The end ...

The last few entries have been catching up with things that have happened over the last 3 months.

Fast forward to the present day and it is May 6, 2011 - exactly 9 months since the harpsichord kit arrived on August 6 last year and I am going to declare it "finished" - for now at least ...

Overall I am very pleased with the instrument - the back 8' has a nice warm, clear, singing character to it and is, I think, already very close to where it should be - the front 8' is a little more incisive and, when played on it's own, the top octave is perhaps a little brittle - it will probably need more work but right now it just needs to be played for a while. The two voices combined blend very well together and produce a very satisfying effect.

Tuning appears to be quite stable with the caveat that this instrument does appear to be very sensitive to changes in humidity - much more so than the French double that is in the same room only a few feet away - a change of 5% relative humidity can shift the pitch of the Neapolitan by 15 cents while the double hardly seems to notice - even when this happens the instrument does stay pretty much in tune with itself and if you don't mind leaving it slightly sharp or flat you can get away with only touching up a few notes - on the other hand it is an extremely easy instrument to tune and a complete tuning doesn't take more than 15 or 20 minutes.

At the outset I did intend to keep track of exactly how much time I spent working on the instrument but I completely failed to do that. The one thing that I do know is that I spent at least as much time planing and thinking about the best way to do things as I spent actually working hands-on during the construction phase which lasted almost exactly 6 months. The last 3 months were all taken up with voicing and just playing the instrument. Construction could certainly have been done in much less than 6 months elapsed time - I had originally estimated about 4 months but I had some other commitments that took up more of my time than I had expected.

Anyway, here it is, alongside its larger and older cousin ...

Voicing 3

Once the stop lever for the back 8' was installed I had to make few adjustments to the voicing since the precise position of the register in the "on" position had changed very slightly - just enough to make 5 or 6 notes unreliable. In each case the plectrum was just slightly shorter than it needed to be and all that was required was to push the plectrum just slightly further through the tongue. I also had to adjust the dampers slightly so that they still damped the string when the register was moved into the "off" position.

Here you can see a close-up of some of the front 8' jacks before voicing. The register for the front 8' is in the "off" position and the plectra have already been cut to approximately the correct length so that they are clear of the strings.


This is what it looks like after voicing with the dampers in place. The front 8' register is now in the "on" position.

The last thing that needs to be done is to regulate the action to get the plucking order right. The two sets of jacks should pluck their respective strings at slightly different times when the key is depressed otherwise the touch will feel unpleasantly stiff and heavy when playing with both registers engaged. The back 8' has a natural tendency to pluck first because the angle at which the back of the key rises when the front of the key is pressed. The exact length of the plectrum also helps to determine the precise moment at which the pluck occurs and finally the length of the jacks can also be adjusted slightly if necessary.

I had tried to make the plectra for the front 8' just slightly longer than the ones for the back 8' and most of the notes were already plucking the strings in the correct order but in many cases they were still very close together and the touch was quite stiff. While I had done my best to get the jacks set up so that the spacing between the plectra and the strings was consistent there were a few of the back 8' jacks that were a little short - padding the bottom of the jacks with 4 or 5 thicknesses of masking tape brings the plectrum closer the string so that it plucks earlier. In a few places I also shortened the back 8' plectrum to get it to pluck sooner. Similarly with the front 8' shortening the jack increases the distance between the plectrum and the string and delays the pluck as does pushing just a little more of the plectrum through the tongue.

It took quite a while to get this right - at first I still had both jacks plucking much to close to each other and the touch was really stiff - you don't want the plucks to be too far apart but they do have to be quite distinct. Eventually I got a few notes to both sound and feel right and then it was easier to make the others behave the same way.

Voicing 2

Once the back 8' seemed to playing reasonably well I turned my attention to the front 8'.

