This idea for a post came from a customer question: 'how can I tell the difference between LP and HP clarinets?"
Its a damn good question! For those of you who aren't familiar with the terms, LP stands for Low Pitch (A=440) and HP for High Pitch (approx. A=456). The latter was a pitch system in use in Europe in the late 19th/early 20th cen, and crossed the ocean with emigres bearing clarinets. Thankfully, it died out in the 30's, as the two systems are about a quarter tone apart and little or nothing can be done, (with longer barrels, etc.), to reconcile the two!
You'll see these poor beasties on eBay with some frequency and they always have a lonely, under-appreciated look to them, generally selling for $30 or $40 to someone who didn't ask for markings or measurements and thinks they're getting a hell of a deal! Well, they are, after a fashion: I've had a couple show up here and had to sit the owners down, with a box of Kleenex, and explain the harsh realities of multiple pitch systems to them.
The sad thing is that identification is not difficult! In the 1920's, with LP ascendant and HP on the way out, most instruments were marked one or the other on the main body sections. Before that, especially with European made instruments, you have to depend on measurements. A modern Bb clarinet is 23 1/4" assembled, without the mouthpiece. I've seen older examples that varied from 23 to 23 1/2", but nothing longer or shorter than that. By the time you're down to 22 7/8 or a bit less, you're looking at a Bb HP. Shun it! Run away! It will make a wonderful lamp or doorstop, but its days as a musical instrument are sadly past, unless you like playing clarinet by yourself...
On my Blogspot page, I have provided a chart of lengths for HP and LP clarinets in all the common keys (and a couple rare ones). The URL is http://vintageclarinetdoctor.blogspot.com/p/blog-page_14.html , if you'd like to check it out....
The Licorice Shtick Blog is the creation of the Vintage Clarinet Doctor, a Winston Salem, NC based woodwind instrument repair shop specializing in vintage and antique clarinets, saxophones, and the occasional flute.