Deliberately Angled Soundpost

[TimDasler]

I had a customer in the shop today who had only ever let Rene Morel work on her cello. Since his passing she hadn't let anyone change her setup until today. The primary issue was that the post was no longer tall enough for the cello even now in the drier season. I noticed that the post was far from straight, but was clearly fit at that angle deliberately. The top of the post was about 3mm inside the bridge foot and 3mm behind, but the bottom of the post was about 12mm closer to the rib and about 6mm towards the bridge. If it didn't fit I would have thought it had moved somehow.

I made careful note of the location and traced pencil marks around the post so I could get back to that spot. His last adjustment, according to the customer, was a quick adjustment that did not include a refit, but he gave the post a couple tugs, to resolve whatever the current concern had been. I presume that was the bottom coming further out to tighten it up. 

I started by tacking a 1/2mm shim to the bottom of the post to test it with the same placement and fit, but more compression. Ultimately I ended up putting in a straighter, taller post with the top 3mm in and 5mm back. I couldn't get the response, balance, and well rounded tone without a pretty significant angle to the post. I ended up with the bottom a bit towards the bridge, but not quite as much as Rene had it. It does seem as though angling the post had a different effect than just shortening the post. I was able to get the quick response, but it sounded a bit choked and thin without the angle to the post. I could not get the same effect with a post standing straight.

So, Rene taught me a lesson from the grave I think. I'm hoping someone (perhaps one of his former protege) might be able to shed further light on when and why he might put such a strong angle on the post. My impression is that the angled post has a similar effect to a more flexible back. It has more give because of the angle, and it is a different feel than just a shorter post. Not sure if that impression is accurate.

Also, for what it's worth, the instrument is a Czech cello made by Ladislav Prokop in 1933. Seems to be a unique model (or at least one I couldn't identify) with high arching and a fairly flat table arch that dives down rather steeply rather than the gradual transition and recurve of the Cremonese instruments. At 3,000 g it's not excessively heavy and didn't seem over-built. The top has saddled a bit and looks like it had an excessively tight post at some point (or took a hit to the top that didn't leave a post crack) prior to Rene's post, which sat partially over a dent in the top, so at first glance it appeared to have a gap on one side. Turned out to be the edge of the post overlapping the dent in the top by a small margin.

Thanks in advance.

[David Burgess]

The positions for the top and bottom of the post will sound best where they sound best. There's no reason that the ideal spots for each end of the post will result in a post which looks vertical.

[Bill Merkel]

There's probably no reason a totally raggedy as hell homeless looking and fitting sound post would sound worse than a perfectly upright smoothly groomed politically correct urbane citizen of a sound post, either.  Next up -- bridges.

[David Burgess]

2 hours ago, Bill Merkel said:

There's probably no reason a totally raggedy as hell homeless looking and fitting sound post would sound worse than a perfectly upright smoothly groomed politically correct urbane citizen of a sound post, either.  Next up -- bridges.

The fit and the runout of the grain do seem to matter....

[nathan slobodkin]

Moving the bottom of the post out and forward in relation to the top position would be one way of making the back act a bit stiffer. I never saw Rene use the kind of radical angles that Tim describes but he certainly was no slave to strictly vertical post position particularly as regards the "East- West axis. I do remember C.Becker being pretty emphatic about the need to have the post really vertical however so different strokes etc. I do think that posts that are not pretty close to vertical will tend to move more and for working and touring clients I do everything I can to make my adjustments resistant to unwanted changes.

[phutatorius]

I played a violin with a non-vertical soundpost at a local shop.  The violin was made by a maker who posts or who used to post here.  I would think that a slanted post would be more likely to fall or slip, and that it would be more difficult and thus more expensive to get a new sp fitted sometime later.  Thus, for me, it would be a reason to avoid that violin. 

[martin swan]

We have discussed this before in relation to a well known Strad.

the combination of a heavily slanted post, deformed arching, and quick tugs ... gives me the heeby geebies. Thank god its only a Prokop.

[Jim Bress]

13 minutes ago, martin swan said:

We have discussed this before in relation to a well known Strad.

the combination of a heavily slanted post, deformed arching, and quick tugs ... gives me the heeby geebies. Thank god its only a Prokop.

Prokop?  I tried looking up the definition.  I found some rather colorful ones, but I think your meaning still escapes me.

[Bill Merkel]

6 hours ago, David Burgess said:

The fit and the runout of the grain do seem to matter....

So good fit and runout will always sound better than poor fit and runout?

[phutatorius]

"Also, for what it's worth, the instrument is a Czech cello made by Ladislav Prokop in 1933."  That's from the OP's post.  Nothing too colorful there.

[Jim Bress]

17 minutes ago, phutatorius said:

"Also, for what it's worth, the instrument is a Czech cello made by Ladislav Prokop in 1933."  That's from the OP's post.  Nothing too colorful there.

(slaps palm to head) Missed that, thanks.

[Don Noon]

2 hours ago, martin swan said:

We have discussed this before in relation to a well known Strad.

The skewed soundpost was discussed in this thread a while ago.  

I don't skew the soundpost as radically as it appears to be in the Betts, but my starting (and usually ending) position for the post is non-vertical by about two degrees.  It seems to work better for me, and it's not that far off so that the post is likely to fall over.  It's not all that obvious just looking in thru the soundhole.

[David Burgess]

5 hours ago, Bill Merkel said:

So good fit and (less) runout will always sound better than poor fit and runout?

That has been my impression, so far, with higher level players. Some people may prefer a mushier, more muted, or less responsive instrument, based on what they are accustomed to, but that's a little outside my skillset.

[Dave Slight]

6 hours ago, phutatorius said:

I played a violin with a non-vertical soundpost at a local shop.  The violin was made by a maker who posts or who used to post here.  I would think that a slanted post would be more likely to fall or slip, and that it would be more difficult and thus more expensive to get a new sp fitted sometime later.  Thus, for me, it would be a reason to avoid that violin. 

Even if that instrument did indeed sound it's best with an angled post, I can see no reason why it would cost any more to have a soundpost replaced further down the line. Anyone who knows what they are doing should be able to cut whatever angles are required at the end of a soundpost, not base the charge on how much of an angle is needed!

I do agree that a post which is significantly off vertical has the likelihood of slipping towards the centre of the instrument, but it's all a matter of how much can be considered too much.

What I don't like is when someone has heavily angled a post which is far too short for the instrument, and that post is wedged on just two points, usually resulting in the inside of the belly becoming marred by the pressure point.

[David Burgess]

4 hours ago, Don Noon said:

The skewed soundpost was discussed in this thread a while ago.  

 

There is also a very nice and informative thread (including the humor), if one is willing to read 25 pages or so. I would definitely not recommend it to someone who needs to pick up the kids or grandkids from daycare in an hour or so.

https://maestronet.com/forum/index.php?/topic/329754-why-sound-post-fit-matters/&page=1

 

[PASEWICZ]

The position of the top of the post does different things than the position of the back of the post.  There are times when adjusting  the post closer to “straight” is called for, but in my experience not often.  The necessity of straight posts, straight bows, and level fingerboards, are myths perpetuated by the assumptions of the under informed.

[Jim Bress]

6 minutes ago, Jerry Pasewicz said:

The position of the top of the post does different things than the position of the back of the post.  There are times when adjusting  the post closer to “straight” is called for, but in my experience not often.  The necessity of straight posts, straight bows, and level fingerboards, are myths perpetuated by the assumptions of the under informed.

I think there is a lot of valuable information here, written between the lines.  Unfortunately my eye site is not good enough to read print that fine.

[PASEWICZ]

23 minutes ago, Jim Bress said:

I think there is a lot of valuable information here, written between the lines.  Unfortunately my eye site is not good enough to read print that fine.

Rene put a great deal of emphasis on the support the back was giving to the post, and the amount of spring that resulted.  As an example, while having lunch at his bench a young ambitious shop elf  that worked for him would ask about soundpost adjustment.  He would say nothing, hold the end of his ruler at the edge of the bench like a diving board, pluck the ruler,  and as it was vibrating he would slowly slide the ruler farther onto the bench making the “diving board” shorter and shorter.  After the pitch got higher and higher and eventually stopped, he would turn and say in a French accent “that is all you need to know”.   So, on this instrument, the top of the post was placed where it was because that is where the balance of the strings was the best, and the back of the post was placed where it was because that is where he got the “diving board” he wanted.  On some older instruments the soundpost area on the back is burnished so gettting the desired spring in the traditional place would not be possible, moving the back of the post to a less flexible place was the result.

[Jim Bress]

Thanks Jerry.  A good answer to help me think.  I've red and re-read the paragraph half a dozen times already.  While I read it I feel I understand.  Then as I think about it I realize how much I don't know...then and I read it again.  I mean it, it's a good answer.  Although I will probably not sleep before the weekend thinking about it.    

Thanks again,

Jim 

Edited December 20, 2017 by Jim Bress

[Bill Merkel]

If a boinging ruler is all you need to know then you don't need to know the post must have a good fit and no runout.  Please fight it out among yourselves and get back to me...

[TimDasler]

Thanks for all the replies. The shops where I have worked have alway stuck with the dead straight post and I've never explored the tonal implications of a little angle to it. I'll have to do some exploration and go over those other two recommended threads, too. 

Jerry, that example with the ruler is one that I remember you mentioning at a VSA convention, and I actually used it when explaining to the customer what I was doing. 

This conversation has gotten me thinking about trying an experiment with a post with a little gas spring in it, which could be altered by a set screw to drive in and increase or drive out to decrease the pressure within the chamber by a small amount. The idea would be that it would have a firm stop of length, but would be intended to replicate a similar stiffness to a spruce post. The set screw would simply be a way to adjust stiffness of the post so one could hear the effect without changing other attributes.

My grasp on the engineering behind such a device isn't great, so it may be a fools errand. I'm just throwing it out there because it's been bouncing around in my head for a while and some of the engineers on MN would probably have a sense of how hard it would be to make such a device and whether it would have any likelihood of teaching us anything. I can see several potential problems, but I'm no engineer.

I'm always thinking of ways to try and isolate a single variable to play with it and hear the effect, but if it were easy then someone would have already sorted it out.

[Jim Bress]

11 minutes ago, Bill Merkel said:

If a boinging ruler is all you need to know then you don't need to know the post must have a good fit and no runout.  Please fight it out among yourselves and get back to me...

Past readings, set-up workshops and lectures, personal conversations, experimenting with sound post adjustments to understand how movement usually (not always) affects sound, 3D plate animations...etc.  Eventually seemingly abstract information starts to jell into cohesive ideas which spawn into new thought models or the reevaluation of old ones.  Jerry's post meant a lot to me.

Tim finished writing before I did.  Apparently Jerry's post has other people's gray matter boiling as well.

Cheers,

Jim

[Bill Merkel]

^I went through that phase as a child.  Now I require practical, factual information or it's get out of town, you phony.  Don't care who it is.  If Morel boinked a ruler and said that's all you need to know, I'd have boinked him upside the head and said I don't think so, bitch.

 

[JohnCockburn]

6 hours ago, TimDasler said:

 

I'm always thinking of ways to try and isolate a single variable to play with it and hear the effect, but if it were easy then someone would have already sorted it out.

You can do this kind of thing to some extent with the new carbon fibre posts. It's very enlightening.

[martin swan]

Absolutely - this is one of the real benefits of the Hamberger soundpost, that you can easily move it or even to some extent adjust the tension while remaining certain of the fit.

One of the reasons Chi-Mei got behind it as a concept is that it doesn't run the risk of damaging the inner table through poor fitting. It can of course be cranked up to the point where it deforms the arching, which is why it is only to be fitted by competent individuals. 

And it's not as if you couldn't deform arching by bashing at traditional soundposts, or even by responding to every request for adjustment by tightening the post.