• FAQ  • Search  • Memberlist  • Usergroups   • Register   • Profile  • Log in to check your private messages  • Log in 

Valve Passages (large bubble/new horn)



 
Post new topic   Reply to topic    trumpetherald.com Forum Index -> Cornet/Flügelhorn
View previous topic :: View next topic  
Author Message
zr1100
New Member


Joined: 16 Jul 2020
Posts: 1

PostPosted: Tue Aug 11, 2020 12:03 pm    Post subject: Valve Passages (large bubble/new horn) Reply with quote

Hello--is it common for a mfr to build up an area in a valve passage to affect the air-flow in a certain way? I have a new Adams cornet--but not a ton of brass experience. (2nd valve--large bulge, almost the width of the opening)--
Thanks
Back to top
View user's profile Send private message
JayKosta
Heavyweight Member


Joined: 24 Dec 2018
Posts: 1144
Location: Endwell NY USA

PostPosted: Tue Aug 11, 2020 1:18 pm    Post subject: Reply with quote

Yes, that is typical of the internal shape of pathways in piston valves.
In order to keep the length of the 'valve stroke' distance reasonable, the shape of the pathways has to be altered (from completely circular) to allow space for the other pathways through the valve.

Jay
_________________
King Super 20 (S2 1048, HN White)
Bach 7
The 'next note' is the most important one.
Don't take a '20 minute mouthpiece' to a 1 hour session.
Looking out my backdoor
http://users.hancock.net/jkosta/2020_Sept_25_web.jpg beginning of Fall
Back to top
View user's profile Send private message
Bflatman
Veteran Member


Joined: 01 Nov 2016
Posts: 475

PostPosted: Wed Aug 12, 2020 4:53 pm    Post subject: Reply with quote

The constriction does not affect the air flow as much as it might appear to.

The venturi effect is such when a smooth constriction is encountered by an air flow the air speeds up as it passes the narrowest point and then slows down again after it has passed this narrowest point, but the overall flow rate remains the same.

A depression forms at the point of the smallest cross section where the air flow is greatest this is the principle used by the carburettor venturi in a motor car.

The jet in the carburetor is positioned at this narrowest point and the gas is sucked out of the jet by the depression.

Additionally the air flow in a trumpet is negligible so the constriction in the valve has little effect on overall resistance to flow through the instrument.
Back to top
View user's profile Send private message
Brassnose
Veteran Member


Joined: 07 Mar 2016
Posts: 426
Location: Germany

PostPosted: Wed Aug 12, 2020 8:08 pm    Post subject: Reply with quote

Meinlschmidt makes the MAW valves which supposedly do have less resistance. Having said that, I don’t think the bump has been the major issue limiting my trumpet skills for 40 years
_________________
Martin Schmidt eXcellence - Curry 7TC
Bach 43GH/43 - AR Resonance ME40/40S
Kühnl & Hoyer 15 - GR 65FL
Prisma Bb bass trumpet - Couesnon 3
Orchestra & a teacher 😎
Back to top
View user's profile Send private message
Bflatman
Veteran Member


Joined: 01 Nov 2016
Posts: 475

PostPosted: Wed Aug 12, 2020 9:49 pm    Post subject: Reply with quote

Brassnose makes a good point about the MAW valves but he also nailed it saying that they supposedly have less resistance.

Some improvements are simply supposed improvements.

By coincidence I demonstrated yesterday long tone playing on a single breath and I demonstrated a single sustained note of around 2 minutes on one single breath.

During that playing of a note the airflow through the instrument and out of the bell was tested and there was no detected airflow out of the bell during the note.

If there is little or no detectable airflow during playing then minor constrictions are not significant.

Of course it is possible to push gargantuan volumes of air through the instrument whereupon turbulence can appear.

I prefer not to wake the dead during playing as a general rule.

Constrictions and restrictions only affect airflow when they result in turbulence in the flow of air. When there is no detectable flow of air turbulence is not an issue

This is because there is a minimum airflow threshold before turbulence appears of around 20 miles per hour. The significant words here are minimum threshold.

At very low airflows turbulence is simply absent.