Zuckermann provide a wooden lever stop level which moves the register for the front 8' so that it can be turned on and off. There is, however, no provision for controlling the register for the back 8' and before voicing the back 8' I had carefully set it into the correct positions by inserting shims at either end of it.

This means that, in order to voice the front 8', you have to remove the jacks for the back 8' which is less than ideal for several reasons - it makes it difficult to find the right balance between the two voices and it leaves the strings for the back 8' completely undamped which means that when you play the front 8' you have to contend with the sound of sympathetic vibrations from the back 8'.

After a frustrating week of not making much progress I decided that, at the very least, I needed to be able to turn the back 8' on and off on a temporary basis while I was voicing the front 8'. Since the jacks for the back 8' pluck the strings on their left this means that the register needs to be moved slightly (somewhere between 1mm and 1.5mm) to the right in order to get it into the "off" position. Since there was already a shim of approximately the correct thickness at the right hand end of the register all that was necessary was to remove it. Unfortunately, however, the gap between the end of the registers and the case is hidden by the wooden plates on which the jack rail supports are mounted which makes it impossible to get at the shims without removing all of the jacks, removing the spine plug and removing the registers from the instrument.

Once I had the back 8' register set up so that it could be turned on and off and had made some progress with voicing the front 8' I decided that it would be worth making an additional stop lever for the back 8' and making it a permanent feature of the instrument.

Here is the original stop lever for the front 8':




I made a copy of it - slightly longer than the original because it has to reach the back register


and here it is fitted in place

Voicing

I finally started voicing the harpsichord in early February.

First the jacks have to be cut to the correct length so that the plectrum will be about 1.5 mm below the string. On this instrument all of the jacks are going to be very close to the same length but each one will have to be individually adjusted so at this stage I aimed to cut them just slightly over length.


Almost done with the jacks for the back 8' - two of the jacks in the picture have plectra fitted to them so that I can check that the length of the jack is correct.


Voicing is conceptually very simple - all you have to do is insert a plectrum into the slot in the tongue of the jack, cut it to the correct length and remove a few thousands of an inch of material from it with a sharp knife until the note sounds right then fit a small piece of damper cloth into the slot at the top of the jack so that it damps the string when the key isn't pressed. Repeat the process (for this instrument) 106 times and you are (almost) done.

It turned out that I had perhaps been a little too cautious when cutting the jacks to length - the plectra were mostly either touching the string or sometimes just a little above it so I had to take 1 or 2 mm off the length of each jack. It took a little while to figure out the most efficient way of doing this but eventually I settled on using some 80 grit sandpaper to remove most of the excess length and then making the final adjustments with a fine toothed file.

My main goal for the initial voicing was just to get the instrument playing and to get some idea of what it could do without worrying too much about the details. I had voiced a few plectra for my French Double but that was much easier because the rest of the instrument was already voiced so it was very clear what it should sound like and it was even possible to look at the plectra for adjacent notes to see roughly how the plectrum should be cut. This was different because I was starting from scratch with only a vague idea of what the instrument could or should sound like.

I started with middle C and then did the notes one and two octaves above and below - initially just getting them to sound reliably and then trying to thin the plectra down to the point where the note started to sound "right". One thing that became apparent very early on is the extent to which voicing is both a tactile and an aural process - at first the plectrum is far too thick, the key feels very stiff, there is a very strong pluck and the sound is harsh but as the plectrum is gradually cut thinner and thinner both the touch and the sound improve and both start to feel "right" at about the same time.

Once I got all of the C's voiced, I did the G's and then E's giving me a C major triad.

Here is what things looked like at about that point. All of the plectra have been fitted to the back 8' set of jacks and cut to approximately the correct length.

The jacks that have been voiced have dampers fitted to them.

In the second picture you can see that some of the unvoiced plectra are still sitting above the strings because the jacks have not yet been filed down to the correct length


Then it is just a matter of going through all of the other notes one at a time.

