983, it hasn't been right since for almost 40 years! Basically, it seems as if many authors of articles about the DX7 and FM don't do their background research properly and just copy the same old fake news and myths. 

(Oh, and hardly anyone ever notes that the original 'number' proposed for the DX7 was the DX5...)

Doing it right!

In total and complete contrast, in every way, a recent blog post from Ken Shirriff is throughly recommended because it not only gets everything right, it also goes very deep into how the DX7 works

https://www.righto.com/2021/11/reverse-engineering-yamaha-dx7.html

Congratulations, my admiration, and kudos to Ken Shirriff for an excellent article!

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Monday, 8 November 2021

The Chase Bliss EXP Pedal...

At the low end of the guitar pedal marketplace, you have budget pedals: small, very affordable, and all very similar: fuzz, overdrive, chorus, phaser, flanger, delay, reverb...

At the opposite end of the market there are what are often called the 'boutique' pedal manufacturers: sophisticated, beautifully engineered and as some marketing people like to say: 'reassuringly expensive' - but most importantly: diverse and unusual. You won't find conventional 'me too' phasers, loopers or delays here. Instead you will get informed, flexible, powerful, eclectic pedals - plus many other words associated with innovation and exclusivity.

EXP

A perfect example of this (and actually, pretty much a perfect pedal) is the recently announced EXP pedal from Chase Bliss Audio. Wikipedia describe Chase Bliss Audio as being 'high-end', whilst Anderton's Music Company says: '...not just another pedal company, no...21st Century Trail-blazers...'. Chase Bliss Audio themselves say it very nicely on their web-site: 

Chase Bliss makes pedals that mix digital wizardry with analog goodness to create weird and wonderful sounds.

However, the EXP pedal is slightly different - it is just 'analogue goodness'. (No digital inside at all!)

In these days of 'Do you want a microprocessor with that?' turning up in everything, then this is a bold move, but it is a great move.

The reason why this is such an amazing move is that EXP is the expression pedal, reinvented. 

I will let you think about that for a moment...

Instead of an angled foot plate that you move with your foot to control guitar pedals via the 'Expression' input, the EXP pedal looks more like a very robust, very engineered modulation wheel that has escaped from a synthesizer - maybe someone like Expressive E. So you can use it on top of a studio desk, where it gives a nice, convenient, tactile interface to controlling guitar pedals being used as outboard effects, and the classy black metal case with its minimalistic labelling, plus the 'executive toy' knurled texture on the wheel, plus the glossy numbers wrapped around it, mean that it looks like it belongs there. Alternatively, put it on the floor or on a pedal board, and the rugged metal box, plus the grippy metal wheel that can be moved with your foot, mean that it is right at home there as well. 

And whilst you are visualising your foot moving the wheel on the EXP pedal, here's an interesting practical thought: have you ever knocked an expression pedal whilst feeling about with your foot for a foot-switch on a pedal board? Well, the wheel on the EXP is almost immune to such accidents, because unless you put your foot on it and move your foot forwards deliberately, then it isn't going to get accidentally moved... The reason that you may feel the world wobbling a little at the moment is a large number of guitarists all nodding (with a slightly embarrassed smile on their face at various live 'incidents'), plus more nodding of heads from all the live mix engineers who have had to suddenly pull back the sliders for the guitarist who just jumped up 20 dB in the mix.  

So let's look at this design. Instead of 15 to 30 degrees of angular movement from your foot, you have something like 270 degrees of rotation of a wheel, or about 150mm (6 inches) of linear movement of a foot (or hand). So that's lots of fine control, plus there's a big number that shows from 0-10, so you know where you are in the range. I can't recall ever seeing a foot pedal marked off in degrees...

Inside

Now, I have never been able to resist opening up gear, and so that's what I did next...


That's a single piece of bent metal that isn't fastened to either the base of the case (as you can see), nor the top part. It is held in place by the base when the case is assembled, and the electrical connections to the top part of the case are made thru a Molex sparse ribbon cable. As you can see, the wheel occupied all of the available vertical space, nearly touching the base - but it doesn't, of course! What you also get hints of here are some bearings (the thick metal casting in the lower left, and of some mechanics in the central fold hole. 

Sharp-eyed readers (viewers, actually) will probably have spotted that there are two 'stereo' jack plugs connected at the back, and these are for the two electrically separate outputs. The two rectangular hole near the top have two switches just below them, and these can reverse the direction of the outputs, so you can have heel and toe the same or both, or both reverse, or heel and toe opposite in two ways. I set the switches to opposite positions, so that I have two outputs that are the inverse of each other. So whatever I control with expression on one pedal, I can control the opposite on another pedal. But as you can see, just by removing 4 bolts and flipping a switch, I can change that at any time. 

I was pretty impressed with the mechanical minimalism here. I was expecting something much lighter and that the switches would be more awkward to get at. I like good surprises.

(What is interesting here is the forced perspective. You might be wondering why the base looks so much smaller than the case.? The clue is the shadows... Yes, the top part of the case is actually much higher up because I had to stand it on a couple of wood blocks because the wheel sticks out of the top of the case. So the top part is much closer to the camera, which is why the shadow for the top part of the case is diffuse, whilst the shadow for the base of the case is so sharp - it is on the blue background, whilst the top part of the case is about 30 mm above it. So now you know! You eye assumes that the two objects are both on the blue background, and so the base must be smaller even though it is the same dimensions!)

Going a bit deeper was interesting. That single piece of bent metal IS the holder for all the mechanics, and it is not fastened to the top of the case at all. There is just the sparse black ribbon cable. So you just lift out the bent metal...


As I said, the wheel has substantial bearings in those solid blocks of metal. The wheel connects to the pot using a toothed rubber drive belt, so no slipping. and the potentiometer is, as expected, a dual gang linear potentiometer, which explains how the two outputs can be electrically separate - one gang is used for each output. It looks as if the circuit board is held in place by the two jack sockets, so, that's a neat solution as well. The diameters of the wheel gear and the potentiometer gear appear to be pretty much the same size, and so the wheel uses the whole 270 degrees of rotation of the potentiometer, which is why you can invert the ranges for the two outputs.

So the mechanical design is very cool. There are no fastenings needed for the main bent metal assembly to hold it in place inside the case, other than the case itself. The four bolts that hold the base of the case in place, also hold the mechanical assembly securely and solidly in place. The metal is bent to form the supports for the bearings and the potentiometer. I just love it. Minimalistic, with no levers, easy disassembly and it looks like servicing (replacing the rubber belt, or the bearings, or the potentiometer) should be very easy and quick. I'm struggling to find anything to criticise here. 

Even if I was very picky and said that dust might get inside through the rectangular hole in the top of the case for the wheel, then just opening up the case and blowing away the dust is probably going to be all that is required. If liquids get inside, then it is all passive components, and the potentiometer is unlikely to cost a fortune to replace. 

Using it

Expression pedals are made to allow you to control things - to make them expressive. So next, I look at using it...

Well, it works. Wonderfully. It's like an expression pedal, except that you don't rock it from heel to toe with your foot, instead you roll from one end to the other, which seems to be about 270 degrees of rotation, and the end stops feel solid and not sloppy, and not particularly padded. Rather like a lot of synthesizer modulation wheels, actually. Perhaps a little stiffer, but it may loosen up as I use it more. But not a problem. My only criticism is that moving rapidly from heel to toe requires a little bit of practice with your hand (or your foot). 

And there's the amazing thing. It feels right either as a desktop hand operated controller for expression, or on the floor as a foot-operated controller for expression. It is quite heavy, so there's no skittering when you stick the rubber feet on the bottom, and the base is smooth and matt black paint, so Velcro is going to hold it well on a pedal board base. 

There isn't very much room, but I'm sure that someone is going to find a way to put a couple of LEDs inside so that the wheel hole lights up...

(I've tried modding one of my ordinary expression pedals so that they have two outputs, and the problem is that you need a pedal that uses the whole 270 degree range of the potentiometer - and the pedal I used didn't do that... My advice is to only try this on a pedal if you are expert in mechanics, which isn't me...)

With the EXP, it is very cool to be able to seamlessly blend from two very different effects, or even to find interesting points in-between the extremes. As with this type of thing, the more you play, the more you will find. So there's plenty of scope for exploration, and as for robustness, then I would have no hesitation using the EXP live or taking it on tour. 

Expression, and Voltages...



Now I could have used a photo of the EXP connected to the 'Expression pedal' input of a guitar effects pedal, and it would be ever so slightly boring and obvious. Instead, here's a photo where the guitar effects pedal is off camera, way to the left, and instead, the EXP is connected to a little bit of hardware (the 'EXP CV' box) that I threw together, because the design of the EXP also makes it well (maybe even uniquely) suited to also being used as a robust CV controller.


Nope. I haven't gone mad. Expression pedals output a voltage, which used to be somewhere from zero Volts-ish to somewhere less than 5 Volts. These days, processors tend to run on just over 3 Volts, and so somewhere in the range of 0-3V-ish is where you expect an expression pedal to output. 

(What happens is that a guitar pedal 'expression socket' does two things: it provides power to an external potentiometer inside the foot pedal, and then it receives the output of that potentiometer back as an input! So older pedals provided 5V power to the external foot pedal, whereas modern pedals only provide 3.3V. The potentiometer just taps off a percentage of the voltage, so if it is half-way round its whole rotation, then it outputs 50% of the voltage, so for 5V that would be 2.5V, and for 3.3V it would be 1.65V. The guitar pedal knows what voltage it outputs, and so it can calculate how far the foot pedal has rotated. This dual-function: providing a voltage output and a 'rotation' input, is why you need to use a 'stereo' cable for expression. So three (3) wires are needed: Ground (common to both functions, the Power (5V, 3.3V...), and the Rotation CV from the potentiometer - and a 'stereo' jack provides three connections. Note that the foot pedal doesn't care about the voltage - the potentiometer only outputs a 'rotation' CV that is proportional to how far it has been rotated. )

The range depends on the mechanical linkages used in the pedals - levers don't always seem to rotate the potentiometer through the full 270 degrees - as I noted earlier. But the EXP pedal does use the whole range, and so you can have two opposite outputs that both go from heel to toe. This is so cool, especially when you've tried to make a pedal like this and failed! 


So the mysterious box that is connected between the distant guitar pedal and the EXP is a new generation of my expression pedal range tester. It is ridiculously simple: two stereo jack sockets connected in parallel, and a 3.5mm mono jack socket for the CV output. 

To this simple circuit I have added a cheap three-wire voltage display module (a voltmeter) from Amazon, plus four AA batteries in a holder to provide power for the display. One of the things that isn't well publicised about voltage displays is that the two wire versions are powered from the voltage you are trying to display, and they typically need at least 4.5 Volts to work. So you can typically measure (and display) voltages from 4.5V to about 30V. When the display goes off, then you know that it is below 4.5V! 

But a three-wire voltage display module has an extra wire (usually white or grey) that connects to the voltage that you want to measure, whilst the usual black (the common ground connection) and red (power) wires go to a separate power supply - in my case, those four AA batteries in a holder. Anyway, the display is thus powered separately from the voltage that is being measured, and in this case, separately from the expression pedal socket of the guitar pedal. The end result is that the batteries give me a 6V power supply for the voltage display, which is fine for measuring the 0-5V (max) that expression pedals normally output. 

Using this voltage display technique to make some measurements, my M-Audio Expression Pedal can output between 0-2.75V to 2.84-3.14V for a 3.3V expression pedal socket, my Bespeco between 0-3.18V, my Nektar between 0-3.07V, and my Casio VP-1 between 1.68-2.56V. I will leave it as a challenge to you to figure out which pedal I tried to put a dual gang potentiometer into... 

The EXP? It produced 0-2.76V for one switch position, and 0-3.04V for the other position. So, for the first time in the review so far, a not-quite perfect result. But bear in mind that this is not a specified parameter for the EXP, or for any other expression pedal that I have ever bought, so I am being way beyond picky here. And when connected to a range of pedals (Empress, EHX,  TC Electronic, and Keeley), the EXP performed exactly as it should. 

One thing to remember when doing this kind of testing is that most guitar pedals seem to detect when an expression pedal is connected to their expression pedal input only when the power is turned on. So you need to power the guitar pedal down, insert the expression pedal (or EXP!) jack into the expression socket, and then power the guitar pedal up. The expression pedal (or EXP) will then be recognised! 

(If you just plug an expression pedal into a guitar pedal without cycling the power, then it may not be recognised at all - as I found out when doing all the unplugging and plugging...)

Anyways, in the photo above, the mysterious box displaying 1.24 Volts in blue digits is showing the output of the EXP when set to about a setting of 5, with the 'source' voltage from the guitar pedal's Expression socket of about 3.3Volts. That 1.24 Volts is what appears on the orange 3.5mm jack plug.

Yep, not a 'converter', more an extractor, or a rerouter, or an 'in another way' box. But yeah, it takes an EXP and outputs a CV. So what can we do with that?

First off, lets check the voltages and how they correspond to the EXP wheel setting:


Okay, so zero on the wheel is zero Volts. Cool.


Aha! So 10 on the wheel is 3.04Volts. Makes sense. So we have 3 Volts of CV range to play with... So 6 and a bit on the wheel would be about 2 Volts?


Yep.

One thing we could do with this is connect the orange 'CV' patch cord into something modular. The Rebel Technology 'Witch' is a good example. It is a programmable synthesizer, processor and effects unit that has CV and Gate inputs and outputs (plus audio I/O), is a USB Audio interface and Host, and does way more than you would expect for such a small box. A tiny modular system in a little box, and huge amounts of fun with elastic/flexible capabilities because you can reprogram what it does from a library of patches (and store eight patches inside the Witch for instant recall with those round buttons!). In this case, the CV input is controlling Input A, which sets the pitch of a drone patch. Now if the other EXP expression output was controlling a pedal using the expression socket, we have even more sound-making capability in a tiny space. Wooh!


Getting a CV output from an EXP is nice, but it isn't a MIDI Controller. or could it be? Here's that control voltage (the red cable) going into the CV input of the amazing Befaco VCMC - a Voltage Controlled MIDI Controller. So the MIDI socket in the top left hand corner of the VCMC is outputting MIDI Continuous Controller messages using a CV extracted from the expression control output from a Chase Bliss EXXP Pedal that is simultaneously controlling a guitar pedal off to the top left. Oh, and 8 on the wheel outputs about 2.64Volts...

Now to use this CV output in a larger modular Eurorack (or other modular), then you would need to scale this voltage to make it slightly larger. So some sort of Utility or Maths module would be the first port of call. After that, then you could use it to control just about anything. For me, having those numbers on the wheel means that I have a repeatability of setting a value that I don't get with foot pedal controllers, and being able to control two guitar pedals (in opposition, if I want) plus having a CV available as well, opens up huge avenues to explore...

Voltmeter displays

I need to point out that low-cost Voltage displays from Amazon are not always very accurate in my limited experience (Some may be - your experience may differ. Other voltage displays are available.). I've compared the values displayed here with my own slightly more expensive multi-meters, and whilst the multimeters are 'reassuringly' similar in the value they display, the voltage display tends to be about 0.3Volts lower. Not perfect, and so there should really be a little sticker on my EXP CV home-brew box that says: 'For Indication Purposes Only. Not Calibrated'. But for indicating what sort of voltage is coming out of the EXP, it works fine. And blue displays just look super cool!

Oh, and the EXP CV box that you see here is my own personal home-brew hand-built utility box. Not connected in any way with Chase Bliss Audio. It is not for sale (I don't do Klon pedals either...). If you happen to make a box anything like it yourself then that (and what you do with it) is entirely your own  responsibility - you do it at your own risk. 

The EXP pedal 


And that about wraps it up for this quick look at the astonishing piece of mechanical engineering that is the Chase Bliss EXP Pedal. There's a lot you can do with it, and it puts 'expression' control of guitar pedals into a rather different place when you go beyond the usual 'foot pedal' user interface. I really like having a 'Mod Wheel' for expression, and I intend to use my EXP a lot! Congratulations to Chase Bliss Audio for a very different approach to controlling expression!

I bought the Chase Bliss Audio EXP pedal with my own money. I am not getting paid by Chase Bliss Audio for this review. But I do think they make very interesting pedals. My kind of pedals! (And hopefully, yours too, now!)

Links






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Sunday, 31 October 2021

Vintage Synth meets 21st Century Multi-Effects (and a live gig!)

Back in the 1970s, analogue monophonic synthesizers didn't often have on-board effects. In the 1980s, DCO-based polyphonic synths added chorus to try and make up for the single oscillator. When the DX7 ushered in digital synthesisers in 1983, that didn't have any effects either. It wasn't really until the late 1980s that effects started to appear, particularly on workstation keyboards like the M1. 

Aside: Mawhrin Skel et al

As I've mentioned before, I have a couple of vintage synths, and enough outboard gear to do quite a lot of transformative processing on their sounds. But going to a live 'showcase' gig at the Smokehouse in Ipswich, kind of gave me a different perspective on current live performance. When you have seven performers in 4 hours, you need to be pretty slick with changeovers, and the solution they used was to have tables for the early acts (I spotted a 404 Mk1 (maybe II), a Crave, a Model:Cycles (or Samples), an (original?) MS-20 and more), with the penultimate act, Girl in a Gale, having a Nord Stage Piano, looper and various other bits of gear set up at the back of the stage, and the headliner, Mawhrin Skel, using a custom multi-tier stand with laptop on top, Push 2 for control, and various other bits of gear.  

Compact, minimalistic, and easily transportable were definitely high on the priorities for the rigs that were being used, and it was a refreshing alternative to the H9000s, H9 Max, Big Sky, Empress Zoia and CXM1978s that you find in all of those flashy 'home' studio pictures on Instagram. Which got me thinking about the opposite of Gear Acquisition Syndrome (GAS), which is something like Making The Most Of Budget Gear (MTMOBG - the acronym definitely isn't going to catch on!)... 

In fact, I was deep in thought about this when Girl in a Gale leaned over to me and revealed that ear plugs were available at the Bar. As it happens, I had actually bought my own ear defences: almost invisible and scarily hi-tech German ones that were totally essential at that amazingly loud Ableton Loop Concert in Berlin... But the sound at the Smokehouse was more constrained and controlled - I saw the sound engineer using a spectrum analyser on his phone, as well as an SPL meter. So, the usual low frequency 'physical' wobbles to remind you that music is visceral, and one of the early acts was intent on producing standing waves at about 70 Hz, but the PreSonus desk was coping very nicely, thank you.

An excellent gig, by the way... Mawhrin Skel was suitably sci-fi and enthusiastic, Girl in a Gale was a powerhouse of skilled invention, giving glimpses or sketches of music that left you wanting more, and overall, a varied 'selection box' of electronica. Venue and Music: Recommended.

The Opposite of Expensive...

But anyway, back to the opposite of expensive out-board gear... Some time ago, I started to look at something to process my Yamaha TX7 (the one where I replaced the LCD with a back-lit version ...), and started with thinking about something 'Multi', like an Eventide H9 or a MOD Devices MOD Duo, rather than a Sytrmon Big Sky, and then I realised that I was approaching this from totally the wrong direction. I was going to use a multi-effects pedal that was several times the original cost (and current value) of the synth - which seemed silly. So I happened across multi-effects designed for guitarists, and after realising that the top-end (the Line 6 Helix, Boss GT-1000, Headrush et al) was a money magnet, I deliberately looked at the opposite end - Amazon. (Well, Smile.amazon.co.uk, to help charity a bit). 

I've got a couple of pedal boards. The 'cheap and nasty' one has those 20 to 30 quid Behringer 'Boss' clone pedals on it, and is fine for live use and abuse. But I have learned that pedals boards, even with the considerable investment of crazily expensive switching/routing units, suffer from problems with recalling specific sounds. You can put the effects pedals in the right order, but what were the settings of all those knobs and switches? High-end pedals can use MIDI to store and recall presets, but that seems dangerously like a full-time job. 

It turns out that there is an alternative to the 'Pro' guitar multi-effects - for about 130 quid (150 Euros or dollars) you can get tiny little boxes that have built-in Expression/Volume pedals, colour LCD screens, and a couple of foot switches, and which do a very good job at providing quite a lot of the functionality of the 'around a grand, mate' 'Pro' multi-effects boxes. So, after a bit of research on YouTube (I hate the adverts!) I bought a Valeton GP-100 and connected the TX7 to it...

