Adjusting the sound post in a cello

[Tostra]

I finally finished my project this week and now have a surprisingly amazing cello! I spent an evening adjusting the sound post and think I found a good place for it in the end. The wolf tone at F is possible to work around to some extend, the sound is free and very ressonant and everything is really good. However, I do want to change something. I fiddled a bit with it and got it be relatively easy to play as well, but I feel like it can still perform better. It is a little bit slow to react and doesn't respond very well when I bow closer to the bridge. It sort of breaks or crackles or don't really grip the string but akate on top a bit. It's hard to explain, but I'm sure you all know what I'm talking about. It's not bad anymore, but I would like it to be more reactive. It's not happy to play things with fast attack or really loudly (although it does play very loud in itself).

I've been searching the internet so much that I've confused myself, so I would really like someone to tell me what moving the soundpost in each direction is supposed to do. This is my first time doing anything with a cello except play it, so I'm a bit lost. As far as I've understood, this is the case:

Moving the sound post to the treble side makes for a bigger sound that needs more energy to come out. It also makes the sound brighter
Moving the sound post to the bass side makes the sound smaller and darker and more controlled.
Moving closer to the bridge makes the sound more dense and projecting.
Moving further away from the bridge makes the sound more ressonant and loose, but may be less projecting.

Now if this is true, I should probably move the post to the treble or bass side. I'm just not sure if the slow response/skating is due to the post not being far enough to the treble side and therefore not handling the pressure of the bow very well or if it's too far towards the treble side and needs too much energy to produce the sound.

What I'm experiencing is not very serious. It could simply be because it needs to be played for a few months to settle, but it's aa bit annoying. My main issue here is that it doesn't handle loud staccato playing well and that I feel a bit unable to control the dynamics properly. It plays wonderfully far from the bridge at moderate pressure, but with a heavy bow it complains. Also, if I go closer than approxomately 2 cm to the bridge, it doesn't produce much pleasant sound. I'm used to moving quite a lot on my old cello, and having this much narrower bow interface annoys me.

A bit of extra info in case it matters: I'm using Larsen A and D and Spirocore G and C. The bridge might be just a little thick below the heart compared to the bridge on my old cello, but it follows the "standards" I found (10,5mm at the feet, around 8mm at the top of the legs narrowing to 2,5mm at the top arch). The bows I'm using gives slightly nicer response on my other cello.

That was a lot of text. I hope I have explained myself well enough and that someone out there knows just what I have to do :-)

Best regards, Tobias

[ClefLover]

Too close to the bridge will result in a nasally tone.  Too far away can be a structural issue. In terms of treble and bass configuration, assuming you are not shortening the post, I’d comfortably wedge it in there, not too loose and not too tight (enough where it won’t fall out by itself before strings apply pressure).  Some people like 5-8mm from bridge, I have found 7-11mm optimal. 

[barnesviolins]

If you move the post towards the treble or bass side without shortening or lengthening it, then you will be tightening  or loosening the tension between the plates.  This will have a greater impact that what you describe as the characteristics of moving it that way.

My gut tells me that if you move the post south (away from the bridge) you might get better response. But then again, without feeling the tension under which it is set, its is hard to give good advice. It could need a little tightening.

 

Good luck!

 

Dorian

[PASEWICZ]

14 hours ago, Tostra said:

I finally finished my project this week and now have a surprisingly amazing cello! I spent an evening adjusting the sound post and think I found a good place for it in the end. The wolf tone at F is possible to work around to some extend, the sound is free and very ressonant and everything is really good. However, I do want to change something. I fiddled a bit with it and got it be relatively easy to play as well, but I feel like it can still perform better. It is a little bit slow to react and doesn't respond very well when I bow closer to the bridge. It sort of breaks or crackles or don't really grip the string but akate on top a bit. It's hard to explain, but I'm sure you all know what I'm talking about. It's not bad anymore, but I would like it to be more reactive. It's not happy to play things with fast attack or really loudly (although it does play very loud in itself).

I've been searching the internet so much that I've confused myself, so I would really like someone to tell me what moving the soundpost in each direction is supposed to do. This is my first time doing anything with a cello except play it, so I'm a bit lost. As far as I've understood, this is the case:

Moving the sound post to the treble side makes for a bigger sound that needs more energy to come out. It also makes the sound brighter
Moving the sound post to the bass side makes the sound smaller and darker and more controlled.
Moving closer to the bridge makes the sound more dense and projecting.
Moving further away from the bridge makes the sound more ressonant and loose, but may be less projecting.

Now if this is true, I should probably move the post to the treble or bass side. I'm just not sure if the slow response/skating is due to the post not being far enough to the treble side and therefore not handling the pressure of the bow very well or if it's too far towards the treble side and needs too much energy to produce the sound.

What I'm experiencing is not very serious. It could simply be because it needs to be played for a few months to settle, but it's aa bit annoying. My main issue here is that it doesn't handle loud staccato playing well and that I feel a bit unable to control the dynamics properly. It plays wonderfully far from the bridge at moderate pressure, but with a heavy bow it complains. Also, if I go closer than approxomately 2 cm to the bridge, it doesn't produce much pleasant sound. I'm used to moving quite a lot on my old cello, and having this much narrower bow interface annoys me.

A bit of extra info in case it matters: I'm using Larsen A and D and Spirocore G and C. The bridge might be just a little thick below the heart compared to the bridge on my old cello, but it follows the "standards" I found (10,5mm at the feet, around 8mm at the top of the legs narrowing to 2,5mm at the top arch). The bows I'm using gives slightly nicer response on my other cello.