I think that the initial voicing of the 53 notes of the back 8' took me about 10 hours over the course of a week. A lot of this time was spent just getting the jacks down to the right length. Cutting the plectra was also very slow at first, but started to get a lot faster by the time that I was about half way through. Partly this was a result of acquiring the manual dexterity to manipulate the jack, the voicing block and the knife efficiently but the really big time saving came once I started to learn how much the plectra needed to be cut in order to make a particular change in the voicing. This greatly reduced the number of times that I needed to try the jack in the instrument.

Here is how things looked just after the the initial voicing of the back 8' was finished. The blue masking tape on the jack rail is a temporary measure to hold the cloth padding the underside of the jack rail in place.


At this point the instrument was actually playable for the first time and, although the voicing was still quite rough it was possible to get some idea of how it was going to sound.

One of the first and most obvious things is that I like the way that the keyboard feels - the depth of touch is quite shallow and I had been a little concerned about how that would feel but in fact it feels really good - there is a very direct connection with the sound and it just feels "right".

Overall the sound was good as well although I thought that the top octave was perhaps a little weak and the octave below middle c was a little loud. This is really quite difficult to judge when sitting at the keyboard and I noticed that the balance between different parts of the instrument sounds noticeably different when standing over it.

I played the instrument for a few days and then started to rework the voicing of the back 8'.

Some of the plectra, although they sounded reasonable had been cut very unevenly and others had been cut very narrow and were clearly not going to be amenable to any further voicing so I set about replacing them. I also wanted to see how much sound I could get out of the top octave so I replaced most of those plectra and left them all voiced just a little bit too strongly. In the end I probably replaced more than half of the original plectra but this went much faster than the original voicing and only took a couple of hours.

For the next 2 weeks I just played the back 8', fixed problems as they came up and every few days went over the voicing taking just a little more off any notes that seemed a little too loud.
Overall there were very few problems although I did have a few "hangers" that were difficult to diagnose at first. A "hanger" is a jack where the plectrum fails to slip back under the string when the key is released and instead "hangs" on top of it. This can happen if the plectrum is too long or isn't cut correctly or if there is a problem with the jack tongue or the spring that prevents it from swinging back to allow the plectrum to slide past the string.

The problem notes were almost working but sometimes the jack tongue just wouldn't swing back quite far enough to allow the plectrum to get past the string. This puzzled me until I noticed something that almost all of the jacks with this problem had in common.

The spring that holds the jack tongue in place is just a small piece of steel wire that presses against the back of the tongue and runs down through a small hole in the jack body and ends up in a slot in the back of the jack. The problem jacks all looked like this one where you can clearly see the end of the steel wire in the slot in the back of the jack body.

The problem is that the steel wire is not seated properly in the slot. Because of that the part of the wire that presses against the back of the tongue is leaning forwards at a slight angle and applying just a little too much pressure. The solution was just to push the wire right down into the slot as seen below and suddenly the jack starts working correctly.

Stringing 3

Once all of the bridge pins are in place the instrument can be brought up to pitch - a process that takes several days to complete. Actually tuning the instrument only takes about 20 or 30 minutes but the strings are all new and stretch slightly during the process which means that, by the time you have finished, the first strings that you tuned will already have dropped in pitch by quite a significant amount and a day later the whole instrument will be about a semi-tone flat.

If you are just replacing a single string you can get it somewhere close to stable in 10 minutes or so by repeatedly bringing it back up to pitch but with a new instrument there is no point in trying to do that - all of the hitchpin loops and the coils on the tuning pins are settling in and the whole instrument is adjusting to being under tension so you might as well just start tuning and checking things once a day for the next few days until the instrument settles down.