Okay, so there's a definite set of design decisions about the 99 Factory presets - and this is a 'Guitar' multi-effects (Actually, because of the 'Will be Mis-Used by Guitarists' design requirement, it is all-metal construction, and feels like it might survive live use quite well!). So there's a lot of fuzz, overdrive, saturation and just plain distortion, exactly as you would expect. But those 99 User presets and a computer editor (or the front panel controls) and you can concentrate on the Modulation, Delay and Reverb effects, plus a few extras that you might not be expecting: like a Ring Modulator, or a 4 Step Filter Sequencer. also, it turns out that having IR-modelled Amps and Cabs can give subtle tone variations, and you can load in your own .wavs for the Cabinet modelling, which opens up all sorts of experimentation. Oh, and you can arrange the effects in any order you like - so the Reverb does not need to be last in the chain... There's a looper built-in as well, and a Tuner. That's a lot for your money...

A couple of hours programming, and I had about fifty 'synth-oriented' presets that turned the TX7 into a host of alter-egos. One particularly nice sequence (the Arturia KeyStep is your friend) ended up as the sting/jingle for a corporate video I was working on... (I forgot to mention that it is also a class-compliant USB Stereo Audio Interface... which made recording it into my DAW a doddle...) Because every setting (and order of effects) is stored by the preset, then it just becomes a quick 'Paint By Numbers' 'Choose-a-Preset' procedure to turn a bland TX7 sound into something that sounds like it came from... well, from something else entirely. No need for trying to remember which pedals to switch in, and what the knob/switch settings were - you just select the preset. Simple - the sort of thing that even I could get right live!

Hiding the Truth...

I am considering putting the TX7 and the Valeton GP-100 inside a box (with suitable ventilation, of course) so that it isn't immediately obvious what is making that killer bass sound, or those ambient jangles. But regardless of pimping it up, it has been the bargain of the century. My only problem is that I have a feeling that at some stage, GAS is going to kick in and I'm going to end up upgrading... But they do say that:

Limitations are the Spur to Creativity...

So perhaps I should leave well alone, and leave my TX7V as my 'live' minimalistic secret weapon.

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Saturday, 16 October 2021

My Pianobook.co.uk Virtual Instrument User Interface

The world on which we live is precious, unique, too often taken for granted, fragile, not loved enough, beautiful, amazing... and continually astounds me.

I have always had the crazy idea that if I make a user interface that is totally obvious to me, then it must also be intuitive to everyone else as well. Sometimes (Well, my Probably M4L sequencer is a good example), I am very wrong. Actually, reset that word 'sometimes'. Just about every time I think this, it seems that I get it wrong. My user interfaces work for me, but not for everyone. For this I apologise. I'm not perfect, and neither are my user interfaces.

To try and fix it, here's the 'Words & Pictures' part of a series of resources that I'm producing with the aim of making my user interfaces for my virtual instruments on Pianobook.co.uk easier for people to get their heads around, and use!

Mattress


As you can see from the screenshot above, I'm going to use my 'Mattress' virtual instrument as the example. I've uploaded it to the review queue on the newly re-launched Pianobook.co.uk version 3.0 web-site, so it should be available there for download at some stage. My 'Spoken Pads' virtual instrument (Sample Pack) went from upload to being published in a couple of hours just before the launch event, but the site seems to have slowed down a little since then.

A quick shout-out for Rachel K Collier, whose YouTube channel just released a 'How to do a remix' video featuring Mary Spender's latest 'predictive' single (Adele, not John Mayer, this time), and this rather distracted me. I did make the third comment though, so I was a little early. I'm going to use the 'amazing' word again for both of these amazing musicians!


Yes, I'm using my current favourite, Decent Sampler, again. As you can see, there are two major parts to the user interface. On the left: Timbre controls. On the right: Synthesizer controls.

Timbre Controls



My interfaces have two (sometimes three) horizontal rows of controls. They are essentially little mixers, made out of the 'Mic' sliders that you sometimes find in sample players for choosing microphone polar pattern/response shapes and characteristics, plus their positioning. So you might have a cardioid close up to capture an 'intimate' close-up sound, and an omni far away to pick up the room. And no, a 'shotgun' microphone is not used to pick up the sound of guns!

To give some leeway in levels, I deliberately set the volumes of my samples so that a slider setting of about half-way is okay for most purposes. You can set it higher to make something stand out, but overall, about half-way is good. Too many maximum settings may well overload things, which is either what you want, or what you don't want - your choice.

Sometimes, for samples that are minor, special 'tiny' 'Mic' sliders are used, typically half the width of the ordinary 'Mic' sliders. These work the same way - they just take up less room, and are less important!


When there are two (or three) horizontal rows of 'Mic' sliders, then the intention behind the design is then same - you choose one or more 'Mic' sliders from each row, and set them to about half-way (don't overload things, remember?). 


One exception to this would be those tiny 'Mic' sliders, where you can add them to the main, big, 'Mic' sliders! Remember that they are small because they have one, special purpose - often sine waves or noisy sounds.


The basic 'initial' preset usually has the left-most 'Mic' sliders set to about half-way up. The idea is that you work your way across to the right, auditioning 'Mic' sliders until you find the ones that give you the sound you want.


Here's another reminder about those levels. Half-way is fine!


The rows are often organised into smaller blocks, sometimes internally arranged in pairs. There is often a gradual change from left to right - so 'Pure' sounds on the left might gradually change into 'Noise' sounds on the right. Sometimes the left to right arrangement is octaves: sine waves are often low pitched to the left, and higher pitched as you go to the right. 

Synthesizer controls



On the right hand side are the 'synthesizer' controls, which change how you can use the timbre that you have set using the controls on the left hand side. These are more about 'shaping' the sound, rather than setting the timbre itself.


The very first control would traditionally be on the far right hand side in most classic 70s and 80s synthesizers - the volume control. But in a sample player, then the major use for this control is very different - it isn't used to set the output volume of the synthesizer and then never touched again during performance (which is why it is way on the right (or sometimes the left in 21st century synths)). Instead, this control is used for 'Expression' - the minor changes in volume that a performer makes all the time with a real instrument. 

People who use MIDI to sequence music often use velocity for this purpose, because when you play a synthesizer with both hands, then you don't have any hands left to move an Expression control. Now, this isn't the case for a traditional pipe organ player, where their hands are playing at the same time as their feet are playing bass on those long wooden 'keys', or even controlling volume (Expression) using a foot pedal. For some reason, synthesizer players don't seem to use volume pedals very much, perhaps because at least one of their feet is controlling the sustain footswitch. And it seems that very few multi-dextrous pipe organ players move over to playing synthesizer. If you do see a synth player who uses expression pedals, then they are probably special!

If you are programming orchestral instruments in a DAW, then velocity is a strange way of controlling a violin, flute or oboe. Instead, the Expression control (MIDI Controller 11, usually) is a good way of having a continuous controller on the DAW screen that shows the 'volume' of that part as a line. Velocity of notes is normally shown as individual events, and it is harder to see trends, as well as being harder to edit. Some instruments ARE more suited to using velocity: pianos, double basses, brass instruments, and  percussion are some examples.     


