Double duplexing

[Barry98]

Has anyone any idea what "double duplexing" means.
I assume it is to do with improving the clarity/sound of the treble notes but I cannot find any technical description. My new Irmler possibly has it but their literature (which is still in German) is no help
Thanks for any replies
Barry

[richarddale]

this is the only definition I could find

Duplex Scaling
Normally, the length of string outside the speaking length is damped by a strip of cloth woven between the strings. In some grands and uprights this length is undamped and subdivided so that in vibrating sympathetically with the speaking lengths it reinforces particular harmonics. Called duplex scaling, the back duplex is formed between the bridge and an aliquot which bears on the string before it passes round the hitch pin. The front duplex at the tuning pin end of the string is formed between the capo bar (or agraffe) and a ridge moulded into the iron frame.

Aliquot scaling
Patented aliquot scaling was invented by Julius Blüthner in the 1870s. An extra string, unstruck and undamped, runs above the main strings. The idea came from the harpsichord. It is used to add harmonics and overtones mainly in the treble.

[Melodytune]

Duplex scaling is used certainly on Steinways and Yamahas, its function - to enhance the tone throughout the mid and upper treble which helps to give greater clarity in tone especially in a concert hall where the piano's tone needs to be projected over the length and bredth of a hall.

A few years ago I was asked to put listing cloth (the material usually used to "damp" or prevent the back string lengths from vibrating in sympathy with the corrasponding notes)in the treble on a Yamaha grand as it was in quite a small room and the customer (and I) was concerned about the (unwanted) harmonics the duplex scaling produced in this case.

[Barry98]

this is the only definition I could find

Richard
Thanks for the info. Are there any drawings which would make me understand? My new pianio will not arrive until May and I am curious. I have seen the Aliquot strings on Bluthner grands but it is the double duplex I cannot really visualise
Barry

Duplex Scaling
Normally, the length of string outside the speaking length is damped by a strip of cloth woven between the strings. In some grands and uprights this length is undamped and subdivided so that in vibrating sympathetically with the speaking lengths it reinforces particular harmonics. Called duplex scaling, the back duplex is formed between the bridge and an aliquot which bears on the string before it passes round the hitch pin. The front duplex at the tuning pin end of the string is formed between the capo bar (or agraffe) and a ridge moulded into the iron frame.

Aliquot scaling
Patented aliquot scaling was invented by Julius Blüthner in the 1870s. An extra string, unstruck and undamped, runs above the main strings. The idea came from the harpsichord. It is used to add harmonics and overtones mainly in the treble.

[Barrie Heaton]

My new pianio will not arrive until May and I am curious. I have seen the Aliquot strings on Bluthner grands but it is the double duplex I cannot really visualise
Barry

Well first your new piano has not got Duplex Scaling

Double duplex scaling this could be a terminology problem here

A piano string has two termination points the hitch pin and the wrest pin, the wrest pin it were we tune form the hitch pin is were the string if fixed. The string runs form the tuning pin and passes under the capo bar this section is normally a dead length of string and is muted from the capo bar the string stretches to the soundboard bridge this section is called the “speaking length” the string pass over the soundboard bridge and passed the bridge pins, from here the string then travels to the hitch pin this section is also a dead section as is normally muted.

Now on the section from the soundboard bridge to the hitch pin a second bridge (duplex) is put in place, on the iron frame, so the string form the soundboard bridge to the new duplex becomes a “speaking length” However, this “speaking length” vibrates manly in sympathy with the harmonics form other played notes and a small amount of energy form the played note – Now some sales persons call the section form the duplex bridge to the hitch pin a second duplex scaling. However, there is the other dead length from the wrest pins to the capo bar, this is also used by some makes and a duplex bridge is placed there, the length of string form the capo to the new duplex bridge becomes a “speaking length” which vibrates manly in sympathy with the harmonics form other played notes ( and if not done correct is a pain when you are tuning) this has be called many names by sales folk including Double duplex or capo duplex However, piano tuners have there own words for it most not very complementary.

Barrie,

[Melodytune]

Extremely well put Barrie - especially the last paragraph.