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ESQ/SQ80 Clav Shootout

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Kirk Slinkardís Classic Transoniq Hacker Article

   MAY 1994



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I had barely begun this Clav shootout when my synth guru and all around musicianís musician Kirk Slinkard reminded me that he had covered this territory a good 15 years before I even started thinking about it.  Typical.

Anyway, with Kirkís kind permission, I have HTML-ized his original hacker article and posted it here, complete with patch sheets for both the ESQ and SQ80 patches, as well as the patches for the, err, alien machines (Rainerís term.  I like it). Kirkís patches will be available in the bank dump that accompanies the results of the Clav Shootout, so donít bother squinting to type them in. Make it easy on yourself and learn how to load system exclusive bank dumps into your machine.

Enjoy Kirks article. Iím sure youíll find his more methodical approach superior to my by-ear digressions. Especially appreciated is Kirkís work with an original Hohner, and his forensic work discovering the exact source and settings of the clav sample loaded into the SQ80ís wave ROM.

Synthesizing the Clavinet

Kirk Slinkard

I've recently started a new hobby - collecting ancient musical instruments and related devices (1960s - 1980s). Among my recent acquisitions is a Hohner Clavinet model D6. I've heard a lot of different clavinet patches from commercial sources and in the Hacker, but they were all artistic interpretations - not one of them was a realistic imitative patch. So I hooked up my Hohner and my SQ-80 and VFX-SD into the same amp with no equalization co that I could do some in-depth A/B type tweaking and adjusting to get a set of imitative patches that were as accurate as possible. It was a fairly tedious operation matching filter settings, envelope decays, etc. across the keyboard, but I ended up with three patches that can be substituted for the real thing, and one reasonable facsimile. So this becomes my first attempt at a "quadra-lingual" synthesizer article.

Clavinets and Sticks

In case you don't know, the Hohner Clavinet D6 is an electrophonic descendant of the clavichord. The clavinet is just basically a small, portable version of the clavichord. I saw an acoustic version of the clavinet played in a period movie, so it would seem that it's been around for a while. The Hohner D6 version isn't acoustic, but electrophonic, meaning that the physical vibrations of the strings are converted into electronic signals by pickups (magnetic in this case, like with most electric guitars). Very roughly, it's similar in size and shape to most Ensoniq instruments. The ones that I've seen in music videos and in most advertisements have wood-grained hinged top panels and four screw-in legs that can he stored inside the instrument. Mine is a more recent model, having four rubber feet and being covered in black vinyl panels, black padded panels, and black-painted metal panels, making its appearance a bit closer to that of Ensoniq instruments. Its keyboard has one note less than the usual five-octave C-to-C keyboards common on synthesizers and organs. The Hohner has F as the lowest note and E as the highest.

Transoniq Patch Sheets

Decades ago, due to its compactness, the clavinet became a popular rock and jazz band substitute for general harpsichord-type applications, and its own unique sound also made it popular on its own merits. As I first listened to mine, I was struck by how similar its sound is to The Stick - a very close relative of the electric guitar.

I looked inside, and sure enough, the strings are vibrated in almost exactly the same way as The Stick - when a key is depressed, a small rubber bumper attached to its bottom side pushes a string down against a raised metal fret near the end of the string where its tuning peg is, causing the length of the string between the fret and the bridge to vibrate. A Stick player taps the strings against its fretboard with the tips of his fingers.

On the short length of the clavinet's strings, between the frets and the tuning pegs (underneath the keyboard), the strings are heavily interwoven with yarn which quickly damps the whole strings when the keys arc released (The Stick uses a piece of felt above the first fret for this function). Unfortunately for my purposes here, the Hohner Clavinet D6 has a four-band equalizer with each band having its own On/Off switch, plus two guitar-like pickup select switches to choose different combinations of it's two really long pickups.

Transoniq Patch Sheets

Figure 1

Figure 1 shows the primary control panel, which is located to the left of the keyboard. The volume slider panel is next to it, closer to the player. The pickup switches select between the treble pickup, the bass pickup, or both, and chooses whether or not they are in phase with each other. So these two switches give the user a choice of four basic tones to send into the equalizer.

The clavinet also has a mechanical slider knob to the right of the keyboard which is used to apply a big macho strip of felt to all the strings close to the bridge (like where a guitarist would mute his strings with his hand). When activated, this makes all the notes very short and plucked-sounding. This combination of switches, including the mute, actually gives 120 sound variations (and that's not counting the volume control or the silence when all equalizer switches are off).


Transoniq Patch SheetsRather than trying to do 480 patch sheets for this article. I thought I would settle for four that simulate typical, somewhat bright settings on the Clavinet - the settings that most closely match the Ensoniqs in tone color. This way, you can turn the filter cutoff frequency(s) up or down a little to simulate other more or less bright sounds. Ensoniq has already done the hardest part by supplying most of their synths with a waveform that appears to be a single-cycle sample from an actual Hohner Clavinet. On he SQ-80, this is called "CLAV," newer types have the "CLAV" and "CLAV.VAR" waves. The "CLAV.VAR" sounds brighter and more appropriate for a general clavinet patch of this particular kind, plus it's the closest match for the SQ-80's waveform.

The SQ-80's "CLAV" waveform produces a tone comparable to the Hohner D6 with the pickup select switches in the "CB" position, and only the "BRILLIANT" switch activated in the equalizer controls. The VFX's "CLAV.VAR" waveform sounds like a Hohner with its pickup switches in the "DA" setting and, in this case also, with only the "BRILLIANT" switch on in the equalizer, If you change the VFX's or SQ-1 's waveform to "CLAV," it sounds as if you have changed the equalizer to have only the "SOFT" switch activated. On the down side, these waves don't change their tone across the keyboard in the quite the same manner that the Hohner does. Also, the Hohner has a more complex attack that I haven't been able to exactly duplicate here. And the Hohner changes its waveshape slightly as it is sustained (independently of brightness and amplitude decays). But don't worry too much about these differences, they're not really terribly significant, I never even realized they existed until started doing these nit-picking A/B comparisons.

As for the ESQs, we'll have to come up with a substitute for the "CLAV" and "CLAV.VAR" waveforms. I figured that a logical starting point would be a narrow pulse wave - the real thing, not the questionable "PULSE" waveform supplied with this synthesizer (see pulse width modulation article in Issue #85). So the "SYNC" function is applied to oscillator 2 which is set to a "SQUARE" waveform, which ends up giving us a real variable pulse wave. To make it closer to an authentic clavinet tone, here it is combined with the "KICK" and "VOICE1" waveforms.

Filters and Amplitude

I used the VFX/SD1's And newer SQ-'s two filter sections together as 4 single 4-pole lowpass filter so that it would be easier to make all the patches as similar as possible (the ESQs and SQ-80 have this filter configuration only). The VFX/SD1and the newer SQ's velocity responses in the envelopes are set to linear, not only because the ESQs have only this type, but also because the actual clavinet responds to velocity in a linear fashion. Envelope decay times were adjusted separately for high notes and low notes, first for the filters and then for the amplifiers. I sure am glad that I don't make patches for a living. Both the filter and amplifier envelopes have short release times to simulate the quick, but imperfect damping of the clavinet strings upon key release.


The Hohner Clavinet has a keyboard feel that I found to be surprisingly close to most organ and synthesizer keyboards, The main differences are that Hohner Clavinet keys offer just a little bit less resistance when you play them, and you can feel a little of the string vibration when you hold a key down, especially with the lower notes. So basically, playing one of these patches feels and sounds very close to an actual Hohner Clavinet D6, except that here you are missing 4 notes on the high end of the keyboard, and you have 5 extra notes on the bottom. Keep in mind that in many popular recordings, the clavinet gets some treble boost. To get this sound, just turn up the fitter cutoff frequency(s) until it sounds right.
Transoniq Patch Sheets
If you mellow out the sound a little by lowering the filter cutoff frequency value(s), you can also use these patches in applications that call for a Stick.

Since the D6 has a single output jack, these patches are all panned to the middle of the stereo field with no pan modulation. On the SQ-1 and VFX patch sheets, notice that the outputs are routed to the dry bus and no effects are specified. Like with a real clavinet, you have to choose your own effects (if any).

These patches are designed to be very accurate and usable as they are, with no modifications, but I like to think of them as a place for you to start in making your own custom patches. May you clav long and prosper.

--Mod You Later,
--good 'ol Kirk.

Bio: Kirk Slinkard hangs out near Denver, plays synthesizer, and collects and restores vintage rock stuff. His favorite color is ultraviolet and he'd the same age as Marcia Brady (a year older than Kevin Arnold).
_/ \_



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