As it happens I was kept quite busy because I has to replace quite a few strings during the process. There were one or two hitchpin loops that obviously weren't quite as good as I thought they were because they slipped and the strings would not stay up to pitch so obviously they had to be replaced. I also broke quite a few strings, almost all of which were in the octave below middle c. They all broke at the hitchpin loop just at the end of the double helix where the wire is twisted together. After some investigation I came to the conclusion that I had been twisting the wire just a little bit too tightly when making the hitchpin loops and that this was the cause of the problem. The wire on this instrument ranges from 0.022" in the bass to 0.009" in the treble. The strings that broke were all about 0.012" - it seems that the thinner wire could survive being twisted quite tightly and that the thicker wire was just a bit stronger but the 0.012" just didn't like the way that I had been treating it. I had to replace about 15 strings but all of the replacements held OK.

Pinning the nut

Now that all of the strings are in place it is time to pin the nut.

The "nut" is the bridge which sits on top of the wrest plank between the tuning pins and the bridge.

It is the pins on the nut and on the bridge attached to the soundboard that control the exact position of each string, and it is really critical that they are in exactly the right place because there is essentially no margin for error if all of the strings are going to end up in the right place relative to the jacks.

Since this instrument has two registers there are pairs of strings each of which sound the same note. These pairs of strings fall on opposites sides of the jacks for each note and the jacks face in opposite directions. The front jack plucks the string on its right and the back one plucks the strings on its left.

The size of an octave on this instrument's keyboard is about 162 mm which only leaves 13.5 mm per note into which we have to fit the width of the jack (about 4 mm) and two strings (which range from about 0.25 mm to 0.5 mm in diameter). What that means is that the pair of strings for each note ends up having a width of about 10 mm, centered on the 4 mm jack leaving about 3 mm between the jack and the strings. That leaves us another 3 mm separating the string pairs for adjacent notes. (and yes, there is another 0.5 mm in there somewhere that you can put wherever you need to in order to make things fit ...)

To make it easier to get the strings into the correct position we use a marking gauge which drops into each jack slot in the register and which has lines marked on it indicating exactly where the strings should be. Once you have that in place all you have to do is to insert a pin into the nut at the correct place. The catch is that you don't just want to get the string into the correct position at a single point - you want it to cross the registers at right angles and maintain the same distance from both sets of jacks - and that can only work (especially in the treble where the strings are very short) if the pins that have already been inserted into the bridge are also in exactly in the right place.

Before doing anything else I went used the marking gauge to go through all of the strings looking for any obvious problems - everything seemed to be OK, but it looked as if I was going to have to take about 1.5 mm of the right hand end of the registers to get everything to line up correctly. I was pretty sure about this but also a little worried because the parts in this kit have all been cut amazingly accurately and the registers already looked as if they fit perfectly.

However, when all else fails, try reading the instructions ...

The instructions were to set the rightmost string into a specific position (1 19/32" from the inside edge of the case), and use that in conjunction with the marking gauge to determine the correct position of the register. Amazingly enough, when I actually followed the instructions, I determined that the back register needed to be in exactly the position that I thought it needed to be in - about 1.5 mm to the right of where it was. So, I took about 2.5 mm off the end of the register (an extra 1 mm to allow for future adjustments) and set it back in place with some shims at either end to fix it in the correct position.

By the way, this instrument has what is, for an Italian harpsichord, a distinctly inauthentic but very practical feature - a hole in the spine of the instrument covered by a removable plate which allows the registers to be removed without the need to also remove most of the strings ...

Once everything was in place the actual drilling of the holes and inserting the pins was quite easy.

The result looks like this:



Here is the marking gauge being used to check strings that have already been pinned.

The distances involved are so small that you have to be very careful to look directly down on the string when checking the alignment. Here the camera angle makes it look as if the right hand string is slightly to the left of the mark but in fact both of these strings are lined up in exactly the right place.

In the end everything went very well and I only made one mistake (at least, only one that I have found so far).

There were three pins that didn't quite end up in the right place. They weren't out by much and I could probably have just gotten away with bending the pins a lot to force the strings into the right place - but that would have left me with no possibility of doing any fine adjustment on those strings and since everything else appeared to be "just right" I decided to go back and fix them.

