Home General Asylum

General audio topics that don't fit into specific categories.

John Challis harpsichords- the hubris of wrong-minded engineering

PHOTOS: John Challis harpsichord single manual, 1975 Opus 372, GG-g”’ 61 notes. 3 foot pedals (8', 4', Harp/Buff). 58” spine, 35” w. > From Harpsichord Clearing House

David Aiken,

For three months in the early 70's I used a Challis single manual 2X8' harpsichord as a practice instrument, almost identical to the one on the photos above. This instrument was what I suppose would be Challis at his pinnacle of modernity- aluminium frame, open bottom, soundboard, wrestplank, and the drilled out aluminium bridges, wood case with reverse keys (ebony naturals and boxwood accidentals, pedal stop controls. The keyboard was a piano dimension octave span and piano keypad depth. The jacks were metals as well and, fatally, there was a separate set of jacks for the dampers.

Overall, this was a terrible harpsichord in all the important aspects except that the craftsmanship, materials, and finish were excellent. The action was among the worst I've ever tried- it felt like the keys were being retained by a foam strip- the feel was mushy and heavy from the metal jacks and the extra set for the dampers. Challis, failed as as an engineer in my view by actively subverted one of the elegantly efficient design aspects of harpsichords- just having a little square of felt jammed in a slot on the upper side of the jack for the dampers- which worked perfectly for 400 years.

And, worse, was the sound. You're intuition serves you well, as the sound was alien harpsichord. A fundamental problem was the heavy metal structural frame. The Challis I used was under 6' long and I'd guess it weighed over 100 lbs- where a historic instrument the same size would be perhaps 70-80 lbs- an Italian would be 40 lbs or so. All that mass and the open bottom was a disaster- there was almost no resonance and the sustain was poor- less than a typical Italian, despite the long scale length and consequential high string tension, which typically gives a longer sustain. But the coup de grace was the aluminium soundboard and bridge. Challis was secretive about the soundboards, but I learned these were two sheets of thin metal- (and they're anodized a bizarre greenish colour) with a fairly low-density foam in between. There was little capacitance in the soundboard. The bridge is silly too, as it is a milled and drilled out for lightness, and I can't remember the detail exactly, but I think the bridge was screwed to the soundboard in such a way as to prevent the bridge from continuous contact with the soundboard- perhaps to keep it from buzzing. If I'm correct, this would mean far less- and far less even transmission of vibration to the soundboard.

As I've been writing, I've been trying to think of a similar sound - something we all come in contact with, but I've never heard anything like it- a kind of tubby, hollow sound that is somehow defocused, muddy- and over with all too soon. I could only suggest anyone serious about buying a Challis first buy two sheets of 12ga. aluminium, glue them to both sides of a sheet of 1/4" foam core of the kind used for architectural models and then strike the sandwich with a metal spoon. Is there such a term as "thumpblobby"?

Challis was another example of what happens when 400 years of refinement through craft is suddenly thrown out, combined with some really counter-productive engineering. A dog's dinner of poor design choices that favours innovation for it's own sake over results. The 20th C. Germans- Neupert, Speerhaake et al did a lot of terrible re-engineering, but at least the wood structures and soundboards produced a harpsichord sound and thought the keyboards were piano dimensions- the octave span and length of the naturals

Still, I suppose someone had to be John Challis and put the harpsichord through an experimental phase if only to expose the hubris of modern engineering when applied under false goals.


Bambi B

This post is made possible by the generous support of people like you and our sponsors:
  Analog Engineering Associates  

Follow Ups Full Thread
Follow Ups


Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.