Most pictures and diagrams I see show uprights with the normal two bridges. Why do some uprights have three bridges? Was there any advantage or disadvantage to this design?

Usually when there is a third bridge some designer is trying to create a smoother transition from one bridge to the other. The transition being in the scale design and related tone quality as this is always a problem area for scaling.
The reasons for the third bridge could vary depending on when the piano was made -modern or early 1900's- and the make.

Gene, could you perhaps elaborate on this? I am interested in this question because my 1880s Bluthner (grand) has three bridges.

May not elaborate enough for your satisfaction but:
Early scale designers just are not as good as modern simply because we now have all the calcs on spreadsheet so scale redesign is considerably faster and easier. Plus we have more experience and wire is higher quality. That said, I really do not have a good idea of what early designers had in mind uness I could look at the piano and do some measurements - even then I could easily miss it.
More modern designers may add a third bridge to a piano in the lowest tenor similar to the Charles Walter.
Some rebuilders will do similar work and it definitely can make a better tonal transition. This third bridge can be an extension of the long bridge or a completely separate bridge.
There are techs on the forum that would have a greater knowlege of the Bluthner than me.

Where in the scale is the third bridge on your Bluthner?

In my case it's a 57" upright. The bass bridge has A0 thru E2, the "extra" bridge has F2 thru C#3 and the treble bridge has D3 thru C8. I'm unsure of the exact age because when I sent the make and serial number through the age lookup service I got a year back that isn't possible. It was made by Gildemeester & Kroeger (serial#4855) and I believe it to be from the 1890's.

Gene, thanks!

Dale, the bass bridge in my Bluthner has 6 monochords and 20 bichords, from A0 to Bb2. The tenor bridge has 10 trichords, from E2 to Ab3. The treble bridge has A3 to A7.

The tenor strings run alongside the bass strings, at the same height. The tenor strings are overstrung over the treble, as are the topmost bass strings. However the treble bridge does not extend very far beneath the bass, so that most of the bass is not overstrung. Thus the bass end of the piano looks almost straight strung.

The crossing of the two sets of plain wire trichords (tenor and treble) creates rather a striking visual effect.

I would be most interested in any comments that anyone may have.

David, a picture of it posted here would be most welcome. I can tell that Gene must have talked to Del Fandrich about this. I agree with what Gene said. The design of this early Bluthner was obviously an attempt to create a smoother transition from treble to bass across the tenor region. From the description, it was an artfully creative attempt but from what is known today, probably not very successful.

How well does this piano stay in tune over seasonal changes? That is an important question. Another important question is how smooth does the transition actually sound?

My opinion of the tenor transition bridge is that it is the ultimate design for both problems: tuning stability and smooth transition in timbre from treble to bass.

Modern scale designers must be aware of this but probably also find it either too difficult or expensive to really execute on small, economy pianos. The usual solution today is to simply make a longer bass bridge and put some wound strings on the low tenor bridge. That works fairly well but not as well as the three bridge concept.

LBE,

Gildmeester & Kroeger #2000 was 1880. 1885 started the number #9000.

David,

I believe your instrument was considered straight strung (if it is the Blüthner I am thinking of)

Dan,
Thanks for the numbers, but I'm still confused because if my piano was made between 1880 and 1885, why would there be a patent date of Oct. 19, 1886 cast in the plate? Shouldn't a piano be newer than the patent dates? I find so little information on the company and half of it doesn't match from one source to another. Just about the only thing they all say in common is that Kroeger had worked for Steinway & Sons, Gildemeester& Kroeger made expensive pianos and the Kroeger name was later bought by Koehler & Campbell.

That may have been when they decided to take out the patent on that particular plate scale design; maybe they made a few variations of that design and then decided upon that one to be the patented one……….. I am only going by the numbers in Pierce Atlas. Yes, all the numbers line up with Kroeger, and after 1924 also Brambach.

Pianos between the 1880’s and 1920 were as competitive as computers are today. Numbering systems for pianos were not that accurate; lots of the companies were fudging their output numbers, or changing them to a new series each year. Sometimes it is really hard to find information on particular instruments; you might try the archives of the city records where the instrument was built. Factory records or business info might be found there……

The best way is to look for information on the back of the action; there might be a signature or a date when the action was installed.

Example:
I was just working on an instrument I thought was 1930 from the numbers in the atlas. When I pulled the action, it was installed, regulated and signed on August 5th 1921. Oh well, what can you do sometimes…..

It shall remain a mystery like the age of the house it came in. There was a big fire in our county court house long ago so a large number of houses in our area (like mine) have deeds listing the house's age as "999" because the origional records were destroyed and nobody knows the exact years they were built. I like the house and I like the piano, that's all that really matters.

Bill, thank you for your thoughtful and informative post. It is interesting that you feel that the three-bridge idea is a good design solution both for tuning stability and for a smooth transition at the break.

In answer to your questions, tuning stability on the Bluthner has been excellent, and has never been a problem (though I do control the humidity in the room). The transitions are not glaring, but differences across the breaks can be heard.