Anyways, in sample players, the Expression control is one of the most important ways of controlling the ebb and flow of an instrument relative to all the others in an arrangement. In DAWs, you will see people record the notes first for a violin or woodwind part, and then go into that track and adjust the expression by editing MIDI Controller 11 to give the 'feel' that they want. You will also then see the same person record a piano part using velocity to control the 'expression' or volume. Just as in a real orchestra, the way you perform music with different instruments varies.

So the 'Expression' control is lots more important to orchestral composers who work in DAWs, and they tend to be the people who use lots of virtual instruments. Keyboard players who normally use velocity and record MIDI into a DAW and then edit the velocities, are probably not going to use the Expression control anything like as much. (Unless they know about this and deliberately exploit velocity AND expression...) This, by the way, is the sort of knowledge that expensive courses on arranging and orchestrating sell you...)


The Expression control affects volume on the grand scale. At the opposite end, the 'Envelope' controls affect the volume of each note over the time it plays. Historically, there's a very popular way of representing how the volume of a note changes over time: the start bit, where the note goes from silence to being heard, is called the Attack; the next bit where the sound falls back to a lower level, is called the Decay; the level that the note stays at is called the Sustain level; and the final bit, where the sound falls back down to silence again, is called the Release. These tend to get abbreviated to ADSR, and some manufacturers have the Release and the Decay set to the same value, but the models is more or less the same in all cases: three times (ADR) and one level (S). Of course, if you set the Sustain level to the maximum, then no Decay can happen and the sound just goes to the maximum and then falls when you let go of the keys - an AR envelope (and yes, it should be ASR, but conventionally, that isn't done!). 

One of the things that confuses people who don't know that the envelope is three times and one level, is that the shape made by the envelope controls (especially sliders) isn't what the envelope actually looks like. So in the example above, you could be forgiven for thinking that the note would start out loud, then go quieter, then go louder again, and then go quieter again. What those slider positions really mean is that the sound takes some time to do the Attack 'segment' of the note (i.e. it isn't a fast abrupt start, but it isn't a slow laboured one either), then decays slightly faster to a middle 'Sustain' volume, and then dies away slightly slower than the initial Attack. 

If you haven't use an envelope before, then set the Sustain all the way to the top, ignore the Decay control, and play with the Attack and Release controls. When you understand how the A and R controls affect the 'shape' of each note, then set the Sustain to the minimum, and then try adjusting the Decay control, plus the Attack and Release as before. When you have got that figured out, then set the Sustain to half-way up (or down) and listen to what the ADR controls do this time. You shouild now have a good feel for how envelope controls work.


If you listen to most musical instruments, then the start and end of notes is not linear. Notes start quite quickly, but seem to take longer and longer to get to the maximum. When a note ends, then it drops away quite quickly at first, but then it seems to take a long while to vanish altogether.  You can see this in the shape of envelopes that are used on screens and in diagrams - the segments are curves, not straight lines (in most cases!). 

As a further complication, whereas the Sustain control generally work as you would expect, the relationship between the 'time' controls and what happens in reality may be different. Some synthesizers and sample players can require moving the control almost to the very maximum to get a really slow Attack, Decay or Release, and some can only do fast ADR when they are very near to the minimum. This can vary a lot. Taking a few minutes to get a 'feel' for what positions of the ADR controls does what in terms of time can be very useful.


 To reinforce the importance of 'what the sliders show is NOT the envelope shape', the two envelopes above show this very clearly. If you have spent time learning the controls, then this should now make more sense to you.


The next controls affect the tone of the sound that is produced. For historical reasons, many synthesizers (and sample players) tend to use a low-pass filter for controlling the tone. 'Low-pass' means that when the frequency control is set to a low value, then the only low frequencies can pass through the filter, and as you increase the value of the frequency control, then more and more higher frequencies can pass through the filter. So a low-pass filter 'cuts-off' high frequencies - and so the frequency control is called the 'Cut-off' frequency. 

In sample players, the Tone control is often assigned to the Modulation Wheel (MIDI Controller 1), so moving the mod wheel up opens up the filter and makes the sound brighter, whilst moving the mod wheel down makes the sound darker and bassier. In most synthesizers, the mod wheel usually controls the amount of LFO modulation (hence the name) to the Pitch of the notes or the Filter cut-off - or many other parameters. Once again, sample players and synthesizers differ slightly in the eay that they are controlled. In a virtual instrument from a Sample Pack that you have downloaded from Pianobook.co.uk, then it will probably have the controls of a sample player, so the Low-pass filter cut-off frequency (the 'Tone') will be controlled by the Modulation Wheel as MIDI Controller 1.

The other control over tone is the 'Q' control, which comes from radio terminology. A more musically appropriate word here would be 'resonance'. At low values of Q, there is no strong resonance in the filter, and so as you increase the cut-off frequency control, higher frequencies can pass through the filter, so it gets brighter and brighter in tone. But as you increase the Q control, the the filter becomes more and more resonant, and so it emphasizes the frequencies at the cut-off frequency. This makes the harmonics in sounds stand out more, and gives a characteristic 'Weeyaheeoouuh' sound (you can do this when you open and close your mouth and make a sound). 


The final two controls on the right would be unusual in a 70s or 80s synthesizer: reverb. But again, in a sample player, reverberation is very common in the 21st Century. 


Again, there are two controls. The 'Size' control sets how large the reverberant space is, and so changes how big it feels, as well as how long the reverb lasts.


The other control, shown in my user interface as 'Verb', is just the Wet/Dry mix of the reverb. So the higher the control value, the more reverberation you will hear. This is assigned to MIDI Controller 19 in my virtual instruments, but this can vary with manufacturer for other sample players. 


Summary

And that's how the user interface for my Pianobook.co.uk virtual instruments in Sample Packs are intended to work. Some of the instruments have variations of the controls (older instruments may have rotary controls instead of the new linear ones in the latest ones), but the principles remain the same, and the idea is that you should move sliders around, listening as you go, and gradually home in on the sound you want. Decent Sampler lets you save any sounds you particularly like by using the Developer>Save Preset... menu options. This is how I made the presets which come with some Sample Packs.

One thing that maybe isn't immediately obvious is that I try to ensure that each of my instruments contains a lot of different timbres and sounds. Even simple sounds like the Synthfest UK Water Bottle have multiple controls that change the mix of the separate timbral components. Or 'Parallel Inversions', where what might initially sound like an organ is something much stranger than you think, with all sorts of tricky detunes and autos... It is nice to see people discovering the unexpected details in their reviews - and I love reviews! You probably won't be surprised to know that my favourite Spitfire Audio product is BT Phobos, which is much the same idea: give people lots of possibilities and lots of control, and let them find their own sounds! So maybe I should call them 'Sample Libraries' instead of 'Sample Packs'.