This was really quite easy and didn't even take very long to do.

First I removed the three offending pins and drilled the holes out slightly to 1/16".


Then I plugged the holes with small pieces of cherry which I had whittled down from a spare piece of soundboard molding. This is exactly the same way that I plugged the holes left by the nails that were used to position the nut when it was being glued down. In fact you can see one of those plugs right in the middle of this picture.


Once the glue dried I cut the plugs off flush with the nut and sanded carefully with a small piece of sandpaper.


After redrilling the holes and inserting the pins you really can't tell that anything was done (except for that fact that the pins are now in the correct position ...)

Stringing 2

Almost done ...

At last all 106 strings are in place:

Stringing

Now that all of the hitch pins are in place it is time to string the harpsichord.

This instrument is strung entirely in brass wire ranging from 0.009" to 0.020" in diameter with 2 sets of 53 strings.

Each string has a loop at one end which goes over the hitch pin and the other end is wrapped around a tuning pin which is inserted into one of the holes in the wrestplank at the front of the instrument.

The string loop is created by simply twisting the wire together to form a double helix like this:


The tuning pins are hammered into holes that are just slightly undersized and are held in place by friction. It is very important that they turn as smoothly as possible in their holes and traditionally they would probably have been lubricated with either wax or powdered chalk but I am going to use micro fine powdered Teflon.






There are 106 strings in total and at this point I am just over half way through.

Inserting the hitch pins and fitting the rose

The ends of the strings are anchored to small iron pins known as hitch pins which are inserted into holes drilled along the edge of the soundboard. On some instruments the molding that runs along the edge of the soundboard is known as the hitch pin rail and the pins go through it but on the Neapolitan harpsichord the molding is purely decorative and the pins go directly into the soundboard and down into the liners.

Before drilling the holes for the hitch pins I experimented with some scraps of wood and discovered that the pins seemed to be very loose in the 1/16" holes that were recommended in the instructions. At first I thought that I might be drilling the holes over sized but, when I checked the diameter of the pins I found that they were about 0.060" to 0.061" in diameter. Since 1/16" is 0.0625" it didn't seem too surprising that they were loose. I asked Zuckermann about this and was assured that the 1/16" holes were OK and that provided that I drilled the holes to the correct depth and then hammered them into the hole so that the tip of the pin embedded itself into the liners everything would be fine. Well I tried this several times but never managed to get what appeared to me to be a satisfactory result - in most cases it was possible for me to pull the pin out with my fingers even after hammering it in to the depth suggested.

While I was reluctant to simply disregard what I had been told, it obviously wasn't working so I experimented with some slightly smaller drill sizes and eventually came to the conclusion that a 1.5mm drill (approximately 0.059") was what was going to work best for me. With that size of hole it was possible to push the hitchpin about 1/4" into the hole and then tap it in the rest of the way with a hammer - this did not require a lot of force but the result was a pin that was very firmly seated in the hole.


I did invest in a couple of special tools from The Instrument Workshop - a hitch pin setter and a bending tool which is used to bend the hitch pins back at an angle away from the direction of the string. While certainly not essential, these did make it a great deal easier to get all 106 pins in place without any mishaps.


The final result looks like this:


Once all of the hitch pins were done it was time to glue the rose in place:

Finishing the lid

Not much has happened over the last month but I have managed to finish the last few things that needed to be done before I can begin stringing the instrument.

The lid is complete - like most harpsichord lids it is in two pieces - one piece that covers the keyboard and wrestplank and a larger piece that covers the soundboard. Originally I had intended to hinge these together but in the end it seemed simpler to just leave them separate so that they can be lifted off the case independently of each other. I varnished the lid with shellac (which came out a slightly more yellow color than I really wanted) and glued some strips of felt around the underside to prevent it from scratching the case.

The final result looks like this: