We are now (officially) offering custom baseplate Laser-Cutting service. You get two custom baseplates for the minimal $15 service fee. The baseplates are precision cut based on your specifications and individually hand-buffed to perfection. Send us your specifications: http://www.cycfi.com/contact/ and we will send you back a CAD drawing (DPF and DXF) for confirmation (see example below).
Category Archives: Design
A little background: I’ve written a series of articles before about Virtual Pickups and how they are implemented in software (DSP). It’s a three part series: Part 1, Part 2 and Part 3. I wrote about Standing Waves, Nodes, Antinodes and Pickup Position, Comb Filters, some underlying Math and Simulation in DSP code. I also presented what I thought was a minimal interface I really like.
It has taken a while (I can’t believe it has been almost 2 years now!), and now I’m back to writing the software. What has transpired since then? Production of the XR and the Nu took the most of our time and I’m left with very little time to do what we I best: R&D. Now that the Nu is out, it makes sense to go back, pick up and continue where we left off, starting with the GUI.
It’s nice to see our pickups in the academe. Chengxiang Ren and Jeffrey Huang, Cornell University, Electrical and Computer Engineering, used the Cycfi Neo (now Nu) polyphonic pickups in their Master’s project. I’ll try to learn more about this project and these cool people. Their ideas are perfectly aligned with mine.
In this project, we designed a computational guitar that consists of a hexaphonic pickup and a digital signal processor (DSP). As an example application, we implemented a pitch correction algorithm that corrects the pitch of each string in real-time, which enables us to play the guitar “in-tune” when it is not. Our pitch correction algorithm operates in real time on a Texas Instrument DSP board (TI DSK6713) and combines frequency-domain pitch detection and time-domain pitch shifting.
Last time, I hinted at ways to mount the pickups. Surely, a guitar builder will find a zillion ways to mount these modules. I’ve had inquiries, not only from Guitars builders but from Violin and Cello builders too! I bet these builders have cool ideas how to mount these bad boys. Here are some examples. Images convey a lot of information, so here again are some 3D renderings for your perusal. Click the images to zoom in!
Which one do you prefer? Comments and suggestions welcome (in the comments box below or in our FB forum).
How do you mount the Nu modular pickups? You’ve seen the basic Nu capsules before. Mounting these miniature pickups might be tricky. One way involves making a printed circuit base-board where these pickups are soldered into. As I said in the previous post, the problem is that we need a multitude of base-boards for different string spacings, number of strings and skew. That defeats the intent of the modular design.
The Nu modular pickup is ready. It’s been ready for quite some time now. The design and implementation is just about perfect, I would say. The next evolutionary step from its predecessor, the Neo, the sound is superb, the clarity and separation is amazing.
So… for those who have been patiently waiting, if you want them now, send us a message. We can arrange for an initial batch for manufacturing. But here’s the thing… At this point, the initial batch will be for uber-tech-savvy builders only. Be warned that this goes way beyond a standard pickup install. A multi-channel system requires an elaborate setup for processing each channel. I will assume that you know what to do with these pickups. If you are a builder with background in electronics, then this is for you. You know how to incorporate these pickups in your design, including mounting, power, audio routing, wiring the multi-pin connectors, and perhaps building a breakout box. All designs (schematics, PCB layout, software, bill of materials, and CAD drawings) will be provided.
But There’s More…
Innovation is so hard! People often ask me why I don’t just do it like everybody else; —you know, the “tried-and-true” path. The easy path. Well, I enjoy innovating and I’m not complaining. Such is the nature of Research and Development. Anything worth doing is not easy. We have this box full of failed projects as proof!
Now it turns out that the multichannel sidewinder project is another dead end. All tests (power tests, noise tests, spectrum analysis) ran perfectly, except one. It failed the crosstalk test. The original Neo multichannel pickup still proves to be the king of the hill with measured -38dB crosstalk. Contrary to what I initially expected, crosstalk is worse with the side-wound pickups measuring an abysmal -24dB 🙁
The side-wound double coils are both a blessing and a curse. Its sensitivity is very good! But that also proves to be its undoing, at least for multichannel pickups. It can easily detect signals from adjacent strings. On the other hand, it is a blessing for the monophonic sidewinder where the extra sensitivity gives it better balance and uniform response.
In short: the monophonic sidewinder is still a go. We are gearing up for production now. All tests are as perfect as ever! As for the multichannel sidewinder, we’re back to the drawing board with the goal of surpassing the original Neo multichannel pickup‘s performance. Now that’s a tough goal!
We want to push the limits of what we can do with the electric guitar. The Neo project (starting from the Six pack project) is a stepping stone towards our goal. And from the very start, our goal has always been polyphonic sustain. Polyphonic sustain, plus extensive processing for each string, will give us musicians full control over the dynamics of the guitar. This is my holy grail and as you can see in our previous proof of concept demonstration, we’ve come closer to that goal than ever before.
Presenting the Infinity Polyphonic Sustain system:
It takes a lot more than just slapping together six EBows. A very early prototype employed a 6x analog feedback system just like the Ebow. It worked but was rather unwieldy and impractical. The phase at the driver (neck position) lags behind the phase at the pickup (bridge position) and you need some form of phase shifting (using analog filters) to align the phase properly for sustained oscillation. Without phase shifting, you have to use more force than necessary to get the string to oscillate, and that wastes too much power.
All it should take is a little nudge. That’s what I always say. I think current breed of analog sustainers inefficiently use too much power. If you pull at the right moment with just the right amount of force, you can get something to oscillate indefinitely. That’s the essence behind sympathetic resonance. With just a little amount of force, at the right frequency (and phase!), you can make a very sturdy bridge collapse, for example.
We favor a digital approach with a microcontroller (MCU) doing the phase and frequency locking and synthesising a waveform that’s fed back to the driver (more on this later). A digital system vastly simplifies the required electronics. The MCU can do the phase corrections, analyse the envelope of the input and control just the right amount of signal to drive each string to oscillation.
A digital system buys us a lot of flexibility. For instance, with a digital system, we can feed any kind of waveform back as long as it is coherent with the input. Recently, we’ve tried square, pulse, triangle and sawtooth. Wave tables would be cool, for example! How about samples of bow noises or wind blow noises? How about the human voice? Guitar or Piano samples? That might be cool. And, needless to say, there are no nasty squeals that plague analog feedback systems. It’s just pure sympathetic resonance!
Acoustic synthesis is a powerful concept. It involves the creation of new sounds by controlling the vibrations of actual physical objects, in this case, the strings.
I’m sure most of you are aware that hexaphonic sustain has been done in the past with the Moog guitar (or the more recent Vo96 Acoustic Synthesizer). So what makes this project different? Unlike the Vo96 —a pure acoustic synthesiser, we opt to combine both traditional synthesis and acoustic synthesis.
The Moog guitar, and the newer Vo-96 system use pure acoustic synthesis and advertises zero post processing. In my opinion, that is not necessary. You do not need an elaborate system for controlling everything, including timbre and dynamics. Just because you can do something, doesn’t mean you should.
Instead of pure acoustic synthesis, we prefer to post-process the polyphonic signal. You can do a lot with post processing on individual strings including control of attack and decay. An advantage of our approach is that it is simpler, requires less power, and does not require special strings! You only need to get the string sustaining, plus introduce some harmonics along the way. There’s so much potential in polyphonic processing that the Vo system shuns. A simpler system should cut the cost down considerably.
For example, we will not perform sustain dampening acoustically like the Moog did (the banjo effect). Instead, we intend to do DSP processing for each string. With post-processing, it’s easy to sculpt an envelope to achieve the muted banjo like effect. DSP processing will give us full control over the dynamics of the guitar (e.g attack, decay, sustain in addition to harmonic control). With these controls, you can have anything from banjo like short-sustain to long piano-like sustain and of course, infinite sustain.
But it should not be limited to dynamics control. We’re also looking at timbre control and the injection of harmonics using various forms of synthesis techniques such as Waveshaping for timbre control (polyphonic fuzz in steroids!) and Kurplus Strong synthesis (e.g. having a number of virtual strings in memory excited by the inputs from the Neo pickup potentially modifying the parameters in real time). You can have drone strings, doubles, triples, etc. There will also be pickup placement simulation (using comb filters and short convolution for applying captured impulse response of other instruments (e.g. acoustic guitars).
The software is hosted in your laptop (or desktop). A software plugin (AU, VST, RTAS, AAX) does the multi-channel post processing and control; sending downstream MIDI data to the MCU inside the guitar for controlling feedback. The in-guitar MCU can also send upstream MIDI to control performance parameters (e.g. volume, pan, pitch-bend, cutoff-frequency, resonance, etc.) using potentiometers and other forms of user-control hardware directly from the guitar.
My observation is that in general, guitar players are conservative when it comes to guitar sound. I think that is the reason why digital emulations of amplifiers, speaker cabs, pickups, guitars, etc., are quite popular, for example. Take the Roland VG guitar. You see emulations of electric guitars, acoustic guitars, all sorts of amplifiers and speaker cab emulations, all sorts of pickup emulations (single coil, double coil), effects emulations, even microphone emulations and placement, etc. The same can be said of all the current generation plugin effects available for computer based recordists.