I hope that you enjoy using my Sample Pack virtual instruments. A lot of time and effort goes into producing the samples and the instruments, and there is often special thought given to the musicality of the user interface and the sounds. There are even some minor Easter Eggs in the form of inverse controls or ranges or pairings, just to surprise the unwary. I also can't praise enough the amazing people who produce the Pianobook.co.uk Demos - they are experts at extracting the maximum musicality out of virtual instruments, and you should definitely listen and learn from what they produce.

YouTube

There is also a video of this topic, with the same diagrams, but without any distracting text, and no voice-over!


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Friday, 1 October 2021

Behind the scenes of the 'Straight Maths' Virtual Instrument on Pianobook.co.uk

I have been exploring the possibilities of mis-using a sample player recently. Dave Hilowitz's excellent 'Decent Sampler' is, imho, not only much better than merely 'decent', but it has also allowed me to go slightly outside the usual territory of samples and to become an intrepid explorer. Huge thanks also to the team behind Pianobook.co.uk - a great contribution to the world of sampling, created by Christian Henson.

So here is a quick recap of the design thinking behind two of my recent releases on Pianobook.co.uk.

Parallel Inversions

'Parallel Inversions' was my first really developed idea that isn't just a sample replay. It deliberately breaks the rules to produce an 'alien' instrument. In a 5 star review, Michael Milburn said; 

'I don’t understand what these are, but do enjoy the sounds.'

The user interface is the first thing that hits people with this virtual instrument. The top row of controls has 23 vertical faders that look a bit like the 'Mic' sliders that you see in many sample players - except that instead of 2 or 3, or maybe 5, or (extreme) 7 or higher, there are almost two dozen of them! They are split into four sections, and there are some subtleties in the way that these are put together.

The most important section is the one that has the 0 to 4 'Mic' sliders in it. The 'Zero' slider is set at about 75% in the default preset, so that you know it is important. This slider plays the 'fundamental' frequency that is played by Decent Sampler, or rather, it plays that frequency sometimes - the XML code that Decent Sampler uses to specify how samples are played allow all sorts of manipulations, and I'm exploiting this here. So the 'Zero' / '0' slider plays three different octaves, using a random 'Round Robin' assignment. So if you play a C3, then you will actually get a C3, or a C4, or a C5. The ratios are set asymmetrically, with the 'octave down' option half the probability of the others. So for every chord that you play, you may get that chord, or you may get a biased inversion of it instead (a 'bass-light' inversion). This isn't how many instruments work! (But it is an 'alien' instrument...)

The 1 to 4 Mic sliders are actually pitched in semitones up from the 0 (zero), which is why they are arranged in the staggered 'piano keyboard' arrangement. This is immediately obvious if you increase the '1' slider, because you get a C / C# discord! So the 0 to 4 section controls parallel pitches, which (again) isn't how many conventional instruments work - organ drawbars are a bit like this, but...).

The next section to the right is from 5 to 11, and again these are parallel semitones up from the 0 (zero) pitch. The '5' (fifth) slider is set at about 75% in the default preset so that you know it is important (just as with the 0 (zero) slider. So the default preset plays two sine waves, a firth apart, and in both cases, the pitches are inverted (or not) at random, with a preference for one octave up instead of down. All of the inverted pitches are slightly detuned relative to the fundamental pitch, which gives a more interesting tone. All of these 'Parallel & Inverted' sliders are centred in the stereo image.

The combination of fixed parallel intervals (the default 5th is just intended as a hint to get you started) and random inversions kind of breaks 'the rules', and gives this instrument an interesting and unusual character. Have fun breaking all those conventions that you are supposed to follow, and embrace performances that are never the same twice!  

On the far left, there is a single '-12' slider, which was supposed to play a pitch one octave down from the fundamental. Unfortunately, I'm not the world's greatest programmer, and so it actually plays the same pitch as the '0' (zero) slider, except that the random inversions mean that most of the time it plays a different octave. Although Parallel inversions has had 3 versions, I have left this defect in there, because serendipitously, it sounds good. 

The A to K sliders are different again. This time they are panned either hard left or hard right, and they are distorted sine waves, instead of the purity of 0 to 11 and -12. So the A to K sliders add timbre and broaden the stereo image. Again, this isn't how normal instruments tend to work, but...

Finally, the lower row has more 'synthesizer'-type controls than is normal, with a full ADSR 'envelope' control, and I recommend the 'Attack' control for giving gravitas, and the 'Decay' control (with 'Sustain' set to near zero) for adding a 'Radiophonic' or synthetic character that sounds like it is from the 1970s. 

Straight Maths

'Straight Maths' has a busy user interface, but it extends some of the ideas in Parallel Inversions. The left hand side has 48 'Mic' sliders (yep, a lot!), whilst the right hand side has the extended 'synthesizer' controls, but in a more compact vertical format.

The three rows on the left are devoted to three different types of sound source. 

S - Top Row - additive synthesis

The top row (S) is sine waves (with twists) to provide simple Fourier additive synthesis. The '0' (zero) slider is again set as a hint that it is the fundamental in the default preset, but it does tend to get lost with all the other sliders! 

The three blocks of four Mic sliders on the top row have, from left to right:

- a Sine wave (0, 1 or 2 octaves up, shown as 0, 1 or 2), panned to the centre,

- a hollow-sounding, slightly square waveform (-), panned to the centre,

- a slightly bright, slightly sawtooth'y waveform (N (get it?)), panned to the centre, and 

- a detuned stereo 'sweetener' sine waveform (s) that adds a bit of interest and broadens the stereo image. If you want, you can ignore the 's' sliders and add your own preferred chorus effect via VST or outboard...

Yes, there's a bug with the 'S' in the two octaves up section, but that's part of the charm of the user interface, and does not affect the tone! 

The '-2' and '-1' mic sliders are sub-octave sine waves that can add low end to sounds. Use with care! 

As with all additive synthesizers, you mix and match the sliders to give you the combination of harmonics that you want, and then use the ADSR controls to give the sound a bit of shape in time. 

M - Middle Row - Karplus-Strong physical modelling

The second row has 16 different samples of metallic-sounding decaying sounds, derived from the Karplus-Strong hammered/plucked string physical model. '13' is my personal favourite, but it is way too strident for most purposes, and so just the merest hint of it is usually plenty! I resisted the temptation to arrange the sliders in any sort of order (previously I tried a 'tone-to-noise' arrangement), mainly because when I have tried to do this, I have rediscovered just how difficult it is to arrange multi-dimensional differences into a linear order. So I'm afraid that you will just need to play with the sliders until you get used to the sounds. Oh, and 10 and 11 ARE different, but not as different as I wanted! 

The 16 sliders are all tuned slightly differently, and are all stereo. This means that you can use combinations to add harmonics and detuning

My preference is to use the middle row to add a little bit of metallic 'bite' to sounds that are mainly top-row additive at their core. You can completely ignore this and do your own thing, of course!

W- Lower Row - Risset physical modelling

This row mis-uses Risset's work on synthesizing drum sounds, and adapts it to producing 'woody' sounding fast-decaying thumps and clunks to add percussive starts to the higher row sounds. There are four sets of sounds, arranged with the left-most sound in each set being the thickest (three sounds at once) and the others just single sounds. The detuning is toned back for most of these samples. These sounds are in mono, centered in the stereo image. I did play with stereo samples, but at low frequencies there isn't much to gain. To show how self-contradictory I can be, my '9126 Sawtooths' instrument on Pianobook.co.uk has way too much stereo bass!

It is quite fascinating how just a brief 'blip' of woodiness at the start of a sound that is all sine waves can totally change the character and timbre that you perceive. (Oh, and too much reverb is always a good idea!) This low row is influenced by the clicks found in old tone-wheel organs (the idea of adding percussive starts is not 'new' in any way!) and by the rather novel use of samples of the starts of instruments that Roland used in their D-50 synthesizer to augment a simpler digital synthesis technique for the sustained sounds. Roland called this mix of samples and synthesis 'Linear Arithmetic', so 'Straight Maths' is my way of paying homage to a classic 'personal favourite' synthesizer from the 80s. Okay, so now you know where the name comes from!

As before, the lowest row is used to add a little extra bit of character to the sound. The default preset  deliberately adds too much 'W' so that your first experience of 'Straight Maths' is 'Wow!'. Maybe that what the 'W' really stands for? But remember that subtlety is often the best approach, and too much 'W' may take you into cheesy territory...

Trivia

The rows were going to be labelled as: J, AK and C, for Joseph, Alexander, Kevin and Claude, but I thought this might be too obscure. What is interesting is that you now know a famous 'Kevin' - although Karplus still sounds uber-cool to me!

Letiti gave 'Straight Maths' a 5 star review, which is much appreciated, including this comment:

'One of the most innovative and unusual Pianobook entries'

For which I am enormously grateful!

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Thursday, 30 September 2021

Step sequencer for echo delay time...

Now if this was a YouTube channel, then I might well be posting videos with click-bait titles in an ongoing quest for subscribers (or publicising an amazing device like the Rebel Technology 'Witch'!). 

But this is a blog, and I'm happy to post anything I do, that might be useful, which is why there's an eclectic mix of topics on here. And yes, I know that I haven't covered MaxForLive for a while, and there's a very good reason for that. 

Anyway, here's a little bit of fun that might be useful to some of you, or could serve as inspiration for further exploration. I'm almost tempted to post a version on YouTube with a Click-Bait-oriented title just to see what happens... 'Expression Sequencing - What you need to know!' 

Photo by Steve Harvey on Unsplash

Step Sequencing

Okay, I admit, I've been a fan of step sequencers since seeing Tangerine Dream back in the 70s at the Liverpool Empire. Dry ice clouds, mist curtains, mirror balls, CO2 lasers, guitar solos from Edgar Froese and just one or two step sequences - it was quite an experience. Since then, I have acquired a few hardware step sequencers (a Zaquencer, for instance - very nice!), and programmed a few (several in MaxForLive, for example), but my latest acquisition is a little bit different: a mix of old school (8 steps!) and new-ish school (MIDI Clock sync!). But not a Eurorack module - nope, this is a 'guitar' pedal. 

Now, I was raised on Electro-Harmonix pedals (I always wanted an Electric Mistress Flanger!) and I've gradually been getting a few modern examples, purely for research purposes, you understand. The 'pedal' in this case is on the borders of the pedal-world - it is the 8 Step Program: a CV/Expression sequencer. 

Sequencers in pedals are quite unusual, or at least, from my limited viewpoint, that seems to be the case. The Strymon 'Night Sky' has a sequencer to ty and liven up the shimmer reverb, is one example, and I'm not immediately familiar with any other examples. Of course, with thousands of pedal manufacturers and hundreds of pedals released every month (week? day? hour? minute?), then there could well be many other examples, but I'm beginning to think that it is not humanly possible to keep up with pedal releases any longer. Although, if anyone can, it would be Josh Scott of JHS Pedals...

Actually, the step sequencer that I'm talking about is quite unusual, even in a world where unusual and rare seems to be the starting point for a product, and you probably need endorsements by several online influencers just to rise above the lowest levels of noise and avoid being totally ignored. Electro-Harmonix do not shy away from making radically 'different' pedals, and they have a huge range, plus a long and fascinating history. 

Anyway, the '8 Step Program' is s step sequencer for Expression Pedal control signals.

My EHX 8-Step Program pedal!

You read that correctly. Whilst it can also output control voltages (from 0 (zero Volts) to 5Volts), it is mostly intended to act as an automatic Expression Pedal, so instead of you having to move your foot from heel to toe on an Expression Pedal, then the 8 Step Program will do it for you, repeatedly if you prefer, at a user-variable rate, or you can advance through the steps manually, or just trigger a One-shot single run-through. At the borders of 'step sequencing', there is also the ability to select steps at random, which always sounds more like a slow random noise generator to me, although it outputs a very structured type of noise where the levels are known, but when they will occur is not known.  I'm going to step away from this topic before any 'unknown unknowns' are mentioned!

Oh, before I forget, sincere thanks to Andertons for managing to procure me an '8 Step Program' on special order. It is definitely worth the wait!

Ubiquity or Not

Lots of guitar pedals have a socket marked 'Exp' or 'Expr'. Not all pedals have them, and for those that do, there are at least two different ways to wire the socket (and the pedals) in common usage (see this blog post...). So not quite ubiquitous, but certainly widely available. As that previous blog post rather gives away, I'm one of those people who likes to use a foot pedal to change one or more parameters on a pedal, and so I have 'one or two' Expression Pedals'. 

I've always been confused by the naming convention for guitar pedals, and that ignores the weirdness that you can use them with things other than guitars! One of the first pedals I ever bought was a Colorsound Wah-wah pedal (Not this modern re-creation and not from Macari's, but way older and from somewhere else, lost in the fog of time...) and this was indeed, a pedal. There was a bit that you put your foot on and moved it, and it changed the sound, and it looked like a sort of hi-tech equivalent of the pedal that my Mum used to control her sewing machine. So my mind is forever locked into the mind-set that a pedal is a thing that you move (heel and toe positions, plus in-between) with your foot. A foot-pedal. A Guitar foot-pedal. 

But then there was another type of guitar pedal, and it didn't have a wobbly bit on top where you put your foot. Instead it had one (and sometimes more!) push switch that made a metallic snicking sound when you pushed it - and this turned the effect on or off. Bypass was the word - on or off. To change the effect, you turned small rotary controls - too small and awkwardly placed for your foot, of course. Most of the foot-switches were chrome cathedrals of mechanical complexity, but there were also ones with black plastic tops that didn't have the same satisfying metallic clunk, and which were apparently notorious for 'going wrong'. Nowadays, I only ever see the all-metal variety of foot switch, so I imagine that the plastic-top ones have died out. 

When there are two things that are different but share the same name, then confusion is not far away. As I said earlier, I've always been confused by guitar pedals: some of which have a foot pedal, and some of which don't, but they are still called pedals. Expression Pedals, which don't process audio at all, and only control other guitar pedals, via a TRS or 'stereo' cable, are a third type of pedal again. Your task, should you choose to accept it, is to try and persuade me that there are three types of totally different device, all called the same, where:

- one device processes audio

- one device processes audio, and has a pedal that your foot moves

- one device does not process audio at all, but controls a device that does process audio.

 And these are all Pedals?

Sequencing...

Let's look at what you can use Expression for. That Colorsound Wah-Wah pedal is a good starting point. The foot pedal bit changes the audio that passes through the Wah-Wah pedal - it's a band-pass filter where the centre frequency of the filter is controlled by the foot pedal that your foot moves. The sound is a rough approximation to the band-pass filter that your mouth makes when you open and close it. Try saying 'wah wah wah...' and see how your jaw moves, your mouth opens and your lips move. If you say 'Waaaooouuuw' then your mouth, lips and jaw will all be moving a lot! 

Take a moment here to let the skin on your face return to normal after all that stretching...

Auto-Wah removes the foot pedal and replaces it with an LFO - a Low Frequency Oscillator. A circuit that wobbles something - in this case, the wah-wah effect. So the centre frequency of that band-pass filter wobbles up and down in frequency, and you don't wear out your foot or ankle by moving the pedal back and forth all the time. So the foot pedal bit has gone, and we have just a 'Bypass' switch to turn the effect on or off. 

Of course, some Auto-wah pedals have Expression inputs, and if you connect an Expression Pedal into that input, then you have a foot pedal that controls another pedal!  So if you don't want repeated Wah-Wahs at the rate set by the LFO, then you can use the Expression (foot) pedal to do the 'wah'ing yourself, at whatever rate you want. 

The 8 Step is like an Expression pedal, except that it doesn't have a foot pedal bit that you move with your foot: instead it has 8 linear slider controls that are activated in turn by an LFO. So you get up to 8 different settings of a non-existent foot pedal, sent down a TRS 'stereo' cable, to another pedal where those settings affect the audio. 

If you really want to blow your mind, then the 8 Step Program also has an input for... an Expression Pedal!

Wah, not wah...

I haven't been using the 8 Step Program to control Wah-wah effects. I've been playing with Echo Units or Delay Lines - audio boxes that apply echo or delay to audio signals. Small cyclical changes to the delay/echo time produce flanging, chorus, tremolo, vibrato and other 'Modulation'-type effects, but sudden jerky changes have a very different effect - they change the rhythm of the echoes. If you change the timing of echoes or delays with a Step Sequencer, then you get a sequence of different rhythmic echoes. It's an interesting and unusual effect - particularly because it doesn't settle down into a fixed rhythm. The echoes are always changing, and if the rate of the Step Sequencer (in the 8 Step Program) is not synchronised to the timing of whatever audio you are processing (a drum machine, or groovebox, or a synth playing a sequence, then the two different rates should drift past each other, and you should get 'skying', where things gradually change in a way that is beguiling, non-repetitive, and addictive.

So, above is the setup. The 'Expression' control signal goes along the TRS 'stereo' cable from the 8 Step Program device to the Echo pedal, and inside the Echo pedal, the Expression is mapped to control the delay time. The 8 Step Program's 8 numbered 'step' sliders are set to a rising stepped 'sawtooth' type of waveform, and the Rate slider on the 8 Step Program is set so that each step is close to one repetition of a drum pattern or a sequenced synth line. 

The results are 8 different patterns of syncopated echoes, because the steps from the 8 Step Program give the equivalent of 8 different settings of the 'virtual expression pedal' that the 8 Step Program is emulating.  Unlike a human being, the 8 Step Program reproduces those 8 steps more or less exactly the same each time, and so it is possible to really hear the 8 different patterns cycling through. Best of all, the Rate slider of the 8 Step Program and the audio clocks are not in sync, and so the patterns gradually change as predicted. 

What I haven't checked out yet is to use a MIDI Clock to do the exact opposite: put the 8 Step Program and the audio into sync. Even when I do, then there is still scope for additional experimentation. The 8 Step Program allows the number of steps in the sequence to be changed, so the length could be set to 7 steps instead of 8. This would mean that even though the 8 Step Program, I mean the '7 Step Program', and the audio drum machine or synth sequencer are in sync, there is a 7:8 ratio of timing, and so they will drift or slip against each other, and so they will generate long repeating patterns that last over many bars. So that is ratios of 1: 8 through to 7:8, plus 8:, which is in sync.

The 8 Step Program also allows the step sequence to run in Reverse (which isn't going to be very different - the patterns will just be different), and in Bounce mode, where the steps go back and forth from 1 to 8 to 1 to 8 etc., scanner-style. Now this 'bouncing' is 15 steps in length, which means that we can have ratios of 9:8 through to 15:8. There's quite a lot to play with here.

There's one final mode for the step sequence., and that is Random, where the steps are not output in sequence, but at random. So after step 1, then any of steps 1 to 8 could follow. This will again give 8 different syncopated echo patterns, but they won't be in any order, and so there will be less obvious patterning for a human being to detect - plus the patterns will not repeat after the same number of bars each time, because the patterns are selected randomly. Again, there is lots of scope for exploration here.

Other devices... 

I've always liked Echo as an effect, but any pedal with an Expression input socket can be used with the EHX 8 Step Program. So Reverb, Flanging, Phasing, Tremolo, even Wah-wah could all be controlled using the 8 Step Program. And all of this complexity and syncopation is totally DAWless!

The 8 Step output is also a Control Voltage (CV), and so with a 1/4 inch jack to 3.5 mm jack, could be used to control Eurorack modulars. In fact, the Expression Pedal input of the 8 Step Program can be used to control parameters like Rate, Depth, Glide (You can set how quickly the steps go from one to the next - a bit like Portamento on a keyboard..) and Sequence Length, as well as a Clock input, so there are many more interfacing options there with modular synths. 

MIDI-wise the 8 Step Program has full MIDI Control over programs of steps, plus all the parameters.  Future investigation for me...

Summary

The Electro-Harmonix 8 Step Program is just a small pedal, but there are lots of ways of using it in a DAWless setup to do things which will sound complex, syncopated and yet, can have the unpredictability, drifting and all of the unexpected serendipity of analogue modular. Using the 8 Step Program to drift through some syncopation delay effects from a DAW output might also change some opinions about the inherent boring repetition that you get with a DAW. I'm wondering if there is scope for a contest where people compete to fool a panel of judges with their DAWless or DAW systems... Now that sounds like an interesting event for a synthesizer booth type gathering!

So you can hear how all this sounds, there's a YouTube version of this blog article on... YouTube!  There are only a couple of examples, but I'm sure that you can come up with your own. Just tell EHX or  Andertons that I sent you when you get your own 8 Step Program!

The EHX page for the 8 Step Program lets you download the manual, which is full of loads of details about what it can do. Please try not to drool onto your screen...

(Note that I bought the EHX 8 Step Program with my own money, from Andertons. This blog post was not sponsored by EHX or Andertons. I just buy stuff from them because I like them!)

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