I suspect that the problem that demands a MAW solution is more in the head of the player than in reality.
Back to top
View user's profile Send private message
shofarguy
Heavyweight Member


Joined: 18 Sep 2007
Posts: 6524
Location: AZ

PostPosted: Wed Aug 12, 2020 10:29 pm    Post subject: Reply with quote

I think I've been fortunate to be able to look into a few different makes of trumpets and study the designs of the valves, with their port layouts and how that affects things like the siamesed areas in the piston port tubes that you mentioned. When touring the now defunct Kanstul factory, I saw a technician rounding out those very tubes using a funny little ball shaped tool that spun on a motor. He would punch the ball into those very thin walled tubes to size the hole and round it out.

Of course, when he shaped one tube, another would be deformed, as the ball pushed one tube into the space of the other, creating a dimple in the second tube. Then, he would size the adjoining tube and push out that dimple. Eventually, the technician would try to arrive a a flat surface in both tubes.

I find it interesting how different makers have distributed their ports to minimize these areas. It isn't about air flow, it's about acoustic wave distortion. So, the less distortion to the port tube, the less disturbance to the acoustic wave. The first trumpet I had was a Holton Collegiate student horn from 1970. I seem to remember it had the most pronounced dimples of any horn I've ever seen. After that, I had a 1976 Benge 5x, which had small, donut shaped dimples. Of course, now I own a Kanstul-built Wild Thing trumpet and flugelhorn. Also, I've owned a Schilke X4 and got to study a 1956 Martin Committee large bore for a time.

The Benge and Schilke had "straight through" transfer ports between valves, like the old Besson design. The WT has more Bach-like curved transfer port tubing. Those curved transfer tubes make a little more room in the piston for a shorter stroke, while maintaining little to no dimpling. The Martin valve design rotated certain entry and exit ports to do even more to minimize the dimpling and created a uniquely slender trumpet in doing so.

The MLP Benge valve design spread the piston ports vertically to gain more internal room, while maintaining the traditional "straight through" Besson-style arrangement. Consequently, the + models had unusually long-stroke valve action.
_________________
Brian A. Douglas

Flip Oakes Wild Thing Bb Trumpet in copper
Flip Oakes Wild Thing Flugelhorn in copper


There is one reason that I practice: to be ready at the downbeat when the final trumpet sounds.
Back to top
View user's profile Send private message
JayKosta
Heavyweight Member


Joined: 24 Dec 2018
Posts: 1144
Location: Endwell NY USA

PostPosted: Thu Aug 13, 2020 5:00 am    Post subject: Reply with quote

shofarguy wrote:
... It isn't about air flow, it's about acoustic wave distortion. So, the less distortion to the port tube, the less disturbance to the acoustic wave. ...

-------------------------------------------------
YES, the concern is with how the air pressure (~wave shapes) behave (vibrate) within the tubing. The movement of air itself is not significant.

Jay
_________________
King Super 20 (S2 1048, HN White)
Bach 7
The 'next note' is the most important one.
Don't take a '20 minute mouthpiece' to a 1 hour session.
Looking out my backdoor
http://users.hancock.net/jkosta/2020_Sept_25_web.jpg beginning of Fall
Back to top
View user's profile Send private message
Bflatman
Veteran Member


Joined: 01 Nov 2016
Posts: 475

PostPosted: Sat Aug 22, 2020 7:09 am    Post subject: Reply with quote

I agree the air flow is not significant I raised that because it is a common belief.

I am uncertain however that the small reduction in cross sectional area at the valve due to the bump adversely affects the standing wave.

The leadpipe close to the receiver is much smaller than the opening in the valve and it is further constricted by a venturi.

The standing wave must negotiate the small cross section of the venturi and the later valve bump is hardly significant.

The principle in engineering is to remove the worst constriction first. That would be the venturi.

I am open to being educated on this.
Back to top
View user's profile Send private message
shofarguy
Heavyweight Member


Joined: 18 Sep 2007
Posts: 6524
Location: AZ

PostPosted: Sat Aug 22, 2020 8:50 am    Post subject: Reply with quote

Bflatman wrote:
I agree the air flow is not significant I raised that because it is a common belief.

I am uncertain however that the small reduction in cross sectional area at the valve due to the bump adversely affects the standing wave.

The leadpipe close to the receiver is much smaller than the opening in the valve and it is further constricted by a venturi.

The standing wave must negotiate the small cross section of the venturi and the later valve bump is hardly significant.

The principle in engineering is to remove the worst constriction first. That would be the venturi.

I am open to being educated on this.


In my mind, it's not the constriction, but the sudden protrusion that makes the cross section un-round, if that's a word. The port tubes in my old Holton Collegiate had a cross section more like a kidney bean in places!