That was a lot of text. I hope I have explained myself well enough and that someone out there knows just what I have to do :-)

Best regards, Tobias

Where are you located, who cut the post, when was the post cut, and what is the after length.

[Tostra]

Now those are really good questions,  Jerry. I cut the post myself and it was cut just about a week ago. I actually haven't  measured the afterlength till now because the tailpiece isn't the one I'm going to keep on it, but the string length is 69,2cm and the afterlength is 10,5cm right now.

When I fit the post, I fitted it quite loose. Not so that it would fall, but it was just wedged in. After I have fitted everything i have moved it around a lot, but I'm pretty sure I have tightened it a bit, and I have moved it to just about 5mm behind the bridge I think.
I watched a few videso by Edgar Russ where he says that the optimal starting position is the thickness of the top behind the bridge. So my top is 4,2mm where the post goes, so I should put it 4,2mm behind the bridge. The thing is, he's the only one saying this. It seems that everyone puts it much further back. The thing is, it sounds really good around 4-5mm behind the bridge, but maybe it's just too close to the bridge to move freely. I just haven't tried moving it out of that position yet, but I'll try moving it south one of the next days when I have the time.
I've heard that the posts shrink, so maybe I'll also try to tighten it a bit more. 

One thing I really need a tip for before I start moving it again: How do you move it west/against the bass side? Every time i've done it without the strings, the post has fallen, both on the cello and violins I've set up. I'm not eager to find out what will happen if it falls with the strings on. 
I've usually done it by just pushing it with the sound post setter, but I feel like that's not a good way. Edgar Russ suggested  pushing it with a ruler..?

Don't get me wrong though. This cello sounds great as it is. Not nasal, just perfect in my ears except it's maybe a bit thin on A and D. The response is not bad at all, and it's only a problem because of my playing style. I like to change a lot and sometimes have very hard starts, bow softly near the bridge, play very loud etc., and that's just not natural right now.

[PASEWICZ]

Try just one thing at a time.  First off, without moving the post, change the after length to 13.9 and see how that changes things.

[Barry J. Griffiths]

Jerry, can I ask how you came to an after length of 13.9 from a string length of 62.9? 

[PASEWICZ]

49 minutes ago, Barry J. Griffiths said:

Jerry, can I ask how you came to an after length of 13.9 from a string length of 62.9? 

It was 69.2.

1/5 plus a smidge for stretching/adjusting the bridge.

Quick shorthand for input regarding compliance.

[Tostra]

Isn't it supposed to be 1/6 of the string lenght? 

[David Burgess]

1 hour ago, Tostra said:

Isn't it supposed to be 1/6 of the string lenght? 

Not necessarily. That's a reasonable starting point though, to get an idea of what further changes the instrument wants.

[Tostra]

I don't think I can get the afterlength much longer with this tailpiece, actually. I'll try when th other one arrives and play with the sound post till then :-)

[nathan slobodkin]

You can't move the post much without taking the length into account. As you point out you can only move the post toward the bass if it was too tight before, otherwise you must cut a longer one to keep proper tension.

I don't know who Edgar Russ is ( I'll look him up) but the "thickness of the top rule" applies to violins and possibly violas but on cellos the post is almost always proportionally further back.

Adjusting an instrument consists of balancing ALL of the elements and you can't get a true picture of what is happening without isolating single variables which is quite difficult or even impossible in strict scientific terms.

[Davide Sora]

4 hours ago, nathan slobodkin said:

I don't know who Edgar Russ is ( I'll look him up) but the "thickness of the top rule" applies to violins and possibly violas but on cellos the post is almost always proportionally further back.

Adjusting an instrument consists of balancing ALL of the elements and you can't get a true picture of what is happening without isolating single variables which is quite difficult or even impossible in strict scientific terms.

I would beware to trust someone who calls himself "Distinguished Violinmaker"..........

I'm just kidding...........Hi Edgar....

 

 

[Tostra]

I think I found a really good position. It's got a clean, complex tone that projects relatively well, and it respinds better than it did. I messes up a bit, so I'm not entirely sure what I did, but I think I loosened it slightly and moved it around half a millimeter away from the post. 

I'll play with after lenght and gut material when I can. 

[trick-nobody]

I think that every cello has its limitations. On new/cheap instruments we often experience poor C and G string resonance, slow responses from the bow and a harsh A string. I think it can be compensated a little by the overall setup and maybe it doesn't hurt to put the soundpost a little "south" (away from the bridge) so that it has a more rounded and not too punchy A string and maybe a little "west" (toward the center line or to the bass bar) so we have more sustain and texture and more G and D resonance and better bow response. The soundpost needs to be long enough for this, if it isn't long enough and doesn't fit tightly it will cause issues. What is sacrificed is a strong projecting C string with a rich texture and clean sound, it would require to move the soundpost to the "east" and make it shorter.  Unfortunately, new/cheap cellos often can't handle this. This setting will result in terrible bow response, it will require too much pressure on the strings and produce a crushing sound when playing FFF close to the bridge. 
I think it can get a little better with age, but only few instruments will significantly improve when played regularly. On other instrument the C string will be always muffled and not focused. It's all about the quality of the wood and construction and experience of the maker, and if everything is not optimal, you can't compensate these problems entirely with the setup alone.