This design dates from the 1870s, and was the standard Bluthner design for about 15 years. At that time (I understand) piano designers had not yet learnt to achieve a uniform tone over the range of the keyboard. That is certainly true of the Bluthner. The treble has a wonderful sparkly warmth to the tone that is quite beautiful, right through the fourth, fifth and sixth octaves. The bass is a complete contrast. In its clarity and incisiveness, I find the bass of the Bluthner much more effective than the bass of many modern 6-foot pianos; this allows the bass voice to be heard quite distinctly against the treble. This can be very effective in (for instance) Mozart and Schubert. The difference in timbre that goes with this is something that I am quite happy to accept. The weakest part of the range is the tenor, which tends to have a slightly “absent” quality, though this is minimised when the piano has been tuned, voiced and regulated.

The tone is nothing like the famed “mellow” sound associated with older Bluthners. Those are of a later generation, typically early 1900s. The treble is more akin to the sound of modern Bluthners, though with added warmth.

The piano was reconditioned by David Winston of the Period Piano Company about 10 years ago. He replaced the strings, hammer felts and tuning pins.

Here are some pictures. You will see that the arrangement is as if there were two straight-strung halves, slightly angled into each other. I would love to know whether (and how) this arrangement is responsible for the amazing tone of the bass, and the warm tone of the treble.

If anyone has any thoughts or comments, I would be very interested.

I can tell that Gene must have talked to Del Fandrich about this.

The treble has a wonderful sparkly warmth to the tone that is quite beautiful, right through the fourth, fifth and sixth octaves. The bass is a complete contrast. In its clarity and incisiveness,
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I usually think of the treble as the 6th and 7th octaves. Also I am not certain if the incisive tone is in the bass or the upper octaves based on your discription.
IMHO - the tenor section tone that you do not care much for - it is probably more to do with available crown and string bearing than bridge placement, or it being a third separate bridge.
It appears that the intermediate bridge is mounted on a cantolever. Over time the cantolever can give way under the string bearing and create irregular shapes in the board that will hurt the tone.
Yes I do talk with (mostly listen to) Del Fandrich - also Dale Fox and have learned most everything I know about pianos and rebuilding from them.

The “third” bridge—i.e., the transition bridge—is most commonly used to ease the transition between the bass section and the tenor section when this transition point is located so far down the scale that plain steel strings cannot be made long enough to maintain more-or-less uniform tensions with the rest of the tenor section.

Many of the traditionally designed scales in shorter pianos have a bass/tenor break that is placed somewhere between E-20/F-21 (as seen in pianos like the S&S Model A) and A#-26/B-27 (as seen in the S&S Models S, M, O and L). As well, most verticals (including those large old uprights) have their transition points rather far down the scale. I currently have a couple of wonderful old Bush & Lane uprights in the shop with transitions between C-28 and C#-29.

The problem with placing the transition point this far downscale is that the lowest plain steel strings have to be foreshortened else they would extend through the end (or bottom) of the piano. Even in pianos as large as these Bush & Lane uprights (one is about 55”, the other about 57”) and with 28 notes in the bass section there is noticeable foreshortening of the lowest tenor strings. Foreshortening is also obvious on scales such as the S&S Model B, which has its bass/tenor transition located between notes E-20 and F-21. When the low tenor strings are foreshortened one of two things must happen: the tensions of the lowest tenor strings must be allowed to drop precipitously or larger gage wire must be used. Neither technique has proved fully satisfactory.

Other methods have been used to ease the bass/tenor break. The most common is to use wrapped strings in place of plain steel strings for the lowest few unisons the tenor bridge. Done well this can be musically satisfying but it does present problems for the tuner.

Enter the transition bridge. Using this bridge the lowest notes in the tenor section can use wrapped strings and, with careful scaling, both the requirements of balanced tone and smooth tuning (i.e., a smooth inharmonicity curve) can be met. Done well the bass/tenor transition can be made musically transparent. I am always pleased when I can demonstrate the bass/tenor transition to a room full of experienced piano technicians and they fail to reach a consensus about just where the transition takes place.

The transition bridge was fairly commonly used on early pianos. It fell out of favor largely because the scaling was so poorly done. Most of the early transition bridges used tri-chord wrapped strings—or some combination of tri-chord and bi-chord wrapped strings—and most of them used far too much length offset. Acoustically they were often very little better than the more crude foreshortened tenor bridge.

I have been using transition bridges more and more over the past few years. Transition bridges are a common feature on the pianos I redesign and rebuild. The scaling always uses bi-chord wrapped strings and the length offset is kept relatively low. It is rare to be able to audibly detect the bass/tenor transition point on one of these pianos.

Transition bridges are also found on some of the new pianos I design; the Walter 175 grand, for example. A transition bridge will also soon be seen on at least one piano in the 225 to 230 cm range. (Sorry, I cannot be more specific at this time.)

ddf

Great pictures David thanks for posting them. I like the close up of the crossed string pattern……….looks to be around the 7ft mark in length?

Love the music rest too. Very nice……

Jurgen Goering might have some history on this one if he is around. Also you could contact Dr. Christian Blüthner for historical information at
http://www.bluethner.de/