Most of us have read how James Becker takes a bell bow and rounds out the cross section through there and it improves the intonation and feel of the horn. I remember a story of Byron Autrey claiming he could put a dent in a specific place on a trumpet and it would cause it to be unable to play a corresponding note properly. Then, he could remove the dent and the note would come back.
_________________
Brian A. Douglas

Flip Oakes Wild Thing Bb Trumpet in copper
Flip Oakes Wild Thing Flugelhorn in copper


There is one reason that I practice: to be ready at the downbeat when the final trumpet sounds.
Back to top
View user's profile Send private message
Bflatman
Veteran Member


Joined: 01 Nov 2016
Posts: 475

PostPosted: Tue Sep 15, 2020 8:33 pm    Post subject: Reply with quote

I conducted an experiment.

I assumed that if your contention is correct, then an aligned valve should not adversely affect the tone or pitch but a misaligned valve should adversely affect the tone or pitch.

Furthermore varying the alignment should have immediate and clear effects on the tone or pitch.

Deliberately misaligning valves as I sound a note is a simple test to conduct, we do this as we operate the valves in play, so I conducted it.

I sounded a note in an instrument with aligned valves and then slowly depressed a valve to misalign it.

I predicted that I would hear an immediate change to the note as soon as the valve alignment was lost.

I discovered that no such change occurs until the valve reaches around 3 mm out of alignment.

A trumpet bore is around 11.5 mm so a 3 mm misalignment constricts the bore to around 8.5 mm. This is a profound change to the bore size.

This behavior happens consistently on all valves on all instruments tested at both top position and bottom position.

A 3 mm misalignment introduces both a large step in the bore and a constriction that should in my opinion profoundly change the note sounded if the information you base your conclusions upon is correct.

No such profound change happens in all the tests I have conducted so far. There is not any detectable change to my ears when misalignment is less than 3 mm.

I have conducted this test around 30 times on different instruments on different valves with different notes sounded at both valve extremities.

The behavior is always the same no change is heard as the valve alignment changes below 3 mm.

I am at a loss to explain why this test shows no change to the note sounded as the alignment changes given the large number of players who have stated that even a small misalignment is significant and profound in its effects.

I must be missing something here.

What I am missing right now is any result that supports a contention that correct valve alignment is critical to the pitch of the notes.

Maybe the alignment issue simply does not concern the pitch itself but the playability which I cannot test in this way.

I am confronted however by your report that constrictions in the bore can make a note disappear and not sound. I see nothing to support this in the limited tests I have conducted.

The bottom line is I find no detectable change to the note sounded when the alignment is off by 1 mm or 2 mm or 3 mm. Beyond 3 mm the note is changed.

This strongly suggests that a constriction of up to 3 mm would have little effect on the pitch.

The pitch is the result of the standing wave alone, this then strongly suggests that a constriction of less than 3 mm does not affect the standing wave.

I also would have expected any pressure effects to be revealed as a note change in some manner during this test. I detected nothing to suggest a pressure effect on the standing wave.

I do find valving notes to result in smooth pitch changes note bends and glissades and satisfyingly expressive play. This is consistent with the behavior I am seeing at small valve misalignments

I think more work is needed on this to better understand this.
_________________
Conn 80a Cornet
Boosey & Hawkes Imperial Trumpet
Olds Fullerton Special Trumpet
Selmer Invicta Trumpet
Yamaha YCR 2330II Cornet
Selmer Student Trumpet
Bohland and Fuchs peashooter Trumpet
Boosey and Hawkes Regent Cornet
Lark M4045 Cornet
Back to top
View user's profile Send private message
etc-etc
Heavyweight Member


Joined: 19 Jan 2008
Posts: 5733

PostPosted: Tue Sep 15, 2020 11:21 pm    Post subject: Reply with quote

Bflatman wrote:
I agree the air flow is not significant I raised that because it is a common belief.

I am uncertain however that the small reduction in cross sectional area at the valve due to the bump adversely affects the standing wave.

The leadpipe close to the receiver is much smaller than the opening in the valve and it is further constricted by a venturi.

The standing wave must negotiate the small cross section of the venturi and the later valve bump is hardly significant.

The principle in engineering is to remove the worst constriction first. That would be the venturi.

I am open to being educated on this.


Renold Schilke made gap-less horns to alleviate that issue.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    trumpetherald.com Forum Index -> Cornet/Flügelhorn All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group